Tau Leonis (Struve-A 19)

Sketch of Tau Leonis (Struve-A 19 / STFA 19)

Sketch of Tau Leonis / Struve-A 19

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Observation Notes:

I saw this widely spaced, colorful double as Orange-yellow and blue. Despite a G8 primary and G5 secondary, other observers also pick up the blue color contrast in the companion: 33 Doubles – Tau LEO. Sissy Haas sees them as lemon yellow and gray. They make a striking, low-power, double-double with nearby 83 Leonis.

Subject Tau Leonis (84 LEO / Struve-A 19 / STFA 19)
Classification Double Star
Position (J2000)* Leo [RA: 11 27 56.2 / Dec: +02 51 22.6]
Position Angle AB: 185° [My Measurement 2009.9]
AB: 181° [WDS 2004]*
Separation AB: 90″ [My Measurement 2009.9]
AB: 88.9″ [WDS 2004]*
Magnitudes* A: 5.1; B: 7.1
Spectral Types* A: G8II-III; B: G5
Date/Time NOV 27, 2009 – 5:15 AM MST (NOV 27, 2009 – 12:15 UT)
Observing Loc. Flagstaff, AZ – Home
Instrument Orion SkyQuest XT8 Dobsonian (203 mm dia./1200 mm F/L)
Eyepieces/Mag. Pentax XW10 + 2X Barlow (240X)
Meade Astrometric EP + 2X Barlow (200X)
Conditions Clear, cold, hazy
Seeing 3-4/10 Pickering
Transparency Mag 5.5 NELM
*References The Washington Visual Double Star Catalog (Mason+ 2001-2009); Catalogue of Stellar Spectral Classifications (Skiff, 2009); SIMBAD; Double Stars for Small Telescopes – Sissy Haas

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