C87
Globular Cluster in Horologium
About
NGC 1261 is an old, dense star ball in Horologium, about 53,500 light-years away and logged by Dunlop in 1826. It is roughly 10 billion years old and holds about 340,000 times the Sun's mass.
Imaging tips
- Too small to frame with a normal lens: it needs a long focal length and a fine pixel scale.
- Several distant background galaxies sit in the field, and one deep image described the cluster as almost embedded in them, so a longer integration may reveal them.
- One deep example combined about 5 hours of LRGB, with L, R, G and B each captured as 15 five-minute frames.
- Globular clusters need broadband only, no narrowband filter.
- Best around October and November, but it never rises from 50°N and peaks near 0° from 35°N, so it belongs to southern skies.
Facts
- Size
- 4′ × 3′
- Magnitude
- 9.3
- Coordinates
- RA 3h 12.3m, Dec −55° 13′
- Framing, APS-C
- longer than 4000 mm
- Framing, full frame
- longer than 4000 mm
- Best months
- Oct, Nov
- Peak altitude
- never rises from 50°N, never rises from 35°N