Messier 5

April - May 2014

This project (along with the first part of the Virgo Cluster and M51 in H alpha) was the first project after the long delays due to the 2013 equipment upgrade.

Messier 5 is a bright, large Globular cluster in Serpens Caput. It lies just two degrees north of the equator. It sports a collection of red giants which the image below clearly shows.

This is a NB4Stars project. Instead of using LRGB filters I use two Stromgren filters (V and Y) and a special 20nm Hydrogen Alpha filter.

click for a 1/2 frame image

Annotated Image

The image below is 1/2 frame of the camera. The markings on the stars are the B-V values. These can be used to determine whither I got the colors correct.

Since this is outside the plane of the Milky Way many dim galaxies were also captured in the picture. This links to a second annotated image that shows all of the galaxies captured in the frame.

Map

Processing Details

The images were processed with PixInsight.

Filter	Exposure
sV	16 x 900
sYel	16 x 900
Ha20 (20nm H alpha)	13 x 900

The color correction for this image was based on a G2V star

R= .210
G= .166
B = 1.00

Since that led to the Blue in bright stars being blown out I did an additional step of limiting the Blue channel

B = min ( G * 1.5, B)

This limited the amount of B in bright stars to a reasonable level.

Copyrights for Photos

Except as noted, all work on this site by Robert J. Hawley is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 United States License. This permits the non commercial use of the material on this site, either in whole or in part, in other works provided that I am credited for the work.