|
Hi all,
Thank you for the great feed back... It is a great feeling when things workout. Hanging to get back out there and do it again, and try to not only get a bit more detail but also get some color data. Perhaps there will be more surprise details like the "Kiwi nebula" spotted by Brian.
Bo and Bruce, getting guiding sorted and getting some descent shots for a change feels like being a kid and getting a new toy at Christmas.
Things can only get better from here, Raymo.
Chris I think my guiding will be ok for longer exposures, since during the whole time the subs didn't move a single pixel, so I don't see why I should have any trouble getting 30 minute or longer subs, judging by the last exposure even a couple of hours should be OK!!!
Pat, these pics were taken through a F6.3 focal reducer then cropped to get rid of the vignetting... I still can't get the flats working properly, every time I try, my pre-processed subs in Nebulosity 3 look washed out, so I decided just to crop the images and get rid of vignetting that way.
Cam and Michael, the way I got to the bottom of this dilemma that was haunting me for ages was experimentation and trying different things, but I'll tell you that as it turned out, I was polar aligning properly and quite accurately to the SCP for a while, but my drift errors were caused by MIRROR SHIFT!!! The 8SE mirror is mounted quite solidly, judging by when focusing back and forth, the star doesn't move in the view like I've seen in other SCTs, but non-the-less over time there is enough of a mirror movement during the exposure to ruin anything over 5 or so minutes. That explained also why I fluked a 20 minute exposure about 6 months ago and couldn't replicate for all this time... basically I was exposing close to north and there the mirror was getting pulled only down by gravity, so once it settled it obviously didn't move any more and the 1200 second exposed pic came out spot on.
Now all I need is a bit of luck for a few clear cloudless nights between last and first quarter moon dates...
Mariusz
|