Gradient Removal

[Macavity]

One may not want to get too deeply into the finer points of imaging, but one thing frustrates me: Particularly during warmer months, with shorter exposures, fewer frames etc.: The dreaded (thermal) gradient across the image!

With such low signal to noise ratios, my attempts to bring out any details with "levels and curves" etc., have mostly only succeeded in accentuating the "mush" at the lower left and losing genuine details at the upper right.

Enter IRIS: http://www.astrosurf.com/buil/us/iris/iris.htm

(A little "unusual" with it's semi command-mode style?)

http://www.astrosurf.com/buil/iris/tutorial4/doc14_us.htm

But, after a little practice, I do believe there is some improvement...

No darks, no flats, and using my battered old ST102 for a wider field!

But every little helps. Perhaps pointing the way to greater things...

Question: I am aware of PixInsight and various PhotoShop addons,

but is there anything (cheaper / free) to handle gradient removal?

[Davey-T]

You can do it in P' Shop, see Doug Germans YTube vid.

Dave

[Macavity]

Ta - I am actually still hoping to avoid renting(?) Photoshop...

With a bit of thought / application (gasp), I'm impressed with IRIS.

It seems gradient removal can be added to previous processing

and much can also be salvaged / improved retrospectively...

As ever, I'm not looking for a "work of art", merely a collection of

many images that I can think about - write (blog) about even?

Of that ilk, NGC1977 in Orion (An O'Meara's "Hidden Treasure"!):

Before:

After:

Taken right under the full Moon, so I wasn't expecting much...

[Davey-T]

Couldn't get on with Iris, too much typing

Perhaps you can do it in Gimp, only a bit of masking and gaussian blurring.

Dave