Click on image to see full size image...

Object:
Pelican Nebula near NGC7000
Date(s):
22, 25, 27 June 2014
Location:
Rancho Hidalgo, NM
Telescope:
Takahashi TOA-130 at f/7
Mount:
CGE mount
Camera:
SBIG ST-4000CM
Single-Shot Color:
Yes
Exposure time:
2x2 Mosaic comprised of 24 20 minute images (-1 that lost guide)
Comments:

It was easy to create mosaic map and center points of each of the images of the 2x2 matrix using TheSkyX Pro.

It was easy to compose the script to shoot the images automatically using ACP.

It was easy to let ACP accumulate images. I could shoot about 8 each night. (I slept through it of course... :-) )


Creating a seamless mosaic image where you could not tell where the images in the array were joined was HARD.

I tried the Mosaic subsystem of Maxim DL but was unable to achieve seamlessness. The Mosaic subsystem of Maxim DL is really nice for assembling the matrix but does not provide enough control over brightness, contrast, etc, while within the tool. After you get out of the tool, you no longer have access directly to the frames making up the array.

Was impossible for me to create a seamless image. And I did try EVERYTHING. I think Sky Glow is the problem. Shooting 8 20 minute images in one night means that some are taken at a low altitude and some are taken at a high altitude. I think skyglow declines as the altitude is increased.

Finally resigned myself to using PhotoShop. It is not my favorite program because it is so wierd. Rotating an image was a real puzzle for example. Only one of a bunch of things I had to research to apply the procedure below...

Followed procedure in http://www.robgendlerastropics.com/Article3.html. I found what I think was a better way to apply the "Curves" operator to blend the images so that the seams are not obvious. It looks like PhotoShop is the only way to achieve success but it is drudgerous... Still difficult to achieve seamlessness! But it can be done...

I have WAY too much time invested in this!

However, mosaic imaging is a way get images that cover much more of the sky than you can get with a single image.

The above image was color corrected using eXcalibrator. Additional processing in Paint Shop Pro. Used Maxim DL extensively of course... And PhotoShop.

Thank you Bernard Miller for your comments on my first mosaic attempt, the NGC6910 area, where you noted: "You black clipped the data. There is a lot of data in the shadows that you are missing. Check your levels when processing..."

Yes, I could not figure out how to hide the seams so I opted for that. I will try to get back to those images and redo the mosaic now that I have more experience with this...