Otto Struve 72


 
Bob Hogeveen
Star: Otto Struve 72
Date & Time: November 14, 2001
Seeing: 5 <1-10 Seeing Scale (10 best)>
Transparancy: 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 C11
Magnification: 93x, 140x
Harshaw Scale: 2 <1-5; 1 best>
A pretty one, this one. The primary is deep/golden-orange. 
The secondary is much more faint but can be seen easily with the C11.

The pair was in exactly vertical position at the time of observation. This gave it a funny look. The faint B was hovering a bit above the bright A. Somewhat like a setting sun with a small detached part or reflection above it. 
 
 
 

 


 
Rafael Barberá 
Star: Otto Struve 72
Date & Time: 23/11/2001, 22:30 and 23:30 UT
Seeing: 6-7 <1-10 Seeing Scale (10 best)>
Transparancy: --- <1-10 Seeing Scale (10 best)> 
Location of site: Manises (Valencia - Spain)
Site classification: Urban - Suburban
Sky darkness: 4.0 <Limiting magnitude>
Moon  : One quarter
Telescope: TeleVue 85
Eyepieces: Televue Ploss 20mm, Eudascopic 15mm,
Eudascopic 10mm, Eudascopic 5mm, Celestron Ultima Barlow (2x)
Magnification: 30x, 40x, 60x, 120x
More dificult that Struve 495. A very hard one!. I can detect barely the companion at 120x only. It has a DI of 86.5. My previous high mark was (and still is) Epsilon Bootes with a DI of 90.07, but I think that Epsilon Bootes is easier that this one, because I have more light to use that in this situation. Remember that I'm using an 85mm refractor. With an sky of 6 or 7over 10 and a lot of background light, this double is very hard to observefor me.

At lower power (40x) the main star makes a beautifull ultra wide and colorful pair with the field star SAO 93781, that lies at 12.5'. SAO 93781have spectra A0 and Struve 495 is K0. On a wide field eyepiece Struve 495 looks like the Sun reflected over gold, and SAO 93781 blue. A very beautifull not_double experience.
 

 


 
Eddy O'connor 
Star: Otto Struve 72
Date & Time: Monday, December 10th, 2001
10 p.m local; UT +10
Seeing: 6 <1-10 Seeing Scale (10 best)>
Transparancy: 9 <1-10 Seeing Scale (10 best)> 
Location of site: Terara, New South Wales, Australia, Long.150º.38 ; Dec. S 34º.52. 
Site classification: Suburban
Conditions: No Moon
Temp. 17ºC.
Sky darkness: --- <Limiting magnitude>
Telescope: 8" Newt. F9
Eyepieces: 25mm K, 12.5 mm Ortho
Magnification: 144x
Harshaw Scale: 2 <1-5; 1 best> 
 
This beautiful object is found in a hammock-like asterism of mag. 5.5 stars northwest of the Hyades. Mag. 5.9/9.7; Sep.4.6"

Comments: The Primary is a rich deep yellow star with the spark-like 
delicate secondary just revealed at X144
 
 
 
 

 


 
William Schart 
Star: Otto Struve 72
Date & Time: 9:00 -> 9:40 pm CST. 
Seeing: 6 <1-10 Seeing Scale (10 best)>
Location of site: Killeen, Texas
Site classification: Suburban 
Sky darkness: 4 <Limiting magnitude>
Moon: No moon in the sky
Telescope: 8" Celestar SCT
Eyepieces: 25mm, 17mm, CMG (12.5mm)
Magnification: 80x, 120x, 165x
 
Although slightly wider than the last pair, this proved to be a tougher split. Not much at all at low power, elongation at mid power, I used the Microguide as a simple EP to get a clean split. I attribute the difficulty to the magnitude difference (almost 4). 

The primary tends drowns out the seconday, but I could pop it in view with averted vision. The primary is a bright golden yellow; the seocndary too faint to tell.
 

 
 
Stuart Clough
Star: Otto Struve 72
Date & Time: 29.12.01 2040 - 2345 UT
Seeing: 6 <1-10 Seeing Scale (10 best)> 
Location of site: Near Halifax
West Yorkshire, England.
Site classification: Suburban
Temp: -4ºC
Conditions: Clear except between 2110 & 2240, when mainly overcast, 
Wind SW - NW 5/15kts
Sky darkness: 3.0 (U Mi) <Limiting magnitude>
Telescope: Orion Optics UK GX250
Eyepieces: 25 mm Ortho, 20 mm Plossl, 9mm Ortho, 7.5mm Plossl
Magnification: x10 (finder) x48, x60, x133, x160
 
This double was quite tough. I suspect that it is never easy because of the difference of 3.8 magnitudes between the two components. On the day, the full moon was also something of a factor. At x60 there was no indication of duplicity at all. At x133 I thought I saw a faint point of light close to the bright glow of the bright golden yellow primary, but could not be sure. The small increase in power to x160 confirmed the pale ember that is the secondary in the suspected position. Having done that it was possible to see the comes clearly on return to x133. No colour could be discerned in the faint companion.