| M45, the Pleiades and known by the name "Subaru" in Japan (which explains the logo on the car hood and name of the Japanese telescope on Mauna Kea) Distance ~440 Ly TOA 150 Super Reducer STL11K L 41x200 Sec, R, G, B ~38x240 Sec each. Luminance is L+R+G+B, effective Luminance ~4.8 Hrs Mouseover for inverse luminance to see extent of nebulosity |
| M45 The Pleiades |
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This target was difficult because of the very bright stars in the field. I had to reduce subexposures to 200 - 240 sec each and still had bright internal
To fix this I took about 1/2 the images with the camera one way, 1/2 the images with the camera reversed, made masters of each, then subtracted one master
from the other, leaving only the reflections (more or less). I truncated that subtraction (ie I only used the pixels with positive values on one image and only the
pixels with negative values on the other image) subtracted the result from each master, removing the reflections then finally I combined both masters. I did
this for each channel.
It worked but was tedious to say the least.
In the animation below the "Camera upright" "Camera reversed" and "Final" Blue channel images alternate. Note the eccentric reflections not centered on
stars.
To fix this I took about 1/2 the images with the camera one way, 1/2 the images with the camera reversed, made masters of each, then subtracted one master
from the other, leaving only the reflections (more or less). I truncated that subtraction (ie I only used the pixels with positive values on one image and only the
pixels with negative values on the other image) subtracted the result from each master, removing the reflections then finally I combined both masters. I did
this for each channel.
It worked but was tedious to say the least.
In the animation below the "Camera upright" "Camera reversed" and "Final" Blue channel images alternate. Note the eccentric reflections not centered on
stars.
