M83

[gregbradley]

I hope you are not sick of me posting so much.

Here is another galaxy image from last weekend.
The famous M83 galaxy.

TEC180FL F7,field flattener, robofocus, Tak NJP mount, FLI ML8300, Baader clear, Astrodon 5nm Ha, Astronomik RGB filters.

HaClearRGB 40 130 60 30 50.

One of the nights had very good seeing probably 7.5/10 or higher.

http://www.pbase.com/image/109630053

Greg.

[Dennis]

Hi Greg

Wow – an island galaxy indeed! What a lovely image. This is one of the few images I have seen of M83 where the tones and texture in the fainter arms look very natural and are noise free.

Cheers

Dennis

[Bassnut]

Holly cow Greg, you cranked processing up there :D, try feathering selections, the zone transitions are a bit sudden ;).

Other than that, a striking pic.

[gregbradley]

Oh I see what you mean - the coloured areas to the white star areas?

Hmm, I didn't really crank that up I didn't think that was general curves. I'll check it again.

Greg.

[gregbradley]

Thanks Dennis.

The light capturing ability of this scope is surprisingly good. I love this scope and it was worth the money. Yuri could stop making them at any time just like AstroPhysics did their 180 and 206mm.

Greg.

[strongmanmike]

OK now I'm mad :mad2::mad2::mad2::mad2::mad2::mad2 ::mad2::mad2::mad2::mad2::mad2::mad 2::mad2::mad2::mad2: breath....:mad2::mad2::mad2::mad2:: mad2::mad2::mad2::mad2::mad2::mad2: ...?....:sadeyes: :sad:

Yep another :rolleyes:...great job Greg :thumbsup:

I think Fred was right though and I see you've changed it already?

Between going to your dark site so many nights and sitting at your computer processing...do you get in trouble for neglecting the family :whistle:

Mike

[gregbradley]

Hehe yes I did smooth the transition.

I have also added 2:30 from 12.5 RCOS data. Not sure if its better. In fact I'd say the TEC180 outperforms the 12.5 RCOS. The RCOS data has a bit more contrast in details and a bit more detail around the core but otherwise is less pleasing. The TEC data has more depth and is smoother and sharper but the RCOS shows a bit more contrast but the contrast is a bit blocky if that makes sense.

Here is the combo.

What do you think?

http://www.pbase.com/gregbradley/image/109634265

You can click on previous in the top right corner to get the TEC only version for comparison.

Greg.

[strongmanmike]

I have to say that looks mighty deep for just 2hours of Lum (even without the RC data added)..?

How are you bringing out the apparent faint very outer arms/halo? are you lasooing> feathering > levels/curves/brighteing? Are you doing this in layers on layers?

You must have blended to add the various layers and RC data, how did you handle the transitions as you went out from the galaxy and around the edges?

Mike

[bloodhound31]

Magnificent Greg. You have set the bar for many of us mate.

Baz.

[gregbradley]

It varies a bit depending on the image but basically curves and blending the image with a bit of extra curves in with the original so it doesn't washout the colours using a mask. I only blended in the inner areas of the RCOS as it didn't actually show hardly any faint outer arms. Only the TEC does that.
Roland Christen did an interesting writeup about that overnight. Mirrored systems have a lot more scatter than APOs hence APOs can go deeper and be stretched harder to reveal faint detail more easily than mirrored systems. I have found this to be true and your Centaurus A image also proves that point.

The point here is you can't bring out those faint details with photoshop trickery only enhance what your scope captured in the first place. Its a strength of APOs that should be taken advantage of and pushed.

Also I started using sum combine in the combination method of combining the subs as it gives finer control and brought out the fainter stuff just that bit better thna median. The price is more artifacts like cosmic rays etc you have to clean up with the healing tool later but its not that bad.

[strongmanmike]

Well that's not entirely true, Here's the delema, at some stage you must decide where is the boundary that you lasso? Is it an arbitrary line you make up yourself? Then if you use curves/levels you have brightend the area as defined by you and not what may in fact be the the reality, you then blend it again by imparting a similar arbitary judgement and feather? It is not as important in say a nebula but trying to show a very faint circular halo you must be very careful or you risk only creating an imaginary halo..? When I check your halo shape with that produced by a very deep amplified plate by David Malin with the UK Schmidt your halo doesn't seem to be the same shape..?



I have always only used sum or add for exactly this reason.

Mike

[gregbradley]

[quote=strongmanmike;416713]Well that's not entirely true, Here's the delema, at some stage you must decide where is the boundary that you lasso? Is it an arbitrary line you make up yourself? Then if you use curves/levels you have brightend the area as defined by you and not what may in fact be the the reality, you then blend it again by imparting a similar arbitary judgement and feather? It is not as important in say a nebula but trying to show a very faint circular halo you must be very careful or you risk only creating an imaginary halo..? When I check your halo shape with that produced by a very deep amplified plate by David Malin with the UK Schmidt your halo doesn't seem to be the same shape..?


I know what you mean but I am not using a lasso and I am careful not to produce an artificial boundary.

There was an artifact that got removed that may have affected one small part of the image but the rest should be accurate. Where is the David Malin's deep image?

Also my image is rotated compared to common orientations. Not sure how this worked out but that is how it came out of the camera.
Greg.

[Paul Haese]

From my perspective this is a lovely image. Only small downside is the star sizes of the foreground but I am assuming this is a cropped area and of course in that case the stars look bigger. Hoping to one day come a little close to this myself by probably not with the 40D. Just humouring myself here.

I love all the Ha regions captured in your image.