Re: CCD sensitivity and resolution

Davoud:
If (and I recognize
that's a big if) Hubble GSC 2.2 is accurate, I have captured mag 21
stars with my Tak 180mm f2.8 astrograph and SBIG STL-11000 from my
suburban location.

Chris L Peterson:
That sounds about right. Do you recall what kind of exposure time was
required?

About three minutes.

The magnitudes (21--or less) are correct, but I made a misstatement. I
see that GSC 2.2 has a magnitude limit of 19.5. Sure enough, using
XEPhem with field stars set to mag 30, the dimmest stars displayed are
in the mag 19 range. I have stacks of FITS images that show stars
dimmer than shown in XEPhem, though they don't always show up in my
reduced images because I try to process for aesthetics.

Davoud

--
usenet *at* davidillig dawt com
.

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