Quote:
Originally Posted by jase
The ST4000xcmi coupled to the FS-102 would be a good combination John. 63.8 arcmin squared fov @ 1.87 arcsec pixels would frame many objects extremely well.
I don't know how well these one shot colour camera hold their value. I've seen some secondhand YankeeRobotics cameras on Astromart go extremely cheap considering they "buy new price". I guess there is a high churn for the one shot colour camera. As astro-imagers gain experience, they want to move up ("graduate") to something that offers the flexibility and performance and of a mono chip. Expected delivery of the SBIG ST4000xcmi is flagged for Oct.'07. I feel certain we'll see some seconds on the market by mid next year.
I see your point Fred. IMHO, the discussion of guiding and filters is over-rated. Its really not a big issue with adequate knowledge and acquisition planning.
The price vs. performance is always an argumentative point.
A user supplied 350D costs ~A$1,300 to get modified for cooling (based on prices obtained at http://www.centralds.net/en/price.htm).
The 350D when it originally came out to by new was ~A$1,400. You could possibly do the cooling mod yourself, but looks rather "intense" - http://www.centralds.net/en/process1.htm. (Is the cooling active and controlled i.e with a set temp point for consistency)??
Then, to make your 350D Ha sensitive by replacing the filter - it will set you back another $450 - http://khromagery.com.au/ir_conversions.html. Again you could do this yourself if keen - http://www.astrosurf.com/~buil/350d/350d.htm
So you tally ~A$3,150 for a decked out 8mp, Ha sensitive, cooled DSLR.
Regardless, the cost is certainly under the asking price for the ST4000xmci @ A$4,800. However, its the total package we need to consider. Internal guiding is a excellent advantage and a clean solution. No off axis guiders or guidescopes required. If we add guidescope+rings and dedicated guide camera to the equation, it may begin to balance $. We must also consider sensitivity/well depth, gain and read-out noise into the formula. These values are never easy to get a quantitive answer on with CMOS chips. The CCD will also provide greater dynamic range 16-bit vs. 12-bit for the DSLR. The 350D has 8mp vs 4mp for the ST4000. 350D has 6.4um pixels compared to 7.4um for the ST4000.
Tough call to make. |
Jase the filter is part of the package in the modding of the camera - see his filter specs and results on yun's website. it is very Ha sensitive!! so you dont need to get another filter job done saving you the $450 for David Burren's modification. and it is sealed and moisture proof - he has a heated element to dispell the dew formed by cooling
