A hazy M13

[ampleamp]

I nearly binned my entire run of yesterday's M13 as after a fabulous day, the night haze obviously considerably worse than anticipated. However, I decided that a practice run wouldn't hurt.

I can see I definitely need to redo my flats (green especially) but for what its worth, here is my rendition of The Great Globular Cluster in Hercules. I will try to do a better job next time ;-)

This was 16x300s R, 17x300s G and 21x300s B taken at 900mm with my old SX-H694

Thanks for looking

[wimvb]

That's a really nice image with nice small stars and good star colour. The core seems over exposed / over stretched, but it really isn't. I took the liberty of downloading your image and applied HDR compression in PixInsight. Also adjusted the background a bit. Hope you don't mind. Normally you wouldn't do this on a jpeg, but it shows clearly that the stars are well defined in the cluster.

[tooth_dr]

Great M13, and a nice reprocess. Gorgeous colours in the stars. 

[ampleamp]

Hi Wim,

no problem, that is quite an improvement; can you tell me what you did with HDR comp. and how you adjusted the background; really quite glad I didn't dump this now ;-) . 

thanks,

Alistair 

[wimvb]

The process in PixInsight is called hdrmultiscale transformation. The process splits the image in layers of decreasing detail (layer 0 is single pixel features, layer 1 is 2 pixel features, etc), and applies contrast enhancement to each layer. Then the image is put together again. I used the process with default settings. Then I aligned the histograms. The red and green histogram has double peaks, indicating a slightly uneven background. This I didn't correct.

[ampleamp]

ok, thank you, I will take a look a bit later and see what I can achieve on the original data ;-)

[PatrickGilliland]

That's nice and fizzy  nice work, well resolved too

[ampleamp]

re-process.

I decided to try a reprocess of this after trying out a few suggestions @wimvb above made, and a trial/error approach to the green cast. The raw rgb was terrible but a bit of patience has hopefully resulted in an improvement of my original though there is still that green flat deficiency just right of centre. This is as good as i can get it at moment and i fear i am in danger of overdoing the NR to calm everything else down.

Lesson, don't hit delete too quickly ;-)

 

[Swoop1]

Cracking images. I'm glad you didn't delete!

I find these images particularly pleasing as M13 is the first globular cluster I observed on my own kit as a result of my own work.