Observation Notes:
While enjoying the view from the summit of Haleakala on Maui, I was able to make a binocular observation of the wide double, Mu Crucis. This wide double was a nice binocular target and was only difficult to split when the wind was shaking my lightweight tripod. The primary was bright blue and the secondary appeared to be an elusive orange color. This must have been a contrast effect, since the secondary is a B5 star. This is as far south as I’ll be getting on a double star for a good long while: -57° declination is 2 degrees below the horizon in Flagstaff, and about ten degrees below a useful altitude from here.
| Subject | Mu Crucis (DUN 126) |
| Classification | Double Star |
| Position (J2000) | Crux [RA: 12:54:35.5 / Dec: -57:10:40]* |
| Position Angle* | 17° (1826) |
| Separation* | 34.9″ (1826) |
| Magnitudes* | A: 4.03 / B: 5.17 |
| Spectral Types* | B3 / B5 |
| Date/Time | JUN 3, 2007 – 9:30 AM HADT (JUN 4, 2007 – 10:30 UT) |
| Observing Loc. | Haleakala Summit, Maui, HI (10,000 ft.) |
| Instrument | Oberwerk 15 x 70 Binoculars |
| Eyepieces/Mag. | 15X |
| Conditions | Clear, cool, Breezy |
| Seeing | – |
| Transparency | NELM Mag ~6.5 |
| References | The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Catalogue of Stellar Spectral Classifications (Skiff, 2005) |
*Based on published data.