Object info

M45 is a star cluster which was known already from pre-historic times. At least 6 members are visible to the naked eye, while this number increases with better observing conditions.
This cluster actually contains over 500 (mostly faint) stars. The cluster also known as the "Seven Sisters", is dominated by mostly hot blue stars and lies at a distance of 440 light years.

Processing

DSLRFocus was used to focus the scope and create the imaging series. ImagesPlus 2.8 was used to calibrate the light frames with 45 dark frames and 23 flat frames (incl. flat-darks). The flat frames were shot using the 2 reflective surface (1 diffusing) technique as described by Ron Wodaski. Photoshop CS2 was used for post-processing, levels and curves adjustments. Noel Carboni's astronomy tools were used for DSO enhancement and noise reduction.

Comments

Out of the total of 52 frames which were taken over 2 different days only 31 were used to create the stacked image.
The quality of the single exposures varied due to the sometimes very bad sky conditions - high humidity and fog.

Previous versions

Oct 05, 2007 - 1024 x 768 Pixel (344 kB)
Optics : TMB 80/480 + Baader UHC-S
Mount : Losmandy G-11 + Canon 350D
Exposure : 20 x 240 sec @ ISO800 = 1h 20m

Nov 07, 2005 - 836 x 627 Pixel (162 kB)
Optics : Orion 80/600 ED + Baader UHC-S
Mount : OTE150 + Canon 350D
Exposure : 20 x 180 sec @ ISO800 = 1h