M13, part two. More data definitely helps!

[arad85]

Hi all,

My second go at M13 (using this to practice on as it's relatively bright and I'm not guiding at the moment). So, this is:

C80ED on two star+2 calib star aligned/all star polar aligned/two star+2 calib star aligned CG5-GT, unguided

Camera 450D, 800ISO, 65 of 70 x 1min subs, 7 darks.

I'm a lot happier with this than my first attempt: http://stargazerslounge.com/imaging-deep-sky/83392-m13-isnt-where-everyone-begins.html

[Aza]

Much better result!

Colours are coming through nicely now.

I think you have made the background too dark though, some fainter stars have been lost.

Good work though

[arad85]

Ta... will have another go...

[Catanonia]

Starting to get there mate Progressing very nicely.

[adamsp123]

Coming on nicely, I would have a play with DSS settings and when you get the "final" DSS pic, have a play with the colour sliders, the level sliders and saturation colour settings (but not alot of colour) saving each update if it looks sort of OK.

Then play with the tiff files, I would recommend that free paintshop proX software, open play with - adjust - smart photo fix and play with the controls and some of the other stuff under the "adjust" menu.

[arad85]

Any better

[adamsp123]

much better IMO but I think you could still tease out a bit more in the way of stars, try not to make background too black

[Aza]

Definitely much better!

As Adam says though you could get even more from it

Which is good, as it shows the quality of your data!

[arad85]

Restacking now in DSS... but this time, taking the best 37 images (there were some thin wispy clouds so about 50% of frames are almost worthless - still it's all a learning curve eh?). In my haste, I stacked at 95% rather than taking a look at the data Looking MUCH better now... Watch this space...

[Aza]

Another thing you can look at in DSS is the score applied to each frame.

If you list the frames in order of score, it is recommended that you only use scores that are 50% (or higher) than the top scoring frame, discounting the rest.

However this is only a guideline really!

[arad85]

And with fewer frames, I have this...

The bright stars are HIP81673 (mid left, mag 7.2) and HIP81848 (top mid, mag 6.8) as well as NGC 6207 top right (not noticed that untill I did the last processing run)... Is that better

[Aza]

That looks a vast improvement! Good work

I would say that you have brightened the background a little too much though.

In Photoshop if you open the INFO window and hover over the background, you can see values for RGB. Currently you have them around 40. I would aim for something around 20.

If you open the levels function, you can make adjustments to the black point, then hover over the background again to see what the difference the adjustment makes before clicking to proceed.

In the image below I dropped the black point down a bit, and also the mid point too, to bring the RGB values to about 20:

[arad85]

Cheers Arran,

Getting there now... Lets see if the next one can be done without so many retakes

[Aza]

Absolutely. The difference from your initial post to your latest version is huge

[Taff]

Hi' Thats a nice image of the glob.Mark