Messier 15


Object Details:

Designation:  M15, NGC 7078    Constellation:   Pegasus
Visual magnitude:   +6.2              Apparent size:  18′ 
Diameter:   178 light years.        Distance:   34,000  light years.

Robert Burnham Jr described M15 as “one of the richer and more compact globulars” – and it is certainly an impressive sight, despite its distance of 34,000 light years from us.

Orbiting outside the Milky Way galaxy, i contains over 100,000 stars and I also read that it is one of the densest globular clusters, with half the mass located inside a radius of about ten light years.

That seems to imply that there may be 50,000 stars inside that relatively that ten light year radius!

What an amazing “night” sky there would be for anyone living on a planet orbiting one of the stars inside that radius. Spending a night under the stars would have a whole new meaning!

However, because a black hole is believed to exist at its centre,  the x-ray environment would not be conducive to life as we know it.

Also in image:  See overlay of my image at

Blog ends here. Here comes a load of technical details:


Exposure:   9 x 143 sec = 21.45 min.
Gain: 210
Date:  2019-10-23
Location:  semi-dark rural.
Moon: no.
Conditions:  clear.
Sky:   0.24  e/pixel/s


Image acquisition:  SharpCap.
Method: Live stacked.
Darks: 6x
Image post-processing:  GIMP.
Cropping:  yes



Telescope: SkyWatcher Esprit  Type: 120ED triplet refractor
Focal: 840 mm F/7 Mount: SkyWatcher EQ6-R Pro
Camera: ZWO ASI 071 MC Pro
Type: CMOS 28.4mm 16 Mpx
Optical aids: Flattener: Y; filter: LP Guiding: Yes
Polar aligning: QHYCCD PoleMaster Polar Error: 3’45”

Geek Log:

[ZWO ASI071MC Pro]
Debayer Preview=On
Output Format=PNG files (*.png)
Capture Area=4944×3284
Colour Space=RAW16
Hardware Binning=Off
Turbo USB=40
Frame Rate Limit=8 fps
Timestamp Frames=Off
White Bal (B)=50
White Bal (R)=53
Cooler Power=56
Target Temperature=-10
Auto Exp Max Gain=300
Auto Exp Max Exp M S=30000

Auto Exp Target Brightness=100
Mono Bin=Off
Anti Dew Heater=On
Banding Threshold=35
Banding Suppression=0
Apply Flat=None
Subtract Dark=C:\Users\Roger\Desktop\SharpCap Captures\darks\ZWO ASI071MC Pro\RAW16@4944×3284\143.3s\gain_210\dark_6_frames_-10.0C_2019-10-23T10_03_19.fits
#Black Point
Display Black Point=0
#MidTone Point
Display MidTone Point=0.5
#White Point
Display White Point=1

Image © Roger Powell

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