Zeta Piscium (Struve 100)


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Observation Notes:

I had a very difficult time determining color on this double. At low power, the primary appeared pale yellow with a white secondary. At 240X, the color appearance switched from blue/yellow to white/yellow to yellow/blue. I decided to go with the low power color appearance, since it was the steadiest by a slight margin. I measured a PA of 61 degrees and a separation of 32 arc seconds. The WDS lists 64 degrees and 23.6 arc seconds from 1832. Recent measurements are all within an arcsecond of the 1832 WDS measurement. This leads me to believe I was sloppy and noted 3.7 hatch marks in the astrometric eyepiece when I probably should have noted 2.7. That would have yielded a measurement of 23 arc seconds. I’ll need to re-observe this one and check the separation again.

There’s no accounting for reckless record keeping =)

Subject Zeta Piscium (STF 100)
Classification Double Star
Position (J2000) Pisces [RA: 01:13:45.3 / Dec: +07:34:41]*
Position Angle* 61° [my measurement]
64° [1832 WDS]
Separation* 32″ [my measurement]
23.6″ [1832 WDS]
Magnitudes* 5.23 / 6.26
Spectral Types* A7IV / F7V
Date/Time SEP 20, 2007 – 10:45 PM MST (SEP 21, 2007 – 05:45 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SVP 6LT Reflector (150 mm dia./1200 mm F/L)
Eyepieces/Mag. 10 mm Sirius Plössl + 2X Barlow (240X)
12 mm Meade Astrometric EP + 2X Barlow (200X)
Conditions Breezy, 1st quarter moon, patchy cirrus
Seeing 5/10 Pickering
Transparency NELM Mag ~5.0
*References The Washington Visual Double Star Catalog, 1996.0 (Worley+, 1996); Starry Night Pro Plus 5.8

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