On 3/29/2010 3:17 PM, Stefan Lilge wrote:
A guy from Potsdam (which is the capital of the german state "Brandenburg",
which borders directly to Berlin; you leave Berlin to the southwest and
enter Potsdam at the same time) recently posted a good image of NGC 2392 in
a german astro-forum. He did it with 2 second-exposures with an
EMCCD-equipped camera. This camera goes incredibly deep with short
subexposures. See
http://www.astronomicum.de/modules.p...ewtopic&t=7620 for
50x5 seconds of M27 in the upper row and 25x10 seconds in the lower row (the
columns show different gain settings for this camera).

I wanted to try something similar with my SXV-H9 camera, as I think that it
has by far the best "conventional" CCD chip with antiblooming.
I cheated a bit though and used 10 second subexposures.

Taken from the middle of Berlin with a 10" Meade ACF at f/7.2 on a G11
mount, SXV-H9 camera, 42x10 seconds L, 17x10s R + 15x10s Ha, 28x10s G,
25x10s B.

http://ccd-astronomy.de/temp3/2392colourgut.jpg

Stefan


I was thinking Luky imaging needs sub second exposures. It would here.
I've found that in 5 seconds the FWHM of a star is pretty much the
same as for many minutes. At 2 seconds I see a slight difference.
Below that the star usually is too dim to get a good reading but
watching the video camera I had before it fell out and I stepped on it,
I'd need half second or shorter to have much improvement then I'd have
to throw out 80% of the frames. Easier to wait for that super night.

http://www.spacebanter.com/attachmen...tid=2262&stc=1

Rick

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