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Hilmi
Post Laureate
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
STT-8300 First light report
      #5522236 - 11/16/12 03:52 AM

***WARNING, THIS ARTICLE SHOULD NOT BE USED TO JUDGE THE QUALITY OF THE PRODUCT, I AM ONE CUSTOMER AND THIS DOES NOT CONSTITUTE A REPRESENTATIVE SAMPLE, MY PREVIOUS EXPERIENCE WITH SBIG WAS SO GOOD WHICH IS WHY I WENT FOR THIS CAMERA***
---Disclaimer: my camera is S/N 66 of the line; I was expecting problems from the beginning as this is not a mass produced product, they build them piece by piece and a suspect a big part of the work is done by hand---
OK, so I got my brand spanking new STT-8300 last Saturday just as I was traveling abroad for a week of work. I spent an entire week fiddling around with the hardware and seeing how things work. During that week, the first thing I noticed was the shoddy power connector. Any minor movement and the camera would lose power. This is a minor problem if you have convenient access to an SBIG dealership. For me, I have to pay several hundred dollars of shipping to get things resolved. I was advised on the Yahoo group that I should widen the split of the center pin of the power connector. How unfortunate, this is precisely the reason I normally pay a premium for American products, between this and my Losmandy mount, I wonder if there was much wisdom in my way of thinking. Next thing I noticed is that to use the built in OAG you need to use an STL thread. This was not mentioned anywhere in the marketing material, so you buy your camera and then after it ships to you, that’s when you find out and you have to go around shopping for the needed adapters. Also, it is not recommended that you use the camera with a T-thread adapter when using the OAG. This pretty much makes my Televue 60is a useless telescope as the field flatner comes with built in T-threads, which means I can never use the OAG effectively with this camera. You would think the marketing material would remember to advise you on such a point “before you make the purchase” not after.
So last night I started using the camera for the first time and I noticed some curious restrictions in the way MaximDL handles the camera. First of all, it assumes that the camera is using the same shutter for the main and guide chip. I don’t know if this is from the driver or MaximDL. If it is from the driver, then it is a silly idea. Sometimes you want to take advantage of the time you taking dark frames to other useful things, such as calibrating the guider.
Next thing I noticed is that I could never reach perfect focus on the OAG ( I am using my SCT @ F10 now as I am lacking the needed adapters to use it with my focal reducer). Every attempt at reach perfect focus leads to my hitting the hard stop.
After it was midnight, between battling the mount and battling the camera, I managed to get everything working to within reasonable tolerances. Guiding was a breeze and other than the difficulty of finding a guide star at F10 (which was made easier by my moonlite focuser’s ability to rotate), I set up an imaging sequence and went to bed. In the morning, I came back upstairs excited to see my 50 exposures which I was expecting. Guess what I found? After 4 exposures, I get some kind of filter wheel error

So first light was a frustrating and totally unpleasurable experience for me.

P.S. I can't seem to make autofocus work with this camera. I have no idea why. Worked fine with my previous camera. I suspect this is to do with the load carrying adjustment of my Moonlite and nothing to do with the camera itself.


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MattThomas
Vendor (SBIG)


Reged: 07/28/06

Re: STT-8300 First light report new [Re: Hilmi]
      #5523075 - 11/16/12 03:35 PM

Hilmi,

I am sorry about your dissatisfaction with the STT.

The locking power connector is one we have been using for years in cameras. At times, the center pin on the camera can become compressed and not make good contact with the power supply. There are various reasons why this can occur over the life of this power connector. Use a small screwdriver to spread the center pin on the camera slightly and you should get a significant improvement in the mating of the connector. This is a minor tradeoff with this locking power connector. In fact this is the same connector you have on your ST-402.

I am sorry that it was not clear about the 2.156" thread on the front of the guider cover. We can get you a t-thread plate for the front of the guider cover if you would like. It will vignette the guider, but you may be willing to accept the vignetting with your Televue 60mm telescope.

The separate shutters on the imager and the guider can be controlled independently – but this would have required significant changes across the entire platform from MaxIm/CCDSoft/etc. through the driver and in the camera. Changing this operation would have resulted in significant new development for Software Bisque, Diffraction Limited, and any other company that is controlling our cameras. So a conscious decision was made to make the STT shutters act as close as possible to our previous cameras. Yes, this means you cannot take dark frames and calibrate your guider at the same time. I am sorry that this is an important feature to you.

We tested the camera and guider on an SCT @ f/10 and had no trouble reaching focus. We will test it again to ensure something didn’t change. Are you certain you had the mirror adjusted properly? It is possible that your mirror was too far off axis and you were not able to correct for the field curvature on the SCT.

Finally, as to your filter wheel, this is certainly not good. Do you know what the filter wheel error was? Can you replicate the error? Is there any other information you can provide? What is the serial number of your filter wheel?

There is no question that getting new equipment running properly on the first night is always a challenge. Stick with it and I think you will be running smoothly in no time. Feel free to contact me here, or contact our technical support email directly with any further questions.

Thank you.


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pfile
Post Laureate


Reged: 06/14/09

Re: STT-8300 First light report new [Re: MattThomas]
      #5523175 - 11/16/12 04:42 PM

hi, as you know i also have one of these cameras/filter wheel combos. i am seeing similar filter wheel errors, though the errors are apparently mostly ignored by Equinox Image. i have not yet had an imaging plan fail due to filter wheel errors.

the conclusion seemed to be that the OSX-side drivers are not as up-to-date as the windows drivers, but maybe there is more driver work to do on both platforms, or perhaps some updates to Maxim are necessary.

i wonder if one thing that could be added to the driver would be the ability to open the guider shutter and leave it open. inbetween imager exposures the guide camera is (correctly, of course) opening and closing its shutter on ever guide camera frame. but i wonder if this puts un-necessary wear and tear on the guider shutter mechanism.


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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: pfile]
      #5523760 - 11/17/12 01:19 AM

Hi Hilmi,

Could comment- I posted also on Yahoo. I think I was the second unit shipped... bleeding edge of technology.

1. I have no problems with the power, but have all the cords tied down to prevent shake. It would be a big pain shipping from Qatar. If you have it hooked up and powered on, and you touch the plug, does it go out? You should be able to verify where the loose connection is.

2. There are known issues with the filters, just discussed. These are non-existant for me now that I have all the firmware updates... can image all night. There is one error that persists, will not image starting a new series on the same filter it rests on. Need to move it before you start. Bottom line, make sure you have all the updates using their updater (carefully).

3. On the guiding, I am guiding with a C8 and no focal reducer, i.e. f10 and 2032mm fl. Mount is a standard Atlas. The stars are not perfectly round in the OAG, but there are many and they are OK if binned and I update every 3-4 sec. I do think this could be an issue as I have not quite tweaked the guiding to what I had with PhD (Currently using Maxim). I am reserving judgement here.

4. PS I screwed up by selecting the wrong filter wheel in the settings... I believe it is the Standard one... reread the instructions... this cost me a lot of time.

Edited by jerryyyyy (11/17/12 01:25 AM)


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5523884 - 11/17/12 06:56 AM

OK, I would like to re-iterate that my experience is not representative. I was just venting some steam and I did not intend to put the manufacturer in a bad light. Managed to get things working again last night, I had not fiddled with the power connector, but it seemed to have worked fine for a full night of imaging. I also did not face the filter wheel error again. This leads me to suspect it is triggered by the power connector loosing power, since it seems that the camera never lost power last night, that would explain why I did not get any filter wheel errors.

I had not seen the post about moving the OAG pick of mirror further in before I tried the camera last night, and therefore did not get the chance to try that advice.

Matt,

Don't get me wrong, I am not dissatisfied with the camera, I am just frustrated with a less than stellar first light. After a full week of practice in a controlled environment, I thought I would just screw on the adapter, balance the mount and go trigger happy with photos, you can imagine my frustration when things didn't work out that way. My only true complaints which I would have is that you should clearly mark the need for an STL style connector for full performance in the marketing material, this will help people make other equipment choices, such as what other adapters to add to their shopping basket. (I did notice it later in the drawings of the filter wheel, but it wouldn't hurt to just flat out say it in the specs. My second complaint would be that power connector issue occurred so often that it should have been spotted at the QC stage, unless something happened during shipping and the connector was damaged at that time.

The workmanship on the body of the camera is a work of art, the cooling performance is outstanding and the case the camera came in was a joy. I won't talk about image quality as I am not qualified to assess this and the 8300 chips have been around for a while, I will say one thing though. I just managed to take an exposure yesterday and compared it to my ST402me, and although the old camera was far more sensitive, the low level of noise on this camera is unbelievable. My images are so clean compared to my old camera. If I could change one thing in the design of the camera I would have attempted to find quieter fans as the ones installed sound like a 747 in my observatory. I guess if I wanted to enjoy a quiet night in the observatory I would have to use water cooling.


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alpal
Post Laureate


Reged: 06/15/09

Loc: Melbourne Australia.
Re: STT-8300 First light report new [Re: Hilmi]
      #5523914 - 11/17/12 07:55 AM

Hi Hilmi,
I don't know anyone who had a trouble free first night with a new camera.
There is always going to be something to iron out.

Good luck with it as I'm sure you'll get to the bottom of any problems.


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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: alpal]
      #5524095 - 11/17/12 10:32 AM

Hilma, you moved along a lot faster than I did.

Make sure about the drivers (the .dll files) AND the firmware updates. There are two parts.

Also, get some of those little plastic cable ties. Once I had the USB and power cables seated I put a little slack in the cables and then tied them down twice along that grey handles on the back of the camera. This way no matter what the camera does at night there is no pull on the attachments.

PS I am going to try the reducer when the clouds clear here (Sunday) and see what that does for my guiding. The 2032mm fl is too narrow anyway. I did not want to use the FR until I was sure the images coming out of the camera were clean, and as you point out they are.

PPS I have been running it at -20. This seems to be only 20-30% of the capacity. I wonder how clean the images would look at -30... but I have all my darks at -20 and hate to start over... you might run some tests before you go into production....

Good luck!


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5524154 - 11/17/12 11:03 AM Attachment (41 downloads)

Jery,

I updated both the drivers and the firmware first thing before the camera was even hooked up to the telescope.

Now I have found that the filter wheel error's are not related to the power. I have had the following errors (6, 35, 100) out of MaximDL. And looking at the error code description from the MaximDL website doesnt tell you much.

I am finding guiding at 2000mm focal length challenging. Yesterday I got reasonably good performance guiding on the Horse head nebula, today I can't seem to make the guiding behave on M74


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pfile
Post Laureate


Reged: 06/14/09

Re: STT-8300 First light report new [Re: Hilmi]
      #5524256 - 11/17/12 12:02 PM

i am running at -30C with relative ease (40-50% cooling power, depending on ambient.) one night i pushed it down to -40 just to see if it could make it. the ambient temp was 10C. it took a while and got down to -39.8C and i decided to back off to -30C again.

the only issue i've had with the camera (aside from the power thing) is attempting to use flats that are too short. i got a very weird gradient in my calibrated subs, but i think that's to be expected. i've used a darker t-shirt and with 4 second L flats, everything seems fine.

the following image is messed up due to the flats problem, and my telescope is out of collimation, but i was pretty happy about the SNR especially in this very light-polluted location.



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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: pfile]
      #5524500 - 11/17/12 02:44 PM

Hilmi, your stars look better than mine.... I think we are pushing it guiding at 2000mm... imagine how small the changes are that it tries to track. If I just watch the star in the Maxim DL guide window I can just see the atmospheric affect it.

This is my first effort at narrow band filtering with a telescope:



I have also been working on M74... it is just sitting there... and as pfile notes... flats are a pain. With my DSLR I could get short flats and they were fine. Here I could not get 2 second ones and there is again some funny interaction with the camera and the filter wheel. SBIG explained it to me and it was again rocket science. Bottom line is I am not happy with my flats either.

The suggested a plugin for Maxim DL that I am trying: Sky Flats Assistant. I have been using Sky Flats and they are good only part of the 15 or so minutes it takes to collect 20x8 filters. Supposedly this plug-in will adjust exposure length to get the right ADU (more rocket science).

I could not get my T-shirt to work.... too white???!!!


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Peter in Reno
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Reged: 07/15/08

Loc: Reno, NV
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5524520 - 11/17/12 02:53 PM

Remember that your camera has a mechanical shutter and if you take too short exposure for flats, you will see shadows caused by mechanical shutter. I have read that you may need to expose longer until you no longer see shadow on your flats but you will also need to dim the light box so the flats will not be over exposed. If you use T-shirt method, add more layers of T-shirts.

Peter


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pfile
Post Laureate


Reged: 06/14/09

Re: STT-8300 First light report new [Re: Peter in Reno]
      #5524540 - 11/17/12 03:03 PM

yep, that's what's going on. the type of shutter SBIG uses is more amenable to short-ish flats than an iris-type shutter. but with my 'normal' flat setup i had to be way down at 200mS and that's just way too short. DSLRs are designed for really short exposures, but these cameras not as much.

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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Peter in Reno]
      #5525055 - 11/17/12 08:42 PM

Quote:

Remember that your camera has a mechanical shutter and if you take too short exposure for flats, you will see shadows caused by mechanical shutter. I have read that you may need to expose longer until you no longer see shadow on your flats but you will also need to dim the light box so the flats will not be over exposed. If you use T-shirt method, add more layers of T-shirts.

Peter




You are correct on all this, we need a FAQ addendum to their manual.... I have not lost hope, given what I have invested here....


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5525517 - 11/18/12 04:36 AM

I took successful flats using my EL panel with Ha filter, I have not yet tried it with the other filters which allow in more light.

Pfile, I'd say you are getting along very well with your own camera.

Jery,

My tracking is worse than yours on last nights attempt, but that has nothing to do with the camera, it is MaximDL and the mount.


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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Hilmi]
      #5525856 - 11/18/12 10:54 AM

I think I will have clear skys tonight and will work on the tracking. May I suggest the Helix for a good target for the filters. I am now working on Mel 15, which is a lot tougher.

I am going to try to fine tune the focus and other setting on the guide camera... I want to make sure I am at the limit of what I can get out of the guide camera to optimize the tracking. With the 2000mm FL I am pretty sure I am into watching the atmospherics, but I want to be sure.

If I can take some images from the guide camera using Maxim, I'll post them.

Cheers


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5525982 - 11/18/12 12:01 PM

The camera does it's part in the tracking, usually it's the mount. I just did some investigation and I found some burs on my worm gear, so I swapped the DEC & RA gears and now I am getting good guiding. This took me months to figure out.

I guess today I will see how the camera works out of the clouds clear up.


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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Hilmi]
      #5526196 - 11/18/12 01:54 PM

I lucked out with a good Atlas out of the box. Unfortunately it is clouding up in California, so not sure what I will get tonight. Good luck.

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Roy Salisbury
professor emeritus


Reged: 05/26/09

Loc: Las Vegas, NV
Re: STT-8300 First light report new [Re: Hilmi]
      #5526293 - 11/18/12 02:58 PM

I've had my camera on order for about 3 weeks now and hope to have it in about 3 more weeks. I am a bit worried about the STL thread requirement. From my understanding, it comes with an STL to 2" nose piece. Is this not true? Do I need to get the proper adapter?

If I need to get one, I will probable just get the Moonlite focuser adapter with STL threads. That way it will screw directly into the draw tube threads for a snug fit. Then I just have to worry about the rotation. But, I will no longer be able to use my field flattener as it only has T-Threads. I will need to find a replacement for my AT106 or hope that things work ok without it.

As for the focuser not working correctly. I found the last time that I was swapping out part on my setup, that if the focuser was sideways or upside down, then I could not get it to maintain focus. When I rotated it back to level it worked fine. So I must have been slipping due to the weight.

I have also ordered a separate power cable for my Paramount MX so I can run the power through the mount ... hopefully it does not have the same issues as the stock power adapter.

I am beginning to wonder however if I should have got the self guiding FW or not. The lack of field flatteners that fon't use T-Threads is hard to find (if not impossible).

Roy


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MattThomas
Vendor (SBIG)


Reged: 07/28/06

Re: STT-8300 First light report new [Re: Roy Salisbury]
      #5526426 - 11/18/12 04:30 PM

Quote:

From my understanding, it comes with an STL to 2" nose piece.




Roy,

This is correct. It does come with an STL to 2" nose piece.

Thank you,


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Roy Salisbury
professor emeritus


Reged: 05/26/09

Loc: Las Vegas, NV
Re: STT-8300 First light report new [Re: MattThomas]
      #5526574 - 11/18/12 06:32 PM

Thanks for confirming that Matt. I think I will still get the moonlite m68 to STL locking adaptor. That way it is a nice snug fit. I have also found the TS 2.5" field flattner that should work with my AT106. Just may have to have some special adapters made for the connections.

Roy


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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Roy Salisbury]
      #5527639 - 11/19/12 10:30 AM Attachment (38 downloads)

Hello,

For Hilmi, here is how I have the cables tied down... the extra grey cable is just in case the heavy sucker slides out and wants to take a fall...

PS This is where I got my connector for the C8... they seem to have everything:

ASTRO PHYSICS INC
11250 FOREST HILLS RD
MACHESNEY PARK, IL 61115
(815)282-1513

Cheers


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Hilmi
Post Laureate
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5529308 - 11/20/12 02:13 AM

Thank you for the cable guiding picture, it sure is useful to see how others are doing things.

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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Hilmi]
      #5537395 - 11/24/12 03:33 PM

Hilmi, can I send you a couple FITS images and see if you are getting the same ADU values? I am having trouble getting flats right?

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Chuck Faranda
professor emeritus
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Reged: 03/31/07

Loc: Florida
Re: STT-8300 First light report new [Re: MattThomas]
      #5811985 - 04/20/13 10:33 PM

Where is the Maxim plugin for the STT-8300 and self guiding CFW that will allow RBI preflashing, and have a selection for the CFW? The plugin should also expose the preflash modes so automation software like CCDAP can use it to flash for bias, darks, lights and flats but allow focus and plate solving to use the fast readout mode without the flash.

CCDOPS has a check box for flashing without details of user setable iterations and times. PRIMITIVE implementation in my opinion.

Had I know this was absent I would not have bought an SBIG


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5812202 - 04/21/13 01:34 AM

With regards to the plug in for supporting the camera's features:
-SBIG say it would require big changes in MaximDL to make the extra features work from inside MaximDL
-MaximDL say it the responsibility of the camera manufacturers to make ti work
-SBIG yahoo group was very responsive
-MaximDL yahoo group regularly ignore questions that they do not want to answer. I have posted multiple questions about this in the MaximDL group and not so much as a polite response to tell me that it is SBIG's job to do it. I have also had the same experience with other questions I have asked on that group. I once posted a question about support for the Canon7D in MaximDL before I renewed my license. I basically wanted to know if I should spend the money on MaximDL renewal or just go for BYEOS. It took weeks till somebody responded to tell me they have had support for the camera for a full year now. Why does it take weeks to answer such a simple question?


My conclusion, the lack of a plug in is due to both SBIG and MaximDL team. It is in the interest of both parties to support the functionality, especially considering the popularity of the SBIG cameras in general. You would think MaximDL development team would have incentive to support such large user base, but then again, what do you expect, they still do not support dual core processors even after so many years on the market. Because of this, you can't even do simple multi-tasking inside the app without causing something else to completely freeze till you finish your current task.


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Jared
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Reged: 10/11/05

Loc: Piedmont, California, U.S.
Re: STT-8300 First light report new [Re: Hilmi]
      #5812315 - 04/21/13 04:36 AM

The short term workaround on the RBI per flash is to connect the camera in CCDOps, enable it, and then disconnect and switch over to Maxim. The setting remains in non-volatile RAM, so it will remain turned on until you turn it off.

The current universal drivers in Maxim should let you run all other features of the camera. It is unclear to me how many per flashes are involved. The difference in time to expose and down load with RBI turned on is only a second or two, so the RBI feature must be using a fast readout mode, so no real need to change back to RBI "off" for plate solves and focus subroutines.


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Jared
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Loc: Piedmont, California, U.S.
Re: STT-8300 First light report new [Re: Jared]
      #5812317 - 04/21/13 04:38 AM

Oh, I should mention that this is all based on my experiences with an STXL--I'm assuming it's the same as the STT.

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Chuck Faranda
professor emeritus
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Reged: 03/31/07

Loc: Florida
Re: STT-8300 First light report new [Re: Hilmi]
      #5812368 - 04/21/13 06:13 AM

Well, as far as Im concerned the camera is **edited since I am no longer as tired** incomplete without having its features accessable in the most widely used camera control software.

Edited by Chuck Faranda (04/21/13 09:45 AM)


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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5812377 - 04/21/13 06:36 AM

Chuck, I wouldn't go so far as calling it a pile of junk. I would check first if the competing cameras with same features are having the same issue with MaximDL. Maybe it is MaximDL that's your problem.

Jared,

There are other features you can not control in MaximDL such as fan speed, fan on/off and internal processing.


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Chuck Faranda
professor emeritus
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Reged: 03/31/07

Loc: Florida
Re: STT-8300 First light report new [Re: Hilmi]
      #5812395 - 04/21/13 06:54 AM

Nope, FLI works as expected, preflash fully setable as is needed for my remote use.

I will qualify my statement, pile of junk for me as it relates to using it with a very popular SW package The camera is nicely made, and appears to perform to spec. But, not being fully active with Maxim Has anyone tried the new camera control in TheSkyX? I wonder if it has all the features there..........


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Raginar
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Reged: 10/19/10

Loc: Rapid CIty, SD
Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5812569 - 04/21/13 09:26 AM

I wouldn't say MaximDL is popular, it's the only option for doing what most of us want to do .

SGP is getting pretty good; and they are open to supporting their product. Obviously lacks all the image processing that most of us do in other programs anyways.


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Madratter
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Re: STT-8300 First light report new [Re: Raginar]
      #5813002 - 04/21/13 12:46 PM

I'm having my teething problems with SGP, but for the life of me, I don't understand why people will pay 500$+ for MaximDL. I have the trial, and I just flat don't get the attraction of it. I keep waiting for someone to tell me why it is so wonderful. There has got to be something I'm missing.

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psu_13
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Re: STT-8300 First light report new [Re: Madratter]
      #5813054 - 04/21/13 01:24 PM

I like the image calibration engine in Maxim. The capture stuff is certainly OK, but the way you can setup a single set of dark/flat/bias and have the program calibrate and stack in one go is really handy IMHO. I assume other software has similar functionality ... but the especially handy thing is how it uses meta-data in the FIT files to match light frames to calibration frames automatically.

This video summarizes some of how it works.

http://www.youtube.com/watch?v=PD3tXJ1Yqak

As always, YMMV.


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Zoeff
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Re: STT-8300 First light report new [Re: Madratter]
      #5813064 - 04/21/13 01:34 PM

Quote:

I'm having my teething problems with SGP, but for the life of me, I don't understand why people will pay 500$+ for MaximDL. I have the trial, and I just flat don't get the attraction of it. I keep waiting for someone to tell me why it is so wonderful. There has got to be something I'm missing.




My experiences with Maxim haven't been stellar actually. A few minor versions ago the lodestar driver completely broke. In the current version they claim to have fixed it but every now and then the entire program stops responding completely when trying to download a lodestar light. Because this problem isn't something that happens immediately you'll end up returning to your computer at a later time just to see it got stuck on downloading a lodestar image. >_<

For 500 dollars? No way. It's too dated imo.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: Zoeff]
      #5813074 - 04/21/13 01:37 PM

What is 'SGP'?

See Maxim DL features for the list of what it does. Well worth the $$ in my estimation.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: Madratter]
      #5813077 - 04/21/13 01:39 PM

Oops, forgot the Maxim link. http://www.cyanogen.com/maxim_features.php

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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5813095 - 04/21/13 01:56 PM

The main attraction of MaximDL is the ability to accept 3rd party plug ins and the ability to script it.

So you get plug ins like the flats wizard, and you get programs like focus max, pole align max and ccd autopilot.

It also has built in auto-guiding so that if you have a camera with a built in guide chip, the only way to guide it is via the same software as your imaging platform.

That is the main true attraction of MaximDL.

Otherwise, it is clumsy antiquated interface and it is slow in processing compared to even some free offerings.


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jerryyyyy
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Re: STT-8300 First light report new [Re: Hilmi]
      #5813397 - 04/21/13 03:33 PM Attachment (15 downloads)

Guys, looks like I dropped in on this a bit late... actually have been processing images with the help of the Gurus at PixInsight [they are magicians].

There are a lotta gotchas here... speaking as someone with now 17 months astroimaging experience who had to buy everything from scratch over that time.

IMHO there is no way to automat image collection without Maxim... it integrates to the SBGI camera alright, and it integrates to CCDComander alright and RoboFocus integrates to CCDComander.

Why is this important?

Last night my wife had me to go out... so I turined it all on at 530PM and imaging started up at sunset 8:40 took a plate image near my focus start, autofocused, and at 5AM dozens of images were taken... I went out and slept all night.

If there were another way to do this, I would have tried it...

I have to say that on the processing side now I am in love with PixInsight. Those guys over there had me upload some of my heavily LPed images and they processed them and showed me what to do.... I can now go right from the output of Maxim to images including doing that stacking and flats processing...

I have had probably one too many cups of coffee this AM... but below is the image they helped me process and I think I am geting somewhere inally with the STT8300 and the software.

PS Narrowband is a LOT easier.


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mmalik
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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5814546 - 04/22/13 01:49 AM

Quote:

I have to say that on the processing side now I am in love with PixInsight.




Good to hear. I had put together some PixInsight instructions... for my own learning sake; please review and see what could be improved upon given your new found love. Thx


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LoveChina61
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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5814643 - 04/22/13 04:41 AM

NICE image! Which object is that by the way?

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jerryyyyy
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Re: STT-8300 First light report new [Re: mmalik]
      #5814936 - 04/22/13 10:18 AM

Quote:

Quote:

I have to say that on the processing side now I am in love with PixInsight.




Good to hear. I had put together some PixInsight instructions... for my own learning sake; please review and see what could be improved upon given your new found love. Thx




Wow! Quite and effort! But I know why you do it. I got one image processed correrectly and it took 87 steps... unfortunately not written down.

I searched and could not find that you have looked at using BatchPrepocessing to stack RGBL images... if I could get this to work consistently, I would be golden. I (and others) have had problems moving files over from CCDStacker to PI.

BTW, my complements on using SkyDrive to host the pdf.

Finally, do not want to hyjack this thread on the STT8300, but one tiny STT note. There was a post on Yahoo this AM about frosty sensors at -30DEG. Not hurt me, hope others are OK on this. Definately better images for me at -30 compared to -20.


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jerryyyyy
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Re: STT-8300 First light report new [Re: LoveChina61]
      #5814949 - 04/22/13 10:24 AM

Quote:

NICE image! Which object is that by the way?




The galaxy is NGC2903 in Leo. http://en.wikipedia.org/wiki/NGC_2903 ..... There is more there with Ultraviolet filters. This image is a total of about 3 hours exposure.


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MattThomas
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Re: STT-8300 First light report new [Re: Hilmi]
      #5820292 - 04/24/13 05:20 PM

I just want to clear up some of the concerns posted here regarding RBI on the STT cameras (and STX/STXL as they act the same).

The RBI readout mode is enabled via a non-volatile selection in the camera flash memory. Once enabled, the RBI flashing is done on every exposure.

The RBI mode on these cameras adds only about 1 second to the download process. This does not impact the performance of the cameras significantly. Thus the need to enable and disable this feature for Focus or Plate Solves is significantly reduced. (Especially compared to other manufacturer's cameras I have tested that take up to 120 seconds to download an image when RBI mode is enabled.)

Because of the minimum impact on the image download, it was never a priority to have the option be easy to turn on and off. Enable it if you want to use it and then don't worry about it anymore.

However, just to reiterate as I always do, the RBI Pre-Flash adds noise to your image. This reduces the dynamic range possible out of the sensor - especially if you are imaging very faint targets that are not sky background limited. So use with caution.

Thank you.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: MattThomas]
      #5820747 - 04/24/13 08:20 PM

Quote:

<SNIP>
However, just to reiterate as I always do, the RBI Pre-Flash adds noise to your image. This reduces the dynamic range possible out of the sensor - especially if you are imaging very faint targets that are not sky background limited. So use with caution.

Thank you.




Matt,

What type of noise you are talking about? I have been using RBI flood/flush/integrate for several years without seeing increases in 'noise' in subsequent frames. Thanks.


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MattThomas
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5821120 - 04/25/13 12:03 AM

Quote:

Quote:

<SNIP>
However, just to reiterate as I always do, the RBI Pre-Flash adds noise to your image. This reduces the dynamic range possible out of the sensor - especially if you are imaging very faint targets that are not sky background limited. So use with caution.

Thank you.




Matt,

What type of noise you are talking about? I have been using RBI flood/flush/integrate for several years without seeing increases in 'noise' in subsequent frames. Thanks.




Chuck,

Measure your dark current with RBI enabled.

Warm up your camera, turn off RBI, then cool it back down again.

Measure dark current again. It is much lower with RBI disabled.

Thank you,


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Re: STT-8300 First light report new [Re: MattThomas]
      #5821350 - 04/25/13 06:50 AM

Quote:

Quote:

Quote:

<SNIP>
However, just to reiterate as I always do, the RBI Pre-Flash adds noise to your image. This reduces the dynamic range possible out of the sensor - especially if you are imaging very faint targets that are not sky background limited. So use with caution.

Thank you.




Matt,

What type of noise you are talking about? I have been using RBI flood/flush/integrate for several years without seeing increases in 'noise' in subsequent frames. Thanks.




Chuck,

Measure your dark current with RBI enabled.

Warm up your camera, turn off RBI, then cool it back down again.

Measure dark current again. It is much lower with RBI disabled.

Thank you,




I will perform your prescribed test on all my RBI flood capable cameras and report the findings. Regardless of the out come, increased dark current is better than ghosts from RBI in my view.

Thanks Matt


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freestar8n
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Re: STT-8300 First light report new [Re: MattThomas]
      #5821375 - 04/25/13 07:15 AM

Quote:

Measure dark current again. It is much lower with RBI disabled.




Wouldn't this take the form of an effective increase in bias noise rather than dark current? There would be a higher baseline noise from read noise and (uniform) rbi shot noise from the pre-flood - but the dark current would add noise on top of that at the same rate - wouldn't it? Or are you saying the dark current really is higher with rbi enabled?

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5821517 - 04/25/13 09:08 AM

Quote:

Quote:

Measure dark current again. It is much lower with RBI disabled.




Wouldn't this take the form of an effective increase in bias noise rather than dark current? There would be a higher baseline noise from read noise and (uniform) rbi shot noise from the pre-flood - but the dark current would add noise on top of that at the same rate - wouldn't it? Or are you saying the dark current really is higher with rbi enabled?

Frank




Yes, and ample cooling will offset the extra charge from flushing the traps. I have reread the emperical data offered on the NASA site and others. A web search on the subject will reveal significant work in this area.

So, the good news is that the STT has RBI to flood/flush/integrate and enhanced cooling >-50 T to minimize the extra charge from the traps.


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freestar8n
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5821950 - 04/25/13 12:22 PM

I expect that the charge from rbi is emitted as a current with a changing rate that decays more slowly at cold temperatures. So at higher temperatures it would be mostly drained early in an exposure - and be "bias-like" - while at colder temperatures it might be leaking at a nearly steady but small rate.

The whole point of low temperature is to reduce the noise by lowering the dark current, but if you need to flood to avoid rbi and you get an increased noise as a result - then it may still be beneficial, but it would be good to have specs on all these parameters and how they relate to temperature so you can quantify the noise contributions and assess the tradeoffs.

Frank


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MattThomas
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5822033 - 04/25/13 12:55 PM

Quote:

Quote:

Quote:

Measure dark current again. It is much lower with RBI disabled.




Wouldn't this take the form of an effective increase in bias noise rather than dark current? There would be a higher baseline noise from read noise and (uniform) rbi shot noise from the pre-flood - but the dark current would add noise on top of that at the same rate - wouldn't it? Or are you saying the dark current really is higher with rbi enabled?

Frank




Yes, and ample cooling will offset the extra charge from flushing the traps. I have reread the emperical data offered on the NASA site and others. A web search on the subject will reveal significant work in this area.

So, the good news is that the STT has RBI to flood/flush/integrate and enhanced cooling >-50 T to minimize the extra charge from the traps.




Actually, no. A bias is too short to see increased noise from the RBI pre-flash.

Remember that the root problem is that the substrate traps charge and slowly leaks it out into the active pixels. The lower the temperature, the slower the leakage.

So, when you have a bright object in the frame the substrate traps the charge from the object. Over the course of the next long image that charge in the substrate slowly leaks out into the active image area resulting in a ghost image.

With the pre-flash, you are saturating the substrate to mask the presence of any charge from a bright object. So now you essentially have a ghost image that covers the entire CCD. Over the course of the next long exposure that charge in the substrate will leak into the active pixels - resulting in a ghost image over the entire CCD. This appears like increased dark current.

So the only way to measure the increase in noise is to look at a long exposure - as if you were measuring dark current. The bias frame will not have much leakage from the substrate - especially if the CCD is very cold.

When testing dark current in our production cameras, we can easily see this effect by cooling the CCD, exposing the CCD to light, then closing the shutter and measuring dark current. The dark current is much higher (sometimes >10x higher) than normal as a result of the saturated substrate leaking into the image.

The best way to clear RBI without impacting the noise is to warm the CCD after the offending image.

I hope this helps.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: MattThomas]
      #5822162 - 04/25/13 01:26 PM

Quote:

Quote:

Quote:

Quote:

Measure dark current again. It is much lower with RBI disabled.




Wouldn't this take the form of an effective increase in bias noise rather than dark current? There would be a higher baseline noise from read noise and (uniform) rbi shot noise from the pre-flood - but the dark current would add noise on top of that at the same rate - wouldn't it? Or are you saying the dark current really is higher with rbi enabled?

Frank




Yes, and ample cooling will offset the extra charge from flushing the traps. I have reread the emperical data offered on the NASA site and others. A web search on the subject will reveal significant work in this area.

So, the good news is that the STT has RBI to flood/flush/integrate and enhanced cooling >-50 T to minimize the extra charge from the traps.




Actually, no. A bias is too short to see increased noise from the RBI pre-flash.

Remember that the root problem is that the substrate traps charge and slowly leaks it out into the active pixels. The lower the temperature, the slower the leakage.

So, when you have a bright object in the frame the substrate traps the charge from the object. Over the course of the next long image that charge in the substrate slowly leaks out into the active image area resulting in a ghost image.

With the pre-flash, you are saturating the substrate to mask the presence of any charge from a bright object. So now you essentially have a ghost image that covers the entire CCD. Over the course of the next long exposure that charge in the substrate will leak into the active pixels - resulting in a ghost image over the entire CCD. This appears like increased dark current.

So the only way to measure the increase in noise is to look at a long exposure - as if you were measuring dark current. The bias frame will not have much leakage from the substrate - especially if the CCD is very cold.

When testing dark current in our production cameras, we can easily see this effect by cooling the CCD, exposing the CCD to light, then closing the shutter and measuring dark current. The dark current is much higher (sometimes >10x higher) than normal as a result of the saturated substrate leaking into the image.

The best way to clear RBI without impacting the noise is to warm the CCD after the offending image.

I hope this helps.




Matt,

Are you saying the noise does not come from charge being detrapped from the traps after the flooding?

Should the noise from the de-trapping be time dependent since it is a relic passed to the following image? To follow what you stated previously, the noise is increased in subsequent images from the flood/flush. If it is the additional dark shot noise associated with trap leakage then wouldn't it show in bias frames and all others too? In any event, for me this is still far better than dealing with the residual image of the stars and the dark fixed patterns caused by the non-uniform trap distribution if no flood/flush is used.

Edited by Chuck Faranda (04/25/13 02:03 PM)


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freestar8n
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Re: STT-8300 First light report new [Re: MattThomas]
      #5822337 - 04/25/13 02:42 PM

My second note describes what I mean by "bias-like." If the temperature is high enough that most of the rbi charge is released in one minute, then for exposures of 5, 10, 20 minutes - that charge would not correspond to a steady dark current, but a burst of current (and noise) that does not increase much after that initial burst - which makes it "bias-like" in that the noise contribution doesn't increase much with exposure time.

If the temperature is low enough then the rbi current would be more steady - but it would still be dropping somewhat over time.

I don't think ccd's with rbi pre-flash and low temperature cooling tend to spec. these things - e.g. the 1/e timescale of the pre-flash current decay. Without specs for these things, it's hard to assess the benefits of pre-flash as a function of temperature and exposure time.

Frank


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Alph
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5822444 - 04/25/13 03:40 PM

Quote:

In any event, for me this is still far better than dealing with the residual image of the stars and the dark fixed patterns caused by the non-uniform trap distribution if no flood/flush is used.



It has been said multiple times that there is very little benefit to cooling the KAF-8300 below -20C. Perhaps if you kept the KAF-8300 at -20C or -15C then you would not have to deal with RBI and still have very low dark current.


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Re: STT-8300 First light report new [Re: Alph]
      #5822569 - 04/25/13 04:48 PM

Quote:

Quote:

In any event, for me this is still far better than dealing with the residual image of the stars and the dark fixed patterns caused by the non-uniform trap distribution if no flood/flush is used.



It has been said multiple times that there is very little benefit to cooling the KAF-8300 below -20C. Perhaps if you kept the KAF-8300 at -20C or -15C then you would not have to deal with RBI and still have very low dark current.




Cooling most certainly reduces the charge leakage created by RBI management, and subsequent total dark current charge. So, the colder the better regardless of who says otherwise. However, I am open to see the data they used to leap to the conclusion so often repeated.

For me, RBI is a must to avoid ‘ghosting’ artifacts (I know the artists out there can work their Photoshop magic to color them out). Therefore, to not have to worry about dark current + RBI mitigation trap leakage charge overtaking read noise I look for camera like the STT that boast >50+ C DT cooling.

Should anyone be interested, the NASA site, Google, and http://astro.cornell.edu/~mmhedman/papers_published/ISS_calibration_PSS.pdf have a wealth of articles on the subject filled with data most of which are far too complex for me to grasp.

Edited by Chuck Faranda (04/25/13 04:49 PM)


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Alph
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5822666 - 04/25/13 05:24 PM

Quote:

So, the colder the better regardless of who says otherwise.



Not if you want to avoid RBI. RBI is weaker and dissipates faster at higher temperatures. Normally RBI is not an issue with the KAF-8300 unless you are over-cooling and over-exposing.


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Re: STT-8300 First light report new [Re: Alph]
      #5822693 - 04/25/13 05:38 PM

You can eliminate RBI by simply inserting at least 5-10 seconds delay in between subs. Many image capture software allows you to insert delay in between subs. It's simple and free. No need to pay extra cost for a camera to remove RBI and add noise.

Peter


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MattThomas
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Re: STT-8300 First light report new [Re: Peter in Reno]
      #5822718 - 04/25/13 05:57 PM

Lots to reply to...

Chuck:
Quote:

Are you saying the noise does not come from charge being detrapped from the traps after the flooding?



No - that isn't what I'm saying. The but the "detrapping" is a function of time. It can take more than 5-10 minutes at cold temperature for the substrate to fully purge itself of the flooding. Even longer for some CCDs. (Note that the KAF-9000 CCD takes minutes to clear the RBI even at room temperature!!!) This "detrapping" will appear as added unwanted signal (a.k.a. "noise") in your image. In fact you may even get a ghost image of some of the surface treatment (e.g. polishing) of the silicon.

Quote:

If it is the additional dark shot noise associated with trap leakage then wouldn't it show in bias frames and all others too?



It is purely time related. At cold temperatures, a short (bias) exposure will not experience much leakage from the substrate because the exposure isn't long enough to accumulate that charge from the substrate. The active pixels are flushed, then the exposure performed, then the active pixels are read out. This period leaves very little time for the substrate to affect the image. Thus there is no real contribution from the RBI problem.

Frank:
Quote:

My second note describes what I mean by "bias-like."



You posted after I started my reply. I understand what you are suggesting - but even at warm temperatures with some CCDs the leakage from the substrate spans many minutes (e.g. KAF-9000), so I think it is a mistake to think of it as a bias like effect.

Quote:

Without specs for these things, it's hard to assess the benefits of pre-flash as a function of temperature and exposure time.



Correct - there is no spec for RBI from the CCD manufacturers, so we really cannot make any spec related to this artifact.

Peter:
Quote:

You can eliminate RBI by simply putting at least 5-10 seconds delay in between subs. Many image capture software allows you to insert delay in between subs. It's simple and free. No need to pay extra cost for a camera to remove RBI and add noise.



5-10 seconds is usually not enough. As I mentioned before, if time is not an issue warming the CCD and cooling it again is the best approach to deal with RBI.

If anyone likes, I can provide some real measurements of dark current before flooding and after flooding. Just let me know.

Thank you.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: Peter in Reno]
      #5822725 - 04/25/13 06:06 PM

Quote:

You can eliminate RBI by simply inserting at least 5-10 seconds delay in between subs. Many image capture software allows you to insert delay in between subs. It's simple and free. No need to pay extra cost for a camera to remove RBI and add noise.

Peter




Which sensor, and set temp Peter? The KAF-16803 or KAF-9000 have taken hours to totally dissipate the charge even when kept at a sweltering -10 temp!


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Re: STT-8300 First light report new [Re: MattThomas]
      #5822760 - 04/25/13 06:31 PM

Thanks for the response Matt.

Obviously, for some RBI is not an issue, for others the need for 30 minute NB subs creates totally different rules. I will continue to use the welcomed new RBI mitigation and enhanced cooling of the STT (kudos SBIG!) to my best advantage. Moreover, I continue to glean info you and other reliable sources. Indeed, there are volumes of published, peer reviewed, articles and empirical data that should give me a better understanding.


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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5822793 - 04/25/13 06:49 PM

does anyone have any examples of what an RBI-spoiled sub looks like? the other night i did a bunch of 30 minute Ha subs with an STT-8300M @ -30C and there's nothing obvious to me that something could be wrong. maybe the target was not bright enough to cause this problem?

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Re: STT-8300 First light report new [Re: pfile]
      #5822855 - 04/25/13 07:14 PM Attachment (31 downloads)

Quote:

does anyone have any examples of what an RBI-spoiled sub looks like? the other night i did a bunch of 30 minute Ha subs with an STT-8300M @ -30C and there's nothing obvious to me that something could be wrong. maybe the target was not bright enough to cause this problem?




Here is a crop of a 600 second dark taken 20 minutes after a 600 second light of a faint nebula (KAF-6303 sensor). No RBI mitigation applied, you can clearly see ghost stars and the nebula.


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Re: STT-8300 First light report new [Re: MattThomas]
      #5822911 - 04/25/13 07:46 PM

Ok, ok... I know no one asked. But here it is anyway.

From an STT-8300 operating at -35C.

We measure dark current by taking a 3 second dark frame and subtracting it from a longer dark frame and looking at the average charge left in the image. In this test I was using a 300 second dark frame.

With no light on the CCD from when it was warm, the charge accumulated in 300 seconds was 2.09 ADU, or 0.75e- (0.0025e- per second)

Then I enabled the RBI preflash and re-did the test. The charge accumulated in 300 seconds was 60.85 ADU, or 21.91e- (0.0730e- per second).

I kept RBI preflash enabled, redid the test and achieved a similar result. Thus by using RBI preflash the dark signal in a 300 second exposure is increased 29x. This will translate into a larger contribution of shot noise to the true noise in the image (as the ~61ADU of dark signal could be subtracted with a dark frame).

I then disabled the RBI pre-flash and continued measuring dark current with 300 second exposures. (Note that these were not necessarily back-to-back measurements - I had to step away from my desk for some of these, so the actual time for the charge to diminish cannot be determined from this test.)

The results were, in order of time from the RBI pre-flash:
11.55 ADU, 4.16e- (0.0139e-/sec)
6.29 ADU, 2.26e- (0.0075e-/sec)
4.99 ADU, 1.80e- (0.0060e-/sec)
3.60 ADU, 1.30e- (0.0043e-/sec)

So, more than 30 minutes after flashing the CCD there is still charge leaking out of the substrate at 70% the raw dark current rate of the KAF-8300.


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Re: STT-8300 First light report new [Re: MattThomas]
      #5823005 - 04/25/13 08:31 PM

Matt,

Are you saying this indicates that RBI is preferable to managing the leakage noise?

Here is an example of the 'noise' RBI can cause (I've seen worse) if no RBI mitigation is applied? I do not own a KAF-8300 camera without RBI mitigation, but I have seen images from others who do. It doesn't appear to be immune to RBI.

Once I the needed scope adapter arrives I will provide some with and without images for us to pick apart.


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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5823152 - 04/25/13 09:11 PM

Quote:

Quote:

does anyone have any examples of what an RBI-spoiled sub looks like? the other night i did a bunch of 30 minute Ha subs with an STT-8300M @ -30C and there's nothing obvious to me that something could be wrong. maybe the target was not bright enough to cause this problem?




Here is a crop of a 600 second dark taken 20 minutes after a 600 second light of a faint nebula (KAF-6303 sensor). No RBI mitigation applied, you can clearly see ghost stars and the nebula.




Whoa!!!! What if you dither the subs, do you get double stars in every image? Do all Kodak chips do that or just yours?

I cool my Sony ICX694 CCD to as low as -15C and image as long as 30 minutes and never seen this issue. Colder than -15C for Sony chips make very little to no difference thanks to their super low noise chips.

Peter


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Re: STT-8300 First light report new [Re: Peter in Reno]
      #5823190 - 04/25/13 09:30 PM

Full frame, front illumated sensors are prone to this. The Sony has an interline sensor.

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Re: STT-8300 First light report new [Re: MattThomas]
      #5823509 - 04/26/13 02:02 AM

Hi-

Thanks - that is actually what I was looking for. If at -35C you still get much more charge released in the first 5 minutes than in any time after, then in a long exposure the contribution from rbi leakage is relatively fixed and fairly independent of exposure time. In that sense it acts more like read noise because it is relatively independent of subexposure time for long subexposures. In an exposure above 10 minutes, it appears to add about 25e of uniform dark current. If the read noise is about 9e, then the effective read noise in a long exposure with pre-flash enabled is about sqrt(25+81)= 10.3e.

Obviously this is not actually "read noise" because it wouldn't show in a short exposure - but it is like read noise in that it is independent of exposure time for long exposures.

I don't consider this a huge impact on the read noise - and if the dark current remains so low at -35C then overall this is good for long exposures. With pre-flash enabled, long exposures would act like a slightly higher read noise ccd with fairly small dark current - and presumably no rbi artifacts.

Thanks,
Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5823624 - 04/26/13 05:44 AM

I did a fit to the data provided and even though the exposures weren't back to back, they fit well to an exponential decay of rbi charge on top of a constant dark current. The numbers I get, for -35C, are:

rbi total charge, q: 23.4 e
constant dark current, d: 0.0055 e/s
rbi charge 1/e decay time, T: 150 seconds

where the assumed formula for total dark current in an exposure of time t is:

D(t) = d*t+q*(1-e^(-t/T))

q represents the maximum impact from rbi pre-flash, and I assume that if the pre-flash exposure is weaker then q will be smaller, but then it might allow rbi artifacts to remain. So q by itself might be different from different vendors - but you would need to make sure it was effective at eliminating rbi artifacts.

Anyway - thanks for the data - and it all looks encouraging for 8300 with rbi pre-flash.

One note is that with this nonlinear contribution from the rbi discharge, it would be dangerous to do any scaling of darks, so you would want dark times to match light times. You might also benefit from the use of flat darks here - but bias might still be just as good and possibly better than a scaled dark.

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5823952 - 04/26/13 09:59 AM

Guys, could someone be so kind as explain to a poor soul like me with 17 months astroimaging experience what the issue with RBI might be?

I went away from this thread for one day and there are 20 posts on it... WOW.


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Re: STT-8300 First light report new [Re: MattThomas]
      #5824024 - 04/26/13 10:29 AM

Quote:

<snip>The "detrapping" is a function of time. It can take more than 5-10 minutes at cold temperature for the substrate to fully purge itself of the flooding. Even longer for some CCDs. (Note that the KAF-9000 CCD takes minutes to clear the RBI even at room temperature!!!) This "detrapping" will appear as added unwanted signal (a.k.a. "noise") in your image. In fact you may even get a ghost image of some of the surface treatment (e.g. polishing) of the silicon.<snip>




I was wondering what caused that! I stacked up 50 or so dark frames at -35C on my STXL-6303 with RBI enabled and noticed an obvious ghost image, but had no idea what was causing it. It looked almost like a flat frame from a back-illuminated CCD (where the thinning process leaves a similar "ghost" image).

I'll try a set of darks without RBI enabled, and also measure noise differences with RBI on and off. Sounds like there may be situations--especially narrow band images where read noise is critical--to go without RBI enabled.

Thanks for the informative post.


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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5824080 - 04/26/13 10:49 AM

Quote:

Guys, could someone be so kind as explain to a poor soul like me with 17 months astroimaging experience what the issue with RBI might be?

I went away from this thread for one day and there are 20 posts on it... WOW.




Kodak KAF chips (and perhaps other full-frame, front illuminated chips) suffer from something called Residual Bulk Image. The basic problem is that when these chips are exposed to a bright subject--something that saturates or nearly saturates the detector at a given pixel--some of the charge goes into the substrate of the chip and then can leak into the wells on subsequent images. Think of it like looking at a bright light for a few seconds with your eye and then looking at a blank wall--you will see the bright light "ghost" on the blank wall. KAF chips do the same thing, and when you stack up images you can get ghosts in the stacked image.

The standard solution to this problem is to "pre flash" the chip with an LED so that the RBI covers every pixel equally. As Matt Thomas was explaining, you get higher noise levels, but no ghosting. It's like adding a second source of dark current as the RBI leaks into the wells.

The second option is to just raise the temperature of the CCD so the RBI leaks out faster--letting it quickly decay to zero. Then, when you re-cool your chip there is no RBI on your next exposure. However, warming and cooling your chip between every pair of exposures eats up a lot of exposure time. It might still be reasonable if you were taking long narrowband subexposures, though.


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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5824082 - 04/26/13 10:50 AM

Quote:

Guys, could someone be so kind as explain to a poor soul like me with 17 months astroimaging experience what the issue with RBI might be?




You want low noise in an image so you want low read noise and low dark current. You can't control read noise much but you can lower dark current by cooling the ccd. Unfortunately cooling the chip a lot causes it to trap charge, which persists after the image is read out, and it shows again in the next image. It shows typically as weird ghosting or nebulosity around stars - especially when the images are dithered.

So it is a real problem when it happens.

Several years ago some companies offered a pre-flash system that blasts the ccd with a uniform light before each exposure. This doesn't remove the stored charge, but it leaves a uniform charge across the ccd that doesn't show as an image artifact - but it does result in increased noise.

So if you have rbi pre-flash in your ccd, you can either run at a higher temperature so there is no rbi problem, but there is higher noise - or you can run very cool but use the pre-flash - which also introduces noise.

The point of my notes above is that the impact of rbi pre-flash is basically equivalent to a slightly higher read noise - rather than a slightly higher dark current. If you know the various parameters, you can make an optimal choice of what to do.

Based on what I have seen I would do:

1) For short exposures around 5m I would run at a higher temperature to avoid rbi and not use pre-flash

2) For long exposures that are sky limited I also would run at higher temperature to avoid rbi and not use pre-flash

3) But for long exposures that would be limited by dark current rather than sky or read noise, I would run very cold and use pre-flash to avoid rbi. In that case I would effectively be using a very low dark current with a slightly higher read noise.

I am considering a new ccd and if these numbers for rbi and dark current for the 8300 are representative, then the 8300 becomes much more attractive, mainly due to its size, than the sony 694.

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5824431 - 04/26/13 01:30 PM

Does this affect the ST-10 at all?

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Re: STT-8300 First light report new [Re: Raginar]
      #5824704 - 04/26/13 03:38 PM

Quote:

Does this affect the ST-10 at all?



Yes. The KAF-3200 is prone to RBI. You can safely assume that every Kodak NABG CCD will have significant RBI. Anti-blooming gates help to mitigate RBI. They drain excess charge. The KAF-8300 ABG performance is pretty high 1000x and this probably explains why it is more resistant to RBI. RBI shouldn’t be an issue if you don’t saturate pixels and make multiple sub-exposures of the same target over the course of your imaging session. Guide, baby, guide! As Sarah would have said.


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Re: STT-8300 First light report new [Re: Alph]
      #5825606 - 04/27/13 02:06 AM

Alph,

Thank you. I've been wondering what the 'ghosting' is and I think this explains it.


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Re: STT-8300 First light report new [Re: Raginar]
      #5825643 - 04/27/13 03:04 AM

There have been several threads in CN on problems with RBI using the 8300 ccd. It might help this thread if anyone has a recent example to show with the 8300. The idea that images should avoid any saturation and be precisely aligned in each sub-exposure completely ignores the desire to dither exposures, and the common occurrence of nebulosity containing bright stars - or even galaxies with bright foreground stars. Even an object like the bubble nebula has a patch of pure nebulosity so bright that it could induce rbi artifacts.

At the same time, it is true that you can just run the ccd at higher temperature to reduce the impact of rbi - and that is another place where I find the specs for the 8300 all over the map. The dark current is supposedly related to the sensor itself and should not be different among vendors (as opposed to the read noise which depends on the support electronics) but I am finding values for dark current over a wide range.

If one 8300 achieves 0.004 e/s at -15C and another requires -30C to reach that level, then the first one might do fine without pre-flash while the second requires pre-flash. I would like to see firmer specs on values such as dark current and read noise that are neither optimistic nor pessimistic - so that if you buy such a camera and it does not meet the spec you can return it for one that does.

With rbi pre-flash, I would also like specs such as I derived above - which indicate the total charge released due to pre-flash, and the time constant of its release at a given temperature.

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5825724 - 04/27/13 06:01 AM

Since the topic of RBI of broader interest than purely with the STT-8300 cameras, shouldn't we start a separate topic so that it is easy to find should somebody be searching for RBI related information?

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Re: STT-8300 First light report new [Re: Hilmi]
      #5825745 - 04/27/13 06:53 AM

Quote:

Since the topic of RBI of broader interest than purely with the STT-8300 cameras, shouldn't we start a separate topic so that it is easy to find should somebody be searching for RBI related information?




True, and I'm fine with your suggestion. However, I still have a few questions about how SBIG approaches RBI mitigation as it relates to user settable conditions for flood/flush/integrate. This ties in to the technical questions raised by Frank in a previous post. For example, does the predefined 1 second flash and single flush Matt spoke to accomplish the 100X full well level to ensure all traps are filled as Janesick (2001, pg. 664) recommends? If not, then (for me) this will still be a SBIG specific topic related to the implementation of changes that allow client software access to these default settings.


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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5825821 - 04/27/13 07:55 AM

I remain puzzled as I read through the thread as to what to do about RBI.
First off, I have never personally seen it on the hundreds (thousands?) of subs I've taken with my ST-8300M. Maybe it's there on some and I'm not sophisticated enough to spot it? Could well be.
My camera does not offer pre-flash to mitigate RBI.So, what do I do about it?

1/Run at minus 10C instead of minus 20? Even zero C?
2/Run at minus 20C but turn cooling off for a couple of minutes between subs? Perfectly feasible for long NB subs but not practical for LRGB subs of 5 minutes or so.
3/ Just ignore the whole thing until it actually bites me?

Even if my camera did offer pre-flash, after reading here, I'd be reluctant to use it. Raising the overall noise level, quite irregardless of how "uniformly" you do it, seems counter to what CCD imaging is supposed to be about.


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Re: STT-8300 First light report new [Re: dawziecat]
      #5825882 - 04/27/13 08:48 AM

Quote:

I remain puzzled as I read through the thread as to what to do about RBI.<snip>




My questions were posed because the STT cameras implements enhanced cooling and RBI mitigation. Janesick (isbn:0819436984) details the relationship between temperature and RBI as well as the other things we have touched on here. So, I feel the implementation is important when I compare them to the accepted scientific data on the subject.

I hope my inquiries haven't prompted anyone to think they should fix something that isn't broken for them.


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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5825902 - 04/27/13 09:04 AM

Does taking multiple short exposures clear the RBI?

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Re: STT-8300 First light report new [Re: Hilmi]
      #5826290 - 04/27/13 01:10 PM

The only time you would be concerned about rbi is if the camera is very cold, and the only reason you would want a cold camera is if dark current is a problem and noticeably contributes relative to read noise and sky noise. Short exposures tend to be dominated by read noise, so you would not need to have the camera very cold anyway - and would not have rbi.

But if you did have a cold camera, then shorter exposures would reduce the impact of rbi if they kept stars from saturating that otherwise would have. In reality, though, you would probably be better off with longer exposures and a less cold camera.

A key point in all this is - if you don't have problems with rbi - then you don't have problems with rbi - and none of this, including pre-flash, matters. But people running cold cameras should be aware of rbi and know what to look for because it may be happening without them realizing it. And they can try the tests described in this thread.

Oh - and if you are asking simply if the process of reading the camera somehow clears the charge and dumps it - no. That's why you can take repeated darks after taking a single flat - and see the background level slowly going down in each dark - as the person from sbig measured.

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5828829 - 04/28/13 05:55 PM

Thanks for the explanations of RBI... I think this is probably the least of my problems, but at least I understand it.

I do want to post another STT8300M issue here. I also posted this at the Yahoo SBIG Group, so if you look in both places ignore this post [I am not sure how many people overlap].

I am concerned about calculating the right times for "sky limited images" with the STT8300m.

I have gone to the Starzona site:

http://starizona.com/acb/ccd/advtheoryexp.aspx

That descibes the concept of sky limited exposures. Also has a calculator, unfortunate does not cover the STT8300M, though does cover the ST8300M.

In any case, in my light polluted universe for 600s exposures the get the horrible ADU sky readings of approximately 16000-20000 for L using M101 as a target. The readings for RGB are about 6700, 6000 & 5500. The good news is the center of M101 is at least 22000... at least I can see the center of M101...

In any case, It appears the gain of the 8300M is 0.37e/ADU and Read Noise is < 10e- rms. [manual]

Now if I plug my values into the Starzona calculator I get 1.15 for L, 3.46 for R,3.87 for G and 4.22 for B.

If I try to do the calculations manually from the equations I am not sure but I think I get similar results ... 79.3s for L [I believe].

Are these the maximum lengths for sky limited exposures I can expect for each filter? Is the downside that if I expose longer than these the LP will overwhelm the readable signal?

When I look at the 600s images they sure seem to have a lot of noise in the "dark" areas... [yuck].... I guess I better focus on narrow band targets.... I am currently running an experiment using both sets of settings [600s and the shorter ones] on the same nights.

Thanks for any decyphering possible.


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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5829456 - 04/29/13 01:31 AM

I was trying to figure this out too, I am going to a dark sky location at high altitude in a few days time. I put the details of the location I was going to in Skytools 3 and it keeps on telling me the optimal exposure is 1 minute long, this doesn't sound right to me. I would barely be able to capture any data with 1 minute exposures even from a dark site.

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Re: STT-8300 First light report new [Re: Hilmi]
      #5829559 - 04/29/13 05:18 AM

One minute sounds odd at a dark site unless you are using hyperstar or something that is very fast.

On the other hand, 1 minute sounds about right for an L exposure with light pollution. But just because the "optimal" exposure is 1 minute doesn't mean you can't go longer - to 5 or 10 - as long as the image doesn't saturate features too much. But those longer exposures won't help reduce noise much because your main source of noise is the sky itself - unless you go to a dark site. The only way to improve SNR in light pollution is just to accumulate a long total exposure time.

And if you are sky limited then you don't need to run the camera too cool, and you don't need to worry about rbi - etc.

Frank


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Re: STT-8300 First light report new [Re: freestar8n]
      #5829574 - 04/29/13 05:53 AM

This is what skytools 3 reported for the STT-8300 on an F8 8" GSORC scope. I figure I will ignore those suggestions and just see how far I can expose without saturating the stars.

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Re: STT-8300 First light report new [Re: Hilmi]
      #5829785 - 04/29/13 10:00 AM Attachment (21 downloads)

Yes, I am not sure the numbers I am getting are correct. For me the bottom line is what the images look like. So what I am doing is running two sets of images the same night using M101 as a target: One long and the other short. I plan to process them the same way and see what I get.

I think I am going to check with SBIG to see if my math is correct and about the technical details of the camera.

Finally, I know Hilmi has said he is tired of hearing about complaints about light polution when he has to deal with sand storms, but here is an image of what I am dealing with. There was no moon when this was taken.


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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5829802 - 04/29/13 10:07 AM

Looks better than what I get. Think of it this way, the skill you get from such conditions would make you amazing in a dark sky setting

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Re: STT-8300 First light report new [Re: Hilmi]
      #5829927 - 04/29/13 11:07 AM

i wonder if your reducer spacing is right. is it normal to have such strong vignetting with the C8 and celestron reducer?

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Re: STT-8300 First light report new [Re: pfile]
      #5830124 - 04/29/13 12:56 PM

Quote:

i wonder if your reducer spacing is right. is it normal to have such strong vignetting with the C8 and celestron reducer?




I am afraid that is what you get. We also get flares at times from stars in the periphery. I guess eventually a new scope is the solution...

If I take off the reducer the FOV gets small, makes guiding harder and the f goes up to 10.0.....

Any ideas if my calculations above are OK?

I asked the guys at SBIG for a sanity check and they pretty mcuh said I should expose to the max... 600s is fine as long as the center of the object is not blown out.

Edited by jerryyyyy (04/29/13 01:08 PM)


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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5830180 - 04/29/13 01:14 PM

I played around with those exposure calculators but what they told me to do did not match my experience.

For some reason the subject of how long to shoot each frame seems to come up a lot and cause people a lot of worry.

When I got my ST-2000XM I took some pictures at various exposures varying from about 3min to about 5 or 6min. I found that for what I was shooting going longer than 5 or 6min didn't seem to help much, so I stuck with that. At least that's what I tell myself. Probably what happened was that I found nothing really wrong with going for 5min and it's a convenient amount of time, and I took a lot of 5min darks so I just lazily stuck with it.

Later I found three articles about calculating "optimal" subexposure times.

The first is the one that most of the calculators on the web are based on:

http://www.hiddenloft.com/notes/SubExposures.pdf

The second is this one by Craig Stark:

http://www.cloudynights.com/item.php?item_id=1973

The third is this much more complicated one by Charles Anstey:

http://www.cloudynights.com/item.php?item_id=1622

Note that the last two both point to doing longer exposures to improve the SNR of the object that you are trying to capture.

The general rule is to get some reasonable amount of signal in each frame and then shoot as many frames as you can. Each frame you stack averages out the noise a bit more. This is the real reason to use image stacking, btw. It's not so much to get more signal. It's more to average out the noise so you can see the signal better.

The idea behind the Smith paper is that under the assumption that sky noise and read noise are the dominant contributors to what you are putting on the CCD, taking exposures that are longer than it takes for to capture a lot of sky noise is pointless. The later two papers add more possible tradeoffs.

But, the easiest thing to do is to just try a few different exposures and see where you get to diminishing returns and then just go with that.


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Re: STT-8300 First light report new [Re: psu_13]
      #5833430 - 04/30/13 11:07 PM Attachment (23 downloads)

For no good reason, except to liven up this thread, here is my first narrow band with the STT-8300M.

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Hilmi
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Reged: 03/07/10

Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: jerryyyyy]
      #5835623 - 05/02/13 03:14 AM

My STT-8300 just got bricked. It powers on, windows sees it as connected, but it does nothing. You can't connect to it in software. I tried on two computers. Also, just to check if it was a USB problem, I checked the Ethernet connection. It is dead. Ethernet should work regardless of software issues as it has a built in web server that runs it all.

I suspect corrupt firmware, and anything could have caused it, from static electricity to high levels of humidity in the air messing with the electronics. I don't really think this is an indication of any QC issue. But just because it's not a QC issue, doesn't make me a happy man. I now have to ship a very heavy camera at a high cost to the US for repair

I wonder if there is something that can be done at home, such as some software that allows you to flash the new firmware even if the camera is bricked.


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Chuck Faranda
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Re: STT-8300 First light report new [Re: Hilmi]
      #5835689 - 05/02/13 06:40 AM

Did you update to the the new drivers that were issued yesterday? I heard others had some issues with a version released over the weekend.

The instruction from Jan at SBIG was to install the new CCDOPS or installer app too (to make sure all the files make it to your computer).


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Hilmi
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Re: STT-8300 First light report new [Re: Chuck Faranda]
      #5835784 - 05/02/13 08:25 AM

Done all that, but it should not affect ethernet connection, even that doesn't work. All the steps recommended by SBIG didn't help. I think it is just a coincidence that the problem happened the same time that the driver issue showed up.

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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Hilmi]
      #5836839 - 05/02/13 05:48 PM

Hilmi, can you call them over Skype or something? David has been very helpful with me troubleshooting... when I started out would have the cell phone at the scope I had so much trouble with the drivers.

Sorry to hear. Mine is finally working up to expectations, so there is hope.

Edited by jerryyyyy (05/04/13 08:33 PM)


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MattThomas
Vendor (SBIG)


Reged: 07/28/06

Re: STT-8300 First light report new [Re: Hilmi]
      #5836856 - 05/02/13 05:56 PM

Hilmi,

Contact us directly. We may be able to give you something that can help resolve this.

Thanks,


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theskyhound
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Re: STT-8300 First light report new [Re: Hilmi]
      #5843370 - 05/06/13 11:53 AM

Quote:

I was trying to figure this out too, I am going to a dark sky location at high altitude in a few days time. I put the details of the location I was going to in Skytools 3 and it keeps on telling me the optimal exposure is 1 minute long, this doesn't sound right to me. I would barely be able to capture any data with 1 minute exposures even from a dark site.




Hi,

It is important to make sure you have everything set up properly in SkyTools, particularly your level of light pollution.

Remember that you are supposed to be stacking the images, so it doesn't matter what each individual image looks like. What matters is the end result. That said, the estimated optimum sub exposure time for your optical system + conditions is probably not a critical factor in your particular case. The algorithm finds the mathematical "optimum" time but it doesn't currently say anything about how relevant it is. It may well be that it makes no practical difference if it is one minute, or ten. In that case you should use whatever sub exposure time is most practical. So how do you know if the sub exposure time is relevant? Use the Exposure Calculator! The Exposure Calculator is a very powerful tool for investigating just this sort of thing. It is not designed to give simple one-line answers. It is designed as a tool of exploration. To find out if the sub exposure time matters, select a target and night and then vary the sub exposure time. Compare the estimates of the final SNR of the stacked images. If there is very little difference in SNR, then the the sub exposure isn't critical. So use whatever works best from a practical standpoint. Always remember, if the target or observing conditions change, then the result may change as well. There is no universal answer, which is why the Exposure Calculator is so useful. I suggest using this tool to investigate how your optical system works with different kinds of targets under different amounts of sky brightness. You may be surprised how moonlight does not affect your results, or how important the altitude of the object is, etc.

Clear skies,
Greg

P.S. People should consider bringing this sort of questions directly to me, or posting them to the SkyTools group. I don't always see the posts here, and it may take me some time to notice.


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Hilmi
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Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: theskyhound]
      #5928632 - 06/19/13 02:50 AM

I am glad to report that within 2 days of SBIG receiving my Camera, they had repaired it. I was right in that it was a corrupt firmware. Bill also informed me that they had updated my camera with all the Engineering Change Orders that had come out since the camera was released. Mine apparently needed a lot of them since it was one of the early builds of the camera. One of the changes specifically addresses the corrupt firmware issue. This means that new buyers of the camera should not face the same problem I did.

I am looking forward to getting my camera back.


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Madratter
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Reged: 01/14/13

Re: STT-8300 First light report new [Re: Hilmi]
      #5928877 - 06/19/13 09:55 AM

Excellent.

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WesC
Carpal Tunnel
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Reged: 02/06/13

Loc: La Crescenta, CA
Re: STT-8300 First light report new [Re: Madratter]
      #5933404 - 06/21/13 05:40 PM

Great service! But sorry you had to deal with these technical issues.

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pfile
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Reged: 06/14/09

Re: STT-8300 First light report new [Re: WesC]
      #5934548 - 06/22/13 12:31 PM

hmm, i should contact them. the other night i turned off the fans and i think the cooler power went so high that the camera reset itself. also i seem to be having some filter wheel problems from time to time but i'm not completely sure. what i see in the flats does not make sense to me (strong square vignetting, sometimes)

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Hilmi
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Loc: Muscat, Sultanate of Oman
Re: STT-8300 First light report new [Re: pfile]
      #5934723 - 06/22/13 02:32 PM

The manual clearly says to never switch of the fans if you are not using water cooling.

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pfile
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Reged: 06/14/09

Re: STT-8300 First light report new [Re: Hilmi]
      #5934832 - 06/22/13 03:39 PM

interesting. i missed that in the manual. the ambient was pretty low.

still, it's not right for the thing to go into a brownout condition. the power supply i am using can supply a ridiculous amount of current so i don't think that's the culprit. fans on or off, if Tamb is high enough the camera will end up in the same condition.


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Hilmi
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Re: STT-8300 First light report new [Re: pfile]
      #5935640 - 06/23/13 12:39 AM

I think the issue is that without any mechanism to carry the heat away from the camera body, the temperatures rise to maybe 30 degrees above ambient in the enclosure (depending on your cooler set point). This would be far higher than normal operating temperatures for most electronics if I was to do this in Oman.

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jerryyyyy
Pooh-Bah


Reged: 10/06/11

Loc: Stanford, California
Re: STT-8300 First light report new [Re: Hilmi]
      #5936870 - 06/23/13 06:21 PM

I was not aware you could even turn the fans off. I would not want to try that...

Glad to hear you are up and running Hilmi. Was able to finally get some good images processed with pfile's help:



I am sure you will do well once you are back togather.

BTW, I will visit Qatar again in October. I have heard they have an observatory.


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Hilmi
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Re: STT-8300 First light report new [Re: jerryyyyy]
      #5937354 - 06/24/13 12:33 AM

I'm still not up and running, my camera is still not with me, as they had asked for shipping address confirmation just before the weekend. Seems to me like they had not shipped it out yet.

If your time frame allows it, you can always come to Oman, Visas are easy to come by depending on your nationality. I could arrange a trip to a dark site at high altitude away from the heat


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Eric Gage
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Re: STT-8300 First light report new [Re: Hilmi]
      #6086208 - 09/17/13 03:09 PM

Did anyone find a good solution for taking flats with the STT cameras yet?

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pfile
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Re: STT-8300 First light report new [Re: Eric Gage]
      #6086333 - 09/17/13 04:30 PM

i have not had a problem as long as the exposure times can be kept > 1 second. less than that and i had some shutter artifacts.

also i think the dessicant must have gotten full at some point. i started getting really weird "old TV" (curved) borders in my flats. i baked the dessicant and the problem went away, so i assume i had some frost starting up.

i have the window heater on, but i think initially it must be overwhelmed - it seemed like the longer the camera was running the less pronounced the frost artifact would be.


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