Beta Capricorni (Struve 52)


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Observation Notes – May 12, 2008

Before submitting the sketch of this double for an upcoming observing article, I noticed an obvious error in the orientation of the entire field. Whenever the alignment of the double is very close to north, south, east or west, any slop in position angle becomes pretty obvious. So I headed out early this morning for another look and put the astrometric eyepiece on it. The corrected PA and separation can be seen in the illustration above, and the info in the table below. I’m convinced that getting up at 4 in the morning is unhealthy, but the strikingly beautiful color in this double made up for it. It’s very wide and definitely appears best at low power. Be sure to look it up with binoculars or a low power eyepiece when Capricornus makes its way into a more agreeable time slot later this summer.

Subject Beta Capricorni (STF 52)
Classification Multiple Star
Position (J2000) Capricornus [RA: 20:21:00 / Dec: -14:47]*
Position Angle* A-B: 267°; A-C: 133° [my measurement 2008]
A-B: 267°; A-C: 134° [WDS 1835; 1912]
Separation* A-B: 198″; A-C: 224″ [my measurement 2008]
A-B: 205.3″; A-C: 226.6″ [WDS 1835; 1912]
Magnitudes* A = 3.4; B = 6.2; C = 9.0
Spectral Types* A = G9II + B8p; B = A2V; C = F8
Date/Time MAY 12, 2008 – 04:15 AM (MAY 12, 2008 – 11:15 UT]
Observing Loc. Flagstaff, AZ – Home
Instrument Orion XT8 Dobsonian (203 mm dia./1200 mm F/L)
Eyepieces/Mag. 12 mm Meade Astrometric + 2X Barlow (200X)
Conditions Clear, breezy
Seeing 4/10 Pickering
Transparency NELM Mag 5.0
*References The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Catalogue of Stellar Spectral Classifications (Skiff, 2007); Visual Double Stars in Hipparcos (Dommanget+, 2000); Starry Night Pro Plus 5.8

Original Observation Notes:

October 9, 2006: To help provide a consistent style for my double star sketches, the above sketch is a digital update to the original sketch.

I’m not sure if this is a triple or not. The primary is brilliant yellow-orange. The secondary is deep blue (PA 265°, Sep. 4′). The tertiary (if that’s what it is) is orange (PA 160°, Sep. 5′). All elements were widely spread. The actual listed value of 267° PA/206″ (3’26”) sep closely matches the measure to the blue secondary.

Position Angle* A-B: 265°; A-C: 160° [my estimate 2005]
Separation* A-B: 240″; A-C: 300″ [my estimate 2005]
Date/Time SEP 13, 2005 – 12:15 AM MST (SEP 13, 2005 – 07:15 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 10 mm Sirius Plossl + 2X Barlow (240X)
Conditions Clear, breezy, 55°F
Seeing 4/10 Pickering
Transparency NELM Mag 4.8

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