“Their world, too, could shatter with a single breath of the cosmos. They dream of exploring the stars, unaware that they, like bubbles, could vanish in an instant.”
NGC7635 – Bubble Nebulae – SII+Ha+OII (Hubble Palette)
Description
NGC 7635, also known as the Bubble Nebula, Sharpless 162, or Caldwell 11, is an H II region emission nebula in the constellation Cassiopeia. It lies close to the open cluster Messier 52. The “bubble” is created by the stellar wind from a massive hot, 8.7 magnitude young central star, SAO 20575.
Research and Observations
Its star burns a million times brighter than our sun and produces powerful gaseous outflows called stellar winds that howl at more than four million miles per hour. Over time, the winds have pushed nearby gas and dust outward, forming a layer around the star that’s denser in some areas than others. Based on the rate the star is expending energy, scientists estimate in 10 to 20 million years it will explode as a supernova. And the bubble will succumb to a common fate: It’ll pop.
Acquisition Details
This image was captured over the course of one night:
Aug 29th 2024
– GREEN: 10 X 10 min. exposures via Hydrogen Alpha filter
– BLUE: 10 X 10 min. exposure via Oxygen III filter
– RED: 10 X 10 min. exposures via Sulfur II filter
Total Integration Time: 5 hours
Acquisition Start Time: 21h00
Acquisition Stop Time: 03h00
Image Information
| Object(s) Catalog No: | NGC7635 |
| Object Type | |
| Constellation | Cassiopeia |
| Size | 15′ × 8′ |
| Magnitude | 10 |
| Distance | 7100 to 11000 Light Years |
| Field of View | 2.06° x 1.55° |
Conditions
| Date | August 29th, 2024 |
| Astronomical Dusk: | 21h15 EDST |
| Moon Age | 0.2 |
| Moon Phase | Waning Crescent (25.8 days) |
| Temperature | 14.8 |
| Transparency | Average |
| Seeing | Below Average |
| Wind | 9.252 |
| Dew Point | 11.6 |
| Sky ADU | not measured |
| Sky Flux (e/min) | not calculated |
Equipment
Software
| Mount | Retrofitted CGEM (OnStep) |
| Imaging Scope | Orion ED80T CF |
| Guiding Scope | APM 60mm Image Master |
| Imaging Camera | ASI294MM Pro |
| Guiding Camera | QHYCCD: QHY5L-II-M |
| Additional Optics | SharpStar Field Flattener – 2.5″ |
| Filters | Ha, OIII, SII |
| Acquisition | NINA |
| Auto-Guiding | PHD2 Guiding |
| Processing | Pixinsight |
| Planetarium | Stellarium |
Subframe Details
| Filters | L | R | G | B | Ha | OII | SII |
| Camera Temperature | -10° C | -10° C | -10° C | ||||
| Binning | 1×1 | 1×1 | 1×1 | ||||
| Number of sub-frames | 10 | 10 | 10 | ||||
| Sub-frames duration (sec) | 600 | 600 | 600 | ||||
| Number of good sub-frames | 10 | 10 | 10 | ||||
| Number of Flats | 20 | 20 | 20 | ||||
| Flats Duration (sec) | 20 | 20 | 20 | ||||
| Number of Darks | 30 | n/a | n/a | ||||
| Darks Duration (sec) | 600 | n/a | n/a | ||||
| Number of Bias | 0 | 0 | 0 | ||||
| Number of Flat Darks | 30 | 30 | 30 | ||||
| Flat Darks Duration (sec) Variable Brightness | 20 | 20 | 20 |
Auto-Focuser Position: 3498
Autoguiding Average : 0.45″ RMS
Acquisition Notes
Flawless fully automated acquisition.
Processing Notes
SHO palette processing. Used Pixinsight for processing, GraXpert for noise reduction and StarNet to remove the stars while processing.
First time processing with new ASI294MM Pro at 47 MegaPixels. Super large files. Long time to process. Some sort of reflection artefacts possibly due to bright stars. Have to troubleshoot.
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