M52
Messier 52 - Click here for full resolution
Messier 52 (M52), also known as NGC 7654 or the Scorpion Cluster, is an open cluster of stars in the highly northern constellation of Cassiopeia. It was discovered by Charles Messier in 1774. It can be seen from Earth under a good night sky with binoculars. The brightness of the cluster is influenced by extinction, which is stronger in the southern half. Its metallicity is somewhat below that of the Sun. R. J. Trumpler classified the cluster appearance as II2r, indicating a rich cluster with little central concentration and a medium range in the brightness of the stars. This was later revised to I2r, denoting a dense core.
source: Wikipedia
NGC/IC:
Other Names:
Object:
Constellation:
R.A.:
Dec:
Transit date:
Transit Alt:
NGC7654
Scorpion Cluster
Open Cluster
Cassiopeia
23h 24m 48s
+61° 35.6′
14 October
66º N
Conditions
M52 can be very well observed in Autumn, with maximum altitudes reaching 66° in the North. M52 was photographed over 6 nights, mainly during significant moon presence in late September, early October 2024 from the remote observatory at IC Astronomy in Oria, Spain.
Equipment
The default rig at the observatory was used. The core of this rig is a Planewave CDK-14 telescope on a 10Micron GM2000 mount, coupled to a Moravian C3-61000 Pro full-frame camera. The RoboTarget module in Voyager Advanced automated the process to find optimal time-slots during astronomical night.
Telescope
Mount
Camera
Filters
Guiding
Accessoires
Software
Planewave CDK14, Optec Gemini Rotating focuser
10Micron GM2000HPS, custom pier
Moravian C3-61000 Pro, cooled to -10 ºC
Chroma 50mm Luminance, Red, Green and Blue unmounted, Moravian filterwheel L, 7-position
Unguided
Compulab Tensor I-22, Windows 11, Dragonfly, Pegasus Ultimate Powerbox v2
Voyager Advanced, Viking, Mountwizzard4, Astroplanner, PixInsight 1.8.9-3
Imaging
Star clusters are ideal objects to photograph during full moon periods, as was done here. For that reason, all exposures were limited to 180s for both RGB and Luminance filters. The image was shot as a broadband image, using standard LRGB filters. A total of approximately 11.5h of exposure was captured.
Resolution (original)
Focal length
Pixel size
Resolution
Field of View (original)
Image center
9445 × 6275 px (59.3 MP)
2585 mm @ f/7.3
3.8 µm
0.30 arcsec/px
47' x 31'
RA: 23h 24m 46.571s
Dec: +61° 35’ 16.73”
Processing
All images were calibrated using Darks (50), Flats (50) and Flat-Darks (50), registered and integrated using the WeightedBatchPreProcessing (WBPP) script in PixInsight. All further processing was done in PixInsight, including the use of scripts and tools developed by RC-Astro, SetiAstro, GraXpert, and others. For a step-by-step description of the processing techniques applied, see the below schedule.
Regarding the RGB image, for stars-only images, such as star clusters, I typically prefer traditional stretching methods over GHS. A combination of ArcsinhStretch (to preserve colour) and HistogramTransformation, as applied here, usually works very well.
For the luminance image, unfortunately some dust motes had landed on the luminance filter in between sets of flats. Three dust motes were not corrected for. To clean this up, stars were removed, the blemish blaster from SetiAstro was applied, and stars were put back in.
The rest of the processing followed the usual process.
Processing workflow (click to enlarge)
This image has been published on Astrobin.
