Double Stars
The observation of double stars
is really a pleasure with this instrument and it's really easy to reach
the Telementor's 1.8" theoretical resolution on this type of sky objects.
It's really interesting to note that resolution limits are limited quite
often not by optics but from "seeing" and thus, our "Refraktor" will surprise
more than one observer confident with his/her 6" or 8" aperture telescope.
If you get interested in double star observing, please visit the "Spirit
of 33 Web Site". Probably, the most active E-Society of double star
observers on the whole Internet.
Observer:
Luis Argüelles (Spain) |
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Star:
Regulus, Alpha Leonis
Date and Time: 19,
May, 2001. 21:30 UT
Seeing: 8 <1 worst
- 10 best>
Location of Site:
Sena de Luna. Leon. Spain
Site Classification:
Rural
Sky Darkness: 5.5-6.0
<Limiting Magnitude>
Moon: None
Magnification: 21x,
221x
Eye Piece(s): 40mm
Plössl. 3.8 mm Baader Eudiascopic. |
A really easy
double even at the reach of a good pair of binoculars. I used Regulus in
order to polar-alignment the Zeiss. At 21x, Regulus-A was offering a spectacular
view, shining fiercely, while the B component was so far that is a bit
difficult to think of this star as a double.
At 221x Regulus-A shows an
exquisite difraction pattern. A delight in itself. |
Observer:
Luis Argüelles (Spain) |
|
Star:
Epsilon Lyrae
Date and Time: 19,
May, 2001. 22:50 UT
Seeing: 8 <1 worst
- 10 best>
Location of Site:
Sena de Luna. Leon. Spain
Site Classification:
Rural
Sky Darkness: 5.5-6.0
<Limiting Magnitude>
Moon: None
Magnification: 21x,
221x
Eye Piece(s): 40mm
Plössl. 3.8 mm Baader Eudiascopic. |
Using Vega
as a reference, this beautiful star was a show by itself at 221x and reminded
me that we sometimes forget to observe single stars. I think we lose a
lot of beauty not observing these cosmic beacons regularly.
The world-famous "double
double" was really close, so only a gentle touch to the telescope and Epsilon
was inside the FOV. The view of this double represented the
most espectacular thing
on the night. Using only 21x with the Zeiss, I observed a clear elongation
on both components!!!. While it's easy to see the split in a Televue Ranger
at about 80x and even 50x using a 4" Vixen (Japan) achromat, I needed to
rub my eyes to believe what I was observing: A 63 mm (2.5") aperture refractor
was rendering elongation at 21x on Epsilon Lyrae!.
Also, the star located between
both "doubles", TYC 3122-1635-1 (RA: 18h 44m 29s, Dec: +39° 38' 23")
shining at visual magnitude 10.43, was easily rendered with direct
vision on the Zeiss, so
I'm pretty sure this scope can reach 11.5 visual magnitude without great
efforts under dark skies. It's interesting to note that this star is not
visible in the 4" Vixen under suburban skies at 3.0 naked-eye limiting
magnitude, so one always repeated and almost never learnt lesson: "I don't
need more aperture, only better, darker skies and more observing time!".
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Observer:
Tom Teague (England) |
|
Star:
Beta Lyrae
Date & Time:
2001 August 16 (2100UT)
Seeing: 6 <1-10
Seeing Scale (10 best)>
Location of site:
Chester, England
53°11'08"N; 02°51'39"W
Site classification:
Suburban
Sky darkness: Not
assessed <Limiting magnitude>
Magnification: x21,
x53, x84, x140 and x210 |
Easily resolved
at all powers. Pale yellow and greenish to my eyes.
Two other nearby comites
help to form a pretty arrow-shaped asterism.
Many years ago, I carried
out an interesting spectroscopic study of the main component using a Zeiss
prismatic pocket spectroscope in conjunction with my 8.5-inch f/5 Newtonian
reflector. I found that the D3 helium line was almost always visible
in emission, but the H-alpha line only occasionally. There did appear
to be some correlation with the variability period of the star, which would
accord with theory, but the link was a rather weak one. My investigation
only served to confirm what astronomers already knew, which is that the
human eye is a hopelessly inadequate detector for serious spectroscopic
work!
In common with other members
of the group "The Spirit of
33", I could not resist examining the Ring Nebula (M57) while I was
in the neighbourhood. As on many occasions in the past, I found it
obvious at all powers from x21, but improving with each increase in magnification
up to x140. This is, as is well known, quite a common effect with
planetary nebulae. Beyond x140, however, there was no further improvement.
I found the best view x84 and x140, at which powers I saw a lovely blue-grey
smoke ring. The central vacuity is not difficult with a/v, but appears
smaller (and the surrounding bright annulus correspondingly broader) than
in photographs.
|
Observer:
PJ Anway (MI, USA) |
|
Star:
Alpha Lyrae
Date & Time:
August, 18, 2001 03:00 UT
Seeing: 7 <1-10
Seeing Scale (10 best)>
Transparency:
<0:worst -10:best >
Location of site:
Starfest @ Mount Forest, Ontario, Canada
Site classification:
Rural
Sky darkness: 5.5
<Limiting magnitude>
Temperature: 75°F,
24°C
Conditions: No moon,
Cloudy with large holes
Telescope: Zeiss
Telementor 63mm/840mm refractor on equatorial mount
Eyepieces: Televue
18mm, 12mm radians + 2.4X barlow
Magnification: 47X,
70X, 112X, 168X |
Split with
averted vision at 47X, seen as parallel to Epsilon Lyrae, no color.
Ambience: Canada's Starfest
was an excellent star-party with lousy weather. Rain or solid clouds were
the norm for Thursday, Friday, Saturday and Sunday. The only exception
was Saturday afternoon which, though windy, sported regular patches
of clear sky in the clouds and Saturday evening which produced a large
hole directly overhead for about an hour and a half. With over 900 amateurs
starving for some viewing, quite a bit of sun observing was done
on Saturday. I observed with my 100mm for quite a while and tried my hand
at imaging through the eyepiece with a hand-held Coolpix 800 digital camera.
The sun was a bit subdued,
but I managed to image a few sunspots. I also got a chance to view through
both a "Daystar" and a "Coronado AS1-90" H-alpha filters on other people's
scopes and was able to see several small flares - a real treat.
Among the many fine talks
was one that I believe will particularly appeal to this group. It
was entitled "Double Stars at the Limits of Perception" by Jerry Spevak
(a Canadian amateur).
|
Observer:
Tom Teague (England) |
|
Star:
STF 2323 AC
Date & Time:
1,Sept, 2001
Seeing: -- <1-10
Seeing Scale (10 best)>
Location of site:
Chester, England
53°11'08"N; 02°51'39"W
Site classification:
Suburban
Sky darkness: --
<Limiting magnitude>
Magnification: 53x,
140x, 210x |
I was observing
at low power (x53). After completing the measurements, I decided
to examine the star at higher power in order to assess the quality of the
seeing. As soon as I focused the image x140, I spotted a faint and
ghostly companion close to the bright A star at a PA of about 340°.
I realised that I had seen the AB pair, without having any advance knowledge
of where B was to be found - in fact I had forgotten all about B!
This shows what a marvellous instrument the Telementor is, because there
is a brightness difference of about 3 magnitudes between A and B, and they
are separated by less than 4". It was an eerily beautiful sight.
I was also able to see the close companion x210, but not quite as clearly. |
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