| Richard Harshaw | ||||
| Star: 70
Ophiuchius
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: 10mm (207x) |
Position: 1806+0230
Magnitudes: 4.2, 6.0 Sep/PA's: 2.9 - / 155 -! Year of last measurement: 1997 Distance (light years): 17 Luminosity (in suns): 0.56 Eyepiece and magnification: 10mm (207x) Colors noted: yW and yO. Some observers report seeing colors of Y and R, or D and V, or Y and L, or Y and pR, or Y and O, or D and rO. Webb saw Y and V. This star has eight more very faint and distant companions! It was discovered by William Herschel in 1779. First measure 4" @ 148. In 1914, Phillips measured 4.2" @ 143. The A star is 40% as luminous as the Sun, 82% as massive, and 90% as large. The same numbers for the B star are 8%, 60%, and 70%. Star A is also an infra-red source. There seems to be a dark companion with about ten times the mass of Jupiter. The orbit takes 88.13 years (Heintz, 1988), and the stars are at least 23 AU apart (a little more than the distance from the sun to Uranus). Star A is also a spectroscopic binary. I rated this familiar workhorse pair a 2. |
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| Eddy O'Connor | ||||
| Star: 70
Ophiuchius
Date & Time: 9 p.m local; UT +11. Saturday, September 16th 2000. Seeing: 6/10 <1-10 Seeing Scale (10 best)> Transparency: 6/10 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 K) |
This star was easy to locate, as the most Westerly of
a recognisable triangle of fourth mag. stars. Starlist 2000 gives
separation as 3.8" and PA as 147. This mag.4 deep orange star I failed
to split at X72 but X144 revealed the dimmer 6 mag. reddish companion nearby.
Comments : A well-chosen Olympian with a fair challenge to an 8" telescope
and the golden shades of the primary makes it a sterling choice. Hartung
sees the primary as a 'fine, bright yellow, with an orange secondary and
gives the period of binary as 87.71 years. He notes that A is also
a spectroscopic pair of 18.10 years.
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| Patrick J. Anway | ||||
| Star: 70
Ophiuchius
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
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Using the 70mm for 120X, I was able to separate a yellow
primary from an orange-yellow secondary. Olcott gives the colors yellow
and red for the components while Smyth says they are "topaz and violet"
and Flammarion felt that the companion was "rose-colored". Charles
Worley calls 70 Oph "a famous binary" whose "position angle and separation
are decreasing at a fairly rapid rate." The system is only 16.5 light years
away and permits detailed investigation of it's orbital motion. With an
orbital period of 87.85 years and because it has been investigated since the first observations by William Herschel in 1779, the stars have been followed for over two orbits.
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| Tom Teague | ||||
| Star:
70 Ophiuchius
Date & Time: 2000 September 18 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: x53, x84, x140 |
I have observed this glorious pair many times in the past. Despite
the fact that it has been widening quite rapidly in recent years, I found
it more difficult than I had expected. Nevertheless, it wasn't hard
to separate at x84, at which power it appeared cleanly split (but only
just). Possibly pear-shaped x 53. Well seen x140, but the seeing
was too poor for x210.
Yellow and orange - colours best seen x140. In the past, I have sometimes seen the comes as lilac. Interestingly, Burnham states that he always saw this pair as "golden and rusty orange with a persistent hint of violet in the fainter star". I agree with this curious and spectroscopically impossible description. No estimates of PA or sep, I'm afraid. 70 Oph has recently passed through periastron, when its polar coordinates
were changing very rapidly. It is now widening, and still worth measuring
regularly for those who have sufficiently sensitive equipment.
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| William L. Schart | ||||
| Star:
70 Ophiuchius
Date & Time: 9/20/00 9:33 pm CDT Seeing: 8 <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, 120x |
It took me a while to find this pair. There are no prominent stars
or asterisms (at least to my eyes) in the vacinity. I ended up doing a
major star-hopl over from Altair until I found a triangular asterism of
relatively bright stars.I examined each one until I found the pair. This
is a tight pair and I was unable to split it until I reached 120x. Both
stars appeared a nice yellow. Rather tight for a really accurate measurement,
but I got a sep of 4" and a PA of 65.
Ambience: The hot weather is back, and humid too. It was cloudy last night and there were a lot of thunderheads during the day, but by 9:00 it was pretty clear, so I had another go and picked up 2 more pairs off the list. The cat was out standing guard again and occasionally I saw some flashes
that could have been distant lightening.
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| Ilario Melandri | ||||
| Star:
70 Ophiuchius
Date & Time: 21/9/2000 – 18.30 UT Seeing: 5 <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: 140x (Plossl 16mm) |
Separation is increasing, in 2005 it will be 4.9” with a PA 138 deg.
Distance 16.6 light years. The distance between the two components corresponds at 19.4 Astronomical
Units, about the distance Sun-Uranus
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| Tim Leese | ||||
| Star:
70 Ophiuchius
Date & Time: 28 September 2000 (19:45 UT) Seeing: 5-6 <1-10 Seeing Scale (10 best)> Location of site: Cheshire. UK 53° 15' N –2º 33' W Site classification: Suburban Sky darkness: 3 <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 , X96
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Using a magnification of X120 I found the primary star
of this spectacular pair to have a pale yellow/white colour with
the secondary star, at PA 150deg (estimated), appearing to be a delicate
shade of orange. I was unable to separate the pair at X60 because the air
was to unsteady but using the microguide (X96) with the illuminator off
the colours of the stars seemed even more spectacular.
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| Mary Flanagan | ||||
| Star:
70 Ophiuchius
Date & Time: 29 Sep 2000 02:45 UT; 28 Sep 21:45 CDT Seeing: 5 <1-10 Seeing Scale (10 best)> Transparency: 6 (1-10) Location of site: Apple Valley MN, USA 93d 14m 25s W; 44d 45m 17s N Site classification: Suburban Sky darkness: 3 <Limiting magnitude> Telescope: 8" f/6 Dobsonian Magnification: 109x |
Was unable to split this pair; it was pretty low, and positioned over
the neighbors' garage roof, which was radiating the heat it had been soaking
up all day. Nice orange color, though. I was curious about
the disparity between the 3.9" separation on the list and the 2" shown
by SkyMap, and looked it up in NSOG. Learned there that it's a rapidly
orbiting pair, which will open up to 6.8" in 2024 before starting to close
again. (This could have been reported by other list members, and
simply failed to register in my virus-befogged brain.) I'll come back to
it next summer when it's located better.
Olympic commentary: Another bobble on the balance beam, offset by the
fact
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