Struve 1791

Tim Leese
Star: Struve 1791
Date & Time: 11 May 2005, 23:00 UT
Seeing: 7-6 <1-10 Seeing Scale (10 best)>
Transparency:  <1 worst - 10 best>
Location of site: Northwich, Cheshire. UK.
(53° 15' N -2º 33' W).
Site classification: Suburban
Sky darkness:  <Limiting magnitude>
Conditions: High haze drifting by from time to time, Moon, nice view.
Telescope: 200mm f/6 Newtonian reflector
Mount: Vixen GP
Eyepieces: 30mm Ultima, 9mm Orthoscopic, 5mm Lanthanum.
Magnification: X40, X133, X240
 
30mm Ultima----------A lovely view of this delicate pair. A line of bright stars were seen following this double. Normally I would overlook this faint pair if I hadn't been searching for it for this project. Nice one!
 
9mm Or-------Seems to be at one point of a triangle of stars. Primary appeared to be yellowish but no colour could be detected in the faint companion. The companion disappeared from view sometimes but was well seen for most of the time. A visual estimate of PA for the faint companion was 160 degrees.


Alessandro Bertoglio
Star: Struve 1791
Date & Time: 24 May 2005 21.29 UTC
Seeing: III - IV Antoniadi
Transparency:
Location of site: Turin, Italy, 4504N 0742E
Site classification: Urban area with strong light pollution
Conditions: clear, no wind, mild temperature
Moon: full moon rising
Sky darkness: 3 (limiting magnitude)
Telescope: Takahashi Mewlon 300, Dall-Kirkham 300/3572 reflector
Eyepieces: Televue Plossl 15 mm.
Magnification: 238X
Diagonal: Yes, Televue 2" Everbrite
 
Double star comparable to the previous pair: it's not difficult but is pretty faint, sufficiently wide and fairly unbalanced. Primary sufficiently bright with a pale orange colour; secondary fainter but still observable (obscure or maybe orange). No rings. Extimated PA about 165 degrees.
 


 
    

Steve Bodin
Star: Struve 1791
Date & Time: 25 May 2005, 10pm to midnight
Seeing: 3/10
Transparency: fair
Location of site: Silverdale Wa, USA, 47N,123W
Site classification: Suburb
Conditions: 55F, no wind, dry
Sky darkness: limiting mag 5.6
Telescope: Celestron C8
Eyepieces: not used
Imaging: DX8263SL video camera at prime focus, f10, and 2x
Magnification: app. 333x and 666x

 Nice wide pair of somewhat faint stars, primary blue-white and companion
blue. Measurement, 21.75 sec at 157.0 deg PA
 

    

 
   
 
Louis Marchesi
Star: Struve 1791
Date & Time: 29 May 2005 3:04 UTC
Seeing: Pickering 3
Transparency: Below Average
Location of site: New London Township, PA, US (+39d45m,-75d52m)
Site classification: Suburban/Rural
Conditions: Clear, calm, heavy dew, 10C (50F)
Sky darkness: Not determined
Moon: None
Telescope: TMB152 f/7.9 Apochromatic Refractor
Mount: Losmandy G-11
Eyepieces: Baader Mark V Binocular Viewer with 1.25x Glaspath
Compensator
TMB Super Monocentrics 14mm
 Magnification:107x

 Both stars were white and easy at this power. I guessed there was about a one-magnitude difference between the stars in this pair. Struve 1791 formed an equilateral triangle with 9th- and 12th-magnitude stars.

(c) 1998-2005 The Spirit of 33