| Craig M. Carver | ||||
| Star:
75 Ori
Date & Time: 11/24/98 0720 UT Seeing: 6-7 <1-10 Seeing Scale (10 best)> Location of site: Madison, WI (Lat 43.07, Long 89.38, Elev. 500 ft) Site classification: Suburban Sky darkness: 4.8-5.0 <Limiting magnitude> Telescope: 6" Maksutov Magnification: 95x |
This is a nice triple.
The primary is very pale blue. The dimmer (10), closer star (62.7") to
the primary also appears pale blue and is about 90 degrees to the distant
(117") slightly brighter (8.0) third star.
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| Chuck Layton | ||||
| Star:
75 Ori
Date & Time: Dec. 23, 1998, 08:30 UT Seeing: 2 <1-10 Seeing Scale (10 best)> Location of site: Tacoma (WA) Site classification: --- Sky darkness: 3.6 <Limiting magnitude> Telescope: 20cm f/6 Eq. Newtonian Magnification: 76x |
Observed Colorations of Components: A - yellowish white, B - white, C - white. Other comments: Wide triple but the 10.5 mag. B component was tough due to hazy skies. | |||
| William L. Schart | ||||
| Star:
75 Orionis
Date & Time: 1/11/99 10:15 pm CST Seeing: 7 <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: 240x Star: 75 Orionis Date & Time: 2/13/00 10:23 pm CST 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, 48x, 72x, 98x |
Continuing observations
for the 33 doubles in Orion project, I re-visited this star as my previous
measurements did not match published figures. I did confirm that I had
been looking at the correct star. I detected a possible very faint companion
at PA 260 at 52" separation.
After one false alarm eliminated by determining separations, I located this trio. Confirmed by separations of 1 and 2 minutes. A couple of brighter stars with an estimated PA of about 170d, with a faint third member p[opping in and out of view with averted vision, PA estimated here at 270d. |
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| Dave Mitsky | ||||
| Star:
75 Orionis
Date & Time: 1/27/99 06:05 UT Seeing: 6 <1-10 Seeing Scale (10 best)> Transparency: ~ 6 Location of site: ASH Naylor Observatory (http://www.msd.org/obs.htm) near Lewisberry, PA Site classification: Rural Sky darkness: < 5.0 <Limiting magnitude> moonlight Telescope: 17" f/15 classical Cassegrain Magnification: 118x, 202x |
Another wide triple star system that is located near Orion's border with Monoceros. The 6th magnitude primary was blue-white. | |||
| Richard Harshaw | ||||
| Star:
75 Orionis [Bur 96; Jonckheere 408; Finsen 331; ADS 4890]
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): 0335 on 12/31/99 Site classification: suburban Sky conditions: seeing-- 8 out of 10 transparency-- 8 out of 10 limiting visual magnitude-- 5 Temperature: 42 F Telescope: Celestron C-8 Eyepiece: Micro-Guide (160x) |
I made five
sets of measurements with the Micro-Guide illuminated reticule eyepiece
for AB and AC (could not measure Cc) and got averages of 60" at PA 262
and 116" at PA 157. (If you want the measurements themselves, reply to
this posting.)
I noted colors of White,
??, White, and ??. The primary is at the center of a distorted cross, two
arms of which are made by the companions, and the other two by field stars.
To me the 9.5mag
The field is incredibly rich in this area! The primary is an extremely close binary with an orbital period of 8.7 years (Dommanget, 1977). (But Finsen, in 1978, gave 9.0 years.) It also spins at 192 kps. The star is a member of the Ori OB1 Association and rotates at 140 kps. Measurements from 1925:
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| Randall Heckman | ||||
| Star:
75 Orionis
Date & Time: 01/02/2000 AT 1:10 UT Seeing: 4 Location of Site: Heckman Observatory 40 37' 10" N and 99 03' 50" W Site Classification: Rural Sky Darkness (Limiting Magnitude): 5 Telescope: 8" Orion Dob Magnification: 46x
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Separation (Clear or Toughing):
CLEAR
Magnitude Comment: Observed magnitdes seemed to agreed with published values. Color Comment: White General Comment: The observation session of this evening was very short. Immediately after I logged this observation of 75 Orionis it clouded in.
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| Ilario Melandri | ||||
| Star:
75
Orionis
Date & Time: 4/Jan/2000 – 20.42 UTC Seeing: 9 <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 <Limiting magnitude> Temperature: -1C Telescope: 150 mm f/15 achromatic refractor Magnification: 140 x (eyepiece Plossl Clavé 16 mm) |
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| Philippe de Jocas | ||||
| Star:
75
Orionis
Date & Time: January 22, 2000 1h00-7h300 UT Seeing: 3-4 <1-10 Seeing Scale (10 best)>. Location of site: Ottawa/Hull, Canada Site classification: Suburban Sky darkness: 4.5 <Limiting magnitude> Temperature: -25C Telescope: 6" f5 newtonian Magnification: 40x |
75Ori completed the night and finished my chocoloffee, beeing an easy and nice target at 40x. | |||
| Jim Brownfield | ||||
| Star:
75
Orionis
Date & Time: 26/01/2000, 6:30 p.m.- 11:30 p.m. EST Seeing: 3 – 5 (improving) <1-10 Seeing Scale (10 best)>. Location of site: Huntsburg, Ohio, USA Site classification: Suburban Sky darkness: 6 mag., could see ST 855, going to 5th mag. star Rho <Limiting magnitude> Other observing conditions: 83% humidity, 16 degrees F. with 12" snow on ground going to 84% humidity, 4 degrees F. Telescope: 13.1"/F4.5 Dobsonian, with 5" aperture mask for the brighter pairs Magnification: 47x Star: 75 Orionis
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split at 47x, also picked
out 11 & 12 mag stars within 60" of primary
28x showed stars a,b& c, at 128x could split star c 8.5 mag from star d 11.0 mag 4.9" sep. |
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| Richard Bise | ||||
| Star:
75
Orionis
Date & Time: January/29/2000, 8:30 to 10 PM MST Seeing: 6-7 <1-10 Seeing Scale (10 best)> Location of site: 20 miles NW of Tucson Az 32.884N -110.979W Site classification: Suburban Sky darkness: 4 <Limiting magnitude> Telescope: 10 inch Meade Dobsonian Magnification: 49x, 125x (25mm Meade and 9.7mm Plössls) |
Thanks to Mr. Harshaw's
comments about the uninvolved stars in the field of 75, I was able to sort
the true companions. They all loked white to me.
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| John M. Ryan | ||||
| Star:
75
Orionis
Date of Observation: 2/02/00, 21:45UT Location of Observation: Ciudad Rodrigo, Salamanca, Spain 40º 36' N, 6º 32'W, Elev. 800 Meters Seeing: 6 to 7, fog began to degrade seeing (1 - 10, 10 best) Site classification: Urban Limiting Mag. (naked eye): 5 Instrument: Meade 8"SCT Magnification: 167x |
Separation (Clear or Touching):
Clean Split
Magnitude Comment:Very distinct Magnitudes in accordance with the data. Color Comment: The brightest component appeared pale blue the rest were white. General Comment: I resolved this group into an isoceles triangle with the brightest component in the NW corner. The dimmest component was in the NE corner with the intermediate component at the S point. The data list shows three components for this group. This is a rich field and there were other stars very close by that seemed they could be part of the group. Richard Harshaw lists 4 components for this group. |
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| Jay Zimmerman | ||||
| Star:
75 Orionis
Date & Time: 02/09/2000, Seeing: 6 <1-10 Seeing Scale (10 best)> Location of Site: Carbondale, IL, USA Site Classification: Suburban/near rural Temperature: 28°F (-2.22°C) Sky darkness: 5.1 <Limiting magnitude> Telescope: 97mm, f7 apo Magnification: 26.7x, 80x |
A and B split
at 26.7x. 80x and AV needed to bring C into the picture. Colors:
A = B = blue-white; C = ?. You can tell it's getting cold when I stop estimating
position angles.
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| Tom Teague | ||||
| Star:
75
Orionis
Date & Time: 2000 February 19, (2205 UT) Seeing: 7 <1-10 Seeing Scale (10 best)>. Location of site: Chester, England (53 11 08N; 02 51 39W) Site classification: Suburban Sky darkness: 3 (Moon just past full) <Limiting magnitude> Telescope: 63mm Zeiss Telementor refractor Magnification: x56, x112, x210 |
I can see the star at PA = 159 without difficulty at all powers. There is also a slightly brighter star at estimated PA = 345, estimated separation = 2 arc minutes. This asterism reminds me of the naked eye view of Altair and its two companions, forming the main part of Aquila. There is a fainter companion at a similar distance (2 arc minutes) in estimated PA = 100. I can't find any sign of a star at the predicted 258 deg, 62.7". | |||
| John Clemmer | ||||
| Star:
75
Orionis
Date & Time: March 6/2000 1930 EST Seeing: 7, quite steady <1-10 Seeing Scale (10 best)> Location of site: Priceville, Ontario, Canada W80 41'41" N44 10' 40" Site classification: Rural Sky darkness: 6+/10ths 5th mag. if I'm lucky tonight <Limiting magnitude> Telescope: Televue Pronto Magnification: 12x
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40mm 12x note: try Struve 667 1° north of Rigel 7.1 and 8.6 / 4.1" sep @ 314° Primary star K2 quite orange looking, pretty. | |||
| G.E.O.D.A Group | ||||
| Star:
75 Orionis
Date & Time: 11-III-2000, 18.30-21.30 UT Seeing: 7 <1-10 Seeing Scale (10 best)> Location of Site: Manises, Valencia, Spain. GPS coordinates: 39º 29' 36" N, 00º 27' 56" W. Site Classification: Urban-Suburban Sky darkness: 3 <Limiting magnitude> Telescope: Meade 10" LX-200 SCT Magnification: 200x |
Published measures
are the mean of two observations made from two different observers.
d = 82.1-135.2; PA = 260-158
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