Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

The Imaging Source cameras and misc questions. Help appreciated.

  • Please log in to reply
21 replies to this topic

#1 Lunatiki

Lunatiki

    Vanguard

  • *****
  • topic starter
  • Posts: 2367
  • Joined: 07 Aug 2005
  • Loc: Amarillo, TX

Posted 10 July 2019 - 12:00 AM

Greetings, as mentioned, I'm going to start imaging again. My last camera was an Imaging Source DBK2104.AS. I loved the camera and the IC capture software. I just looked at their website and see they are still doing color cameras but no longer carry the DBK and just DFK on color and DMK for mono. Any opinions on these cameras? Can anyone recommend another camera? Must be color. I always got just as good of shots using a color camera and not messing with R G and B filters. I know many disagree and I understand. There were no prices listed on the DFK's, anyone have an idea? I'm going to call them tomorrow, but I'd like to know tonight if possible.  I'm thinking about my capturing and processing and her is my plan, please correct any mistake I'm making.

 

IC capture and the DFK camera

Autostakk3 to process my avi

Registax to do the wavelets.

PSP or PS for more post processing.

 

Another question is and I think I'll have all of them answered. I saw someone said they had a 10 minute video of Jupiter? How is that possible without rotation blur? The norm on stacking frames use to be 800 - 1200, give or take a few hundred.  What is the normal amount of frames a person shoots now and stacks? Thanks to all who take the time to help me get back in the saddle on this.

 

Regards,
Joel

 


  • Mike Phillips likes this

#2 Lacaille

Lacaille

    Viking 1

  • -----
  • Posts: 774
  • Joined: 27 Nov 2015
  • Loc: Canberra and Strasbourg

Posted 10 July 2019 - 02:03 AM

Hi Joel,

A lot of us are using ZWO224MC colour cameras and find them excellent, using Firecapture free software to capture videos. They are not very expensive. Use a barlow to achieve something like f20 for good imaging with this camera. Use a luminance filter or IR cut filter to improve colour balance for this camera as it is highly sensitive in the IR. Get a Zwo ADC for imaging at low altitudes.

You can capture long videos and derotate them in WinJUPOS freeware, but a better strategy is to capture shorter videos. Autostakkert will do a great job of stacking for videos of 3 mins (Jupiter) and 6 mins (Saturn). The fast frame rate of the camera, particularly if you have USB 3 in your laptop, will give you thousands of frames to play with. The proportion stacked varies but typically I would stack several thousand for Jupiter. My rule of thumb is to stack all images that are better than 50% quality as measured in Autostakkert.

Create a sharpened image from each video in Autostakkert and Registax then, if you like, synthesise these images into one better quality image, again in WinJUPOS. In the process this will fix any field rotation issues between successive images.

There are excellent youtube tutorials by WWGweb(google "planetary imaging") and Christophe Pellier and Kokatha Man have great websites for skill development.

Keep posting here for advice and support!

Regards

Mark

Edited by Lacaille, 10 July 2019 - 02:04 AM.

  • eros312, RedLionNJ and KiwiRay like this

#3 Kokatha man

Kokatha man

    Voyager 1

  • *****
  • Posts: 12838
  • Joined: 13 Sep 2009
  • Loc: "cooker-ta man" downunda...

Posted 10 July 2019 - 02:49 AM

I remember you Joel. wink.gif

 

Honest, matter-of-fact advice..? Forget IC Capture & IS cameras for starters - as mentioned the ASI224MC or the ASI290MC are excellent (read really excellent) modern cmos cameras with very low noise & excellent frame-rates, these days you would stack thousands of frames whenever possible & derotate numerous stacks (relatively consecutive) to achieve better SNR as long as they are of roughly equal clarity...as one who normally only uses a colour camera when intermittent clouds are a problem you can see a series of recent results from the 224MC at the top of this page on our website: http://momilika.net/...ter2019Pics.htm  

 

I have an old WinJupos tute that is still absolutely relevant (needs a rewrite) but I need a proper email address for that as it is too large to just PM...

 

As Mark has mentioned FireCapture & AS!3 (both freeware) are the capture & stacking programs of choice for most hi-res imagers, with good old Registax6 still providing excellent wavelet sharpening functions along with other old post-processing programs...check out the tutorials on our website http://momilika.net/...ssing_Tutes.htm  for some insights into AS!3 etc although other links to FireCapture will assist you there. wink.gif


  • eros312 likes this

#4 Lunatiki

Lunatiki

    Vanguard

  • *****
  • topic starter
  • Posts: 2367
  • Joined: 07 Aug 2005
  • Loc: Amarillo, TX

Posted 10 July 2019 - 03:24 AM

Thanks KM, man, those are some killer shots of Jupiter you have in that thread. Color camera results that great, stacking thousands of frames, de-rotating......... Feel like I've been asleep for 50 years. I'll have to read up on FireCapture. Already read up on AS!13. I'll certainly be taking your advice. Would you recommend a particular place to get the 224MC? Again, killer work man, great job and thank you for taking the time to help me.

 

Regards,

Joel



#5 Kokatha man

Kokatha man

    Voyager 1

  • *****
  • Posts: 12838
  • Joined: 13 Sep 2009
  • Loc: "cooker-ta man" downunda...

Posted 10 July 2019 - 06:12 AM

Hi again Joel - I'd suggest straight from Sam at ZWO in China, they're pretty prompt & they might have a special on that model atm...but there might also be one of your US retailers offering a good deal.

 

Keep in mind that there is the ASI290MC which has smaller pixels in the sensor, meaning greater image scale for the same barlow magnification...the 224MC & 290MC are probably about line-ball but I have a very special spot for the 224MC personally - most of this year we have been blighted by cloudy weather despite good elevation in South Oz & nearly all our Jovian images you see on that 2019 webpage were captured with the ASI224MC: conversely, nearly all the Mars 2018 images where we were picking up fantastic detail despite the near-global dust storm http://momilika.net/...ars2018Pics.htm were taken with the mono equivalent of the ASI290MC, the ASI290MM.

 

You'll have Mars at good elevation next year I believe, & either the 224MC or 290MC will serve you well! wink.gif


  • RedLionNJ likes this

#6 RedLionNJ

RedLionNJ

    Soyuz

  • *****
  • Posts: 3667
  • Joined: 29 Dec 2009
  • Loc: Red Lion, NJ, USA

Posted 10 July 2019 - 10:21 AM

+1 on everything Mark and Darryl said here :)

 

And don't forget that ADC, even from Texas!



#7 Lunatiki

Lunatiki

    Vanguard

  • *****
  • topic starter
  • Posts: 2367
  • Joined: 07 Aug 2005
  • Loc: Amarillo, TX

Posted 10 July 2019 - 03:13 PM

Thanks guys, so the ASI224MC shoots at 150 fps? is that right????


  • Mike Phillips likes this

#8 Tom Glenn

Tom Glenn

    Surveyor 1

  • -----
  • Posts: 1904
  • Joined: 07 Feb 2018
  • Loc: San Diego, CA

Posted 10 July 2019 - 03:31 PM

Thanks guys, so the ASI224MC shoots at 150 fps? is that right????

It does up to 150fps if using the full sensor, which you rarely would do for planets.  With a smaller ROI, you can easily exceed 200 fps, with the actual limit usually being imposed by the exposure itself (so as to avoid overly high gain).  200 fps on Jupiter is totally doable, as is 100 fps on Saturn, although you really don't need to go so fast for good results.  Mars at opposition is so bright that you can easily exceed 300 fps if desired.  



#9 Kokatha man

Kokatha man

    Voyager 1

  • *****
  • Posts: 12838
  • Joined: 13 Sep 2009
  • Loc: "cooker-ta man" downunda...

Posted 10 July 2019 - 09:13 PM

Joel, using FireCapture creates a ".txt" file for each & every capture you take: I've joined 2 together here & marked them to make a couple of useful points for you & others... wink.gif Some of this info needs to be enabled when opening FC for the first time incidentally. wink.gif

 

From top to bottom the following: apologies if there are inconsistencies - putting this together is rather onerous! (I'll use it on our website later possibly, revised! wink.gif )

 

"Camera" - FC acknowledges the camera you are using. (if you do decide upon an ASI224MC!)

 

"Filter" is the one you have employed. In this case an "L" filter, or iR/uV cut unit...I have a couple of these but the one used here might well be the one I originally used in my old DBK21AU back in ancient times..! lol.gif

 

"Focal Length" - FC also appraises the f/l you employ via whatever your scope & the imaging train it employs comprises of...this is only accurate when the planet is sitting absolutely horizontal in the sensor with a nice, clear & sharply-focused image, such that FC can measure the diameter correctly - not terribly important when WinJUPOS etc can make an accurate measurement later.

 

"Mid" - The UT mid-point of each capture taken (as well as the (UT) "Date" above this) - important when annotating images forwarded to various organisations as well as just knowing this info yourself to determine C.M.& planetary feature positions etc  - vital also when derotating several capture stacks in WinJUPOS!

 

"Duration" is the timespan you have set for each recording.

 

I've put double red bars for a couple of the info notes - you can see that 6,000-odd frames more were collected in the right-hand .txt file: this brings me to an important point not mentioned as yet...the capability of your capture laptop. A usb3 port & cable connection is needed for the faster fps chosen. (&/or the very large ROI's, these cameras have a usb3 port on them)

 

"Frames captured" Self-explanatory, however, the discrepancy in between the 2 .txt files is something relatively frequent in laptops & modern cameras ( for a few reasons I won't go into here) such that if you cannot achieve the fps you think you should have (more later in this post on that...) shutting down FC & your computer & restarting will often "kick" things into line..! lol.gif This is what happened here although the usb traffic setting was also altered here.

 

"File type" selected here is 8bit avi - despite what anyone will try to tell people, an 8bit avi (256 shades) will deliver as much dynamic range (colour tonal variation) as possibly needed for planetary imaging.

 

ROI is whatever you select from the FC control options: you can use anything from the full sensor size (1304x976 pixels from memory) down to whatever is deemed sufficient. There are a selection of "default" sizes as well as the fact that you can actually "draw" your own around the planet using your laptop mouse to get the size you desire - making sure you then "centre" this ROI wrt the full dimensions of the sensor so that you are actually imaging as on-axis as you possibly can - which is of course where you would have collimated on! wink.gif Note that the ROI's "Height" dictates the maximum frame-rate achievable!

 

"Shutter" in milliseconds is what some might term "exposure" which is exactly what FC calls it in the control panel!!! rofl2.gif

 

It is not termed "exposure" in the .txt files perhaps because of the confusion that could create with the histogram, which many relate to as an assessment of exposure. The shutter speed dictates the frame-rate (fps) but it only does this if the "height" of any ROI selected will allow it...as noted above, every ROI height has an fps limit...the width of an ROI does not affect the fps & is useful for including planetary moons in a wider fov, although of course wider ROI's mean your file-sizes will increase!

 

A "Shutter" speed of 10 milliseconds (10ms=1/100second) will provide 100fps.....similarly, 5ms (1/200second) will provide 200fps...4ms (1/250second) will provide 250fps - but only if the "ROI" height will allow it...& of course regardless of whether the shutter speed & ROI allow certain fps, you still have to be able to find enough "gain" to provide a sufficient histogram for the fps!

 

In the controls under the "Status" heading there are "max" &  "current" (or actual) frame-rate (fps) values displayed: the idea is to try & match both these values for any chosen ROI by altering the "exposure" slider setting so that there is parity or near parity between these 2 figures. (remembering that this "exposure" slider actually controls the shutter speed..!

 

"Gain" is what you set to achieve the histogram you wish to employ. This electronic amplification also affects the noise in the image frames...more gain, more noise, ameliorated by more frames in the stack-size you choose in AS!3: there are inter-dependencies between Shutter speed (exposure time) & Gain but for the purpose of this post the shutter controls fps & gain controls the histogram, or what we would normally call exposure - always under the ROI height proviso! wink.gif

 

"Wblue=95" & further down "Wred=50" are the recommended default settings to achieve correct "White Balance" on these cameras...ie, the correct "colour balance." These are in the drop-down from the little "More" tab in the control display.

 

"Highspeed=on" is the setting usually employed for 8bit RAW data in avi mode. This ensures that you are capturing your data at the maximum possible fps for any given ROI's height. (ref. "File type" above)...you normally capture as a mono-appearing image during capture & in playing back in WMP. (Windows Media Player) The "Preview" control allows you to also view the onscreen image as a colour image before you hit the "Capture" button, whereupon it turns mono for the capture duration...you can capture in colour but it creates much larger files when doing this. Programs such as AS!3 will automatically (or manually) interpret the Bayer colour matrix when loading the avi into them for sorting & stacking & turn this mono image into the correct colour appearance.

 

"Brightness" we usually set at "16" to eke out a little more light unless we are imaging in a bright sky whereupon it should be lowered to "0" to counter approaching or actual daylight.

 

"USBTraffic" - apologies for not double-barring the left hand specs but you can see that on the left it was "80" & on the right "40".....this causes a lot of folks a bit of a tizz but in an ideal world the lower settings ought to provide the best data flow down the usb3 conduit for capture acquisition: besides the restart I mentioned above, you might need to play with the "USBTraffic" setting as we have here to optimise your fps.

 

"Gamma" is similar to that used in the old DBK's etc, "linearity" or "1" being the default recording mode: this represents a value of "50" on the slider display & like with the old IS cameras you can alter it when focusing to assist you there with better contrast. For some reason Torsten reversed the contrasting function of this slider in later versions of FC so that to increase contrast the slider is advanced anywhere up to the maximum of "100" instead of the old method of lowering that figure's value...I have never asked him why he did that but have become used to it over time now!

 

A bit more on adjusting gamma & focusing, along with previewing the image in colour or mono. (black & white) Some people prefer to preview the onscreen image for focusing in colour, although others might find switching off colour in the controls & looking at the image in mono with altered gamma is more satisfactory - we like to alternate at times with these appearances for focusing although on a good night one should be able to focus quite effectively after a capture finishes & without resort to gamma adjustments. (& where the onscreen preview reverts to a colour image).

 

"Histogram" can be read to mean exposure in the general sense, as I hope I haven't made too muddy above wink.gif & this is how you determine how you wish to record any planetary capture as far as the histogram % you desire - fortunately these cameras are designed for very low light levels & the idea is to record with considerably lower histograms than one might normally think appropriate: we rarely capture at more than about 50-55% with the colour camera & for Mars with the mono we use a 40%-40%-45% regimen for the b-g-r captures...for Neptune & Uranus this drops down to about 35%!

 

FC displays a graph to show the histogram with a numerical readout also constantly throughout any single capture - you soon know if your corrector plate is fogging up with an SCT of clouds are drifting through..!.

 

"Limit = 165 seconds" is pretty self-explanatory...ie, how long you set the capture duration for.

 

It is important to note that there are NO default settings for FireCapture as such, which can fool some first-timers: FC will retain whatever settings you employ once you take your first capture. (even trial ones done indoors as I suggest as a worthwhile "first-use" operation further down in this post!

 

Also, a lot of the controls need to be enabled first-up as well, such as displaying the visual histogram etc...

 

The same applies to using mono cameras btw, FC will "remember" whatever settings you set but then it will be separate settings for each filter used, if that is how they are set -but of course if you alter them then it "remembers" the last set of settings you have enabled.

 

When you first open FireCapture there are other parameters to attend to in the "General" settings menu such as the type of processor your laptop has...perhaps enforcing aggressive RAM & the preview rate which we always set to "Max" or 60Hz.

 

Autoguide can also be enabled with these cameras (they have an a/guide port for connecting to your scope's mount) & the dynamic cut-out feature which creates an ROI around the planetary object to "track" it around the ROI, keeping it centred in the fov which many find useful.

 

Things have changed quite a bit since the DBK's 30fps & 640x480 window if I recall correctly..!

 

Another very appealing aspect of this camera is that it is very efficient in near-infra-red...not only can very good images be captured using the appropriate filters but it has proven itself very capable of picking up storm spots on Neptune: a few years back when, if I might be so cheeky as to call those who wouldn't deign to utilise a colour camera "The Mono Smug Set"  Pat & I were the only ones to capture all the storms at the time on Neptune, including <"one storm spot (which) had not been picked up in any images except those taken with large professional telescopes"> to quote a professional...

 

Or to quote from Christophe Pellier about this camera back in 2016 (& who provides excellent advice about the camera, amongst other valuable info) <"I'm beginning a series of articles dedicated to this little imaging bomb that is the ASI224MC camera from ZWO.">

 

A "little imaging bomb" - a fitting description imo! smile.gif

 

EDIT: you can of course plug the camera into your machine & aim it at any appropriate light source to experiment with & get a good handle on all the settings & controls well before you attempt to get out there under the night sky for "First Light"..!

 

This exercise will help you understand how to "turn on" some of the various features I mention here via the settings options. Usually you will need to drape a Kleenex tissue or thin cloth cover over the camera to limit how much light enters it to do these indoor trials, which include actually capturing short avi's  - remembering that when it comes time for the real "First Light" you will need to set them again for each planet - & btw FC will "remember" each planet's last set of settings, everytime you select a particular planet...using the last-used settings until you desire to alter these!

 

2FCtxtFiles.png


Edited by Kokatha man, 11 July 2019 - 08:09 AM.

  • eros312, roelb, KiwiRay and 3 others like this

#10 Kokatha man

Kokatha man

    Voyager 1

  • *****
  • Posts: 12838
  • Joined: 13 Sep 2009
  • Loc: "cooker-ta man" downunda...

Posted 11 July 2019 - 03:57 AM

ps: I've undertaken a pretty comprehensive edit of the last post (Post #9) to better reflect some of what I said earlier...still likely to be mistakes & other anomalies & of course still a lot left out - hopefully I will refine this & add screenshots for the version we'll put onto our website down the track! ;)



#11 Tulloch

Tulloch

    Messenger

  • -----
  • Posts: 487
  • Joined: 02 Mar 2019
  • Loc: Melbourne, Australia

Posted 11 July 2019 - 06:14 AM

Wow, there’s a lot more to set up an ASIxxx camera than I first thought! I knew there were a few settings to get right, but there’s a lot to consider. DSLRs are easy by comparison, just select a daylight white balance, choose 5x live view and set the effective iso and shutter speed to get a histogram max of around 50%. Of course there is a downside to this convenience, such as usb2 transfer speed fixed at 20 fps and higher sensor noise levels etc.

 

However if/when I upgrade (to probably a 224mc) I’ll definitely look up this post and set it up accordingly, thanks for posting your thoughts and advice on this matter.

 

Andrew.



#12 Kokatha man

Kokatha man

    Voyager 1

  • *****
  • Posts: 12838
  • Joined: 13 Sep 2009
  • Loc: "cooker-ta man" downunda...

Posted 11 July 2019 - 08:02 AM

:lol: I've just done another edit while I still can to (hopefully) amend (& improve) what I've said above...even though there is still much more! ;)

 

As I said above, I'll continue to rewrite this & add actual screenshots, although the finished article will be on our website amongst the tute pages. :)

 

Andrew, it might sound rather involved...but in practise it is considerably easier! ;)


  • Tulloch likes this

#13 Lunatiki

Lunatiki

    Vanguard

  • *****
  • topic starter
  • Posts: 2367
  • Joined: 07 Aug 2005
  • Loc: Amarillo, TX

Posted 11 July 2019 - 04:55 PM

Well guys, busy day. I got my NexDome ordered. One extra bay and a ventilation set/motor, 1 brand new HP laptop that will be dedicated solely to imaging, and my new  ZWO ASI 224 Color CMOS Telescope Camera is on the way already. HOPEFULLY I'll have the dome in a month or so. $650 shipping!!!!!! But it sure looks worth it. Now I just need to get the software installed on my new laptop, collimate the CPC 1100, clean it and hopefully I'll start having some luck.  Thank you all very, VERY much for your help and input.


  • gfstallin and Lacaille like this

#14 Lacaille

Lacaille

    Viking 1

  • -----
  • Posts: 774
  • Joined: 27 Nov 2015
  • Loc: Canberra and Strasbourg

Posted 11 July 2019 - 05:59 PM

Joel, while you are setting up your laptop make sure to install the ZWO camera driver from their website. Firecapture needs that to interact with the camera.

Andrew, once adjusted in FC those settings remain, and indeed FC remembers the settings by planet and by filter, so in practice you just end up adjusting gain and exposure to get your histogram right for a particular session. Very straightforward.
  • Pete Gorczynski and Tulloch like this

#15 Lunatiki

Lunatiki

    Vanguard

  • *****
  • topic starter
  • Posts: 2367
  • Joined: 07 Aug 2005
  • Loc: Amarillo, TX

Posted 11 July 2019 - 08:38 PM

Joel, while you are setting up your laptop make sure to install the ZWO camera driver from their website. Firecapture needs that to interact with the camera.

Andrew, once adjusted in FC those settings remain, and indeed FC remembers the settings by planet and by filter, so in practice you just end up adjusting gain and exposure to get your histogram right for a particular session. Very straightforward.

Thanks or the information, much appreciated!



#16 Tulloch

Tulloch

    Messenger

  • -----
  • Posts: 487
  • Joined: 02 Mar 2019
  • Loc: Melbourne, Australia

Posted 12 July 2019 - 12:02 AM

Hi again, something I read earlier but didn’t process at the time was your comment about the settings for “white balance” for these cameras.

 

"Wblue=95" & further down "Wred=50" are the recommended default settings to achieve correct "White Balance" on these cameras...ie, the correct "colour balance." These are in the drop-down from the little "More" tab in the control display.

 

My issue with my DSLR has always been to get the “correct” colour balance, I have always used “daylight” as the setting, which corresponds to a colour temperature of around 5200K, which slightly reduces the amount of blue in the raw images. As a result, I reckon my final images are always slightly more yellow than the other images posted here. 

 

Do you have any idea what the effective colour temperature of your ASIxxx sensors is when using the settings above? 

 

Thanks, Andrew



#17 clarnibass

clarnibass

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 20 Jul 2018

Posted 16 July 2019 - 06:04 AM

I'm in pretty much the same position and considering a ZWO camera for planetary. Since Kokatha man and others seem very knowledgeable and it's related, I hope you don't mind adding my question here.

 

Some recommended cameras for planets (let's say mostly Jupiter and Saturn) are ASI178, ASI290, ASI224 and ASI385 (the MC colour versions). I'm trying to understand what the actual difference would be between them in actual use and result? I can't seem to find layman answer to that.

 

FWIW my telescope is SCT 8" 2030mm ACF.

 

Thanks



#18 George Bailey

George Bailey

    Viking 1

  • -----
  • Posts: 876
  • Joined: 10 Aug 2008
  • Loc: Iowa

Posted 16 July 2019 - 07:19 AM

For one thing, you need to choose a camera that matches your scope system f:

 

System F = 5 x pixel size

 

See:  https://www.cloudyni...w/#entry5317455

 

You would most likely use a 2x barlow with your 8" SCT, so at f/20 you need a camera with pixel size ~ 4 um.

Like the ASI224.


Edited by George Bailey, 16 July 2019 - 07:20 AM.


#19 clarnibass

clarnibass

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 20 Jul 2018

Posted 16 July 2019 - 08:20 AM

Thank you. I'm trying to understand this in a practical sense rather than mathematical or theoretical.

Going with that recommendation... comparing ASI385 and ASI224, the former would just have more sky space around a planet and a slightly slower frame rate? Or you could use a cropped part and maybe take advantage of the larger sensor for other things?

Still going with that calculation, since the ASI290 supposedly doesn't fit as well with this setup, in what way would the end result be worse with it (everything else being the same)?



#20 Lacaille

Lacaille

    Viking 1

  • -----
  • Posts: 774
  • Joined: 27 Nov 2015
  • Loc: Canberra and Strasbourg

Posted 17 July 2019 - 12:52 AM

Hi Clarnibass,

George is quoting a useful rule of thumb deriving from optoelectronics. You don't need to know the details, but it relates to the way pixels respond to incoming photons. You sometimes see it quoted as opimal F is 5 to 7 times pixel size, the 7 being for exceptional seeing conditions.

None of those cameras would be catastrophic, but in this game we are usually trying to squeeze the last incremental gains from our systems. If you went with the 290MC, pixel size is 2.9 microns therefore optimal F is just under 15. You would need a Barlow at 1.5x - these can be hard to find - or use your 2x and, imaging at F20, you would be oversampling. This means the image would be comparatively dim so you would have to increase gain and/or exposure time, reducing your frame rate, to get a satisfactory video. Not insurmountable, but perhaps not optimal.

Re 385 vs 224, yes you can reduce the region of interest to just encompass the planet so the frame rate would come out close to the same between the two. The larger sensor size of the 385 would make it slightly easier to locate the planet prior to imaging, and also allow you to do bigger full frame images of the Moon or say Jupiter and its moons. It looks to be about 50% more expensive than the 224. A lot of us here do use the 224 and know it to be superb.

Regards

Mark

#21 clarnibass

clarnibass

    Explorer 1

  • -----
  • Posts: 81
  • Joined: 20 Jul 2018

Posted 17 July 2019 - 04:00 AM

Thank you

 

but in this game we are usually trying to squeeze the last incremental gains from our systems.

Exactly why I want to be sure I'm getting the right camera. A $100 to either direction is less important. So going with that rule of thumb... with my telescope...

 

ASI385 with x2 barlow is supposedly "good". 120FPS or maybe faster cropped.

ASI178 with no barlow is close (f/12, telescope is f/10). Can be cropped to about 2.2MP at 116FPS.

According to one post, adding an ADC turns the x2 barlow to a x3 barlow, so f/30 and (according to them) still ok for the (approx) 4 micron pixels. Then I suppose it could be a matter of f/20 without ADC or f/30 with ADC... which is better.

ASI290 is "supposed to be" at about f/14. I struggled to find x1.5 barlows. Without a barlow this would have lower slightly resolution ("pixels on target") than the 385 with a barlow.

I guess barlows can also decrease quality sometimes... or not.

I also don't know if and how the ADC affects anything without a barlow... does it magnify it anyway or only with a barlow it makes it even higher magnification? Does it depend on the exact ADC? If it's the former, maybe an ASI290 with an ADC would be good.

 

So I'm not sure how to choose the best option. I guess most also eventually choose an option, maybe have a chance to compare a little, but don't have a real comparison between all the options.

The up side is that, whatever I get, I wouldn't know if a different option would have been better... wink.gif


Edited by clarnibass, 17 July 2019 - 04:12 AM.


#22 Lacaille

Lacaille

    Viking 1

  • -----
  • Posts: 774
  • Joined: 27 Nov 2015
  • Loc: Canberra and Strasbourg

Posted 17 July 2019 - 07:58 AM

I really can't add anything to my reply above or to the thorough and meticulous answer about ADCs and Barlows given to you by Tom Glenn on the thread "A lil' help". He really knows what he is talking about!

I look forward to seeing your images.

Mark


CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics