The Bubble Nebula and the M52

Main Objects: Messier 52, NGC 7635, sh2-162, V628 Cas

Bubble blown by stellar wind

Bubble Nebula
Bubble Nebula map
Bubble Nebula annotation

One of the most well-known pairs of deep-sky objects in the constellation Cassiopeia is the Bubble Nebula and the Messier 52 open cluster. The former is an emission nebula, also known as NGC 7635.

The reddish bubble nebula is named after the most striking shape of the nebula, the bubble-like formation. The bubble was created by a young Wolf-Rayet star (SAO 20575) with brightness of 8.7 magnitude in the middle of the nebula. The stellar wind of the giant star, which is about 44 solar mass sun, blows the interstellar material around it, which is partly a matter thrown away by the star, with incredible force. The star's high-energy radiation glow the hydrogen gas surrounding it, which radiates very strongly at a wavelength of 656.2 nm in the H-alpha line. This is due to the reddish color in the picture. The bubble was created about 300,000 years ago and has been expanding at about 7 million km/h. This star - which has temperatures of more than 37,000 degrees Celsius - is likely to become supernova within a few million years.

The Messier 52 open cluster in the upper left of the image is much brighter than the Bubble Nebula and can be observed with a smaller binocular. According to Trumpler classification this cluster is: I,2,r. It means, it has a clear central concentration (I), medium brightness (2) and more than 100 (exactly 193) stars (r). The M52 is estimated to be 4.6 thousand light-years away, so it has no physical connection to the Bubble Nebula.

In the lower right corner of the image you can see the V628 Cas embedded in nebula. The young Herbig Be eruptive variable star is characterized by a strong outflow of material.

Unfortunately, in the summer of 2019 I couldn't really make deep-sky shots, so it was especially important for me to be able to take at least one shot in the fall. It was the first major test of the new off-axis guider. The gear worked great! Because of the heavy fogging in the dawn, I was able to use only 9.25 hours of the more than 11 hours of photos taken over two nights. 

Name:

Bubble Nebula, NGC 7635, Sh2-162, C 11

Constellation:

Cassiopeia

Coordinates:

R.A. 23 h 20 m 48 s Dec. +61° 12′ 06″

Type:

Emission Nebula

Distance:

11,000 light-years

Brightness:

10.0m

Apparent size:

15' x 8'

Size:

4 light-years

Observable: 

Autumn

Date:

25/10/2019; 26/10/2019

Total exposure time:

9.25 hours

Location:

Tápióbicske, Pest, Hungary

Camera:

Canon EOS 1300D (modified)

Telescope:

Home-made 200/800 mm Newtonian reflector

Mount:

Sky-Watcher EQ6-R Pro GoTo

Guiding:

Lacerta MGEN-II

Corrector:

Sky-Watcher f/4 coma corrector

Focal ratio, length:

f/4, 800 mm

ISO:

800

Light:

111 x 300 s

Dark:

20

Flat:

20

Bias:

20

Processing:

Astro Pixel Processor, PixInsight, Adobe Lightroom, Adobe Photoshop

Location

Annotation

Name:

Messier 52, M52, NGC 7654, Cr 455, Mel 243

Constellation:

Cassiopeia

Coordinates:

R.A. 23 h 24 m 48 s Dec. +61° 35′ 35″

Type:

Open Cluster

Distance:

4,600 light-years

Brightness:

5.0m

Apparent size:

16'

Size:

9.5 light-years

Observable: 

Autumn