Hello,
Whilst waiting for Sirius to climb high enough a few nights ago, I filled in time by grabbing a few shots of M42 using the Canon 40D.
I used the Takahashi Mewlon 180 with Tak X0.8 Reducer/Flattener (efl of approx 1700mm) and ran into a whole lot of coma. The Mewlons are of the Dall-Kirkham design which does have significant coma, but I thought that the x0.8 Reducer/Flattener would produce better results? Maybe I didn’t have the optimum spacing in between the x0.8 R/F and Canon 40D?
This is my first attempt at using Layer Masks in CS3 to blend 3 separate images to cater for the extremely high dynamic range of this object. Some noise has crept in and more practice will improve things, but overall, it was an enjoyable experience.
The (cropped) image is made up of the following:
- 3x5 mins at ISO400.
- 2x60 secs at ISO100
- 2x30 secs at ISO400
Cheers
Dennis