DSS Questions

[AstroAndy]

Hello

Here's something I've been wondering about:

When stacking subs and calibration frames in DSS, and then creating a filelist, how come that wehn importing the filelist, with the same settings

DSS sometimes stacks less than it did before. All the settings are exactly the same (e;g. reference frame, star detection threshold, all paramenters).

It should stack the same as before if nothing changes, correct?

Also, I know, or have read, that DSS needs to find 8 common stars, and "see" fainter stars for some subs in a stack to be stacked.

Would it make sense to choose a reference frame of, say 3 min. in a stack with 5 and 10min subs, being that faint stars in a 3min sub are not so faint in a 5, or 10 one, so as to be sure to stack all the subs.

There doesn't seem to be a problem with unrecognizable (elongated) stars, it just stacks less sometimes.

Andy

[Jannis]

The referance frame should be of similar quality as the frames you're stacking when it comes to ISO and exposure. Also, when once registerd, you shuoldn't need to re-register the frames, just load them and jump right to stacking - and thus with the same settingts and frames, it should indeed stack exactly the same every time.

For star detection, they say minimum is 8. In a low-star image, i try to get 12-20 minimum, and for a high-star image i go for higher. often ~80-100+. This many isn't needed of course, but it dosn't usually hurt either.

[AstroAndy]

Ty, maybe it was the reregistering... I usually take the best image frame in the middle (e.g. 10min longest, 3 min. shortest, I use a 5 min. reference frame.