NGC 6888 & Veil /EOS

[Fay]

Does anyne know if these exposures are as they should be or should I alter the red, as Mark has done, although I was in a more intense hydrogen area. How do I use Photoshop with the RGB in one image.

Thanks a lot
  veil 1x240sec 23.51


Ngc888 1x600sec ISO800 00.13

[JohnP]

Fay - You need to adjust the colour balance...

To get close if you open the image in PS & then select levels & choose the Gray (mid point) eyedropper & then click anywhere on background it should align the RG & B - Try clicking on different parts of the background until it looks right... you'll then need to adjust levels/ curves for high/ lowlights etc...

John

[Fay]

Thanks John, I will have a go at that.

[MarkS]

Fay,

The images I got after modding my camera look very similar to yours below i.e. a pink/purple tint across the whole frame. Once you have RGB balanced them, you will be fine.

Mark

[Fay]

Thanks Mark, will try & master it today.

[mickw]

Could you set up a custom white balance to overcome the bulk of the colour problems ?

[Fay]

I don't know what I am doing, at the moment Mick. I tried to do what John suggested, but does not look too good. Although, there is only one image there, I would only be able to do so much.
I did bring out a lot more detail in The Veil, a lot of nebulosity lower left.
Once I get the hang of it, I will be ok.

Fay

[mickw]

It is rare that I know what I am doing 

If you tamper with the white balance settings on the camera to reproduce a fairly accurate colour rendition of a picture taken during the day (colour card, flower or whatever), that should give you a good starter image at night.  Your camera instructions should tell you how.

I'm sure I will be shouted at if I'm wrong 

[MarkS]

Fay,

I've had a quick look at Photoshop.  I think what you need to do is to use the following menu:

Image | Adjustments | Channel Mixer

You can then reduce the Red channel down to 30-40% or so.  Just play around with the colour balance on Red Green and Blue until it looks correct.

Mark

[JohnP]

Fay - it's tough to do anything with one image - you still need to take multiple images to increase the signal & reduce noise. As you can see from Mark's image if you take enough exposures the results after modification are impressive. Mark's image shows loads more detail. Don't expect too much from one image - the suggestion I made was just to get colour balance correct not to 'magically' bring out loads of detail/nebulosity. If you want to email the raw I can see what I can do...

Cheers,  John.

[MarkS]

Fay,

As John says, you need to treat the EOS like a "proper" astro-camera taking multiple subs and doing a full processing sequence with bias, darks & flats.

It's one of the things I'll cover in my talk on the Thursday's members' evening.

Mark

[Fay]

Thanks John & Mark. I really look forward to your talk, Mark.

[Rocket Pooch]

Fay,

I know the images look a little iffy, but they are good, you got the SLR working and the guiding.  All you need is a good 2" light pollution filter (you can borrow mine if you treat it nicely) and more data.  Remember you really need 16 subs to get the S/N ok.  But at least you will not have to do LRGB.

So does this mean when we go to France you will be wide field imaging with the EOS?  Will you get the Baader and 2" Ha filter and do some very nice wide field narrow band images?

Chris

[Fay]

Thanks Chris, I do have a 2" light pollution filter. By the Baader filter, I am thinking it is the one that was put in there, UV & IR. That was kind of you to offer to lend me the 2"
I hope I have got rid of the dust bunnies, although flats will sort that out, but rather get rid of them.

Yes John put me right today regarding the histogram. I did not realise that the 3 peaks of RGB had to all line up when the grey dropper was used on the background. I thought they all had to stay separate doh!

Tomorrow evening I will be out there & try to get a series of images, although the light sky is still a problem as I can't stay up all night.

I will take it to France in my knapsack!


Fay

[Rocket Pooch]

Fay,

If you get an ample supply of cocaine it will help keep you awake.

Chris