CCD camera advice

[Larryp]

Hi everyone
I am new to digital imaging, my astrophotography experience dating back to the days of hypered film and manual guiding.
My scope is a 90mm f5.5 apo refractor, and I would appreciate some advice on which ccd cameras I should consider. I am interested more in deep space , and don't want to buy an el cheapo entry level that I will outgrow quickly, but also don't want to spend a fortune
I kind of like the look of the Atik range, but open to all suggestions
Thanks

[blink138]

have you thought of dslr first, if you already have a camera of course!
pat

[bmitchell82]

I would look more for the KAF 8300 chip set.

Brands that make them are

FLI, SBIG, QSI, QHY

FLI being noted for its really good electronics and build quality
SBIG being an old school name, but have recently started integrating its equipment
QSI have done a great job of combining the Filter wheel, and guiding into the same bundle. the new 600 series has addressed cooling and download issues. also 36mm filters are able to be used (reduction in cost).
QHY, excelent bang for buck, they are not as refined as the previous three but hey they are generally 1000 cheaper and come as a all inclusive pack (mono cam, electronic CFW and filters to get you going)

The only other thing that you will want to look at is getting a field flattener for your apo other wise you will take photos similar to star trek enterprise going into warp

[Larryp]

Thanks for the advice Brendan and Pat.
I do not have a DSLR and would prefer an astro ccd camera.
Unfortunately my budget for a camera extends to $1500.00 at the most, which rules out most of the recommended ones.
Do you have any suggestions in the cheaper range. I would appreciate advice on pixel size as well.

Many thanks
Laurie

[whzzz28]

Hi Laurie,

You will be limiting yourself a bit with a $1500 budget and i expect that a mono setup will be out of the question.

The three camera's that come to mind that are close to your budget are:


QHY9 OSC (One Shot Color) - http://www.gamaelectronics.com.au/QHY9%20prices.html - $1650
Atik 314L+ OSC - http://www.andrewscom.com.au/site-section-10.htm - $1799
Atik 320e OSC - $1399

Pixel size is interesting, and a bit of a pain to calculate.
Some light reading:

http://www.stanmooreastro.com/pixel_size.htm
http://www.astro-imaging.com/Tutorial/MatchingCCD.html



Given your scope is relatively fast, smaller pixels may be the go for you.
The Atik 320e has 4.4µm pixels.
Atik 314L+ has 6.45 µm pixels
The QHY has 5.4µm pixels.

The Atik 320e has a resolution of 1620 x 1220 pixels
The Atik 314L+ has a resolution of 1392 x 1040 pixels
The QHY has a resolution of3326 x 2504 pixels.
(resolution isn't everything in astrophotography).

Ill leave the maths of calculating the best pixel size up to someone else more knowledgeable, but i think the Atik 320e or QHY will give you the best pixel sizes.

When i first started (6months ago) i too was thinking of going down the road of a CCD. Then i saw the costs and decided to start with a $400 Canon 1100d; which has given me some surprisingly good results!
I then ended up modding the canon and get some decent images. A CCD is better, but if your on a limited budget, you can't go past a modded DSLR.

[bmitchell82]

if your budget only extends to 1500 dollars.... wait for a month or two and get a qhy for a few hunge more. the smaller chips are just too small to do much with (eg you will be lucky to get a A4 print).

Thats my advice but at the end of the day do what you want :)

Pixel sizes are given, you don't need to calculate it.
Arc seconds per pixel get a free program from New astronomy press "Ron Wodaski's CCD calc"

What you want to do in a perfect world is get 1 arc sec per pixel.

[rally]

Brendan,

Not sure how you can come to that conclusion without some very different assumptions to the OP's.

It depends entirely on what the intended use is, his is Deep Space not Solar System

Given the OTA is a 90mm f5.5, meaning its a widefield scope at roughly 500mm as opposed to 1800-4000mm
Trying to achieve 1 arc sec per pix would require a camera with 2.5um pixels.
That would result in extremely poor dynamic range, high noisde and low well depth - not at all suited to DSO astrophotography, not to mention the field of view would likely be small

A popular AP combination that will repeatedly and reliably produce stunning widefield astrophotos is the FSQ106 and STL11000 and that is at an image scale of 3.5arc secs per pixel - I am not suggesting that camera here ! - just illustrating that a larger image scale is popular amongst many highly competent astrophotographers who aren't necessarily interested in getting the maximum resolution that a terrestrial scope could provide.

Given he is also using an EQ3 mount, it would be difficult to track at under at 1 arc sec anyway and that makes it a much more suitable candidate for a large image scale to even out the errors in seeing and guiding.

Regards

Rally

[gregbradley]

I'd second Rally there.

Pixel size is more of an issue for longer focal length scopes.

You can get away with anything with an F5.5 90mm scope. Those sorts of scopes are not particularly affected by seeing as they are not resolving fine detail to that extent. That fine detail kicks in with longer focal lengths.

Look at the numerous stunning images of FSQ/STL11 or 16803 cameras with 9 micron pixels. 9 micron pixels seems to work on any scope by the way so it would seem to be the sweet spot for astronomical imaging where the performance characteristics of the chips, the optics, the available seeing all seem to meet at a nice compromise.

Basically, I think the wider field the scope the less important pixel size matching becomes.

It becomes quite an issue at about 1200mm focal length and beyond and vital at 3 metres. You will see a slightly more alive and vital image using a smaller pixelled camera at around the 1200mm focal length versus a 9 micron pixelled camera. But it would require night of stable atmospheric conditions.

Other considerations are then more important at the short focal length.

Cooling,Noise levels, sensitivity, autoguiding solutions, cost. Bascially high cooling solves most problems with CCDs. Noise, artifacts, cosmetic blemishes like lines.

I agree, one shot colour is your best bet. Simpler, easier and you get nice results (not the 100% best you can achieve but very good regardless).

SBIG One shot colour ST8300's come up on Astromart every now and then. Often around the $1350 band. Add in $250+ for shipping and $150 for GST and you are not far off the cost you had in mind.

FLI, QSI, SBIG, Apogee are the big name brands that all make great cameras.

Atik, QHY are the 2nd tier. Starlight Express is somewhere in there as well perhaps first tier perhaps in between.

For absolute performance of the camera itself FLI still is around top spot with its most powerful cooling, high quality everything but lacks accessories like autoguiding setups. Same with Apogee, great electronics, great performance, bigger and bulkier and a quirky slow cooling system.

QSI have integrated all these features nicely and have caught up a lot with FLI in the cooling, electronics etc so that probably makes them near the top now as they are nicely integrated with filter wheel and autoguiding solutions. SBIG is much the same with their latest round of cameras offering nicely integrated cameras. Their latest offerings of the STT range would appear on paper to be a good attempt at regaining the crown, yet to be reviewed but I suspect they may have taken the crown back.

Anyway that is future for you as all those brands are in the $4000- $8000 band by the time you kit it all up to be a complete system.

Expensive eh?

So the suggestion of the one shot colour makes more sense now or hang around astromart.com for 2nd hand bargains or some appear in the classifieds on this site from time to time.

Brendan is right, you probably don't want to use a chip smaller than the KAF8300 (its something like 19 x 12mm or so). If you do you will get a magnification factor and you'll end up with images that are pushing the scope beyond its ability, too zoomed in for the aperture of your scope. You lose lovely widefield factor.

A formula is 5.5 to 9 micron pixels, with the largest chip you can afford to obtain the widest most detailed images you can.
90mm F5.5 is potentially a fabulous widefield scope.


Greg.

[Joshua Bunn]

Maybe have a look in the IIS classifieds? There is a Sbig st-2000xcm osc for $1000 that just came up.
And another SBIG camera with filter wheel and filters here (http://www.iceinspace.com.au/forum/showthread.php?t=89638) for $1500.

Josh

[Larryp]

A big thanks to Rally,Greg,Brendan, Nathan, Pat and Joshua for all the advice-I have plenty to think about!

[PhilfromOz]

Hi all,
First post! I would like to introduce myself to the IceInSpace community. :thumbsup:

A bit of Background:
I go viewing with a few others in a “Horse Paddock” up at Kenthurst (Dural Pony Club) on reasonable Friday evenings. In the Bintel Monthly (NightSky), the group is listed as the Sydney Northwest Astronomical Society.

My current set-up is a Losmandy G8 Mount with Gemini. Scopes are on a Losmandy Dovetail Side by Side Plate. Guiding is via an Orion Starshoot Autoguider, on an Orion ShortTube 80 Guide Scope OTA. Viewing & astrophotography is either a Televue 76 or a Celestron 8”SCT (usually with 6.3 focal reducer). Connected to the viewing OTA, is a Meade 644 Flip Mirror, Eyepiece and Atik EFW (with Astronomik 1.25”LRGB filters), and Atik 314e CCD. On the laptop, I typically use The Sky (to see what is around), PHD (for guiding control), AstroArt (for imaging control) and EFW S/W (to change filters). As yet I do not drive the mount from the laptop, preferring to use the Hand-control & Gemini.

I assume that the learning never stops with this hobby, hence the fascination, but I am not sure if I am getting the most out of my gear, particularly on the imaging front, with stars appearing larger than I would expect.

In this Post there was suggestion for some light reading, and the following caught my eye

http://www.astro-imaging.com/Tutorial/MatchingCCD.html

Matching a CCD Camera to a Telescope
Using the formula:
Star Size = (Seeing * Focal Length)/206.3

So for the SCT, with a 6.3 Focal Reducer, the result is:
Star Size = (3 * 1,260)/206.3 = 18.32

For the TV76, the result is:
Star Size = (3 * 480)/206.3 = 6.98

Dividing these by the 3.3 FWHM gives me 5.6 and 2.1 respectively. So given the Atik 314e has a pixel size 4.65 uM x 4.65 uM (resolution of 1392 x 1040 pixels) it seems to be over-sampled or under-sampled.:shrug:

Is this correct?

Regards Phil

[rally]

Phil,

The SCT 1260mm/ATIK 4.65uM provides an image scale of <> 0.8 arcsec/pix
The TV76 480mm/ATIK 4.65uM provides an image scale of <> 2.0 arcsecs/pix

The TV76 better matches your local seeing conditions and would probably be considered around the mark as an ideal image scale, whereas the SCT is probably oversampling and would probably only benefit you with deconvolution and with better than average seeing conditions and on smaller targets like faint fuzzies.

Rally

[PhilfromOz]

Hi Rally,
Thanks for the response. These values match what I get from Ron Wadaski’s CCD Calculator, but don’t tie into those on the tutorial website.
Do you have any ideas on this? Also earlier in the Post there was mention that “in a perfect world is get 1 arc sec per pixel” – assuming this, the SCT gets closer than the TV76.
Phil

[graham.hobart]

Phil,
No one but the Hubble gets that arc per second visual or imaging, or maybe in Antarctica on a still day. 2-3 is super excellent from suburbia which is where most of us live. Where I live I am happy to see the Sun sometimes!
Mine would be 3-4 on best of days.
And capitol letters makes it seem like you are shouting.
My advice, get a DSLR. Cheap. Big chip so easy to find the target and focus. Can be modded later for extra sensitivity or cooling (ooh! sounds like a menthol condom). Lots of software for support especially Canons.
I have two CCD cameras. Both of which are on the earlier list. The Atik 314L+- super cooling and a mono camera and a nice filter wheel. I have had it for 18 months and not produced a photo i would put on here yet. The QHY 8 OSc or similar- I love it and even though blowing the cooler up by accident (and the camera being second hand) the QHY folks mended it free of charge and mailed it back to me. Now tell me that is not good product follow up. I also produced a semi decent photo within a week of having the mended one.
Bias is always good, and always good for a poke in the ribs of opinionated folks like myself.
My advice, buy something you will use.
Oh, and buy second hand.
:shrug:

[Poita]

I'd second what Graham said, you can pick up a 2nd hand QHY8 colour camera (or similar) for about a grand, a very capable, almost noise free, cooled CCD astro camera that would suit your setup and give you 6MP images that you can print and display.

By buying 2nd hand, when you upgrade you will lose very little, if any money in most cases, as the resale value is good if you buy well.

[Gem]

Very happy with my ATIK 320E - which fits nicely in the price range.

[gregbradley]

The 1 arc second per pixel is referring to how much angle of view is being received per pixel. It isn't referring to the seeing which is usually expressed as arc seconds as well, hence the confusion.

1 arc second per pixel would be seeing divided by pixel size ie 4 arc second seeing divided by 9 microns = .44.

This whole pixel matching thing gets into sampling theory but suffice to say 1 arc second/pixel is a rough approximation. I was using .63 as a guide and in my 3 metre scope a 12micron pixel should theoretically be a better match than my 9 micron. But I do see a drop in quality using a 5.5 micron pixel camera unless there is a night of excellent seeing.

Greg.

[PhilfromOz]

Hi Rally, Graham, Peter, Grant & Greg
Thanks for your feedback on my Post. My learning will continue and it is great to have differing views. I was unable to get onto IIS last night, as I went to the AFL Giants versus Bombers. I will digest the info and come back with any further queries.
Phil