NGC869 & NGC884 the Double Cluster in Perseus

[Hughsie]

NGC869 & NGC884 the Double Cluster in Perseus

Having spent the last few months imaging nebulae and removing stars from images, it makes a nice change to concentrate on the stars.

One of my favourite star clusters is the Double Cluster in Perseus which is now rising nicely in the North East sky.

The Double Cluster itself is made up of two open clusters, NGC869 and NGC884 that are some 7,500 light years away.

Analysis of the stars spectra show that the light is blue shifted meaning that both clusters are moving towards Earth. NGC884 has five prominent red supergiant stars though the star clusters themselves are young with an age of c12.8 million years. This suggests that both clusters formed from the same interstellar gas cloud.

 

This image was captured on 9 October 2020 from my garden. It is made up of the following data;

• Red/Green/Blue - 18 subs @ 300 seconds for each filter.
• Luminance - 30 subs @ 180 seconds.
• Calibration frames - 50 separate darks, flats and flat darks.

 

Equipment used;

• William Optics Z103 refractor.
• ZWO ASI1600mm Pro Cooled camera.
• Chroma 1.25” filters LRGB.
• SkyWatcher EQ6-R Pro mount.
• Sesto Senso motor focuser.

 

Data was processed on PixInsight;

• After calibration of each filter set, the master LRGB images were created and a crop was applied to the edge of each master to remove stacking artifacts.
• Gradients removed from each master image using DynamicBackgroundExtraction.
• MureDenoise applied.
• RGB masters combined.
• MaskStretch applied to L master and RGB image.
• L master and RGB image combined using PixelMath in the following ratio, 75% RGB, 25% L Master.
• Star reduction applied to the smallest stars so as to highlight the large stars in each cluster.
• Colour added to stars and background colour adjusted with a star mask applied.
• Curves adjustments and colour tweaks applied.
• Small amount of noise reduction applied using TGVDenoise.
• Image size resampled and plate solved to create a separate star chart shown below.

 

Clear skies.........

[geeklee]

Lovely image @Hughsie 

Edited October 12, 2020 by geeklee

[RobertI]

Beautiful image of a beautiful object. Lovely star colours. I eyeballed this the other day through my 102ED and was surprised by the number of orange members in the cluster. 

[geoflewis]

This is a superb image of a beautiful double cluster and one of my favourite binocular targets with my 22x85 Apollos mounted on a P-Mount.  I can lay back to observe it for 30-40 mins at a time drinking in the view. Your image really does it justice

[astro mick]

Indeed a lovely image and a great write up.One of the best Clusters up there.

Mick.

[ollypenrice]

On 12/10/2020 at 20:07, astro mick said:

Indeed a lovely image and a great write up.One of the best Clusters up there.

Mick.

Two of the best clusters, Mick! 🤣   (Actually I once showed them to a friend who was into birding but not astronomy and he flatly refused to see anything 'double' about them. I never could understand this.)

 

Lovely image with the background light enough to allow faint dust lanes to show.

Olly

[michael.h.f.wilkinson]

Very nice indeed