Globular clusters in Serpens: Messier 5 (Robotic, NM)
Messier 5 is a globular cluster found in the constellation of Serpens. It lies close to the star at top right - 5 Serpens which is actually a double (just resolved here). Estimated to contain at least 100000 stars. It is distinguishable from other GCs by its long "spider-like arms".
It is probably the remnant of a dwarf galaxy that has lost its outer stars to the gravity of our large Milky Way galaxy. It is about 13 billion years old.
The cluster contains several RR Lyrae variables whose periodicity/luminosity relationship can be used to work out the exact distance to the cluster - just like Cepheid variables or Type 1a supernovae. RR Lyrae stars are not that bright so can only be used as standard candles in reasonably close galaxies.
This is 18 x 6 minute exposures dithered and drizzled. Processed in PixInsight 1.8. Taken remotely with scope T3 at iTelescope's New Mexico observatory.
Globular clusters in Serpens: Messier 5 (Robotic, NM)
Messier 5 is a globular cluster found in the constellation of Serpens. It lies close to the star at top right - 5 Serpens which is actually a double (just resolved here). Estimated to contain at least 100000 stars. It is distinguishable from other GCs by its long "spider-like arms".
It is probably the remnant of a dwarf galaxy that has lost its outer stars to the gravity of our large Milky Way galaxy. It is about 13 billion years old.
The cluster contains several RR Lyrae variables whose periodicity/luminosity relationship can be used to work out the exact distance to the cluster - just like Cepheid variables or Type 1a supernovae. RR Lyrae stars are not that bright so can only be used as standard candles in reasonably close galaxies.
This is 18 x 6 minute exposures dithered and drizzled. Processed in PixInsight 1.8. Taken remotely with scope T3 at iTelescope's New Mexico observatory.