[Aavso-photometry] Flat Stuff

[Michael Koppelman]

I have had very good luck with twilight/dawn flats (sky flats?) too. 
Mira lets you combine with an intensity scaling. It basically does a 
weighted average so you don't have to worry tons about the low S/N 
frames. I usually change the exposure time a few times during the run 
to try to keep the counts reasonable. It's a great way to go but I'm 
not always around during twilight/dawn (in fact rarely) so I need an 
alternative.

I wonder about these temperature compensating focusers. How can you get 
a good flat when your focus is changing continually? For pretty 
pictures, I can see why the temperature compensating focuser would be 
nice but for photometry I can't imagine it is really necessary, is it?

Cheers,
Michael Koppelman
http://www.lolife.com/astronomy/



On Jan 17, 2005, at 2:19 PM, Chuck Pullen wrote:

> I have pretty much taken to dawn twilight flats.