Yes..Another Centaurus A

[peeb61 (Paul)]

Hi All,
NGC5128 taken with a QHY8L one shot colour CCD camera at prime focus with a Saxon ED80, on a polar aligned EQ6 Pro Mount and auto guided with a Meade DSI using an 8inch f/4 Newtonian.

The image is a composition of 58 x 5 minute exposures at -10deg, Flats and Bias images and was taken over two nights, last Friday 13th April and Friday 27th April 2012.
Stacked using Deep Sky Stacker and processed using Adobe CS5.


Paul

[RobF (Rob)]

That's a great image Paul. You've really captured the glow of the galaxy and contrasting star colours wonderfully. You'd have to be happy with that.

[jjjnettie (Jeanette)]

There's some pretty funky back ground colour happening there. I think maybe you need to set your black point in curves to cure it??
You've got some great data there, it's well worth a repro to try to even out that back ground.

[Peter.M]

Would have thought you would image the other way round, through the newt and guide with the ed 80 but whatever floats your boat.

[ballaratdragons (Ken)]

Originally Posted by Peter.M

Would have thought you would image the other way round, through the newt and guide with the ed 80 but whatever floats your boat.

Peter, the ED80 creams an 8" dob for image quality and resolution

Paul, mighty nice image

58 lights!!!!! Wow!

[RobF (Rob)]

Originally Posted by ballaratdragons

Peter, the ED80 creams an 8" dob for image quality and resolution

Oii ! It ain't so Ken - a properly collimated 8" Newt is up there with a decent 6" refractor in the right hands me would argue. Not that I'm biased in any way
Of course it won't ever have the ED80s nice wide FOV, even at F4

[Ross G]

Nice photo Paul.

Great detail.

Ross.

[ballaratdragons (Ken)]

Originally Posted by RobF

Oii ! It ain't so Ken - a properly collimated 8" Newt is up there with a decent 6" refractor in the right hands me would argue. Not that I'm biased in any way
Of course it won't ever have the ED80s nice wide FOV, even at F4

Guess I'm bias towards the ED80 for imaging DSO's, and bias towards the reflector for visually observing DSO's

I guess it comes down to the user

[Paul Haese]

Deep image with lots of gas and dust. I think you might have an issue with your flats though or there is a gradient that needs addressing. Lower right and upper left has a blue cast in the image. The rest has a liberal level of gold / green cast.

Any chance of seeing a bigger image?

[Stevec35 (Steve)]

Nice deep detailed shot there but there is a problem with the background

Cheers

Steve

[bmitchell82 (Brendan)]

Ken you blasphemer!!!! go wash your blaspheming mouth out!

My 254 pants the ED 80 like a Olympic sprinter and a 5 year old running the 100m in resolution, and light capture!!! geez Rob hear whats these folk are talking about now days!

(btw lovely cen A ill admit there is funky business happening with your back ground but you have caught to most of the degree the outer faint halo! well done)

[peeb61 (Paul)]

Thanks all for your constructive comments.
jjjnettie-tried this black point setting in curves, it pushes the histogram way to the black area and the processing cannot recover from it, unless someone can give me a crash course in its correct use?

PeterM - Still having troubles with the f/4 Newt with collimation issues and the dodgy stars from the outcome of exposing with this setup, thought I needed a break from trying to work it out as I have spent too much time trying to work out were the issue lies and not imaging so I thought I'd flip the system and have a holiday!

Here is the link to my woes here....

http://www.iceinspace.com.au/forum/s...ad.php?t=82670

Paul - Would love to post a bigger image as it would be good if you could have a look at it, only if you have time that is. What are my options for getting it too you?

The background gradient is another thing to try and work out, I never used a deep sky filter, or could there be the chances of scattered light? The second lot of images I took were taken when the crescent moon was on the opposite side of the sky...light from this? I will continue to reprocess to try and weed it out.

Paul

[peeb61 (Paul)]

A quick stack and process minus the flats, just the lights and bias frames.

I think it does need flats.

Paul

[multiweb (Marc)]

Nice repro Paul. Beautiful field and details.

[TheDecepticon]

If you could clean up the gradients, it would be a very good shot! That doesn't mean to say that it is not an already top effort. Go the ED80!

[TrevorW]

Yeah a good effort and FOV

[peeb61 (Paul)]

Thanks Marc, Graham and Trevor,
It still needs work but its fun and I'm also thinking about the skywatcher Focal Reducer to fix the corners of the image.

Back to the drawing board.!

Paul

[gregbradley]

Overall a very good shot. I read about your troubles.
Hey you got some decent tracking!

Generally a reducer does not flattener the field, a flattener does. So putting a reducer on (unless others have experienced otherwise with this setup) you will get worse corners not better.

You need a flattener for your ED80. QHY8 is APS sized chip and the lack of correction in the corners is being picked up by the largish chip.

I think you would be better off sacrificing a bit of field of view in this image and crop it a bit to get rid of those coma'd corners.

Background is better but still not right. There is a light blue haze.
Gradients make it hard to improve contrast and get nice rich colours.
So you need to address them early in the processing sequence.

Cheers,

Greg.

[peeb61 (Paul)]

Hi Greg, thanks for the information regarding the flattener and point well taken. Saves me a bit of money I suppose. This set up is only until I can sort my other problems out to which I will work on this coming full moon phase.

The background of my image is a tough one to work out. (For me anyway.) I am reading different forums regarding this issue in how to combat it.

Many thanks
Paul