M36 - Pinwheel Cluster
| Polish version is here |
The Pinwheel Cluster, also known as Messier 36 (M36) or NGC 1960, is a young, compact open cluster. It was most likely first described by Giovanni Battista Hodierna before 1654. Independently, Guillaume Le Gentil observed it in 1749, and Charles Messier added the object to his catalog on September 2, 1764.
The cluster lies about 4,100 light years away (values in the literature range from 3,800 to 4,300 light years, depending on the measurement method), has an integrated magnitude of approximately 6.3m, and an apparent diameter of roughly 12′. It is composed of young stars with an age estimated at about 25 million years. In many respects M36 resembles M45, or the Pleiades, although it is located much farther from us.
Observations
October 15, 2025, about 11:00 p.m. - Katowice Poland
urban conditions, very high level of light pollution
M36 can be found roughly halfway along the line from Elnath (β Tauri) in Taurus (Taurus) to Menkalinan (β Aurigae) in the constellation Auriga (Auriga). Auriga is easy to identify because its brightest stars form a distinct hexagonal asterism just above Orion (Orion), northwest of Gemini (Gemini) and northeast of Taurus and the Pleiades (M45). It is also worth noting Capella (α Aurigae), the Little Goat, the third-brightest star in the northern celestial hemisphere. In classical tradition it was often identified with the goat Amalthea, the nurse of Zeus.
In good binoculars M36 appears as a grainy, slightly diffuse patch. A telescope at higher magnifications resolves the cluster into several dozen bluish stars partially concentrated in a gently condensed core (Photo 1).
As a young cluster, M36 does not contain red giant stars.
Photo 1 Parameters:
- Total exposure time: 10 minutes (stack of 10 RAW frames at 60s each, using an appropriate number of dark, bias, and flat frames)
- ISO: 1600
- Maksutov-Cassegrain telescope (100/1400), prime focus exposure
- A filter was used to reduce the effects of artificial light pollution and atmospheric glow
- Mount: equatorial mount with tracking, aligned using the drift method and controlled by a custom-built system.
Further readings:
- Wu Zhen-Yu, Zhou Xu, Ma Jun, Du Cui-Hua, The orbits of open clusters in the Galaxy, Monthly Notices of the Royal Astronomical Society, 399 (4), 2009, pp. 2146-2164
- Piskunov A. E., Schilbach E., Kharchenko N. V., Röser S., Scholz R.-D., Tidal radii and masses of open clusters, Astronomy & Astrophysics, 477 (1), 2008, pp. 165-172
- Delgado A. J., Alfaro E. J., Garrido R., Garcia-Pelayo J. M., Search for B-Type Variable Stars in Open Clusters, Information Bulletin on Variable Stars, 2603, 1984, p. 1
- Morata O., Kuan Y.-J., Ho P. T. P., Huang H.-C., Magnier E. A., Zhao-Geisler R., Millimetric and Submillimetric Observations of IRAS 05327+3404 “Holoea” in M36, The Astronomical Journal, 146 (3), 2013, 49
Marek Ples