Hello all,
Clear night last night, so managed to grab some more Ha data of IC2944 - the Running Chicken Nebula.
Not happy with all subs due to focus slip through session (had to bin 3/9) - my own fault...I'm going to stick up a big sign somewhere to remind me - focus,focus,FOCUS!!!!!
Canon 40D (modded)
Canon 300mm f4L IS lens @f4
Astronomik 12nm EOS clip in Ha filter
16 x 15min subs (4 hours total), iso1600, ICNR
HEQ5 Pro mount
Images Plus, PS CS4
Nice work Doug, supprising what can be done with DSLR and stock lens. Focus looks good to me, and guiding is smick. Very low noise for 15min subs at 1600 ISO with ICNR too, amazing.
Looks great. Amazing work with a DSLR. I agree with Fred - focus is spot on and you have remarkably very little noise. The only thing to get it smoother would be to lower the blackpoint a bit I reckon. Top work though.
Thanks all - but I felt there was something poor about this one.
I went back and looked at all the 16 subs and dumped 10 of them due to bad focus. So this will hopefully be a work in progress and I can post something better soon.
On the upside, I got to grips with Shadows/Highlights for bringing out hidden contrast detail whilst doing this image.
To illustrate, I've posted a crop of one of the original Ha subs.
Off topic - As Craig mentions, although 4 hours of data - the ICNR really meant 8 hrs capture time! This I think ties in with the ongoing DSLR v's CCD debate - the much longer subs needed to get passable Ha response from the DSLR means that they're open to tracking/focus errors. And it often shows!! When a 15min shot takes 30mins in the DSLR I may need to check focus after each shot!!! Gawd!
Doug
That's a pretty impressive image cycle there Doug, 15min light followed by a 15min ICNR. A significant amount of data, but to have all those soft subs mixed in there must have been rather frustrating. Also, to be taking 15min subs @ ISO1600, you do a top job of processing a smooth image in the end - roll on the RGB data As per usual, nice work.
That's a pretty impressive image cycle there Doug, 15min light followed by a 15min ICNR. A significant amount of data, but to have all those soft subs mixed in there must have been rather frustrating. Also, to be taking 15min subs @ ISO1600, you do a top job of processing a smooth image in the end - roll on the RGB data As per usual, nice work.
Michael
Cheers Michael - yes, the out of focus subs are a pain. But, I've only got myself to blame. I'll be checking focus more thoroughly in future.
Doug
Any reason you are using ICNR instead of dark subtraction?
When I used a DLSR I made a dark library for different ISOs and times and then made a master dark. With Images Plus and CCDstack you can use adaptive darks and the software adjusts for different levels of noise from different temps and does a very good job at it.
So it would save a lot of time and you could use that extra time for more exposures.
CCD stack was a nightmare with DSLR subs, I was forced to go back to IP for DSLR pics, but the latest version (just out) seems to handle large pics/stacks much better, and then yes, the adaptive dark feature works very well.
Really good job but 8 hours of capture is a lot of work.
Frank
Cheers Mr Guru - keeps me off the streets!
Quote:
Originally Posted by gregbradley
Hi Doug,
Very nice capture.
Any reason you are using ICNR instead of dark subtraction?
When I used a DLSR I made a dark library for different ISOs and times and then made a master dark. With Images Plus and CCDstack you can use adaptive darks and the software adjusts for different levels of noise from different temps and does a very good job at it.
So it would save a lot of time and you could use that extra time for more exposures.
Greg.
ICNR by force of habit and not possessing a darks library. But your reasoning obviously makes sense. All my images are becoming sagas, so I'm going to look into the darks library thing - I'll check out the adaptive dark feature in IP . Thanks for the info.
Quote:
Originally Posted by Bassnut
CCD stack was a nightmare with DSLR subs, I was forced to go back to IP for DSLR pics, but the latest version (just out) seems to handle large pics/stacks much better, and then yes, the adaptive dark feature works very well.
Cheers Fred
Quote:
Originally Posted by bmitchell82
Nice work there doug, as a fellow 40d user i know that Ha can be a royal pain, and with a little apereature it can be very hard.!
what was the ambient temperature that you where shooting in?
Not too sure mate - reckon around 8 degrees maybe.
Ha isn't the easiest on a DSLR that's for sure - checking focus between each shot in the absence of a bright star in the FOV is going to be a nachtmare!!!!
I developed a little routine to help with the "user" program of Synscan which makes life a tad easier (just a tad mind!!) Find a bright star without Ha filter - set it as user object 1. GoTo and Frame the object you want to image - set it as user object 2. Go back to obj 1 (bright star), insert Ha filter into imaging train, focus, slew back to obj 2 - start imaging!!!! Simple Eh!?
The bugger is that if you use this to method to focus in-between shots, you stuff around with the guiding a bit too much.
Doug
ahhh thats why your noise was at a minimum. i have found the magic temp for the dslr to start working better is about 10deg. by the time you get to 5 deg, its humming and when you hit your zeroish deg iso 800+ becomes reality!
As for capture in ha i go the route of using Maximdl, its very accrate and easy to use with its... move scope here function. that is for the start of the night, i hit calibrate, it takes 3 images finding the arc per pixel and the sensor details from the camera.
Making sure the polar alignment is spot on, i then do a star sync close by generally on a bright star, and while im there I focus in the ha tuned dslr, then i progressively get closer to the object, and if its particularly faint ill do a triangle around it. then goto that location, take a photo of about 30 seconds, use pinpointLE to resolve the image, this then puts a overlay of your image on the planetarium prog giving the angle/size and exact location. you know exactly where you sit!
From there its a matter of flipping back to a bright star somewhere in the area focus every few hours. and maxim will bring you virtually back to the same spot again! and you can also center it with the same function i said before. right click, point scope here. No more fiddling like a lerner driver trying to get it centered correctly!
Im currently working on a Ha mosaic of the lagoon area with a 40x60 minute panel 10"+40d and its looking very smooth of late! ill send you a link once i finish it hopefully this weekend.
Im currently working on a Ha mosaic of the lagoon area with a 40x60 minute panel 10"+40d and its looking very smooth of late! ill send you a link once i finish it hopefully this weekend.
.
thats why your noise was at a minimum. i have found the magic temp for the dslr to start working better is about 10deg. by the time you get to 5 deg, its humming and when you hit your zeroish deg iso 800+ becomes reality!
