Wild Duck M11 and Saturn Nebula NGC7009

[riklaunim]

Wild Duck M11
The setup: DSI III Pro, reduktor f/6.3, Radial Guider (+DMK21/PHD), Orion LRGB, SCT 8", HEQ5-synscan.
L-bin2: 15 x 120 sec
R,G,B bin2: 5 x 120 sec
L-bin1: 5 x 300 sec
Not so sharp but colors look nice

RGB, bin 2
http://www.rkastrofoto.appspot.com/s...1-rgb-bin2.jpg

RGB, bin 1
http://www.rkastrofoto.appspot.com/s...10/m11-rgb.jpg

LRGB, bin 2
The (Hirsch) SCT f/6.3 focal reducer introduces chromatic aberration which cause luminescence (IR/UV cut) to be big and uggly. R,G,B are refocused so they don't have such problem... -_-
http://www.rkastrofoto.appspot.com/s...-lrgb-bin2.jpg



Saturn Nebula NGC7009
It has 8 mag, but it's low in northern hemisphere and very small in size. In SCT 8" with 20 mm eyepiece and O-III filter it appears as a bright fuzzy/blurred star. Imaging isn't easy also as it is just to small scale - easy to "overexpose" the image....

DSI III Pro version with Castell O-III
There is a dark line going though the nebula. Stack of ~30 frames with exposition from 10 to 60 sec. 24 deg above horizon
http://www.rkastrofoto.appspot.com/s...eb-dsi-cut.jpg

DMK21
11 sec exposures, SCT 8" f/10, Castell O-III, no guiding/reducer. 14 deg above horizon.
http://www.rkastrofoto.appspot.com/s...tneb-dmk-a.jpg
http://www.rkastrofoto.appspot.com/s...tneb-dmk-b.jpg

Compared with f/10 Jupiter:
http://www.rkastrofoto.appspot.com/s...comparison.jpg

HST
http://apod.nasa.gov/apod/image/9712...09_hst_big.jpg