The Seven Sisters (M 45)

clic for 50% size 1512 x 1196 (497 kB)

About this Image

The well known open cluster M 45 in Taurus is famous due to its visual appearance and also for its faint blue reflection nebula in photographs.
Physically, the reflection nebula is probably part of the dust in a molecular cloud, unrelated to the Pleiades cluster, which happens to cross the cluster's way. It is not a remainder of the nebula from which the cluster once formed, as can be seen from the fact that the nebula and cluster have different radial velocities,
The galaxy to the right is mag 18 UGC 2838.
North is up.

Below you see a 40/100% center crop in full resolution.

clic for 100% size 1948 x 1416 (577 kB)

Technical Details


105mm TMB refractor with flattener at f/6.5

Mount MK-100 GEM
Camera SBIG STL-11000M at -25C, internal filter wheel
Filters Astronomik LRGB
Date Sep 17-19, 2004.
Location Wildon/Austria
Sky Conditions mag 5.5, fair transparency, temperature 10 C,
Exposure LRGB= 150:30:30:40 min (10-minute sub-exposures)
all 1x1.
Processing Image aquisition in Maxim DL 4.0; Image calibration, aligning, mean stacking, DDP and color synthesis in ImagesPlus/Maxim;
Photoshop: Curves, color balance, cropped, Noise reduction by Neatimage;