December 3, 2024

Archives for October 18, 2022

NGC 7635 – The Bubble Nebula in Cassiopeia

NGC 7635 – The Bubble Nebula in Cassiopeia

Telescope: Meade SN10 at f/4, Orion Atlas EQ-G

Camera: QHY 268c, Mode 0, Gain 30, Offset 30, -10C

Filter: 2” Radian Triad Ultra Hb, OIII, Ha, SII filter

Guide scope: Williams Optics 50mm, ASI290MM mini, PHD

Exposure: 16x300sec, saved as RAW16/FITS

Darks: 32×300 sec

Flats: 64×2 sec, tee shirt flats taken at dusk

Average Light Pollution: Red zone, fair transparency, moonlight

Lensed Sky Quality Meter: 18.4 mag/arc-sec^2

Stacking: Mean with a 1-sigma clip.

White Balance: Nebulosity Automatic

Software: SharpCap Pro, Nebulosity, Deep Sky Stacker, Photoshop

This is NGC 7635, the Bubble Nebula in Cassiopeia, with just a bit of the open cluster M52 in the upper left corner. The Bubble is almost the inverse of a planetary nebula; rather than an expanding shell of gas shed from a dying star, the Bubble is formed from the intense radiation of a hot blue star pushing out a sphere in the surrounding gas, making an empty bubble and setting the hydrogen aglow with a beautiful red color.

NGC 7635 is currently high in the southeast at dusk.