* Astronomy

Members Login
Username 
 
Password 
    Remember Me  
Post Info TOPIC: Messier 72


L

Posts: 131433
Date:
Messier 72
Permalink  
 


Messier 72 (also M72, NGC 6981 and GCl 118)is a magnitude +9.35 globular star cluster located 54,570 ± 1,170 light-years away in the constellation Aquarius. 
The cluster appears as a "cloudy spot" in amateurs 4 inch telescopes. More powerful optical  instruments can see a grainy texture and the brightest stars of the cluster can be resolved in telescope apertures of 8 inches or more. 
The brightest star in the cluster has an apparent magnitude of +14.2

The cluster was discovered by French astronomer Pierre Francois Andre Mechain using a 3.5" refractor at Versailles on the 29th August 1780.

Right Ascension 20h 53m 27.70s, Declination -12° 32' 14.3"  

French astronomer Charles Messier looked for it on the following October 4, and included it in his catalog. Both decided that it was a faint nebula rather than a cluster. With a larger instrument, British astronomer John Herschel called it a bright "cluster of stars of a round figure". 
Read more

Messier 72



__________________


L

Posts: 131433
Date:
NGC 6981
Permalink  
 


Title: EMCCD photometry reveals two new variable stars in the crowded central region of the globular cluster NGC 6981
Authors: Jesper Skottfelt, D. M. Bramich, R. Figuera Jaimes, U. G. Jørgensen, N. Kains, K. B. W Harpsoe, C. Liebig, M. T. Penny, K. A. Alsubai, J. M. Andersen, V. Bozza, P. Browne, S. Calchi Novati, Y. Damerdji, C. Diehl, M. Dominik, A. Elyiv, E. Giannini, F. Hessman, T. C. Hinse, M. Hundertmark, D. Juncher, E. Kerins, H. Korhonen, L. Mancini, R. Martin, M. Rabus, S. Rahvar, G. Scarpetta J. Southworth, C. Snodgrass, R. A. Street, J. Surdej, J. Tregloan-Reed, C. Vilela, A. Williams

Two previously unknown variable stars in the crowded central region of the globular cluster NGC 6981 are presented. The observations were made using the Electron Multiplying CCD (EMCCD) camera at the Danish 1.54m Telescope at La Silla, Chile.The two variables were not previously detected by conventional CCD imaging because of their proximity to a bright star. This discovery demonstrates that EMCCDs are a powerful tool for performing high-precision time-series photometry in crowded fields and near bright stars, especially when combined with difference image analysis (DIA).

Read more (433kb, PDF)



__________________


L

Posts: 131433
Date:
Messier 72
Permalink  
 


Messier 72 (also known as M72 or NGC 6981) is a globular cluster in the Aquarius constellation discovered by Pierre Méchain on August 29, 1780. Charles Messier looked for it on the following October 4 and 5, and included it in his catalogue. Both decided that it was a faint nebula rather than a cluster.
Read more 



__________________
Page 1 of 1  sorted by
Quick Reply

Please log in to post quick replies.



Create your own FREE Forum
Report Abuse
Powered by ActiveBoard