Jump to content




M42 Expanded


Recommended Posts

Well, on Friday night I managed to get out again and do some more imaging.

I decided, due to the long focal length of my scope, to try getting the running man (NGC 1977) to add to my M42.

I had great difficulty in adding the mosaic together. First I chucked it all into DSS, which seemed to do the job but the results were not that good (see attached) There was a distinct dark band where the frames overlapped and the stars to the bottom of M42 went a bit funny.

So I decided to stack M42 and tweak in DSS. Then stack the Running Man and tweak in DSS using the same settings as for M42.

In photoshop I then combined the two and masked out the dark band.

M42 - 6 x 600s Subs, 4 x 600s Darks, Bias, no flats

Running Man - 6 x 600s Subs, 8 x 600s Darks, Bias, no flats

Guided with Atik Titan and finderguider

Stacked in DSS

Finished in CS4


Im not entirely happy with the core of M42, it seems a bit grubby, if you know what I mean. I think I need some better subs for the core. Also I have just noticed a slight yellow band between M42 and the Running Man. Still its one to work on.

Attached is the DSS effort, I haven't tweaked other than to resize.


Link to comment
Share on other sites

Oo-er, that's beautifully done.

There is a variety of ways in which to go about this. In Ps you can just expand the canvas size of one image to make room for the other, paste it on, slide it into position and then play with levels and curves on either or both images to get them to resemble each other at the overlap. Then you can feather the joint with a low opacity erasor and flatten, or you can save the adjusted images and feed them into Microsoft Ice, a free compositing software. It does a very good job it there is decent similarity between images.

But that is very seamless and attractive, much nicer for the greater breadth of view. Nothing is so satisfying as a mosaic, I reckon.

On the core, it is so bright that it should stand some unsharp mask done in a well feathered, zoned off bit. When you layer masked in the Trapezium region I think that you got the levels really well but there is a slight change of colour. You can get round this by adjusting colour balance before flattening the long and short exposures. But, hey... it's very good indeed.


Edited by ollypenrice
Link to comment
Share on other sites

Hi guys, thanks for the comments.

Olly, appreciate the feedback very much :)

What you describe is pretty much what I did in PS, that is expand the canvas, add the second image and mask and feather. One thing I haven't tried is the CS4 automate>Photomerge, which usually does a pretty good job.

I see what your saying with the trap and the colour change, Ill have another look at it and see if I can get it to match better.

Billy, I am really pleased with the results I am getting with my D200 its surpassing my expectations!

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.