|Date of exposures:||25.01.2017, 26.01.2017, 27.01.2017|
|Exposures:||RGB: 12 x 300 Sec., Ha: 16 x 1800 Sec., [OIII]: 7 x 1800 Sec., [SII]: 10 x 1800 Sec., Sum: 17,5 hrs.|
|Focal length:||450 mm|
|Filter:||Astrodon RGB E-Series, Ha 5nm, [OIII] 3nm, [SII] 3nm|
Sh2-232 (Sharpless 232) is the biggest but faintest member of a complex of diffused nebulas in the Auriga constellation, about 3 degrees from IC405 (the Flaming Star Nebula) and IC410. The other members are Sh2-235 (botton-left respect Sh2-232), the brightest of the group, and Sh2-231 (at right). The blue dot is a known planetary nebula, PN G173.5+03.2.
The data collection lasted for three nights and also the processing was extremely difficult, since the nebula complex is extremely faint. Especially the [OIII] signal was as good as nothing and in [SII] it was also thin. Through the dominant H-alpha channel, it was a problem to get some of the typical colors within the Hubble palette. Remedy was achieved by the tonemapping method, in which the channels without stars were extremely stretched and contrast-enhanced. The Bicolor version was created without tonemapping and therefore it shows through the mainly existing Ha signal mostly everything red in red. After all, the short RGB exposures enabled me to blend in the stars in natural color, which makes the whole thing a bit more colorful.
If you are interested in more details of the exposure session, here is the blog entry.