This was a great double to observe. The primary is a bright, third magnitude pale yellow star with a much fainter seventh magnitude, blue-gray companion resting right up against it. When the seeing was choppy, this secondary disappeared into the overpowering wash of yellow. I thought it looked a bit like a little bluebottle fly sitting on the edge of a fluttering sunflower.
PA appeared to be about 315Â°. The first diffraction rings seemed to be barely in contact, which indicated a separation of 2.5 to 3 arcseconds. According to the Washington Double Star Catalog, the primary is itself comprised of 2 stars of magnitudes 3.8 and 5.3. The period of the very close AB pair is 15.05 years, and the AB-C period is 890 years.
|Subject||Epsilon Hydrae (STF 1273)|
|Position (J2000)||[RA: 08:46:46.1 / Dec: +06:25:09]*|
|Position Angle*||AB-C=195Â° (1825)
|Magnitudes*||A=3.8; B=5.3; AB=3.6; B=7.8|
|Date/Time||OCT 22, 2006 – 3:55 AM MST (OCT 22, 2006 – 10:55 UT)|
|Observing Loc.||Cinder Hills Overlook, Sunset Crater National Monument, AZ|
|Instrument||Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)|
|Eyepieces/Mag.||10 mm + 2X Barlow (240X)|
|Transparency||NELM Mag 6.8+|
|References||The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996), Visual Double Stars in Hipparcos (Dommanget+, 2000) via VizieR|
*Based on published data.