Yet another NGC 253 (with a DSLR)

[naskies (Dave)]

Hi everyone,

After reaching the end of another busy semester at uni, I've finally started getting back into imaging again Wow, there have been some stunning photos posted on IIS recently!

Here's my attempt at Sculptor Galaxy, plus one of the straight-out-of-camera subs when pointing directly overhead.

The blues are a bit highly saturated, but I blame it on the Mac OS X desktop background

Details: 44x 360 sec subs (4.4 hrs) using a stock Canon 5DmkII at ISO 3200 using a GSO RC8, mounted on an EQ6, guided with an Orion mini guide scope + QHY5.

Thanks for looking!


Dave

[Larryp (Laurie)]

That's excellent, Dave

[Sarge (Rod)]

Well done Dave,

I'll be happy when mine get up to your quality.

Clear skies

Rod

[Paul Haese]

Nice image Dave with good detail and brightness. You might want to consider taking the green cast out of the background. Other than that the image looks good, although it ought to be a little bigger.

[Poita (Peter)]

Thank you so so so so much for posting a untouched sub alongside your image. It is unbelievably helpful to people starting out to know if what they are getting out of their camera is useful or not. When starting on the imaging journey it is easy to get discouraged when the image in your camera doesn't look anything like the wonderful images posted here.
Seeing a sub alongside a processed image lets you know if more work needs to go into acquisition or into processing. As a noob, it is very very helpful.

[strongmanmike (Michael)]

That's a good solid image Dave, the single sub looks pretty good too.

Welcome back, it's a good feeling after a bit of a break huh?

Mike

[cometcatcher (Kevin)]

Wow. I'm seeing some impressive images coming from 5DMKII cameras lately.

[RickS (Rick)]

Great work with a DSLR, Dave! Are you coming over to the dark side after all those fantastic widefields?

Cheers,
Rick.

[Nico13 (Ken)]

Realy good to look at Dave, thanks for posting.
As Peter has said thanks for the single sub as well as I'm running a similar setup as you but with a Penatx K5 SLR.
Some of my work on the same Galaxy looks sad in comparison and I can see why looking at yours.
I had only been doing 210 sec subs at iso 800 and with only 30 minutes worth the other night before it got too hazy my 30 minutes of subs look like your single sub.

I think my next series will be at least 5 min subs and I'll see how I go from there.

Cheers

[naskies (Dave)]

Wow, thanks for the great feedback Laurie, Rod, and Kevin... it's very much appreciated!

I just finished my final exam today, and will have holidays during the December and January new moons. Here's hoping for LOTS of photon gathering!

Originally Posted by Paul Haese

Nice image Dave with good detail and brightness. You might want to consider taking the green cast out of the background. Other than that the image looks good, although it ought to be a little bigger.

Thanks Paul. Yes, there's a complex background gradient because of the vignetting, as I haven't found a 2" T-adapter nosepiece that doesn't vignette on my full-frame sensor. Unfortunately, the SNR isn't very high here so it falls apart quickly at larger sizes... certainly nothing like your inspirational masterpiece!

Originally Posted by strongmanmike

That's a good solid image Dave, the single sub looks pretty good too.

Welcome back, it's a good feeling after a bit of a break huh?

Thanks Mike! Definitely! It's funny that the subs don't show all the cursing and swearing I had to go through to make the set up work... I'd forgotten all the "do X before Y else Z doesn't work" steps I see you've been creating some magic with your new home / dark site - congrats!

Originally Posted by Poita

Thank you so so so so much for posting a untouched sub alongside your image.

No worries, Peter! It's funny you mention the processing vs capturing issue... I spent my first 6 months of DSO imaging thinking that I wasn't processing correctly. One day, I asked the poster to see a raw sub and a-ha! Turns out I was just shooting under too much light pollution... doh!

Originally Posted by RickS

Great work with a DSLR, Dave! Are you coming over to the dark side after all those fantastic widefields?

Thanks Rick! Haha, yes - my DSLR works beautifully shooting at f/4 and -5 deg C ambient temperatures... but apparently not so well at the RC8's f/8 and +10 deg C ambient. I think it's time to take the plunge into a OSC CCD this summer!

Originally Posted by Nico13

Realy good to look at Dave, thanks for posting.
I had only been doing 210 sec subs at iso 800 and with only 30 minutes worth the other night before it got too hazy my 30 minutes of subs look like your single sub.

I think my next series will be at least 5 min subs and I'll see how I go from there.

Thanks Ken! After much experimentation (and the occasional success), I've found that 180 sec, f/4, ISO 1600 is the sweet spot for my camera. My RC8 is f/8 - hence the 360 sec, ISO 3200 to get the same exposure value.

I tend to shoot ISO 1600 or higher for two reasons:

(1) it requires shorter subs for the same exposure value - e.g. 180 sec @ ISO 1600 vs 360 sec @ ISO 800 - which results in less noise, and
(2) stars overexpose and bleed very quickly on DSLRs so shooting at say ISO 400 leads to stars that look good in the raw sub, but which are deformed upon stretching.

I also find that shooting targets when they are within 1 hr of the meridian results in much, much sharper subs. (I assume it's to do with better seeing and reduced atmospheric refraction blurring colours.)

Good luck!

[Ross G]

A great looking galaxy photo Dave.

Ross.

[DavidU (Dave)]

Very cool Dave

[naskies (Dave)]

Thanks Ross & Dave