Quote:
Originally Posted by rally
Alistair,
Ah - the eternal compromise !
Cost Vs performance, Vs weight, Vs purpose, Vs FOV, Vs image scale, Vs compatibility, Vs features . . . .
I'll toss in my thoughts here.
What is the image circle of the 10"F4 ?
How well corrected is it ? - ie how much of it will be useful ?
How much weight can your OTA/focusser support ?
Are you set on only ever using the camera on the one telescope ?
If not what would be the focal length of your possible other ? - Longer or shorter ?
Then there is the other stuff :
Is it compatible with the software you use or intend to use, are there good drivers, that work all the time, and are they likely to be supported in the future versions of the operating systems - there are some that will not !
Do you want to guide internally, in front of the filter wheel, do you want to use AO (probably not at 1000mm), do you want an integrated internal or external guiding system, are you going to use off axis guiding or guide scope, do you want the minimum cable count for cameras, filter wheels, power supplies, is weight a consideration, what about electronic focussing and rotation, maximum cooling, download times, binning capability etc etc - all considerations that are individual to you and your gear and directions.
Rally
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Thanks for all the info Rally,
to answer a few questions,
I'm using a home built Serrurier Truss. Pic attached.
I have spent a fair bit of time on this scope to make sure it is rigid and that it holds collimation at all orientations, thankfully it does. not perfect, but acceptable.
I am using Carbon Fibre Truss nodes to minimize focus shift over the night.
The mirrors are from Orion Optics and the secondary is 70mm.
I've entered all measurements in Newt, and it says that the
100% Illumination Diameter 11.115
75% Illumination Diameter 44.414
Not sure which I should account for when thinking of a ccd diagonal.
the Focuser is a 2" moonlite and although it is not heavy duty per se, I'm told it can easily hold 3 kg's.
But obviously, the lighter, the better.
I am using an Off axis guider - the TS9OAG, and have had no issues with getting consistent 20 minute subs during testing.
Thanks for the pointers Peter, Greg and others.
I've had a look at the SBIG ST10xe specs again and dropped a PM to clive. does look very attractive with a 77k well depth, 70% plus QE and 6.8micron pixels.
As for FOV, I was told by someone here that pixel size determines FOV, apparently not.
The SBIG STF-8300M is good value at US$1995, which would equate to AUD2480 with the local supplier as according to them, purchases from SBIG direct would not carry the 2 year warranty.
I will get the SX filter wheel with the 7 position wheel and 36mm baader filters. that, along with the lodestar and my TS9OAG, would just about be within my budget.
other option is the ST10Xe which comes with filter wheels.
There are some stunning images taken with this camera, But I just worry about reliability given its age.
I've had enough with the qhy series to stay away from them, I've reached a stage where I want something that's reliable and will just work as expected.
the trius series mentions heating of the front glass and are argon filled.
last option would be the 694 chip. the 814's 3.69 micron pixel does seem to small.
As mentioned, I will be using a debayered 600D DSLR as well, not just this CCD.
Cheers
Alistair