M74 processing help

[dsnay]

Okay guys. Let me have it! What can/should I do to make this better?
Collection-wise, I think I might be better served going through the LX90 instead of my 400mm lens, but then tolerances become an issue. I also think I should probably triple or quadruple the data. This is the result of 25' of each RGB with my Lumicon UHC filter providing the green.

Here's a fresh copy of the jpg file. If anyone wants the three .fts files, I can make them available too.



ADthanksVANCE,

Dave

[twilbur]

Too green, you need to figure out a way to get the green channel to behave itself. Do you know if it's the camera that's green insensitive or the filter they sent you? Trying a different green filter or two may show the way.

Also, the background has blotchy noise usually associated with dark current. Are you taking and subtracting darks?

[Ron]

Dave,

Far be it from me to give any advice here, becasue I don't know a thing about assembling LRGB images.

I agree with Ted that it is too green.

It looks to me like the colors are not aligned; I see green at the top of the stars, blue at the bottom, and red on the side.  If it was my projection TV I would say the colors needed converged

It does look like your tracking was pretty good, nice round stars.

On the good side, I hope my first attempt is as good as yours

What software did you use to stack your images?

Ron

[dsnay]

Hey guys,

Here's another version. I aligned the channels more carefully and quieted down the green a bit with levels in PS7.


Ron,

I use the autostarsuite software that came with my DSI-pro to stack each color set and then I use PS7 to merge the channels and all further manipulation. In this case, I really haven't done much other than adjust the levels and run a couple of canned "actions" from Noel Carboni. (Astro plugins, I think they are called).

Ted,

I am using darks, but I don't think I used enough of them on one of the channels. I think it needs more data. I've also heard that I might be best served by collecting new darks for each data set as the air temp changes. Apparently the DSI is affected by as little as a 3 degree change in temp.

I don't know what those three dark spots near the bottom are from. I haven't seen them in any other images, but I'm hoping there is just something on the camera lens that needs to be cleaned off. They're in all three data sets, so it's not a filter issue. It pretty much has to be either on the camera lens or the chip in the DSI (I really hope it's the camera lens).

clear skies,
Dave

[Jean-Yves]

Hi Dave,

That a very good shot, stars are nicely round !
I like your newer version.
You only need more images to get more details.

About the 3 dark spots : did you apply a flat ? Are these spots present on the flats? They look like some dust to me and should be removed by a flat frame.

Cheers

Jean-Yves

[dsnay]

Thanks Jean-Yves,

These spots are new. They're not in any of my earlier images. I cleaned the camera lens since then and they are still there. I'm thinking they're something on the chip. 

I have no idea how to make a flat. I've still got so much to learn, that adding another piece to the puzzle is just too much for me right now. For now, I can just clone them out in PS7 since I'm imaging in an area where there isn't anything where those spots are anyway. 

Dave

[Jean-Yves]

Hi Dave,

Basically, a flat is an image of a white surface, with the focus used for imaging.

Simply take an image of a white board, or a fridge door, anything white with your setup.
Shine some light on the white surface and take a 1 or 2 second image, make sure it is not completelly white washed ...
If the dust is there, it will show very well.

No need to remove the dust, reducing the image with a flat will take care of those marks.

For "nice" flats, have a look in the web, lots of techniques around,

Cheers

Jean-Yves