Sombrero Galaxy 21-04-2015

[PeterSEllis]

Hi Guys,
My first post, so take it easy on me.
I have been doing Astrophotography for a bit less than a year and have about 40 photos, mostly of fuzzies. All my shots have been done from Boronia, Melbourne, Australia, where light pollution is not good. My shots are not going to be featured on the front pages of Sky and Telescope, but as one author said on the subject of Astrophotography, if your happy with them than that's all that counts, and I agree with him.
My set up is a SkyPOD, Celestron C11 (standard the not Edge HD), Canon 1000D, Orion Autoguider. Generally I take about 60 x 1 minute exposures
(any more than 1 minute I find that the light pollution causes more grief than it is worth) stack them with Deepskystacker, then take to the results from DSS then process it with Photoshop. Sombrero is not my best photo, so if there is any interest I will post some more photos.
Cheers
Peter

[theodog]

Welcome.:hi:
Looks OK to me. Nice start Peter.

Don't be afraid to post images. While it may seem intimidating, others are really trying to help with their advise and it cost nothing to try what they suggest. If it helps then good. If not -nothing lost.

So, what else have ya got?

[raymo]

Hi Peter, Welcome to IIS. If that's not your best image I'm dying to see
the one that is. The only criticism I have is that the sky is much too black.
raymo

[guggle]

Hi Peter,

Great effort - I'd be happy with that too!!

I don't live that far from you so I hear what you say about light pollution. I've bought myself a light pollution filter which seems to do a pretty good job. Recently I was able to take 2 minute exposures with it and I was very happy with the result.

I agree with Ray that the sky appears a little too dark, but on a positive note, your stars are nice and round, so your auto guider is doing its job!

Cheers, Michael.

[andyc]

Welcome Peter! :hi: And a nice start too, both this and your other images. I have a couple of queries: What ISO did you shoot at, and also what colour was the background of one of your 1-minute subs?

The reason I ask about the background colour is because I'm surprised that you say you can only do a 1-minute exposure from your location. It is likely at least as dark as mine, and a C11 is 'slower' than my f/5 scope - so with the good guiding you seem to have (nice round stars) you should be able to expose for a lot longer than 1 minute? If you're not already aware (due apologies if you are), you can probably push the exposure up to the point where the background is significantly not black , so that the histogram on the back of the camera is well detached from the left side of the graph. You can get a darker sky back in processing after stacking all the frames, but use curves rather than clipping the black with levels or you might lose low-contrast information. You might be surprised how washed out and grey you can push original subs and still be collecting quality information (more so if you're shooting the higher bit depth RAW images too, which DSS should handle).

Anyways, good luck and have fun!

[rustigsmed]

nice one Peter,

Yep i'd recommend a light pollution filter, I went from 70 second subs at my locality to 3 minutes. makes processing a lot easier too.

Cheers,

Russ

[PeterSEllis]

Hi Andy,
Thanks for your comments.
I use a focal reducer to drop the C11 down from F10 to F6.3. All my shots are done at ISO 1600.
See the attached Photo of one of my subs, a pictures is worth a thousand words.

Cheers
Peter

[PeterSEllis]

Hi Russ,

I would be interested in hearing what sort of light filter you use, most of the sodium vapors are disappearing around here, to be replaced by new broad spectrum fluorescent lights, so I had not considered using a filter for that reason. If you having a success with them, I will certainly investigate the idea further, anything to make the skies blacker has to be a winner.

Cheers
Peter

[rustigsmed]

Hi Peter,

I use the astronomik ccd cls it seemed to be one of the best one from my research although there are a few brand options out there.

While a LP filter is more effective on sodium lit areas vs broad spectrum there still should be an improvement to signal vs 'unwanted signal' as you are blocking a lot of rubbish hitting the sensor.


Cheers

Russ

[PeterSEllis]

Hi Russ,
Thanks for the information, I will order one in and give it a try.

Cheers
Peter

[andyc]

Thanks Peter, and interesting! What's the field, I don't recognise the four galaxies? The sub doesn't look over-dark, but does look quite washed out, lots of background glow from somewhere or LP as you originally suggested. Unless the Moon was bright/nearby, or the sky was hazy, I can only suggest you explore the light pollution filters you're already discussing. I'm not immediately sure what else could be the issue, sorry :shrug:. But good luck!

[PeterSEllis]

Hi Andy,

When I'm suffering serious withdrawal symptoms, I will occasional do photographs of DSO's when the moons up, but not in this case, it fairly typical of my subs. The Field is M85, M86 part of the Leo Triplet. When I moved out here 38 years ago the site was pretty dark, not now, civilization is catching up with me. A filter might be the go, I will get one and give it a try.

Cheers
Peter

[cometcatcher]

I don't know if a light pollution filter will help much with galaxies. I never had them work in that respect. LP filters work best for nebula.