cooled CCD options

[spearo]

Hello,
I know next to nothing about cooled CCDs, except I probably want one !:lol:. I'm using a Canon EOS 20Da now and hope to increase sensitivity, resolution and shave off rig weight by removing the guidescope by using a self-guiding cooled CCD.

I'm taking my time in considering options and just came across this : QSI 500 series WSG model
Seems to have a self-guiding chip fitted in front of filter wheels

I know the SBiG series offer self guiding and also have larger chip (on some models) than this QSI

Any thoughts on this or other options for cooled self guiding CCD cameras?
It would likely be used on a C14 mainly and possibly C9.25 on a G11

thanks for any input / suggestions
frank

[gbeal]

Frank,
let me kick this off. I have used the SBIG gear, and it is nice, heavy as heck, but nice. The self-guiding is good too, and I loved this part the most perhaps.
The QSI line appears to use a fixed in place off axis guider, which is slightly different to a dedicated built in chip. Not saying it is no good, just that if you are going to an OAG why not get one and then get a camera, without having to buy the QSI.
Another option is to get the smaller lighter cameras now populating the markets, SX, or QHY, and retain the guide-scope.
The SBIG stuff works, and well, but the penalty of weight is up there, at least it was with the ones I had.
Gary

[spearo]

Gary,
Thanks for that, I had read this all wrong, the QSI doesnt have a guiding chip, just a pick off prism...
You're right, that's not exactly what I am after.
Basically, at this point, in my fuzzy logic sort of way, Sbig has the top spot on the options list with nothing below given that it's the only one with a built in self guiding chip (i think its the only one?)
...
thanks
frank

[Geoff45]

QSI cameras have been getting rave reviews (http://www.qsimaging.com/500series-reviews.html). It seems that, being a newcomer on the market, they have benefitted from the experience of previous cameras in their design. It looks like you use the QHY5 for autoguiding and since that works with the QSI 540wsg, there won't be any extra expense involved. It seems that the advantage of the qsi is the fact that the pick off prism is in front of the filters, so you don't get problems finding a guidestar when narrowband imaging as is sometimes reported with the sbig (and I'm no expert here--just quoting what I've read)

Geoff

Note added: Whatever camera you buy around the $US5000 mark, I suspect user skill will be far more important as a factor than camera performance.

[rogerg]

I believe SBIG hold a patent over the dual chip design so if I'm right that's why there's no competitors offering it and why there won't be for some time.



Interesting. Perhaps you're right, I haven't compared actual weights accurately. But comparing how heavy my ST7 feels to how heavy my Canon 350D feels, the 350D feels heaver. Compare the ST7 to a QHY-5 (guider) and the Q-guider is a whole magnitude lighter (but it's not cooled and of course is no comparison for the ST7!).

If I were you I'd be comparing what Starlight Xpress, SBIG, QHY, Apogee and Finger Lakes offer. I think Meade's and Orion's are cooled now too aren't they?.. just the lower end of the market.

I expect to stick to SBIG when I upgrade because the internal guide chip seems to make life so much easier than having an external guide scope (but has obvious drawbacks such as the problem with filters going in front). If you're doing RGB imaging then a single shot colour SBIG with guide chip would be nice :)

[Dennis]

Hi Frank

Just from my experience of having owned a dual chip SBIG ST7 for a few years, they are an excellent work horse.

Their build quality is industrial/military and they are a mature, solid product. Also, the camera control software, CCDSoft, is very powerful and easy to use making that combination a winner.

I haven’t tried any of the other alternative cameras, such as the Starlight Express range, but you only have to look at the work of someone like Mike Sidonio to know that these too can produce world class images.

Good luck with the choice!

Cheers

Dennis

[Terry B]

From a different viewpoint I have a ST9E with water cooling etc. It is very heavy when coupled with a filter wheel but my scope copes with the weight.
I almost never use the internal guider but use a QHY5 through a guide scope. I found that the lack of available guide stars to be too much of a problem. If there is a suitable guide star for the target I will very occasionally use it but often find it too much af a bother to change the cables over.

[Geoff45]

The line pushed by QSI on this issue is that the pick off prism is much closer to the chip than a conventional OAG, so you get a wider field of view for the guide camera. They claim to completely illuminate chips such as found in the Orion Starshoot autoguider (aka QHY5), so there should never be a problem finding a guidestar in the FOV. Also, once the guide camera is set at the same focus as the main chip, it's pretty much focused for life because you can screw it down.

[spearo]

Thanks everyone for all the input.

much appreciated
cheers
frank

[Hagar]

Hi Frank, I have and use a QHY8 one shot colour cooled CCD camera and love it. It is short of a guide chip but is cooled and produces quite satisfactory images. The New QHY8 Pro incorporates some nice extras not available to the standard QHY8. The price difference between say an SBIG ST4000 one shot colour at $7200 and the QHY8 Pro at $3600 is quite aa bit for a guide chip and even a guide scope as well. The end results are quite comparable.
The one thing I can vouch for is the after sales service provided by Theo/ Gama. He is the most honest and eager to please dealer I have ever dealt with. An example. My QGuider stopped working. A phone call to Theo, some checks over the phone and the next day a new camera was in my mail box even before the dead one was sent back. This service has to be worth something extra.
This is the link to Theo's site and the QHY8Pro.
Main site: http://web.aanet.com.au/gama
QHY8: http://web.aanet.com.au/gama/QHY8.html
QHY8Pro: http://web.aanet.com.au/gama/QHY8_II.html

Take a look you might be surprised.

[Dennis]

Hi Frank

Don’t overlook the important process taking calibration frames as well as your image (light) frames when using the camera.

I can only write about my experience with my SBIG ST7 camera whose design and camera control software (CCDSoft) make it reasonably simple to take Dark Frames at the same temperature and duration as my image (light) frames due to the ST7’s regulated cooling.

By the looks of it, the QHY Pro8 also appears to have regulated cooling which should make it a breeze to ensure your Darks are at the same temperature as your images.

Another issue is that I know my (old parallel) SBIG ST7 uses a Kodak chip which produces quite noisy Dark Frames compared to those I have seen from CCD cameras using the Sony chips.

Some imagers appear to get away without the need for Dark Frames when using less noisy cameras and this should allow you to be more productive at the telescope?

This is not a “for or against” about the brand of cameras I have referred to, just some notes about my experiences with the current camera I use and what I would be looking for in a new camera.

Cheers

Dennis

[AlexN]

To add a bit to the above post, generally speaking, the QHY8 doesnt benefit much from dark frames.. The inherent noise is just so low that it makes the effort to take darks seem like wasted time..

If I had the money to put into it, I would definitely be looking towards an SBIG, as lets face it, they are SBIG :) However, given my budget, I went for the QHY8 and can honestly say I've never regretted it..

I've also been looking at the Starlight Xpress cameras recently.. and some of them look to be very good also.. Although they seem to be very expensive for what they are... The SXVF-M25C has the exact same imaging sensor as the QHY8, yet the QHY8 is around 1/3 its price. Seems hard to justify to me..

Another thing you might benefit from greatly with your setup is Adaptive optics. A lot of people think that this is an SBIG only pleasure, however Starlight Xpress make an adaptive optics unit that will work with any camera.. You just need to use a Starlight Xpress guide camera with it.. I'm currently looking into the SX Adaptive Optics unit for use with my C11 for imaging.. as the affects of seeing become very noticable imaging at the longer focal lengths..

[renormalised]

Alex, I've been looking for the Oz site for the Starlight Xpress cameras to find the prices, but can't find it. Can you post it here, thanks:)

[AlexN]

theres no aussie site that I know of.. I've been reading straight off the SX website, and on optcorp/starizona sites..

Prices are pretty damn high.. thats for sure :)

[renormalised]

Funny thing, at the main website, they mentioned York as one of their major Oz outlets, but York don't carry any Starlight's anymore. The site needs updating.

[spearo]

Many thanks Again everyone for all the info.

I appreciate everyone taking the time to share their experience.

It wont be an easy decision but At this point I am thinking that it would be nice to get a CCD that is more sensitive than the DSLR and that enables me to do away with the extra weight of the guidescope (though the G11 is a beast and manages it just fine)

I can attest to very very good aftersale service of both dealers for SBIG (Peter Ward is the dealer i got the G11 from) and the QHY cameras (The/Gamma supplied my QHY5).

many thanks for all the input again
cheers
frank

[renormalised]

Looking at the prices they sell for over in the US (we need to "emigrate" just to buy them!!:P:D)...if you add the import duty on them, factor in the exchange rate and then add 10% GST, you'd be looking at $5000-$6000 for a SXVF-M25C. That's without the reseller's markup, for profit!!!.

[AlexN]

lol... yea.. hence why I bought a QHY8 for $1800 :P :D

I have my eye on a SX Lodestar guider and the SX-AO unit for use with my QHY8/C11 though... still 1700US for the AO + 400US for the lodestar guider.. thats pretty big money...

[renormalised]

Well, I won Div 3 in the big lotto....about $1450. That'll probably buy me the "on" switch for the SXVF-M25C:P:D

Or maybe the QHY8 Pro's casing...add one resistor for the standard version:P:D

[AlexN]

1450's got you very close to a QHY8 (non pro) Theres not enough difference in the QHY8pro to make it worth the extra money you know.. sure regulated temperature, but you can DIY this into the QHY8 for about $40... unless you plan to use if on an SCT with Hyperstar/fastar, the standard QHY8 is a better price:performance option from what I can tell...

ps. congrats - $1450 is a good win! :) I'd be stoked... I won $250 a few months back and was happy as!

[gbeal]

Not quite that much now though, $2450.
So $1800 would even be cheap used, LOL.
Gary

[renormalised]

I wish it was still $1800...they're $2450 now!!. Need another high dollar exchange rate. I was reading about Hyperstar....spun out way of mounting your camera!!!. I'd be a bit hesitant on pulling out the corrector place to mount the lens!!!:eyepop:

Thanks...I am stoked about the win. I was one number off the big prize...and the number I needed was on the next line!!!!

[AlexN]

Bah, removing the corrector is easy business.. I'd do it in a second if the hyperstar + conversion kit was 1/2 the price.. :)

[renormalised]

After seeing the results of the hyperstar lens from various scopes, I've just become an expert corrector plate remover!!!:P:D

[AlexN]

heh.... yeah... getting the horse head with good signal to noise ratios in 30sec subs did it for me... now I just need the funds..

I figure 10 minute subs of the horse should be marvellous at 11" F/1.8

[renormalised]

With that much detail in so little time, 10 min subs and it'll look like it was taken by the Hubble!!!!:eyepop::eyepop::D

Move over Jase, Marcus, Mike, Peter and Co......:P:D

Here comes Alex...with Hubble 2:D

[AlexN]

lol.. :) I think im a long way off their level.. you can acquire all the data in the world.. without proper processing the data is useless.. :)

Ps - Woah.... gone waaay off topic.

Alex :D

[renormalised]

You'll become a processing guru in no time:P:D

Not really off topic, just gives Frank something more to think about:)

[jase]

Frank,
Given the focal lengths you're talking about...worst case a C14 @ F/11 delivering 3910mm F/L...you'll want to be guiding on the same optical axis as the imaging camera. Whether that be in the form of a guide chip on camera (SBIG) or via an OAG is up to you. An OAG will alter your imaging train and as such the F/L. Guide star selection will need to be considered with both solutions. Its not really a issue, but you'll need to plan framing/composition. If you're happy with an OAG, clearly you can choose any CCD camera manufacturer.

[AlexN]

As a matter of interest, I've been used an OAG a few times (every night I've been out since I got it) and it does give great results.. the only downside is that my guiding camera isn't very sensitive.. I'm about to get my hands on an SBIG ST4 auto guider to give that a go, but failing that working for me, I'll be getting a Starlight Xpress Lodestar - From what I've read it is a very very sensitive camera, being able to detect stars at 9th magnitude with a 60mm guide scope in a 1sec sub... I hope the ST4 can deliver similar results (documentation claims that when used in an 8" SCT it can get to mag 10 in 1 second..) So given I'll primarily be using it in an 11" sct, I hope to be able to find guide stars with relative ease... the downside is that the field of view will be very small indeed... I suppose it cant hurt to try...

In my 102mm refractor using the DBK31 in the OAG I've had good results on star rich targets, and havent really tried anything that is overly sparse... targets like M42/Eta Car and the horse head have been fine with a 1sec exposure...

I think the OAG is a good idea provided your camera is sensitive.. Your QHY5 should be fine with 14" of light gathering power at its disposal :) That said, I'd still look at a self guided SBIG... :)

[renormalised]

An OAG will certainly save you a bit of money when compared to a guidescope, but as has been mentioned, if you can afford a camera with an inbuilt self guiding chip, like a SBIG, then get one. The only downside of "through the optical axis" guiding is the small FoV in a large scope. That's where a fast refractor used as a guidescope is good. You'll get a decent FoV to play around with, so your choice of guide stars is greater.

In the end, your best bet is to go with what you can afford and what you feel you can handle:)

[spearo]

Thanks everyone,
I suppose that since I already have a QHY5, I could experiment with a pick-off prism OAG in front of the Canon 20Da.

I'm operating at 2 inch opening now (focuser etc) anyone where I could get an OAG that would fit 2inch?

That would get me a sense of what the QHY5 can pick up as guide stars through the main scope.

Where could I get a 2 inch OAG?
thanks
frank