Ptolemy's Cluster (M7)
R/B-band color composite image from the Second Digitized Sky Survey (DSS2), measuring 22 arcminutes across.
Finder chart
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From South El Monte , Ptolemy's Cluster is difficult to observe as it will appear no higher than 17° above the horizon. It is visible in the dawn sky, rising at 02:48 (PST) – 3 hours and 28 minutes before the Sun – and reaching an altitude of 17° above the southern horizon before fading from view as dawn breaks at around 05:19.
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|
Name
Ptolemy's Cluster (M7)
|
Object type
Open cluster
|
Position
| Right ascension: | 17h53m [3] |
| Declination: | −34°47' [3] |
| Constellation: | Scorpius |
| Magnitude: | 3.30 (V) [5] 3.45 (B) [3] |
| Angular dimensions: | 22.2 arcmin |
| Distance: | 301.0 parsec 981.3 lightyrs [2] |
| B-V Color (mag): | 0.15 |
Derived quantities
| Absolute mag (V): | -4.09 |
Sources
Visibility from South El Monte
All times shown in South El Monte local time.
Events
| 20 Jun 2026 | – The Ptolemy cluster is well placed |
| 20 Jun 2027 | – The Ptolemy cluster is well placed |
| 20 Jun 2028 | – The Ptolemy cluster is well placed |
| 20 Jun 2029 | – The Ptolemy cluster is well placed |
| 20 Jun 2030 | – The Ptolemy cluster is well placed |
| 20 Jun 2031 | – The Ptolemy cluster is well placed |
| 20 Jun 2032 | – The Ptolemy cluster is well placed |
| 20 Jun 2033 | – The Ptolemy cluster is well placed |