C82
Open Cluster in Ara
About
NGC 6193, the Firebird Cluster, a young open cluster in Ara about 3,800 light-years away. Its stars are only around 3 million years old. It anchors Ara OB1, a group whose radiation lights up the neighbouring nebula NGC 6188.
Imaging tips
- At 1300–2160 mm on APS-C the cluster alone spans a third to half of the frame. The Ara OB1 association spans about one square degree, so a much shorter focal length is needed to include the surrounding nebula.
- One wide-field image used a 135 mm lens with Hα plus LRGB data; the author found aberrations around the bright stars the main difficulty.
- Light from the cluster scatters off dust into a soft blue haze that broadband captures; Hα adds the emission nebula around it.
- Best in May and June, but it never rises from 50°N and peaks near 6° from 35°N.
Facts
- Size
- 18.7′
- Magnitude
- 5.2
- Coordinates
- RA 16h 41.3m, Dec −48° 47′
- Framing, APS-C
- 1300–2160 mm
- Framing, full frame
- 1990–3310 mm
- Best months
- May, Jun
- Peak altitude
- never rises from 50°N, 6° from 35°N