A New Arrival: New Battle Tank

[Paul Haese]

Part of my long term plans was to buy a replacement to the STL11002M that I own. Whilst it is a great camera, it has a couple of glaring problems. During summer it struggles to keep the sensor at -20C with many nights not being possible at that temp. Another being it only had enough space for 5 filters, something I was not keen on maintaining.

I had planned to use the STL for a few more years and persist with the niggling problems. That was until a couple of weeks back when I looking over my planned imaging targets for summer once the new dome was operational, and then trying to find a remote Guide Head to operate the AOL I had, and on top of that Peter announces the arrival of his AOX. A quick look over my astronomy budget which was blown to hell for the year with the purchase of the Dome, roll off roof kit, PMX, 3" rotator, Atlas focusor, adapters etc, etc, etc.... You get the picture. So I decided what the hell, what is another 12k for the year? Yeah lots I know, don't get me wrong; I know this is incredibly lavish, but I don't plan on spending money on the mount and imaging train again if I can help it. I saved a lot for this complete system and planned for years on having a narrow field system and like many dreamed of the ultimate system for narrow field work.

So in the end I bought a STXL11002 with integrated 8 position filter wheel and guide camera. I bought the gear through ATS (Peter Ward) who had a very competitive price and delivery was quick.

Opening the boxes I was immediately awed by the size of this camera and filter wheel. Within an hour I had the filters in the wheel and that attached to the camera. I have now ordered yet another adapter from the Atlas to the STXL (despite the picture; it is just leaning against the focusor). I hope my sums are correct and I hope Jim Sheng has sent me the correct back focus figures. Time will tell, but for now here is my final battle tank imaging solution for narrow field.

[gregbradley]

Very nice. Any reason you didn't go 16803?
Hopefully you can get the AOx in that system as that will make it really nice.

Greg.

[RickS]

Looks great, Paul!

[Paul Haese]

Interestingly several reasons exist for my decision. As a photographer of 41 years I have always like the width to height ratio of 35mm aspect images. It suits screens, looks great printed and has a natural look to it. Square frames don't look right to me. Even though I started with medium format, it just does not look right.

The other problem is putting a square into an imaging circle which only just covers the sensor comes with its own problems. Ones which I am not keen to spend a lot of time on. If I want a square it only involves doing a mosaic.

The AOX will fit perfectly within the back focus I have left. It doesn't take up much room. And in the end the whole AOX, filter wheel and camera takes up less space than the STL with AOL and MOAG by a significant margin.

[Bassnut]

Nice purchase Paul, well done. Youll find the filter operation noisy, its normal.

Smart move with the filterwheel with guide cam, its very sensitive and bonus, it has a 0.7 reducer built in, nice wide FOV. Remember that when you make the FOV indicator in sky and DL setup.

[gregbradley]

Yeah I get it regarding the square image. That wouldn't be everyone's cup of tea and it was something I considered when I first got an 16803.
I don't mind it now but most pictures and paintings are rectangular.

KAI11002 has its advantages as well. One being a KAI interline chip it does not have RBI which perhaps is some small advantage. There are also millions of great images taken with that chip so its definitely a classic.

Good to know about the backfocus requirements of the 2 systems. I didn't know that. It uses 50.8mm round filters right? It does not need 65mm filters, that's only the STX16803 right?

Greg.

[Bassnut]

Good point I hadnt thought of that, square images, that can be difficult. The other factor of course is, STXL doesnt have a 16803 option. Odd.

[Paul Haese]

Ah good tip Fred, I had not read about the reducer.

I am accustomed to the noise of the rotators, but will find out about the filter wheel soon enough. That does not surprise me though.



Yes it used 50.8mm round filters.

[gregbradley]

I think its still the STX16803. Probably to do with the size of the filters needed for 16803 chip. They need to be 50mm square or in STX case 65mm square to give room for the autoguiding chip. STXL is essentially the same as STX, the main difference is the self guiding chip is in the filter wheel:

http://www.optcorp.com/sbig-stxl-11002-basic-ccd-camera-package.html

It would have been a plus if STXL16803 could have been made to reduce the cost difference of the 65mm filters versus 50mm filters x 7 filters is considerable. Its like the marketing edge QSI have by being able to use 25mm filters instead of 36mm with others with the QSI 583/683.


Greg.

[naskies]

Very nice, Paul... an image train for the rest of us to drool over :lol:

[renormalised]

You mean blow our whistles :P

[Paul Haese]

Something to bear in mind too guys is that the STXL has -60C and the STX only has -50C; certainly a major concern for me is the delta temp.

[gregbradley]

I wonder Paul if that is just a matter of updating the marketing. Isn't it the same cooling system as the STX? The 16803 chip is also 1.5X the size of the 11002 so that would account for lower temp as well.

Greg.

[Bassnut]

Chip size must make difference. My cam is at -35 with 25deg ambient at 65% power, looks like ittle go to 30deg ambient at least which is over the delta 60deg spec. 6303 is way smaller than the 16803, I suspect the general delta spec is based on the STX16803.

[Paul Haese]

I probably is the sensor size but the STX did come out a long time before the STXL. Peter might weigh in here and let us know for sure.

[gregbradley]

FLI quotes I think what the camera's maximum cooling is with smallest chip. For example my Microline does -40C most often and -35C for sure and up to -45C in winter. But the 16803 Proline does -30C all year round but not always -35 and will do -40C on a cold night. But its not worth doing dark libraries based on what it will do sometimes but what it can do every time.

The marketing for STXL says its the same as STX except for 3 things and cooling wasn't one of them.

Greg.

[Peter Ward]

Yep, simple physics... A bit like trying to chill a large room with a flat BTU rated airconditioner. Using the same unit in a small room it will result in colder temperatures....but as I've posted elsewhere, it really matters not
provided your chamber temps are stable...which SBIG do quite well ;)

Besides, anyone using 16803 or 11002 sensors would well know with that sort of CCD acreage cosmic rays rapidly become your biggest noise problem!

The STX 16803 chamber is really quite big as it also houses the guide chip (hence the need for 65mm filters).

Contrary to popular opinion, you can also use 50mm square filters!

SBIG have a 7 position, 50mm carousel, which I use quite often, but in doing so have to use the remote guide head, instead of the internal guider.

I'm quite confident you'll be cranking out some remarkable images with the new "tank" :)

[RobF]

Remind me to duck when the tank opens fire!

Wowser that's a rig and half alright Paul. Actually I think lots of us are really enjoying your recent upgrade threads on the dome etc. Its the next best thing to fantasizing if we wind the lotto ;)