Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Electronically Assisted Astronomy

Pages: 1 | 2 | 3 | 4 | (show all)
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: Dwight J]
      #5685693 - 02/17/13 06:25 PM

He gets a lot out of his setup but with my lack of processing skill (read none) and my lack of time (you could insert laziness also) I will have to stick with my mallincams. I willhave to admitt that mpgxsvcd has me looking real hard at a GH3 later this year.

Post Extras: Print Post   Remind Me!   Notify Moderator  
norden
sage


Reged: 09/08/08

Loc: Norden
Re: Which camera? new [Re: Dwight J]
      #5687068 - 02/18/13 02:49 PM

Thanks friends for all your answers and thoughts! I've come a long way in my decision. It will be a Mallincam VSS. I think more exposure range is an advantage against hyper plus. The question now is which sensor to select? Exview HAD CCD sensor seems to be a sensor for me. Short exposures with my ALT/AZ mount. Are there any of you who use this sensor and have experience with it. Please let me know.

Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Which camera? new [Re: norden]
      #5687279 - 02/18/13 04:37 PM

Norden,
My camera has the EXview HAD sensor, or some variant; I can't remember the details. To see what it can do with 30-56 second exposures on a C8 with f/3.3 focal reducer, go to page 86 of the image gallery at the top of this forum.

You should contact Rock Mallin for advice on the best CCD to have installed.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: norden]
      #5687298 - 02/18/13 04:52 PM

I would opt for the class 0 chip whichever flavor I chose. I am not wanting to start a war but the class 0 chip (however Rock measures it) does have less hot pixels that the standard chip. I have one of each and the "star" fields of the closs 0 chip is much closer to reality. When doing 50 seconds at half gain the standard chip I have shows about 25 or so nice round tight stars more than the class 0 chip. For a lot (most) objects it won't make a difference but it just bugs me for some reason

Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Which camera? new [Re: Stew57]
      #5687688 - 02/18/13 08:08 PM

My chip is a class 0, and has one hot, three moderately hot, and about three dozen warm pixels.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: GlennLeDrew]
      #5687950 - 02/18/13 10:21 PM

How long an integration do you have to do at middle gain setting for the warm pixels show?

Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Which camera? new [Re: Stew57]
      #5687990 - 02/18/13 10:43 PM

I can't recall to any exactitude, as I didn't test for this, but it requires something like 10(?) seconds at mid-gain for those warm pixels to show up. I'll have to look into this...

Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: GlennLeDrew]
      #5688037 - 02/18/13 11:10 PM

My VSS class 1 has a constellation of stars I can count on at 20 seconds with low gain, no matter where I point the scope.

Post Extras: Print Post   Remind Me!   Notify Moderator  
mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Which camera? new [Re: Stew57]
      #5688099 - 02/18/13 11:59 PM

Quote:

My VSS class 1 has a constellation of stars I can count on at 20 seconds with low gain, no matter where I point the scope.



is it changing with ambient temperature ?


Post Extras: Print Post   Remind Me!   Notify Moderator  
GlennLeDrew
Postmaster
*****

Reged: 06/18/08

Loc: Ottawa, Ontario, Canada
Re: Which camera? [Re: mattflastro]
      #5688260 - 02/19/13 03:05 AM

As to any change in the warm/hot pixels with ambient temperature, I haven't looked for such a relationship.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: GlennLeDrew]
      #5688400 - 02/19/13 07:29 AM

My temps are fairly stable through the night normally. They are usually a little on the warmside however. I never tried to test the difference. I really notice the sudden appearence of the particular constellation my class 1 vss shows when the integration is increased past about 12 seconds.

Post Extras: Print Post   Remind Me!   Notify Moderator  
ccs_hello
Postmaster
*****

Reged: 07/03/04

Re: Which camera? new [Re: Stew57]
      #5688449 - 02/19/13 08:16 AM

RE: class 0, 1, 2 CCD sensor "binning" (means grade selection)

1. it is sensor technology dependent
2. there is no common industry-wide standard, different image sensor mfgs play their own. Some are consistent being applied over the years, and some ...
3. some imaging device vendors do a fairly good job on classifying "their own" made, but their is no industry-wide standard
4. Also note that with imaging device in the loop, the observed picture/pixel defects may not reflect the actual sensor quality (e.g., by dead pixel masking),
5. about individual feedback: take it as a grain or salt, since the test/observation is not under a normalized/standard test condition

some info:
- it is image sensor temperature dependent (also active and passive cooling)
- it is time dependent (more than just the temperature factor)
- it is image system gain, post-processing "dosage" dependent
- it needs to be qualified by a scientific method (one man's "hot" may mean another's "warm" pixel

Users of course can state their own observations (more info would be even nicer), I am just stating the caveats.

Now back to our regular scheduled program...


Post Extras: Print Post   Remind Me!   Notify Moderator  
mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Which camera? new [Re: Stew57]
      #5688592 - 02/19/13 10:03 AM

Quote:

He gets a lot out of his setup but with my lack of processing skill (read none) and my lack of time (you could insert laziness also) I will have to stick with my mallincams. I will have to admit that mpgxsvcd has me looking real hard at a GH3 later this year.




My intent is not to sway anyone towards any one camera. They all have their strengths and weaknesses. I am in fact very interested in finding out more about the Mallincam. I think it is a great device. However, I am also skeptical about these Hickson 50 pictures with the Mallincam.

I am not skeptical that they are able to see that object with the Mallincam. I believe them that it can be done. However, I don't believe it is solely because the Mallincam is more sensitive.

The fact still remains that at some point adding more sensitivity will just make the light pollution and sky glow dominate the image. The Mallincam or the users are doing something with software or hardware that eliminates the sky glow effect. There simply is no way around it. You can't see a Mag 20 object in Mag 3 skies without removing the sky glow.

Now the real question is what are they doing? I tried to get the Hickson 50 the other night. However, the sky conditions were not good as we had clouds rolling in. I tried to take images in-between clouds and I could see all of the brighter stars around that area but not the Hickson group.

I was blowing out the sky in 23 seconds with my F4.0 scope and the strongest Light Pollution filter I could find. However, that was while taking RAW images. I tried taking an HDR image and I was able to extend the exposure time to 60 seconds at the same ISO value(ISO 6400) without blowing out the sky.

Basically with HDR I am using a 20 second base exposure and then combining it with a 60 second exposure for the really dark areas and using a 5 second exposure to keep the bright stars under control. I also fine tune the contrast so that it clips the light pollution but not the signal.

Basically when you stack images if you can get the sky glow to be under the lowest black point then summing or averaging zero plus zero will still be zero. As long as the signal you want registers more than zero then it will increase its exposure as you stack more and more images and the sky glow will still be at zero if it is clipped.

The big issue is getting the signal you want to be above the sky glow in very light polluted areas. I am able to reduce the sky glow by 1-2 stops with the light pollution filter and get another 1-2 stops with the HDR and contrast techniques. However, that is no where near enough to get from Mag 3 to Mag 20.

I really want to test out the Mallincam again now that we figured out the settings. I would like to see what it does on the exact same scope as another camera. Changing anything in the optical chain is not a fair comparison. Even my 3rd grade son knows that from doing science projects.

They have been testing the micro four thirds sensors lately at DXO mark. Now these tests are not the end all be all of testing because they only test the sensors themselves and they also neglect some things that I think are necessary. However, it is still interesting to note that All of the newest m4/3s cameras score higher than ALL of the Canon APS-C cameras including the T2i and the 7D. M4/3s still trails the Sony cameras and Nikon D7000 but it definitely shows that Canon APS-C cameras should not be used as the benchmark anymore.

http://www.dxomark.com/index.php/en%C3%83%C2%AF%C3%85%E2%80%B9%C3%A2%E2%82%AC...

If you want to try out m4/3s but you don't want to fork out $1300 for the GH3 then the new Olympus EPM-2 is an outstanding deal at $499 for the body only. This camera has the same sensor as the more expensive cameras and it also retains the live bulb mode feature that mimics the sense-up screen refresh of the Mallincam. It also goes for at least 8 minutes in bulb mode which should be plenty for near real time live viewing.


Post Extras: Print Post   Remind Me!   Notify Moderator  
mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Which camera? new [Re: A. Viegas]
      #5688621 - 02/19/13 10:31 AM

Quote:

Hickson 50 - on the Mallincam Website: Hickson 50

as the caption describes, SCT 10" 15 seconds. no processing whatsoever.

And here is another image, from this forum using 10" Newtonian and 56sec exposure, but under a full moon: Hickson50 under full moon

So... lets see the lodestar with same factors, 15 seconds and 56 seconds, no processing or tweaking.



Al




I doubt that post processing would help enough to get that image. The only thing that could help is doing something in camera. What that is I don't know. However, I don't believe that simply getting a more sensitive camera will allow you to see a Mag 20 object under a full moon. There is something being done to remove the sky glow.


Post Extras: Print Post   Remind Me!   Notify Moderator  
mattflastro
Vendor - Astrovideo Systems


Reged: 07/31/09

Loc: Brevard County , FL
Re: Which camera? new [Re: mpgxsvcd]
      #5688694 - 02/19/13 11:22 AM

Quote:

Quote:

Hickson 50 - on the Mallincam Website: Hickson 50

as the caption describes, SCT 10" 15 seconds. no processing whatsoever.

And here is another image, from this forum using 10" Newtonian and 56sec exposure, but under a full moon: Hickson50 under full moon

So... lets see the lodestar with same factors, 15 seconds and 56 seconds, no processing or tweaking.



Al




I doubt that post processing would help enough to get that image. The only thing that could help is doing something in camera. What that is I don't know. However, I don't believe that simply getting a more sensitive camera will allow you to see a Mag 20 object under a full moon. There is something being done to remove the sky glow.



Have you taken any darks (of equal duration with the exposure you tried) with your camera? Just to make sure what stops you is really _sky_ glow and not amp glow or some in-camera noise reduction that can't be switched off even if you switched off noise reduction ? I have one of my cameras totally unusable for astro due to such a feature, noise reduction off is not actually off .


Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: Which camera? new [Re: mattflastro]
      #5688732 - 02/19/13 11:49 AM

My comparison on hot pixels is between my class 1 vss and class0 xtreme used at the same time and settings. I do not know if the peltier cooling gives the same chip temps or not though. The vss shows a significantly larger amount of hot pixels. They are my best look8ng stars even at long integrations unguided.

Post Extras: Print Post   Remind Me!   Notify Moderator  
mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Which camera? new [Re: mattflastro]
      #5688790 - 02/19/13 12:19 PM

Quote:


Have you taken any darks (of equal duration with the exposure you tried) with your camera? Just to make sure what stops you is really _sky_ glow and not amp glow or some in-camera noise reduction that can't be switched off even if you switched off noise reduction ? I have one of my cameras totally unusable for astro due to such a feature, noise reduction off is not actually off .




That is a good point. Yes I have taken the darks and they don't show any unusual signs of amp glow. However, I am not entirely sure what amp glow looks like? Can you demonstrate it or define it?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dwight J
scholastic sledgehammer
*****

Reged: 05/14/09

Loc: Lethbridge, Alberta, Canada
Re: Which camera? new [Re: mpgxsvcd]
      #5688891 - 02/19/13 01:07 PM

Travis: part or perhaps most of the reason you are reaching the sky fog limit sooner than a Mallincam is due to the actual size of the sensor. The same effect is seen when comparing low magnification to high, fast focal length to slow. When you "see" more sky you lose contrast. Your camera has a chip several times the size of the Mallincam so you "see" more sky. Just outside of the city (pop 90,000) I saw light pollutiion in a 20 sec exp using a normal lens and iso 6400. At the same site I saw sky fog affecting a 3 min exp @ F5 and iso 800. A deepsky filter was used for the last two. In my backyard within the city I can go 112 sec with my VSS and deepsky filter and have plenty of room for adjustment. Keep in mind that brightness and contrast can be adjusted on the fly, something nonvideo cameras can't do.

Post Extras: Print Post   Remind Me!   Notify Moderator  
nytecam
Postmaster


Reged: 08/20/05

Loc: London UK
Re: Which camera? new [Re: mpgxsvcd]
      #5688894 - 02/19/13 01:08 PM Attachment (10 downloads)

No bostin' but another routine and deeper Hickson 50 Lodestar shot from the other night with gxys between mag 15.95[A] to mag 18.45[E] according to Sloan DSS. A short dozen of other field gxys of similar mags marked with horizontal ticks, again identified via Sloan DSS - I'm very happy so enjoy

Post Extras: Print Post   Remind Me!   Notify Moderator  
mpgxsvcd
Carpal Tunnel


Reged: 12/21/11

Loc: Raleigh, North Carolina
Re: Which camera? new [Re: Dwight J]
      #5688998 - 02/19/13 02:25 PM

Quote:

Travis: part or perhaps most of the reason you are reaching the sky fog limit sooner than a Mallincam is due to the actual size of the sensor. The same effect is seen when comparing low magnification to high, fast focal length to slow. When you "see" more sky you lose contrast. Your camera has a chip several times the size of the Mallincam so you "see" more sky. Just outside of the city (pop 90,000) I saw light pollutiion in a 20 sec exp using a normal lens and iso 6400. At the same site I saw sky fog affecting a 3 min exp @ F5 and iso 800. A deepsky filter was used for the last two. In my backyard within the city I can go 112 sec with my VSS and deepsky filter and have plenty of room for adjustment. Keep in mind that brightness and contrast can be adjusted on the fly, something nonvideo cameras can't do.




A couple of things. I see what you are saying about focal length. I hope to test Tony's Mallincam and my GH3 on his 14" SCT when he gets it this week. At 2800+mm that should be a long enough focal length.

A couple of things you said are incorrect though. My camera has a cropped sensor mode. It can literally use the the center 1920x1080 pixels which gives it almost the exact same sensor size with a Different aspect ratio as the Mallincam's sensor. That does not eliminate sky glow though.


In addition the GH3 and Olympus cameras allow contrast and individual white balance adjustments and exposure adjustments on the fly while using the live view. I fail to see the difference between this and what the Mallincam can do.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | (show all)


Extra information
6 registered and 7 anonymous users are browsing this forum.

Moderator:  David Pavlich, JayinUT 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 3387

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics