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Messier 15 ( NGC 7078) & NGC 1502
Jacob Pilarski & Amira Bousaab

M15 NGC 1502

NGC 7078 - Jacob Pilarski

NGC 1502 - Amira Bousaab

NGC 7078 is a Globular Star Cluster and NGC 1502 is an Open Star Cluster. NGC 7078 is found in the constellation Pegasus and NGC 1502 is found in the constellation Camelopardalis.

While both images are star clusters, NGC 1502 has around 45 stars with one bright binary at the center(constellation-guide.com) and NGC 7078 has over 100,000 stars and a large number of variable stars. (https://en.wikipedia.org/wiki/Messier_15)

M 15 (NGC 7078)

The Globular Star Cluster Messier 15, originally named NGC 7078, is approximately 12.0 billion years old (Messier 15).  The M 15 is approximately 33,600 light years away from Earth (Messier 15:Great Pegasus Cluster). It is located in the  constellation Pegasus and was founded by the astronomer Jean-Dominique Maraldi in 1746 which was also included in the Messier Catalog (Messier 15). This cluster is approximately 210 light years across and half of those stars are packed into an area of space just 10 light years in size, which is why the M15 is considered as one of the most dense globular star clusters in the Milky Way (Plotner, Tammy), also the M15 contains Pease 1, the first planetary nebula discovered within a globular cluster in 1928. Just three others have been found in globular clusters since then.(Messier 15).  Now in comparison to earth, the M 15 is approximately 33,600 light years away (Messier 15:Great Pegasus Cluster).

NGC 1502

The open star cluster NGC 1502 is about 11 million years old. It is small in comparison to other open star clusters. It is found at the end of the Kemble’s Cascade asterism in the constellation Camelopardalis (Camelopardalis Constellation), at about 2,700 light years away (Heijen, Math). The Camelopardalis constellation belongs to the Ursa Major family of constellations in the Northern Hemisphere (Camelopardalis Constellation). NGC 1502 was discovered by William Herschel on 11/03/1787 (Michalska, G., A. Pigulski, M. Ste ̨s ́licki, and A. Narwid).. At the heart of NGC 1502 lies a binary star - Struve 485 (A&E) (Heijen, Math). These two stars are nearly equal in brightness, but Stuve 485 E is also a variable star, “which changes in brightness by only 0.3 magnitudes every 2.7 days” (Heijen, Math) making it the brightest star when its at its maximum brightness.

Compare:

Messier 15 and NGC 1502 are both star clusters located in the Milky Way galaxy. NGC 1502 is found in the the Northern Hemisphere for it belongs to Ursa Major, and M 15 is also located in the Northern Hemisphere. Both star clusters emit colors that are blue, gold and white which give us the relative temperature of the stars.

Contrast:

While both stars are clusters, M15 is a globular star cluster and NGC 1502 is an open cluster. Another difference is how densely populated each cluster is; M 15 contains 100,000 of stars while NGC 1502 only has about 45. The apparent magnitude, which measures brightness shows us that M15 is brighter by 0.7, M15 is also farther away making it slightly hotter.

Works Cited (in MLA)

"Camelopardalis Constellation ." Constellation Guide, Omega WordPresshttp://www.constellation-guide.com. . Accessed 27 Nov. 2016.

Heijen, Math. "Object: NGC 1502( Hidden Treasure 23)." Star Observer 2009http://www.starobserver.eu. . Accessed 27 Nov. 2016.

"Messier 15: Great Pegasus Cluster." Messier Objects, Omega WordPress, Apr. 2015, www.messier-objects.com. Accessed 29 Nov. 2016.

"Messier 15: Great Pegasus Cluster." Messier Objects, Omega WordPress, Apr. 2015, www.messier-objects.com. Accessed 29 Nov. 2016.

"Messier 15." Wikipedia The Free Encyclopedia Nov. 2016, https://en.wikipedia.org/wiki/Messier_15. Accessed 28 Nov. 2016.

Michalska, G., A. Pigulski, M. Ste ̨s ́licki, and A. Narwid. "A CCD Search for Variable Stars of Spectral Type B in the Northern Hemisphere Open Clusters. VII. NGC 1502." ACTA ASTRONOMICA, vol. 59, 2009, pp. 349-70.

Plotner, Tammy. MESSIER 15 (M15) – THE GREAT PEGASUS CLUSTER, Universe Today , June 2016, www.universetoday.com/31634/messier-15/. Accessed 28 Nov. 2016.

Purgathofer, A. "Page for Open Cluster NGC 1502." WebCite , WEBDA, Nov. 2015. Accessed 27 Nov. 2016.

 

Object M 15 NGC 1502
Right Ascension (J2000) 21h 29m 58.33s 04h 07.50m
Declination (J2000) +12° 10′ 01.2″ +62° 19.9'
Filters used B (Blue), R (Red), V (Green) B (Blue), R (Red), V (Green)
Exposure time per filter B, V, and R (300s); C (60s x 5) B(30sec x 3), V(20sec x 3), and R (20sec x 3)
Image dimension 1092x736 pixels; 23.8x16.1 arcminutes 901x980 pixels; 19.5x21.2 arcminutes
Date/time observed October 10, 2016 1:30 UT October 10, 2016 1:30 UT

 

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