I realise I am not going to get much further with the drawbacks of a DSLR. I bought a DSLR coolbox last year but for a variety of reasons this has not proved to be satisfactory for me and it only cools to about 8 degrees below ambient.
As you know I bought an Atik 314L mono earlier in the year and decided to sell it. I felt having to do several nights imaging to get one coloured image was too much faff, but additionally I was rather disappointed with the FOV being used to that of a DSLR.
I want to get myself a Cooled CCD with a larger FOV but am undecided which route to go down and would value some advice.
I am currently looking at the QHYL8 (cheaper option than an Atik) but I gather you don't get a lot of support with this, plus the capture software is unknown to me and I'm not exactly a whizz with adapting to new software.
Or the Atik383L - a lot more expensive but I am familiar with the software and support is better.
I was thinking of going for the OSC so I don't have the filter faffing, but every-one says they are less sensitive.
I was quite taken with the idea of adding Ha to RGB images (which I did recently with the horsehead done on my DSLR heavily cropped and the Atik314L).
to be continued:
So currently I am thinking:
1. Do I go for the Mono and add Ha to DSLR images for colour (which I won't have to crop so heavily as with the Atik314L), apparently you can blur the colour image to "rub out the noise" and use the ha for detail.
I have to add I am not a fan of Mono imaging, so would want to produce colour.
2. Do I go for a OSC which will be cheaper and saves the colour filter faffing, and try to use an Ha filter on this anyway.
If I go for option 1 it does give me the option to later go onto narrowband and RGB filters but then I have the faff factor and a lot of extra expense. If I go for option 2, I don't have the narrowband option and I think I am talking myself into option 1 but hoping I don't regret it - AGAIN!!
Either way, do you have any opinions of the QHY8L or the Atik383L bearing in mind the difference in price.
I do already have a 2" screw on Ha filter which I am planning to use on the DSLR (for the time being).
Thanks
Carole
So option 1 is that you buy a cooled CCD camera just to take Ha so you can add it to your DSLR images :-?
If you're not going to be doing narrowband stuff "ever" get option 2 a OSC and take Ha as you would with the DSLR
If you went for mono and you got a motorised filter wheel, you could set it all running and still go to bed
Just seen a Mono Atik383L second hand for sale.
Decisions, decisions.......
B....... it's gone.
Carole
Some of the OSC cameras still have good Ha sensitivity and can be used with Ha filters. The QHY8 is one that springs to mind. If you dont want the trouble of filters then get a OSC. Alternatively spend a bit more and get a mono camera and a motorised filter wheel. That way it can all be done automatically for you.
Whichever way you go, (One-Shot-Colour or Mono) you will end up with the following advantages:
1) A chip with better sensivity than a modded DSLR
2) Almost non-existent thermal noise even in mid-summer
3) No "Canon banding" problem
Without doubt, a mono camera is far more versatile because various filters (narrowband and broad spectrum) can be used. If you prefer colour imaging, then ironically LRGB from a mono camera is actually superior to the colour image from an equivalent OSC (for the same total imaging time). In addition, H-alpha from a mono camera is far superior to that from a OSC because all pixels are being used - not just the red ones.
If you choose mono, definitely get a motorised filter wheel with a set of compatible filters where refocusing between filters is not necessary so you can pre-program your acquisition without manual intervention.
In the OAS, most imagers seem to have opted for mono Kodak KAF8300 based cameras. I think this indicates that this particular chip offers a good compromise between chip size, quality and price at the present time.
Certainly an OSC is easier to use but you do pay a penalty in terms of reduced versatility.
Hi Carole,
If I was to buy a camera today I would buy one of these, well a camera with this chip in it anyway http://www.sxccd.com/sxvr-h694
If QSI used this chip I'd get another QSI, they seem expensive, but they a) work b) filters go into the box and lastly c) the cooling works properly.
Chris
QuoteIf you choose mono, definitely get a motorised filter wheel with a set of compatible filters where refocusing between filters is not necessary so you can pre-program your acquisition without manual intervention.
Mark - Are you sure that refocussing is not necessary...? I would say that even with par focal filters & motorized wheel refocussing would be necessary due to mechanical tolerances etc. I know my RGB filters are meant to be par focal but there is no way I can do RGB without refocussing in between. I think investment in motorized (auto) focus unit would also be needed....
i would always have to refocus mine as well, also what about the flats? they have to be done for each filter
Carole,
I would agree with Chris. If QSI brought out a QSI694 then it would be a killer but alas there is not that much chance since the company are fairly wed to Kodak sensors (I did ask). If you can get a second hand QSI 583 for less than £1800 then it would certainly be worth it for the convenience and save you money through cheaper (smaller) filters - you have to think of the package cost not just the camera !!! The disadvantage of the Kodak 8300 chip (as used in the QSI 583) is that it does not have what's called a global shutter ie. it has to be used with a mechanical shutter. That means flat frames can be an issue as the minimum exposure for the the mechanics still means a very dim light must be used to do the flats (daylight is way way too bright). The 694 sony chip has a global shutter so exposure times can be down to 1ms - no issues doing flats in bright light (with a eps panel for example)
The chip used in the SXV-M25/QHY8 also uses a global shutter so flats are easy but as Mark mentioned Ha would only use the red pixels (every fourth). They would certainly be much better than a cooled DSLR but not as good as a mono camera. Another thing you might want to consider is that with a OSC camera you will be capturing all wavelengths at the same time so if the session was interrupted by cloud then you already have RGB whereas for a mono camera (unless the filters are exactly par-focal) you may end up with a colour missing.
Don't expect a completely noise free camera when the outside temperature is 20 degrees celsius! Most of the cameras you could afford only have 25 degrees of cooling but even that will be luxury compared with a DSLR :)
Robert
Thanks for your replies every-one, that gives me something to think about. I am away and using some-one else's PC at the moment so don't have a lot of time to "research" chips. I see the Atik383L does have the Kodak chip that Mark mentioned, but the Flats issue is something else to think about.
I don't think I am in the market for a QSI and I would have to be extremely lucky for a 2nd hand one to come along at that price.
My current thinking is get a Mono CCD with similar size chip to the DSLR and start off simply by adding Ha to DSLR images, and then work my way up to doing filters as I can afford them. The idea of a motorised filter wheel bothers me as I feel it is not only expensive but just one more thing to have to learn to operate and one more thing to go wrong or have issues with USBs.
Will ponder some more and do some research on the chips and prices.
Does any-one have experience of the QHY8L camera and or the capture software it comes with?
Carole
Quote from: Carole on Aug 20, 2012, 18:47:55
Does any-one have experience of the QHY8L camera and or the capture software it comes with?
No but I have the SX equivalent and have posted images with it.
Robert
The thing is, choice of astro-camera is a real compromise. Once you've got used the the chip size and pixel count of the DSLR you end up wanting the same thing in an astro-CCD and it simply doesn't exist at the present time (at least not at a sensible price). Chris's recommendation is a really excellent Sony chip and I seriously considered myself but it is a lot smaller than the standard DSLR chip so I would be wasting quite a lot of field of view. The Kodak 8300 is a bit bigger than that Sony one but still smaller than a DSLR and it is less sensitive and is noisier (both in dark current and in read noise) than the Sony one - it needs a lot more cooling.
It's the main reason I haven't yet taken the plunge into the mono-CCD world. The Bananascope is a very fast photon grabber ( F/2.8 ) so it overcomes the main disadvantages of a DSLR. So I'm not in a great hurry to change.
If only Sony made a larger version of that chip - it would be a killer chip in the astro world. But it wouldn't have any other mainstream uses so it wouldn't be commercially viable. Kodak is technically bankrupt and their range of chips has already been reduced. This doesn't bode well for the future, either.
If only there were mono versions of some of those DSLR chips. A cooled astro-camera made from one of the those would be worth having!
So if Kodak is technically bankrupt, how does that affect those who already own a CCD with a Kodak chip when it comes to guarantees etc?
Carole
Dunno.
The CCD part of the business has already been sold off as Truesense Imaging in order to raise much needed cash for Kodak. I read somewhere that Truesense has already discontinued some chips in the range - I think that's part of the reason the SBIG range of Kodak based cameras has shrunk:
http://www.sbig.com/Cameras_At_A_Glance.html
Mark
Quote from: MarkS
If only there were mono versions of some of those DSLR chips. A cooled astro-camera made from one of the those would be worth having!
For instance, if Sony made mono versions of the chips in the QHY10 and QHY12 (both of which are APS DSLR sized colour chips) they would definitely knock spots off the Kodak KAF8300.
It looks like the QHY8L range only seems to come in OSC. I am definitely leaning towards a Mono with a large chip, but seems like it's going to have to be the Kodak sensor.
Must look into the guarantee side of things.
Carole
The guarantee would be for the camera itself, if it stops working the supplier of the camera has to repair/replace, if the components aren't available the camera should be replaced by the dealer.
With Starlight Xpress cameras the after sales support is excellent. With my SXV-H9 I had a few issues that Terry at SX fixed, free of charge and very quickly, well after the product was out of warranty. A look around the forums will show other people have had similar experiences. They are a great company to deal with and really look after its customers.
It's a very good point that Mike made and one that's often overlooked. The SX service has always been exceptional with repairs at very reasonable cost and quick turn around time. For instance a complete peltier module replacement for my M25 - cost £40. You would be lucky to get any change from £300 just for sending a camera back to the states and that's just for the return insured postage cost !
Robert
That is a good point Robert and Mike, but I have had a look at the SX cameras and haven't yet found one that has the chip size and is comparable in price. The Atik383L I can get for £1500 from Teleskop Service. The QHY8L I was thinking of seems to be only OSC.
Am I wrong?
Carole
I have bitten the bullet and bought a 2nd hand Atik 383L mono.
As this has a larger FOV than the 314L+ I am planning initially to add Ha to some of my existing DSLR RGB images, and then as I get used to it and can afford it, will add filters. I am keen to do narrowband especially given my LP location, already have a 2" Ha filter, though I bought it for the DSLR so it's only 12nm.
Should be receiving the Atik on Tuesday .
Carole
OK, my 2nd hand Atik383L has arrived. It has hardly been used and seems to work fine.
Any-one an Artemis user?
Just need to understand the looping and "live view" function a bit better for alignment and centering.
Currently I have to wait a few seconds to see stars move and it's a delayed reaction. Also my software was freezing a lot last night, I am wondering whether I have a USB problem. Lower cooling took ages as if I tried to hurry it (and hurry = very slow), again that "hung". Only managed to get down to -1 after ages.
Carole
Carole - I use Artemis Capture all the time. All I do for centring image is set to short exposure & then just loop - it just keeps taking images & downloading till you stop it... In fact I use same function for taking & downloading my LX images. Not sure on Live view...
When you say cooling takes a long time how long are we talking - The 314 takes 2-3 mins to get from say +20 to -5 - The 314 has a max deltaT of 27 deg - I think your 383 can do like 40deg so even on hot summer nights you should be able to get down to -15 or -20deg or so I think? (obviously last 5 deg might take a while)
John
To speed things up just for alignment and rough focusing bin the image by 2 or 3.
Hi Carole,
If its taking 8-12 seconds to download an image its a full frame, if its about 2-3 seconds then its a subframe (providing this is supported by the software). Subframes are quicker for focusing.
I'd have a good read of the manual for the software and check the Atik group on yahoo to ask these questions because I don't think anyone here has one of these Atik's? So although some have used the software the 314 is a lot quicker to use than a 8300 based camera. Not sure about the cooling my QSI get to -20 in about 45 seconds.
Doing what mike suggests is a good idea esspecially if you have an HA filter on because you will only be getting a small amount of light through to the chip.
I'm impressent you nanaged to hijack your own thread :-)
Chris
QuoteTo speed things up just for alignment and rough focusing bin the image by 2 or 3.
Ah yes, that sounds a good idea Mike.
QuoteWhen you say cooling takes a long time how long are we talking
I can get down to about 2 degrees reasonably quickly, but when I click on the set point cooling and try to run it a couple of degrees lower, it would only move down the scale by about 0.2 degrees at a time and then take about 15 secs to reduce by that 0.2 degrees. If I tried to reduce it qucker than that it would just not respond and excuse the pun "freeze on me". So over all it took around 15 - 29 minutes to reduce by about 3 degrees from about +2 degrees. I hope that makes sense.
QuoteI'd have a good read of the manual for the software
I did that when I had the Atik314L+ and the manual doesn't tell you anything much of use, it assumes you know how to work it. I have joined the Atik forum and can ask for help there, but just wodnered whether any-one here used it.
QuoteAll I do for centring image is set to short exposure & then just loop - it just keeps taking images & downloading till you stop it...
That's what I was doing last night John, but the response was very slow even despite lowering the exposure down to a very small figure. In fact it was playing catch up, so when I thought I was slewing in one direction it would go in the opposite direction because it was on a delayed response, this resulted in me not knowing which way to go at times.
Plus Artemis also froze a few times. Which is why I am wondering if it was more to do with a USB problem rather than the software.
I am using the Artemis I installed with the Atik314L+, would it be better if I uninstalled and re-installed from the disc supplied with the 383?
QuoteI'm impressent you nanaged to hijack your own thread
I did wonder about starting a new thread, but thought it was a sort of continuation of the story.
John, as you're round the corner from me and use Artemis, would you mind if I popped round some time and we took a look? Though I guess we do need some stars.
I am sure I will muddle my way through without, but a smoother ride would be preferable.
Thanks
Carole