|
This is getting a bit off my own topic but anyway..
I managed to get in a quick focus offset test tonight before the clouds rolled in. I ran an auto focus routine in SGP, took ten 30 second subs then auto focused again and manually offset the focus outward by an arbitrary amount before taking another ten 30 second subs, I integrated them as separate runs in astro pixel processor and saved them as TIF files so I could open them in photoshop and have a look at the blue channels only, the offset integration had noticably tighter focus on the blue stars at the expected expense of redder stars.
I more or less conclude from that, that even with the OSC I can improve the images some more by investing the time to work out the best focus offset for the blue channel and shooting two lots of subs to pick the red and green out of one set and blue from a focus offset run. SGP makes it easy enough to do, I set up a filter wheel simulator with a blue and lum only, the focus positions are set with the appropriate offset between them, the auto focus routine focuses using the "Lum" filter and the blue has an offset automatically applied. I can then set up two lines in the target sequence, one for the lum "Filter" and one for the blue, the blue will focus as many times as the normal setup would before applying the offset value.
It also means that even this little cheapie scope would likely benefit from a mono cam and RGB filters.
|