Jump to content

Help Processing Pacman Nebula


Recommended Posts

Hi everyone. This week I've been imaging the Pacman Nebula with my Optolong L-eNhance filter. 

I managed to get 4 hours 46 minutes over two nights and got this result (I use GIMP at the moment so can't deal with the gradients).511805662_PacmanNebulaGIMP.thumb.jpg.e9b3496f4e46dfe8187cbbf4ed476993.jpg

Tonight I tried adding some more exposure time to it (now totalling 6 hours 38 minutes) and restacked everything again in Deep Sky Stacker. The problem I am having is that when I stretch the image, the red channel stays against the far left side of the histogram and I cannot get any colour in the nebula except for cyan. 

The sub exposures were all 2 minutes long using ISO 3200 using a Canon EOS 100D and William Optics Zenithstar 61 on a Star Adventurer. I do guide and use Sharpcap to polar align but 2 minutes is about the longest I can get away with before star trailing becomes evident due to polar alignment. The guide error is normally around 2" so stars are a little bit bloated as my image scale is 2.5"pp. I used super pixel mode in DSS to bin the image 2x (is this a good idea?). Is the problem that my sub exposures are just too short (I have an HEQ5 on order so that should fix that problem!) or something else?

Here's the stack if anyone wants to try stretching it. Stack 6Hr 38Min.TIF

Thanks for any help! 🙂

Link to comment
Share on other sites

I don't think I explained the problem very well in the original post. I just had another play with the data I captured. This is 4 hours and 46 minutes. There is clearly a lot of red in the nebula.

image.thumb.png.cf8b705befc59c3e7e8a3f6bb31c3f9c.png

And this is the same data plus another two hours, exactly the same settings used for capturing and stacking. Processed the same way also...

image.thumb.png.6a4ce7fca58490bfdd7ca9902d00ec20.png

And this is the histogram. The red channel is broken up...

image.png.a1a60bdac2949e85835e4621cd7e8f1c.png

Does anyone know what has happened here? 🤔

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.