The
Lobster Claw “is a large and bright emission nebula Sh 2-157 in Cassiopeia (near the northern border with Cepheus) lies 8,150 light-years away and spans another 215 light-years across. Sh 2-157 is described as a ring nebula surrounding the Wolf-Rayet star WR 157, SAO 20512, mag 9.58.” (Anthony Ayiomamitis, [1])
The nearby
Bubble Nebula is an HII emission nebula. The "bubble" is created by the stellar wind from a massive hot (8.7 magnitude) young central star, SAO 20575. The nebula is near a giant molecular cloud which contains the expansion of the bubble nebula while itself being excited by the hot central star, causing it to glow. It was discovered in 1787 by William Herschel. [2]
NGC 7538, which is also located around 9000 light-years from Earth has a total mass of around 400,000 Suns. It is a region of active star formation, in particular the formation of massive stars. Thirteen of the proto-stars in this have masses greater than 40 times the mass of the Sun and the largest is about 300 times the size of our Solar System [3].
At the top of the image
NBC 7510 is an open cluster located around 11,400 light years from Earth [4].
The processing was an experiment. To try to mimic natural colour, the Ha and SII were both set to the red channel and OIII to the green and blue. Later in the processing I shifted the blue-green from the OIII to blue.
The images was taken on November 22 and 24, 2021 using an Esprit 80/400 with flattener and Takahashi FS60CB with 1.04x flattener (so 374 mm). There were:
150x300s Ha, bin 1x1
19x300s OIII, bin 2x2
28x300s SII, bin 2x2
[1]
https://cs.astronomy.com/asy/m/nebulae/452726.aspx[2]
https://en.wikipedia.org/wiki/NGC_7635=12.0pt[3]
https://www.esa.int/ESA_Multimedia/Images/2014/03/Star_factory_NGC_7538=12.0pt
[4]
https://en.wikipedia.org/wiki/NGC_7510
Comments