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Sky-Tonight.com / Nebulae / M7

Ptolemy's Cluster (M7) Observation Details

M7

M7 Daily Motion

M7 will rise at 23:27, during twilight, and will ascend to 55° by the time twilight ends at 05:16.
M7 will be visible until November, 4, when it will move too close to the Sun. During this time, its proximity to the Sun will cause it to disappear from the night sky, making it unobservable for a while.

M7 Visibility Timetable on March 28

M7 Rise and Set Timetable

TimeElevation
Moon Rise, 2.3% illuminated05:0255°
Moon Set17:27-55°
Astrosession begin19:17-47°
M7 rise23:27
Astrosession end04:5254°
M7 transit05:2655°
Civil sunrise05:4055°
Sunrise06:0254°
M7 set11:25

Track M7 Position Throughout the Night

← Fri, 28 March 2025 →

Elevation (degrees)
Time
Altitude
Azimuth
Shift the map to change the time and observe M7 changing position in the night sky.

M7 - Ptolemy's Cluster

Ptolemy's Cluster (M7) is an open cluster located in the constellation Scorpius. It was known to ancient astronomers and included in Messier's catalog in 1764. The cluster is named after the Greek-Roman astronomer Claudius Ptolemy, who mentioned it in his writings around 130 AD.

M7 spans about 25 light-years across and contains around 100 stars. The cluster is approximately 980 light-years away from Earth and has an apparent magnitude of 3.3, making it visible to the naked eye and easily seen with binoculars or a small telescope.

M7 Image Gallery

DSS Blue

M7 photo taken with blue filter
These images are valuable for highlighting the presence of younger, hotter stars, which emit more light in the blue wavelengths.

DSS Red

M7 photo taken with red filter
These images are excellent for detecting older, cooler stars, as well as emission nebulae, which glow primarily in the red due to hydrogen alpha emissions.

DSS Near-Infrared

M7 photo taken with Near-Infrared filter
These images can penetrate dust clouds that obscure visible light, revealing structures and objects hidden within.

DSS Composite image

M7 color image
DSS Color images are composite images created by combining the blue, red, and often near-infrared images to produce a full-color representation.

The photos are taken from the Digitized Sky Survey 2 (DSS2), which was produced at the Space Telescope Science Institute (STScI) under NASA contract, using data from the UK Science and Technology Facilities Council (STFC), the European Southern Observatory (ESO), and the National Geographic Society-Palomar Observatory Sky Survey (POSS II).

Special thanks to the National Optical Astronomy Observatory (NOAO), the Royal Observatory, Edinburgh, and the California Institute of Technology for their significant contributions.

Finder Chart for M7

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Object nameM7
Field of view
Limiting magnitude
M7 coordinates17.89755, -34.79283
Center coordinates17.89755, -34.79283

M7 Passage Through Night

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Current position of M7

Time19:10
Latitude0
Longitude0
M7 elevation-48°
M7 Azimuth-148°
Here you can see the current position of the M7 on the map, as well as its positions for rise and set. This tool allows you to track the M7's movement throughout the night, providing you with accurate and up-to-date information.

Annual motion of M7

Time
DateSat, 29 March 2025
Twighlight start19:13
Twighlight end04:47
Twighlight duration10h 34m
Rise23:23
Set11:21
Elevation at transit55°
Transit time05:22
Equatorial coordinatesRA: 17h 53m 51s", Dec: -34° 47' 34s
Magnitude3
ConstellationScorpius
The graph illustrates the annual visibility pattern of a M7, providing a comprehensive overview of its daily appearances and transit times throughout the year.
The graph is structured with the vertical axis showing the hours of the day, ranging from 12 AM to 12 AM the next day, while the horizontal axis spans each day of the year.
The reddish shaded area indicates the periods when the M7 is above the horizon, visible to observers. The white line marks the times when the celestial object reaches its highest point in the sky each day, known as the transit.

Data Credits

The nebulae information on this page is sourced from the OpenNGC project, developed by Matteo Verga. OpenNGC provides detailed data on the NGC catalog, which is a valuable resource for exploring deep-sky objects such as nebulae.

For more details or to contribute to OpenNGC, visit the official GitHub repository: OpenNGC on GitHub.