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10-05-2015, 05:58 PM
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![Dealy's Avatar](../vbiis/customavatars/avatar17020_1.gif) |
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Join Date: Nov 2013
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Ccd 101
I'm thinking of taking the plunge and delving into the magical world of CCD imaging.
Currently I use an unmodded Canon 1000D on an ED80.
My plan is to go to a GSO 10" F4 with a CCD, maybe an Atik314 or something else.
I don't know what questions to ask and what I need to be aware of. Is there a thread that someone can recommend that can get me started.
Or can someone give me some advice here.
Thanks, Kev
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10-05-2015, 06:25 PM
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![gregbradley's Avatar](../vbiis/customavatars/avatar781_1.gif) |
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Kev,
The most popular CCD at the moment is a camera using the Kodak KAF8300 sensor. That is 8.3 megapixels and is quite sensitive and at 18mm x 13.5mm it gives a reasonable field of view.
There are many manufacturers who use that sensor -
Atik, QHY, Starlight Express, Finger Lakes Instrumentation, SBIG, QSI, Apogee, Moravian even Orion and Celestron.
A lot here use the QHY model. So probably QHY and Atik are the most economical.
Starlight Express would be one of the next cheapest along with SBIG. SBIG has an ST8300 model which is around US$2000.
So it depends on your budget.
The Atik 314 with the icx 285 sensor may be a little small which will make it hard for someone newish to astrophotography as it will magnify all the images like a digital crop. It will make tracking and guiding so much harder.
Unfortunately Astro CCD cameras are quite expensive and there is one shot colour versus mono. Mono requires filters and a filter wheel which adds to the cost but makes better images. One shot colour is a step up from DSLR imaging but processing is very similar. Also no filter wheel and filters are required. So its generally cheaper.
QSI offers a camera with a built in filter wheel and a guider so that is very convenient. Also a range of the smaller sensors like the KAF8300 and the Sony 694, 814 sensors.
Things to evaluate with cameras:
1. The sensor - what is its QE? (quantum efficiency which is what % of photons received does it convert to an electron (signal)). QE of the KAF8300 is about 59%. The Sony icx694 QE is 77%. These are both high numbers.
2. Read noise (this is the amount of noise generated by the action of reading the signal off of the CCD measured in numbers of electrons).
3 electrons is extremely low, 9 is common).
3. Size of the sensor. Large CCDs cost a lot of money and require optics that can handle such a large CCD. Smaller sensors are easier on the optics but have a narrower field of view which magnifies the tracking errors. So a happy medium is needed. The Sony ICX694 and the Kodak KAF8300 are 2 of the popular sized sensors at the moment.
4. How many degrees below ambient air temperature does the camera cool? The cooler the better.
5. Download times - how long does it take the camera to download an image.
6. Other features - SBIG have some self guiding cameras with a 2nd sensor in a filter wheel for guiding, QSI has a built in filter wheel and guider option etc.
7. Cost. KAF 8300 cameras from different manufacturers vary from about $2000 to $6000.
What sort of budget do you have?
Greg.
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10-05-2015, 06:44 PM
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Thanks Greg
Kosh currently has an Atik314 with filter wheel etc for sale now in the classifieds ( http://www.iceinspace.com.au/forum/s...d.php?t=134338)
That is probably in my price range. But you say the 314 may not be the best choice.
I'll do some research into the Kodak KAF8300 sensor
Thanks Greg, that sounds like a good point to start my lernin
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10-05-2015, 07:45 PM
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After a quick Google search it appears cameras with the Kodak KAF8300 may be a bit out of my budget.
The Atik414EX looks like it has replaced the 314L (if I'm not mistaken). Atik claim up to 60% higher sensitivity over the 314L.
I am guessing but does higher sensitivity mean shorter exposures for the same result? And if so would 60% higher mean 60% shorter exposures. And if shorter exposures then tracking and guiding would be a bit easier?
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10-05-2015, 07:58 PM
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Quote:
Originally Posted by Dealy
I'm thinking of taking the plunge and delving into the magical world of CCD imaging.
Currently I use an unmodded Canon 1000D on an ED80.
My plan is to go to a GSO 10" F4 with a CCD, maybe an Atik314 or something else.
I don't know what questions to ask and what I need to be aware of. Is there a thread that someone can recommend that can get me started.
Or can someone give me some advice here.
Thanks, Kev
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Kev, mod your Canon for full spectrum first, you'll get five times the Halpha light. You have a good sensor and certainly you can push that camera much harder, even cool it to delta T levels of -25C with a cold finger mod.
The ATIK 414EX has less pixels than your Canon, if you go mono your going to have to spend on filters and wheel as well. Unless you need to shoot narrow band I can't see why.
I considered a CCD but could not justify it on cost grounds. The CCD mafia will climb all over me with words about well depth, noise, etc but there are excellnt photos produced with DSLRs and cooled ones approach the results of much more expensive CCDs.
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10-05-2015, 08:18 PM
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Quote:
Originally Posted by glend
CCD mafia
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![Smilie](/vbiis/images/smilies/happy19.gif) ![Smilie](/vbiis/images/smilies/happy19.gif) Dangerous words around here I think Glen
I did plan on keeping the DSLR for normal photography. But that's certainly an option that may be worth investigating.
Any idea how much a mod would cost? And where to get it done?
All options are on the table at the moment. I just want the best results within my budget with the least amount of pain to get there.
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10-05-2015, 08:34 PM
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Kev, ha ha, some of my best mates on IIS are CCD people; all I am suggesting is that your Canon is more capable than you might think. I have nothing against CCD users, but it's not for me. I don't have the time to do mono CCD imaging and frankly not really rapt about the whole processing thing. If I wanted to go Mono I could do the debayer mod on my Canon first to get the full 12 megapixels in mono but its too much work (not the mod the integration and processing).There is a photo shop in Sydney that is doing the full spectrum mod for $150 plus shipping, I will find the name and PM it to you, or you can do it yourself using Gary Honis's excellent illustrated instructions and that cost nothing. I have done two and its not hard if you write down each step as you go and attach any screws removed for each step to a run sheet.
I believe there is an IIS member also offering a mod service. There are numerous US and UK businesses that mod Canons. JTW being one.
There is a very good Canon Cold Finger mod thread here on IIS which was started by RCheshire. That's a very low cost mod, just need a TEC, some copper, a temperature controller and that's going to cost you less than $100 in parts, and it's fun. However, if your going to mod you DSLR you need to have some confidence in your ability, it's not hard to do actually.
Now I'll let the CCD guys have a go.
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10-05-2015, 09:05 PM
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Hi Kev,
I am a CCD guy and a member of CCD mafia ;-)
Experience taught me that we also need to consider light pollution. If you have reasonably dark skies, then modified dslr / single shot astro camera would be capable of delivering good data. There are plenty of beautiful images taken with dslrs on the net, but I would dare to say that none originating from light polluted areas are beautiful.
If you have significant light pollution in your area, then narrowband filters would most likely be needed for satisfying astrophotography, and that means longer exposures that in turn require a good mount and ultimately leading to a low noise high QE mono CCD.
Thank you for reading.
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10-05-2015, 10:42 PM
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The big advantage of DSLR is the size of the sensor. Most Canon DSLRs are APS sized which is around 25mm x 16mm which is quite large. They are also fairly low noise and reasonably sensitive. APS is the point where getting round stars to the corner starts to become a problem. A good coma corrector is a must. DSLR imaging though is quite alluring and relatively "easy".
But as Slawomir points out it is pretty much relegated to dark skies. In light polluted skies you will pick up too much pollution very quickly that will drown dim objects and you would be limited to bright objects and short exposures. Narrowband is the solution to suburban skies and that really is CCD territory.
The Atik 414 sample images are impressive. The camera seems pretty good. The high sensitivity is appealing and yes 60% more sensitive means 60% less exposure time to get the same result.
Greg.
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12-05-2015, 05:41 PM
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Thanks for the help and suggestions.
I think I'll just play around on the F4 with my unmodded Canon for a while.
If I'm really not happy I'll take the next step, whatever that may be
CCD's certainly are expensive little things aren't they
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13-05-2015, 08:08 AM
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![gregbradley's Avatar](../vbiis/customavatars/avatar781_1.gif) |
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I think that is a good move. CCD imaging is somewhat complex and expensive but ultimately rewarding. DSLR imaging is more bank for both your imaging buck and imaging time and patience!
I did DSLR for about a year or more before I went to CCD.
The best image you can make is not always about the gear but how familiar and how well you know your setup. If that is a DSLR then you will make better images from that rather than spending a bomb and struggling with it. If you survive the learning curve which can be offputting then ultimately you will have better images but some DSLR images rival the best CCD images.
Just do DSLR really really well.
The best DSLR images seem to come from modded Canon (I notice those lovely Pentax K5 images recently posted as well).
The old Canon full frame 5D would be a good one. I could be wrong but I suspect the earlier Canon models may be better than the later ones as pixels get smaller and noise intrudes more. I noticed in particular the 60D seemed to be a drop in quality of astro images. Perhaps the megapixel race and the monkeying around with "RAW" is getting too much in the road. Of course I could be wrong on this.
A modded 5D2 seems to be about as good as it gets in DSLR world.
Not sure about Nikon, Sony or Fuji. APS is somewhat demanding of the optics and flatteners start to become mandatory and full frame for sure. Full frame may mean a larger focuser and larger openings in the imaging train (ie flatteners and adapters and focuser size).
The full frame CCD SBIG STL for example really requires a 3- 3.5 inch focuser or larger.
I found that out trying everything to make it work on a Tak 2.7 inch focuser on an FS152. No way.
Greg.
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13-05-2015, 06:10 PM
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Thanks for the advice Greg
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