Struve 2491 

Richard Harshaw 
Star: Struve 2491 
Date & Time: 6 July, 2001, 03:00 to 04:55, UT
Seeing: 8 <1-10 Seeing Scale (10 best)>. 
Transparency: 6-7/10 ,variable, due to high hazy clouds 
Location of site: Northern Kansas City, Missouri. 39º 15' N, 94º 30' W, 980 ft above Mean Sea Level
Site classification: Suburban
Sky darkness:  <Limiting magnitude>
Telescope: Celestron C-11
Eyepieces: 25mm Plossl, 9mm Lanthanum 
Magnification: 112x, 311x
Position:  1916+2817 
Magnitudes:  8.24 (A2m), 9.43 
Sep/PA's:   1.3+ / 227+ 
Year of this measurement:  1996 
Distance (light years):  860 
Luminosity (in suns):  38 
Eyepiece and magnification:  25mm Plossl (112x), 9mm Lanthanum (311x) 
Colors noted:  W, pO 

Comments:  Observed at 112x, not split.  At 311x, good, clean split.  Nice field. 
SAO 87008 (6.2m, F6Ib, 780 times brighter than the Sun and 1,700 light years away) lies 21' S.  It is a Cepheid variable (V473 Lyr)- if it is a Population I Cepheid, it has the shortest known classical Cepheid period in the Galaxy. 
Rating:  3 
 


 
William Schart 
Star: Struve 2491 
Date & Time: July/9/01 0500 to 0635 UT
Seeing: 7 <1-10 Seeing Scale (10 best)>. 
Location of site: Killeen, TX, USA
Site classification: Suburban
Sky darkness: 4 <Limiting magnitude>
Temperature: In the 80's F (30's C). Slight breeze. 
Telescope: Celestar 8" SCT
Eyepieces:  25mm, 17mm, 10mm
Magnification: 80x, 120x, 200x
I am only going to claim an elongation on this, even at high power.

 


 
Bob Hogeveen 
Star: Struve 2491
Date & Time: 23 July, 2001, 00:00
Seeing: 8 <1-10 Seeing Scale (10 best)>. 
Location of site: Annen, The Netherlands - 53N, 6E
Site classification: Village backyard
Sky darkness: 5 <Limiting magnitude> 
Telescope: Celestron C-11
Eyepieces: Ultima 30mm , TV plossl 20mm, LV 15mm, 7mm 
Magnification: 187x, 400x
Harshaw Scale: 3 <1-5; 1 best>
The stars of this double were a bit to faint (magn. 8.6 - 9.7) for a good view with 400x. Visible though, and easily separated, but not a nice view.
187x gave a much better view. Better star-images and still a good separation, although very close of course (1.3").
No color noted.

 
Philippe Dejocas
Star: Struve 2491
Date & Time: August 8 2001 
Seeing: 7.5 <1-10 Seeing Scale (10 best)>
Location of site: Canada
Site classification: Suburban
Conditions: Clean skies and warm temperatures.
Sky darkness: 4.5 <Limiting magnitude> 
Telescope: 6inch/f5 newt
Magnification: 225x

 

"A hard hugger even at 225x, but got it too" Then I did a quick check on M56, on my way to STF 2483; this globular cluster really tries to pass itself of as a comet. This one I can understand being seen as one at first.
 
 
 

 


 
Otto Piechowski
Star: Struve 2491
Date & Time: 9 PM EDT Saturday, August 18 to 2 AM, Sunday, August 19
Seeing: 8 <1-10 Seeing Scale (10 best)>. 
Location of site: Lexington, KY, USA 
Site classification: Urban area
Sky darkness: 4.5 (Zenith Unaided) <Limiting magnitude>
Conditions: Clear, a bit of haze, still, c. 65 degrees F, very slight breeze
Telescope: 150 mm Maksutov Cassegrain
(Intes standard MK 67) 
Eyepieces:  30 mm ?, 16 mm Rini, 11.4 mm Rini, 7 mm and 4 mm celestron orthos, 5 mm University Optics ortho.
Magnification: 158x, 360x
Barely resolved at 360X with the UO 5 mm ortho and barely resolved at 158X with the 11.4mm Rini.
 
 

 

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