Skip to Navigation | Skip to Content

M34 Open Star Cluster
Kathryn De Jong

Previous imageUp to Astr110 IndexNext imageM34 Open Star Cluster

Messier 34 is an open star cluster discovered by Italian astronomer Giovanni Bastista Hodierna before 1654. An open star cluster is a group of thousands of stars that were formed from the same massive cloud of gas and dust. All the stars in this type of cluster are similar in age and distance from the earth. M34 lies in the Perseus constellation, around 1,400 light-years away. It is about 15 light-years across, has around 100 bright stars with some as young as 180 million years. Many open clusters are relatively young compared to other stars. Under good sky conditions, M34 can be found near Pleiades and Cassiopeia with the naked eye.

The above photograph depicts the middle of M34 with a size of 2.8 by 4.3 light-years. Using a variety of color filters revealed the brightest stars in a light purple hue, while the smaller stars are shown as red pinpoints. The image was manipulated to highlight the colors. Since the stars are all of similar age and distance, it can be deduced that the brighter stars are also more luminous than the fainter ones. Luminosity is determined by temperature, distance, and size. The more luminous a star, the higher temperature it must be in the cluster.  Therefore the hottest stars appear light purple. 


Frommert, H., & Christine, K. "Messier Object 34." Students for the Exploration and Development of Space. 2007 August 25. Retrieved December 4, 2010 <>

Nemiroff, Robert and Jerry Bonnell. "Star Cluster M34" Astronomy Picture of the Day. 2010 February 11. Retrieved December 5, 2010 <>

Seligman, C. (2007, July 3). The Messier Catalog: Open Star Clusters. Retrieved December 6, 2010 <>

Right Ascension (J2000) 02:42:00
Declination (J2000) 42:47:00
Filters used blue(B), green(V), red(R), and clear(C)
Exposure time per filter

60 seconds in C,V,R

300 seconds in B

Date observed

October 26, 2010



Secondary content.


Side content.