After last nights session, I thought all my problems had been solved.
Not so.
This is 17x5min @ ISO 400
I've only stretched it just enough to show the flaws.
All the camera and stacking settings were exactly the same as last night.
The only difference is that the temperature was a few degrees warmer.
Oh well.
Although my experience has only been with older Canons, both normal and modified 350d and 1000d. I found that I acheived better quality and less noise when I used the In camera Noise Reduction rather than seperate dark frames.
Although I was cutting my imaging time in half, the good quality 800asa and 1600asa shots I obtained were worth it.
We have another 4 clear nights ahead, with frost predicted too. Woot woot
At least I know now not to bother imaging unless the temp is below 8C.
In theory that is, I get to test it this week.
I believe the angled streaks in the background are a sign of a mismatch in temperature between the darks and lights. What does the EXIF say about temperature of your darks versus lights?
Hmmmm, I usually start my imaging session by taking my first handful of darks. And follow up with more as the temp drops.
Terry, I'll check the exif info and see what it says. thanks
I think Terry might be right J.
Here is a herringbone type artifact I got when I used darks
that were wrong by only 2 deg C at most.
First pic...wrong darks.
2nd pic....darks correct to nearest 1/2 degree.
Steve
But I don't understand where the camels come into it???
jj, all I can suggest is try ICNR and bump it up to a minimum of 800iso and I reckon the results will be heaps better
There are so many things right in your image (image scale, positioning, colour, brightness etc), but it just needs a tweak in focus and the iso bumped up. And ICNR is always worth a try. Some like it, some don't.
Some nice detail JJ but as you say the noise is a worry. Remember though this is quite faint and such short exposures will always struggle to get on top of the faint signal you have to work with.
I think I would have been looking at ISO 800 as a minimum for this sort of image on such a faint target. Noise can always be controlled but signal can only be lifted with exposure and ISO.
Don't despair yet. This camera may be different from what you are used to and some changes of habit might be required to get the results you are after. Keep at it.
Don't despair yet. This camera may be different from what you are used to and some changes of habit might be required to get the results you are after. Keep at it.
You're quite right Doug.
But.... if I can only image deep sky with it when the temp is under 8C, to me, it's just not good enough. I've been offered a 20Da.....I think that may be the way to go for me.
I have added another copy of m83, a restack, using NO darks or flats.
So we have narrowed the problem down further.
Next time I'll try shooting at ISO 800 and see what that does for it.
Thanks for the input on this.
.
