Otto Struve 313 in Hercules 

Bob Hogeveen
Star: Otto Struve 313 
Date & Time: May, 23th, 2001 - 01.00
Seeing: 8 <1-10 Seeing Scale (10 best)>
Location of site: Annen, The Netherlands
53ºN, 6ºE
Site classification: Village backyard
Sky darkness: 5 <Limiting magnitude>
Telescope: Celestron 11" SCT f/10
Magnification: 280x, 400x 
Harshaw rating: 3 

 

A first look with 280x was enough to split this double. Very, very close of course, but the star-images were nice and small and sharp most of the time. With 400x the split can really be called easy (no colors noted -> white). 

This is my first sub-1-arcsecond split and it is obvious that with these conditions and with this scope more and closer nuts can be cracked! 
 
 
 

 


 
Tim Leese
Star: Otto Struve 313 
Date & Time: 23- May-2001 (22:40UT)
Seeing: 7 <1-10 Seeing Scale (10 best)>. 
Location of site: Cheshire. UK
53° 15' N -2º 33' W
Site classification: Suburban
Conditions: High drifting haze with good clear patches. 
Sky darkness: 3.0 (UMi) <Limiting magnitude> 
Telescope: 200mm f/6  Newtonian mounted 
over a Vixen GP mount (manual slow motion). 
Eyepiece(s): 6mm UO orthoscopic X2 shorty barlow. 
Magnification: X200, X400. 

 

I couldn't find this star at first but after a systematic search of all the likely candidates in the finder scope I settled on a promising star showing elongation at X200. Checking the listed PA confirmed I was on the correct target so I increased the magnification to X400 and got definite separation in moments of steadier air. No colour could be determined as the stars seemed very pale.( sky haze perhaps). Double checking, using X200 again, I oberved clean separation with this magnification also. 

This nut seemed harder to crack than Struve 1834 for some reason but I was happy to crack my first nut off the "Nutcracker" list. 
 

 


 
Jim Jones
Star: Otto Struve 313 
Date & Time: 06/22/01,  0815 UTC
Seeing: 8 <1-10 Seeing Scale (10 best)>. 
Location of site: Lake Oswego, Oregon
Site classification: Suburban 
Sky darkness: 4.5 <Limiting magnitude> 
Conditions: Bright oatmeal sky on the longest day of the year. Moon not a factor.
Telescope: 8 inch LX50 SCT
Eyepieces: 18mm Radian, 7mm UO Ortho, 2x Ultima
Magnification: 112x, 224x, 285x

 

Est PA without inst...315d or 135d
Very tight double.  Almost equal mag.
It split very nicely at 285x.  Excellent disks and stable, almost complete diffraction rings.  However, as I observed the double I could see the image
deteriorating rapidly. Seeing was changing.

I was pleasantly surprised to find a nice but dim double in the same field as
STT 313.  After admiring it for awhile, I dutifully recorded it.  It turned 
out to be STF 2065 ab. Actually after reviewing my notes from previous attempts to split STT 313 I realized that I knew about STF 2065 but had forgotten about it.
 


 
Thad Robosson
Star: Otto Struve 313 
Date & Time: Aug 25th, 2001
Seeing: 6 <1-10 Seeing Scale (10 best)>. 
Transparency: 7
Location of site: Cherry Rd., USA
34 31.136N, -112 05.078W
Elevation: 4435 Ft
Site classification: Rural
Sky darkness: -- <Limiting magnitude> 
Conditions: Clear, with 1 rst quarter moon lighting the way
Telescope: 8" f/6 Newtonian on EQ mount. 
Eyepieces: TV 5 Radian
Magnification: 240x 
Just barely a black lane for small, fleeting moments at 240x. PA est at 135.  Rated a 3.
 

 

 
 
Bernie Aken 
Star: Otto Struve 313 
Date & Time: Sep 17, 2002, 20:53 CDT
Seeing: 6 <1-10 Scale (10 best)>
Transparency: 8 <1-10 Scale (10 best)>
Location of site: Texas, USA
Site classification: Suburban
Sky darkness: -- <Limiting magnitude>
Moon: 89%
Telescope: Takahashi Mewlon 250
Eyepieces
Magnification:  680x
Haze has begun forming overhead and is quickly eliminating visibility. I see a clean split of the pair at 680x.  Both are Y/W with a slight magnitude difference.

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