| Richard Harshaw | ||||
| Star: Zeta
Aquarius (STF 2909)
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 + Barlow (516x) |
Position: 2228-0002
Magnitudes: 3.7, 4.5 Sep/PA's: 2 - / 200 - Year of last measurement: 1992 Distance (light years): 103 Luminosity (in suns): 41 Eyepiece and magnification: 10mm + Barlow (516x) Colors noted: Both W. Some observers report Y and B or both as yellowish. Webb: Y, gW, and wrote, "A very fine object, in centre of triangle of nearly equal naked-eye stars." Its binary nature was discovered by C. Mayer in 1777 and confirmed by Herschel in 1779. The orbit takes 760.0 years (Heintz, 1983). The primary is 1.13 solar masses, while the companion is 0.85. There is also a third (invisible) companion, of 0.28 solar masses and 0.8% the Sun's luminance. It is probably a red dwarf of dM1 or dM2 class. Both stars are infra-red sources. The actual separation of the pair is at least 100 AU. First measured: 3.6" @ 0. 1781 (Herschel): 4.6". 1905 (Burnham): 2.9" @ 317. 1967: 1.7" @ 249. The close, faint pair B76 (8.5, 10.2; 1.5" @ 335) lies about 11' south. I rated the pair 2. Interesting selection, PJ. |
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| Patrick J. Anway | ||||
| Star: Zeta
Aquarius (STF 2909)
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 7mm for 120X, I separated an equal set of two
light yellow stars, brightness was so equal that it was difficult to distinguish
primary from companion - like a pair of eyes staring back over 75 light
years of space and time. Zeta Aqr is in the center of the asterism of the
"water jar" and one of a group of doubles between the water jar and the
fish (Pisces Australis) below. Olcott says that "the ancients thought that
these stars represented water trickling down the sky." He saw both components
to be white, as did Smyth; however Webb gives white and pale yellow.
Discovered by Christian Mayer in 1777, it was "rediscovered by William Herschel two years later and determined by him in 1804, to be physically connected. Charles Worley says there is a " fainter component that is an unresolved astrometric binary, with a period of 26 years" - while Norton's 2000 gives a period of 856 years for the main components. Paul Couteau says that it is "a good test for small refractors" and Burnham says " it may be resolved with a good 3-inch glass". I had no trouble with my 2.5". An interesting note: at this time Zeta Aqr. is south of the celestial equator, in 2004 it will be on the equator and there after it will be north of it. |
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| Tom Teague | ||||
| Star:
Zeta Aquarius
(STF 2909)
Date & Time: 2000 September 18 (21:25) 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: x140, x210 |
Both stars seem yellow to my eye, with no discernible colour contrast.
I believe that I have resolved this pair in the past with the Zeiss refractor,
although I have not checked my old observing logs. Certainly I would
expect to be able to do so fairly easily under better conditions than prevail
tonight. As it is, I see two slightly overlapping discs x140 and
x 210 - in other words, a figure-of-eight. The separation has closed
considerably since Webb's day, for he described it as "easy with very small
aperture", which is certainly no longer true. His colour description
is interesting: "flushed wh., creamy". First measured by Herschel
in 1781, at 4.56".
I estimated the PA as 175 degrees, which is clearly wrong, and probably an example of the well-known subjective error that often creeps into visual observations of pairs having PAs close to 90/270 or 180/360. Ambience: cold, still, autumnal.
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| Tim Leese | ||||
| Star:
Zeta Aquarius
(STF 2909)
Date & Time: 20-September-2000 (22:30 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 |
A fine double star to observe, this one. Using a magnification
of X120 the components were split into an equal brightness pair of yellow/white
stars. A better view was obtained using a higher magnification of X240,
another pair of glowing eyes to look out for in future. The PA between
the two stars was estimated to be about 200deg. I will return to this double
again in the future!
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| Ilario Melandri | ||||
| Star:
Zeta Aquarius
(STF 2909)
Date & Time: 21/09/2000 – 21.00 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: 5 <Limiting magnitude> Temperature: +13C Telescope: 150 mm f/15 achromatic refractor (lens by Romano Zen, Venice). Magnification: 140x (Plossl 16mm) |
Sep is deacreasing, it will be 2.7” in 2020 with PA 170.
For the sep. of 2.1” at a distance of 98 light years, corresponds a distance of 63 Astronomical Units, a little more than the diameter of Neptun’s orbit around the Sun. |
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