Messier 5 (Serpens)
Fig. 1 - Believed to be one of the oldest globular clusters in our galaxy: Messier 5 (NGC 5904) in the constellation Serpens, photographed with an 8-inch f/5 Newtonian reflector on a ZWO AM5 mount. . The bright star next to it is 5 Serpentis (mag 5.2).
| Object name: | Constellation: | Coordinates: | Apparent size: | Visual brightness: |
|---|---|---|---|---|
| Messier 5 (NGC 5904) | Serpens | 15h19m / +02°05' | 23' | 5.7 mag |
The globular cluster Messier 5 (NGC 5904) in the constellation Serpens. Messier 5 can be seen with the naked eye as a star-like object on very clear nights and in locations with little light pollution. Messier 5 is one of the larger globular clusters known, spanning about 165 light-years in diameter.
A majority of Messier 5’s stars formed more than 12 billion years ago. Within Messier 5, there are more than 100 known variable stars, the majority of them belonging to the RR Lyrae type. RR Lyrae stars are somewhat similar to Cepheid type variables and as such can be used as a tool to measure distances in outer space since the relation between their luminosities and periods are well known. Messier 5 is 23,000 light-years from Earth and was discovered by German astronomer Gottfried Kirch in 1702 when he was observing a comet. (source: Wikipedia).
Exposure time: 3h 30min (70x3min) at gain 100 and -10°C, taken on May 30 / 31, 2025. Processing with Astro Pixel Processor (APP) and Photoshop. Darks, flats, and bias were used.
Equipment: Cooled ASI 2600MC Pro camera, TeleVue Paracorr Type II coma corrector, 8" f/5 "ONTC" Newtonian telescope riding on a ZWO AM5 Strain Wave Mount, ZWO OAG-L off axis system, ASI 174MM Mini guide camera, ASIAIR Plus.
Messier 5 was also captured with a 16-inch dobsonian on an equatorial platform. The image can be seen here.
Fig. 2 - Search chart for Messier 5. Copyright 2025 'The Mag-7 Star Atlas Project', www.siaris.net.