Help with imaging please

[heller792]

Good evening all, I am very new to astro photography and I appear to be struggling. If anyone is willing to help I would really appreciate it. I live in a bortal 6 area so I purchased a IDAS LPS-D2 Light Pollution Suppression Filter for my Canon 5d MkIII. Anyway, I have been learning bits as I go along and decided while the sky was clear last night I would take some images for stacking. I have never stacked before so followed some instructions that I found online. I proceeded to take my darks, bias and images however because of the filter everything comes out green, how do i return colour to my images? I had a go at stacking the images but the final image was not much different to one of my 2m exposures. I understand I have a lot to learn and patience is going to be the key, have I done something wrong when stacking?

The below image is one of my single 2m exposures

 

 

The image below is about the best I can do, nowhere near what I was hoping for to be honest but it is my first attempt.

 

All advice would be appreciate,

Dave

 

[heller792]

my kit is as follows

Redcat 51

IDAS LPS-D2 Light Pollution Suppression Filter

5D MkIII

Ioptron Sky Guider Pro

 

[Seelive]

The stacking software doesn't always give the correct colour balance in the stacked image and removing part of the spectrum won't particularly help in the single image. The colour balance normally needs to be corrected in post processing and even with the IDAS D2 filter you should still be able to achieve a reasonable colour balance.

[wimvb]

Use Photoshop, GIMP or any other photo editing program to adjust colour balance and stretch the image.

Btw, you also need flats in order to remove the vignetting.

[Chefgage]

The stacked image almost always looks worse than one of your single images. This does not mean that something has gone wrong, DSS (if that's what you are using for stacking) has just stacked the images together and has not done any processing of the stacked image.

What it looks like is your red, green and blue colour channels are not aligned so the image has that blue/green look to it. I don't know what software you are using to process but if it's Photoshop or GIMP (what I use) then the process to align the channels is easy to do. When the image is loaded you need to change the histogram setting to show RGB instead of the default (in GIMP) setting of luminance. Then you can see all three channels and how much they are out of align. Then change each colour channel sliders until all three are lined up. If you google colour balance using GIMP you will see examples of this. As you further process you may need to re-align the channels or make one colour more prominent than the others depending on how you want the image to look.

Edited November 8, 2020 by Chefgage

[heller792]

Thanks Chefgage, I will give it a go now, I am using photoshop and DSS.

 

Wimvb, I tried flats using an iPad with a white screen and a t-shirt over the lens but it didn't work.

 

Thanks for all the help , Dave

[Phillyo]

2 hours ago, heller792 said:

Wimvb, I tried flats using an iPad with a white screen and a t-shirt over the lens but it didn't work.

Hi Dave, what do you mean by 'it didn't work'?

Phil