View Full Version here: : NGC1365 with all new data
Paul Haese
22-10-2009, 03:00 PM
Well slowly getting everything sorted. The good news is that I have the guiding working really well. I have also got the flattener on the QSI now, but don't thing it is in the perfect position. You will note that the stars just below the galaxy are near round; at the top of the image nice and round, but at the bottom of the image are showing oval shapes. That means that the camera is not square with the optical line. I suspect that there might be some slight sag causing this issue. Any ideas?
Optically this image is far better than the previous one. More detail can be seen. Compare both images with the links below if you like.
New image (http://paulhaese.net/NGC1365-QSI-flat.html)
Old image (http://paulhaese.net/NGC1365.html)
The image does need nearly double the time that is currently has as a starting point. I will do this in the coming months.
I welcome your comments and thoughts.
Greatly improved processing on this barred spiral Paul. Its taken on a more aesthetic natural feel. Possible camera tilt present, but I think its minor and doesn't detract from the scene. You should be happy with that. Its not a easy target to do well. I know I performed selective masking to handle to nucleus details when I had a shot at it. You are making steady progress. Well done.
bmitchell82
22-10-2009, 03:42 PM
the new image looks alot better paul kudos to you for such a nasty target to image well.
multiweb
22-10-2009, 03:50 PM
Yeah really nice Paul! :thumbsup: The new rendition is 10 folds better in details and you've nailed the colors. Sure there may be a slight camera tilt but it doesn't distract from the awsomeness in the center IMO. Well done again.
Have you measured the flexure? Link (http://www.iceinspace.com.au/forum/showthread.php?t=51009)
This would be a good starting point for the analysis. If the flexure is zero, then check for tilt and collimation etc.
Paul Haese
22-10-2009, 04:09 PM
Thanks guys, comments appreciated.
Jase and Moon, looking at it I think it might be camera tilt. I tested for differential flexure last night. At the zenith the subs looked the same as the subs near the horizon. That said it could be still a small amount of flexure mixed with tilt. When I get the OAG focused this should sort any flexure out. If it is tilt how do I sort this out? I have a feather touch focusor which might have some adjustment on it.
Jase I used masking for the core regions ot prevent burn out. I have been using the techniques on Ken Crawfords site. Seems to work quite well.
Thanks for the link Moon (sorry I think your name is James) I read up and see what is has to say in full. Just did a quick scan.
strongmanmike
22-10-2009, 05:28 PM
Both images have their pluses Paul but I think the latest is pushed a bit too much so is a bit noisey (not that I am shy to a little noise :P), the first was softer and more natural looking... so what if you add the two images together, round up the stars a tad, increase the star saturation a little, rescale and remove the noise granulation from the lower arm.... :D
Of course I am sure you would rather have the stars round from the start :rolleyes:
Just a little bit of fiddling fun, your work is excellent so far :thumbsup:
Mike
renormalised
22-10-2009, 05:38 PM
Nice shot Paul, if a little grainy. But pretty damn good nevertheless.
Only spoiled by that inconsiderate satellite that decide to leave a trail in your piccie:D
Paul Haese
22-10-2009, 05:46 PM
Mike, not a bad idea for getting rid of the noise, but I think I am gonna get capture more data in the next day or so to get rid of the noise. Certainly the last image I did not push as hard but this data seemed to take more. I still have the other data and I might yet take your idea up. I just don't like that soft look that the other image had. It looked ok when I processed it but now I have sorted the collimation and got sharper data this is what I am looking to achieve but obviously a lot smoother. As you can appreciate sharp data makes for better images in the long run.
You did a great job on the data combine, slightly blurred but looks very smooth now. I defer to your skills.
Paul Haese
22-10-2009, 05:48 PM
thanks Carl. Yeah that satellite came through very late. Pretty weird really as it had been dark for 3 hours when it showed up.
Looking superb Paul, only a pity about the lower quarter of stars,but i think you will sort that out soon.
renormalised
22-10-2009, 05:51 PM
The old adage...just as you think everything is going great, something comes along to spoil the party. It probably had it planned to turn up just as you were taking the pic!!:eyepop::P:D
strongmanmike
22-10-2009, 05:56 PM
If you blink the combo image with your latest sharpened version you will see that all the detail is indeed still all there but without the noise, I think you'll find it is just a first impressions illusion that it is blurred :) I have been caught by this illusion in the past myself :doh::whistle:
But, Yes, get more data that is always the best :thumbsup:
Mike
alan meehan
22-10-2009, 06:02 PM
Paul you have done very well indeed ,that is a beautiful shot of this galaxy
Alan
Hagar
22-10-2009, 09:36 PM
Very nice Paul, Detail, focus etc is great. Camera tilt is a real bone breaker to overcome, even with screw together coupling. Keep at it and eventually it will come right.
dpastern
22-10-2009, 10:20 PM
The new image is much better, and I don't mind the noise. Imagine if we were still shooting with film, that grain would be a *lot* worse.
Dave
Paul Haese
22-10-2009, 10:57 PM
Mike, I am gonna take the lead that you and Fred show. This image is getting 10-15 hours worth of data in the coming months. It just needs lots of hours to get the noise down to nill. So that is my goal. Figure if you can go deep so can I.:D
Thanks Alan.
Doug, thank you for your praise. I find this all like planetary imaging really. Every thing has to be controlled precisely too. This camera tilt is going to take some nutting out though. However, I will sort this out eventually.
Dave, yes grain was accepted, not so now though. Funny how 4.5 hours worth of data can still produce noise. 4.5 hours in the DSLR would produce really smooth images, not so with this sort of imaging. Mind you the DSLR images can never be as sharp either really.
bloodhound31
22-10-2009, 10:57 PM
No complaints from me Paul. Exquisite work mate.
Baz.
dpastern
23-10-2009, 12:32 AM
I thought CCD imaging's advantage over DSLR astro imaging was less noise at longer exposure levels?
Dave
Paul Haese
23-10-2009, 08:33 AM
David that is true but many imagers use shorter subs for their colour information. For instance my 10 minute subs are pretty noise free but the 5 minute subs are fairly noisy. Whether this is normal for CCD I don't know. With a CMOS sensor that is cooled, anything over 5 minutes is pretty noiseless. I think where CCD take charge is going that little bit longer and the fact that you can get a whole sensor in one colour, not just a third of a sensor.
dpastern
23-10-2009, 10:13 AM
Yeah, I believe the longer the sub the better. From what Alex was saying to me on another thread, 5 min subs with a dedicated CCD camera aren't going to be much better noise wise than DSLR. It's when you get 20min+ subs that cooled CCD cameras will really start to kick some booty.
Dave
Paul Haese
23-10-2009, 03:01 PM
Dave, the reality is though from what I have been told is that subs are usually no longer than 10 minutes. Anything longer than that can be wasted if there is a guiding error or satellite trail. It is an interesting business for sure.
Paul, I really like this image. None of the minor issues can detract from the fact that this is a fantastic image!
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