Struve 2737 

Richard Harshaw
Star: Struve 2737 
Location of site: Northern Kansas City, Missouri (USA) 
94d 30m west longitude, 39d 15m north latitude 
980 ft above Mean Sea Level 
Date of observations (UT): UT: 02:15 of Sept. 16, 2000 
Site classification: suburban 
Sky conditions
seeing-- 4/10 up to 8/10, in short spans of time 
transparency-- 8 out of 10 
limiting visual magnitude-- 5.0 mag 
Telescope: Celestron C-8 
Eyepiece: 20mm  (104x) for AC.  (It took 697x to split AB.) 
 
 
Position:  2059+0418 
Magnitudes:  5.3, 5.3, 7.1 
Sep/PA's:  AB = 1 / 285 -.  AC = 10 - / 67 -. 
Year of last measurement:  1990 
Distance (light years):  197 
Luminosity (in suns):  51 
Eyepiece and magnification:  20mm  (104x) for AC.  (It took 697x to split AB.) 
Colors noted:  W, W and B.  Some observers note W and B; Webb reported Y and yW.  Very rich field. 
It was discovered by Struve in 1835. 
The orbit takes 101.4 years (van den Bos, 1933). 
Star A is a spectroscopic binary with a period of 1.0313 days. 
First measure of AC (discovered by Aitken):  11" @ 78. 
I rated it 2. 
 
 
 
Eddy O'Connor
Star: Struve 2737 
Date & Time: 8 -10 p.m local; UT +11. Monday, September 18th 2000 
Seeing: 5-6 <1-10 Seeing Scale (10 best)> 
Transparency: 9. No Moon. Temp 18º C. Windy. 
Location of Site: Terara, New South Wales, Australia, Long.150.38 degrees; 
South 34.52. 
Site Classification: Suburban 
Sky darkness: 4.5 <Limiting magnitude> 
Instrument: 8"  F9 Dobsonian 
Magnification: 72X (25mm Kellner)
(Epsilon or 1Equ): This star can , with patience and a good finder, be located by star-hopping from the Delphinus group but the most difficult to locate tonight. I failed to split the close companion of this Light Golden star but the wider C companion was a dainty bluish colour. 

Comments: The closer pair is recommended for X200 power and 8/10" scopes are required for splitting the AB(mag. 6,7.1) components of this triple at 0.8" separation;the easier mag 7.3 C component has a separation of 10.7" and a PA of 70º. The AB pair is closing with periastron occuring in 2021,according to The Observer's Guide. Hartung suggests the orbit of the close pair is in line of sight with a period of 101 years. A gem of a triple which honours the Equestrian 
event. 
 

 
 
Patrick J. Anway 
Star: Struve 2737 
Date & Time: Sept. 17, 2000, 11pm EDT (0300 UT) 
Seeing: 7 <1-10 Seeing Scale (10 best)> 
Location of Site: Munising Michigan USA 
Site Classification: Rural 
Sky darkness: 5.5 (in the holes) <limiting magnitude> 
Sky condition: high clouds, moon rising 
Temperature: 42º F (5º C) 
Telescope: Zeiss 63mm/840mm f/13.3 
Eyepieces: 7mm, 10mm, 16mm, 18mm orthos 

 
 

Using 10mm for 84X components separated into yellow primary and blue secondary. Olcott gives white and blue and Smyth gives white and pale lilac. Discovered by Struve in 1835, the estimated distance of the group is 200 light years. 

I also attempted 4 Vulpecula but was unable to split it and will try later when more holes appear. 
 
This time of year in the U.P. of Michigan you get pretty much the same weather each day. Mostly clouds with occasional holes of clear. Amateur astronomy is kind of hit or miss. You wait for the hole to get where need it and then go to work. With a week of rain in the forecast, I was anxious to get out any evening with holes. Sunday was the night -  despite high patchy clouds with holes, Luna rising in the east and a fairly bright aurora extending above the north horizon. There is also the nip of fall in the air with the temp at 42º F (5º C) and a sprinkling of color among the tree covered hills between me and "Gitche Gumee" to the north. Though sitting between  fronts, the air is surprisingly calm as I climb the grade to Lookum. I'm alone; wife and daughter are content to curl up on the couch inside and watch the happenings in Sydney. In between patches, through the holes, I managed to glimpse 8 Olympiads: zeta Aqr, h2866, 70 Oph, 1 Peg, omi Cap, gamma Del, OS525, eps Equ. 
 

 
 
Tom Teague
Star: Struve 2737 
Date & Time: 2000 September 18 (21:35) 
Seeing: 6 <1-10 Seeing Scale (10 best)>. 
Location of site: Chester, England (53 11 08N; 02 51 39W) 
Site classification: Suburban  
Sky darkness: 4 <Limiting magnitude> 
Telescope: 63mm Zeiss Telementor refractor 
Magnification: x84, x140 
  
 
I don't recall observing this pair in the past.  I doubt whether I could easily have forgotten it if I had, for it's a magnificent double.  An excellent choice by Tim.  Easily separated x84, and best seen at that power.  I find the colour of the comes impossible to define, as it seems to change moment by moment (doubtless a consequence of scintillation).   At times it seems blue, occasionally mauve/lilac, and just once I thought it might be orange.  But the most persistent - undoubtedly subjective - impression was of green!  No estimates of PA or sep, I'm afraid. 

Ambience:  cold, still, autumnal. 
 

 
 
Tim Leese
Star: Struve 2737 
Date & Time: 20-September-2000 (22:10 UT). 
Seeing: 6-7 <1-10 Seeing Scale (10 best)>  
Location of site: Cheshire. UK 
53° 15' N –2º 33' W  
Site classification: Suburban  
Sky darkness: 3.5 <Limiting magnitude>  
Telescope: 200mm f/6  Newtonian scope  mounted over a Vixen GP mount (manual slow motion). 
Any Quoted PA or SEP using micro guide. 
Magnification: X120, X240, X480 
  

 

This is another first time observation of this system for me and, not knowing what to expect, I was pleasantly surprised of what I found in the steadily decreasing FOVs as I increased the magnification. 
 
Using X120 to start with I observed a very nice double(AB-C) comprising of a yellow/white star with a pale blue/lilac companion at an estimated PA of 70deg. Increasing the magnification to X240 the A/B pair showed some elongation and in moments of steadier air a peanut shape or figure of eight star could be detected. Only in odd moments of steady air and using X480 magnification was I able to split the A/B components of this system. A superb system to observe, then I'm biased as this system was my second Olympian!! 
 
Ambience: No wildlife to report tonight except that the stray cat put in a short appearance.  Had to take drastic measures to combat the moisture as the air is very damp tonight also. 
 
 
 
Ilario Melandri
Star: Struve 2737  
Date & Time: 21/9/2000 – 19.20 UT
Seeing: 4 <1-10 Seeing Scale (10 best)>  
Location of site: Italy, Ravenna, San Romualdo, Lat 44 32’N Lon 12 08’E 
Elevation: 0 m 
Site classification: Rural  
Sky darkness: 4.5 <Limiting magnitude> 
Temperature: +15C 
Telescope: 150 mm f/15 achromatic refractor (lens by Romano Zen, Venice). 
Magnification: 250x (Or 9mm)
 
Separation is decreasing, it will be 0.5” in 2010, with PA 283. Distance 130.4 light years
 
The distance between the two components corresponds at 32 Astronomical Units, a bit more than the distance Sun-Neptune
 
 
 
 
William L. Schart
Star: Struve 2737 
Date & Time: 9/25/00 9:33 pm CDT 
Seeing: 6 <1-10 Seeing Scale (10 best)>  
Location of site: Killeen, TX (Lat 31 N, Elev 600 ft)  
Site classification: Suburban  
Sky darkness: 4 <Limiting magnitude>  
Telescope: Orion 6" Dob.  
Magnification: 32x,  72x, 98x 
  
  
 
Again, I swept over from Enif until I found Equalus in the finder, a quadrilateral with one narrow end and one broad end. This pair is off the broad end. Not split until I reached 72x. I measured the separaation at 10" and the PA at 250. the primary was again yellow and the secondary faintly blue, but this could have been a contract effect.