Struve 1604

Sketch of Struve 1604 (STF 1604)

Digital Illustration of Struve 1604

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Observation Notes:

I observed this triple star nearly a year ago for Sue French’s May 2009 Deep Sky Wonders column. I was out at Sunset Crater National Monument so I could get a good view of Comet Lulin. I had just set up the Dob so tube currents were pretty bad. The A star appeared yellow while the C star appeared as a softly tinted blue. The B star was a dull orange color and difficult to view when the seeing was at its worst. Measuring PA and separation to this 9th magnitude star was difficult since the reticle was too bright even at its dimmest setting.

One thing to note is that the B star is the faintest of the three, and is also a high proper motion star that isn’t part of the A and C common proper-motion pair. This leads to a pretty rapid change in measurements over the years.

Subject Struve 1604 (STF 2140 / ADS 8440)
Classification Multiple Star
Position (J2000)* Corvus [RA: 12 09 28.5 / Dec: -11 51 25.4]
Position Angle AB: 89° [My Measurement 2009.1]
AB: 89° [WDS 2006]*

AC: 20° [My Measurement 2009.1]
AC: 22° [WDS 2007]*

Separation AB: 9″ [My Measurement 2009.1]
AB: 9.2″ [WDS 2006]*

AC: 12″ [My Measurement 2009.1]
AC: 10.4″ [WDS 2007]*

Magnitudes* A: 6.6; B: 9.4; C: 8.1
Spectral Types* A: G3V; B: K5; C: G0
Date/Time JAN 28, 2009 – 4:45 AM (JAN 28, 2009 – 11:45 UT)
Observing Loc. Cinder Hills Overlook, Sunset Crater National Monument, AZ
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, slight breeze
Seeing 3-5/10 Pickering
Transparency Mag 7.0+ NELM
*References The Washington Visual Double Star Catalog (Mason+ 2001-2009); SIMBAD