Re: autoguiding with DSI ii and ST4 compatible mount

On Jul 4, 6:01 pm, Chris L Peterson <c...@xxxxxxxxxxxxxxxxxx> wrote:
On Wed, 04 Jul 2007 15:49:20 -0700, pascal <pascal_minvie...@xxxxxxxxx>
wrote:

Thanks Rod, but don't you think that a single DSI can autoguide in
between shots, meaning after the 30s shot if the mount has gone out of
the guiding star, it will reajust automatically?

Some software can do this sort of mount correction. You don't actually
guide between shots, but look for a position error in each image, and
send a mount correction if required. Of course, if your mount is
drifting significantly in just 30 seconds, you aren't going to be able
to image without full-time guiding.

Can you get good galaxy composite pics with tons of 30s shots? I
thought that 2 x30s shots composited have a lower amount of light
compared to a 1 mn shot.

Depends on what you mean by "good". Readout noise is significant at 30
seconds. You can certainly stack a bunch of 30 second exposures and get
a reasonable image, but it won't be as good as starting with longer
subexposures. You are correct that 2x30s is noisier than 1x60s.

_________________________________________________

Chris L Peterson
Cloudbait Observatoryhttp://www.cloudbait.com

Yep. Don't expect Jack Newton quality shots, but you can get a nice
color snapshot of almost any galaxy with this method. I used the DSI
and a C8 to do Stephen's Quintet a while back, and the image not only
showed the whole bunch, but showed some detail. Noisy? Yeah. Pretty?
No....but not bad anyway, not bad at all.

Unk Rod

.

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