THE DOuble cluster

Main Objects: NGC 869, ngc 884

The most popular open cluster pairs in the northern sky

gallery/doublecluster_2400
gallery/doublecluster_terkep
gallery/doublecluster_2400_annotated

On the most well-known open clusters, it is worthwhile to show what we call open cluster. The stars in the open clusters had previously evolved from a common gas cloud to stars. The stars in it are still loose gravitational to this day, ranging from a few dozen to a few thousand. They are mostly found in interstellar gas and dust clouds. There are about a thousand open clusters in the Milky Way, but the total number can be ten times that. A list of the most important open clusters can be found in the Messier catalog, although this is only interesting in the NGC catalog.

The open clusters, also known as NGC 869 and NGC 884, are particularly bright star clusters which contain approximately 300-350 stars and 5000 solar mass material each. They are made up by a few, yet huge mass stars. Another interesting fact is that the clusters, now 7,600 light-years away, are approaching us with a velocity of 38 km/s. Their distance between each other is approx. 100 light-years.

There are still eight small and faint galaxies with PGC in the picture. Finding them is also made difficult by the relative shortness of the cumulative exposure. When choosing the exposure time, I focused on the stars, not the diffuse objects.

I was very happy that I managed to capture the colour scale of the stars. Also, the members of the clusters are clearly separable. I decided to go with an unusually wide zone of vision as it highlights the open clusters even more from the celestial background.

Name:

Double Cluster, NGC 869, NGC 884, C14

Constellation:

Perseus

Coordinates:

R.A. 02 h 20 m 23 s Dec. +57° 09′ 05″

Type:

Open cluster

Distance:

7,600 light-years

Brightness:

3.7m (NGC 869) and 3.8m (NGC 884)

Apparent size:

Number of stars:

Adding approx. 700 pieces

Observable: 

Autumn and winter

Date:

13/10/2017

Total exposure time:

15 minutes

Location:

Tápióbicske, Pest, Hungary

Camera:

Nikon D3300 (unmodified)

Telescope:

Sky-Watcher 150/750 mm Newtonian reflector

Mount:

Sky-Watcher NEQ-5 Pro GoTo

Guiding:

ZWO ASI 120 MC camera - PHD2

Corrector:

Sky-Watcher f/5 coma corrector

Focal ratio, length:

f/4.5, 682 mm

ISO:

800

Light:

3 x 300 s

Dark:

3

Flat:

3

Bias:

3

Processing:

PixInsight, Adobe Lightroom, Adobe Photoshop

Location

Annotation