First image for quite a while. Gradually getting the polar alignment and PEC improved bit by bit.
For this image I pushed the ISO up to a 1000 to see how it would go and try and get away with 200s lights instead of 300s - I have a much better success rate autoguiding for 200s.
It came out quite a bit noisier than I expected. I generally run 800ISO anyway, but this seems noticably noisier and not worth the slight increase in speed.
Anyway here it is. Best 13 of 15 x 200s lights with 40D (unmodified) WO 0.8x focal reducer, YO ED80. I applied darks and flats and processed in Images Plus. Cropped and tweaked up in photoshop. I feather selected the centre and brought out the red.
Hi Rob. You do have a little noise to deal with. The 40D seem to have a much better signal to noise ratio when used at 800ISO but there are a few things you can do if you are going to use higher ISO figures. I hope you don't mind, I have taken a copy of your image and run it through Noiseware on the default setting. You can download a copy of NoisewareCE off the net free at http://www.imagenomic.com/download.aspx Scroll to the bottom of the page. The standard version is very cheap and has more features.
I made no other changes to this image. Hope this helps.
Good Stuff Rob. As Doug points out...A few noise reduction tweaks and shaazzam - a super image. Colours look good and some nice details on display. Keep them coming.
ps... I heard you should stick to the standard iso settings 200,400,800,1600 as the intermediate steps are software based and less worthy!!!!!
Now I'll probably be hung out to dry but I remember that from an Astro or Photography forum somewhere!?
Any comments anyone???
Doug
Cheers Guys, another great tip to stick to standard iso settings... that would certainly explain why 1000 is no much more noisy than 800. I might give a try either side on 800 and 1600 and see how it compares. cheers, Rob
Hi Rob, Glad the link was of help. Another little thing. If you had moved the scope a bit youmay well have fitted both Lagoon and Trifid nebulas in the one shot. It is possible when you are using the 0.8 WO reducer/flattener. I actually fluked it one evening.
We've found the in camera noise reduction on the 350D works really well. Saves mucking about with darkframes etc. Takes a little longer but the end result is worth it. When you stack a lot even at high ISO the grain can be pretty acceptable (Michael {Tilt} taken a great shot recently which I hope he posts that proves this beyond doubt). We also use the mirror lock up function too.
Thanks David - I use Images Plus camera control and it doesn't allow using the mirro lockup so I use liveview. I'll have to give the ICNR a go again one clear night. I find when there's any chance of cloud about I'd rather get all my lights out of the way while the gettings good... also have a limited horizon and the short imaging windows favour the darks. Do you know if the ICNR works with the highest 3200ISO setting? cheers, Rob
Quote:
Originally Posted by Prickly
Hi Rob,
Thats a terrific shot.
We've found the in camera noise reduction on the 350D works really well. Saves mucking about with darkframes etc. Takes a little longer but the end result is worth it. When you stack a lot even at high ISO the grain can be pretty acceptable (Michael {Tilt} taken a great shot recently which I hope he posts that proves this beyond doubt). We also use the mirror lock up function too.
Congratulations.
David
Quote:
Hi Rob, Glad the link was of help. Another little thing. If you had moved the scope a bit youmay well have fitted both Lagoon and Trifid nebulas in the one shot. It is possible when you are using the 0.8 WO reducer/flattener. I actually fluked it one evening.
Thanks Doug, yeh I actually fluked that myself a while back - it's one of my better pics actually... a very pleasing combo . I thought I'd try the other side of the lagoon for this one
He has tested 40D sensitivity and this page shows ISO 100 on the 40D gives the same results as ISO 400 on a 400D and 20D. I think, if you can read between the french, that he is saying they have cranked up the sensor gain in the 40D by a factor of 4.
I had thought that the mirror lockup did work in images plus. Weve been using images plus camera control for the 350D. Maybe we've just been leaving a few secs delay after the image has been taken. Michael (Tilt) has been doing most of this and could tell you.
I really am not sure about this ICNR at 3200 but I believe Michael was using this with 1600 fine. Compared to our early attempts theres just no comparison with ICNR on.
I think Michael was leaving a few secs between images too to let the chip cool (which would be pretty quick here in Canberra at the moment!!)
(like I'm the expert!!!)
