Eta Carina

[rcheshire (Rowland)]

Eta Carina.

Preprocessing in Pixinsight, thought I would try my hand at post processing in StarTools, which has meant a new learning curve.

I am satisfied with the result, but I'm sure that Ivo would do much better, and I am happy to upload the cropped .fit file out of interest.

I did have a little trouble with colour saturation which improved with the application of a full mask. But it's not quite what I was after.

Cooled 1000D @7C - Astrodon Inside filter, 200mm, F/6.3, iso400, 25 x 3.5 minute subs, with bias, darks and flats.

I wanted to replace the stars. Get rid of the spikes and replace with spikeless ones, but came unstuck with that and gave up?

Synth > Refractor > 200mm (should I add the crop factor), aperture 72mm, after that, no idea

Thanks for looking

[billdan (Bill)]

Hi Rowland,

Thats an awesome shot, heaps of stars, probably too many as it tends to overpower the nebula.
If your stacking in DSS you can set the threshold for how many stars are registered. On my image I had to set it to 15% to reduce the number of stars, however mine was only 20 mins in total, whereas yours is nearly 90mins.

I'm only a learner and have no image processing tools, I just do everything in DSS and hope for the best. I'm waiting on the 16 bit Gimp to come out so I can process mine later. So unfortunatly I can't help you with post processing

Regards
Bill

[rcheshire (Rowland)]

Thanks Bill. I see what you mean about the stars. I will have to work on that. I'm just getting comfortable with basic processing - though that is usually in Pixinsight. StarTools is an excellent post processing program and I would like to get more familiar with it. Gradient removal is superior in my view.

I installed GIMP 2.8 on my ubuntu box the other day. I notice a subtle change in the way it saves other than native .xcf. It seems that other formats must be exported.

16bit is available in the native xcf format, but it wants to convert tif to 8 bits. fits files seem to get loaded as 16bit xcf. So I guess whatever output you choose for stacking, it has to be fits if you intend processing in GIMP.

16bit across the board would have been nice.

[multiweb (Marc)]

That's a great field Rowland. The stars are fine and just the right size. Very sharp details in the neb. Well balanced picture. Beautiful.

[irwjager (Ivo)]

Originally Posted by rcheshire

Eta Carina.

Preprocessing in Pixinsight, thought I would try my hand at post processing in StarTools, which has meant a new learning curve.

I am satisfied with the result, but I'm sure that Ivo would do much better, and I am happy to upload the cropped .fit file out of interest.

I did have a little trouble with colour saturation which improved with the application of a full mask. But it's not quite what I was after.

Cooled 1000D @7C - Astrodon Inside filter, 200mm, F/6.3, iso400, 25 x 3.5 minute subs, with bias, darks and flats.

I wanted to replace the stars. Get rid of the spikes and replace with spikeless ones, but came unstuck with that and gave up?

Synth > Refractor > 200mm (should I add the crop factor), aperture 72mm, after that, no idea

Thanks for looking

Great widefield - great framing, heaps to look at and (at this scale) not a hint of problems with your gear, tracking, etc. Textbook stuff!

Happy to help where I can - you got my e-mail address

Rescaling your image for publication, for example on IIS, can sometimes mess with your composition and detract from the main object you're trying to show. What looks good 1:1 (e.g. unzoomed/unscaled) can look busy when scaled. To avoid 'busyness' due to aliasing, try to bin rather than scale your image - it should keep the 'busyness' constant. For those who don't have a binning function available, you can apply a Gaussian blur before scaling. The more you scale the image, the larger the blur.

Failing that, in StarTools, an extremely convenient way of toning down a distracting star field in a rescaled wide fields like this, is to use the 'Life' module's 'Isolate' preset. No parameter changes or masks needed. But season to taste if you feel like it of course...

In this instance, it does a nice job of 'isolating' the nebula and toning down the stars (attached, no further processing done) with 0 effort. Of course there's heaps of other ways of achieving the same thing, but StarTools is all about automation and reducing tedium...

Cheers,

[Forgey (Paula)]

That's looking real good Rowland.