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(IAAC) Obj: Nu Draconis (Kuma) - Inst: 10x50 Binoculars
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Observer: Matt Leo
Your skills: Beginner (< one year)
Date/time of observation: 5/31/1998 2130 EDT
Location of site: Melrose MA (Lat 42o28", Elev )
Site classification: Suburban
Sky darkness: 5 <Limiting magnitude>
Seeing: 5 <1-10 Seeing Scale (10 best)>
Moon presence: Minor - crescent or far from object
Instrument: 10x50 Binoculars
Magnification: 10
Filter(s):
Object(s): Nu Draconis (Kuma)
Category: Multiple star.
Class:
Constellation: DRA
Data: mag 5 size
Position: RA 17:32 DEC 55:11
Description:
For the first time in over a month I've had a combination of clear
skies and a few minutes to spend with the night sky. Auriga and
Gemini have disappeared in the west, and now Hercules Vega are riding
high in the eastern sky early in the evening.
--
The entire body of Draco is now above my local horizon at nine in the
evening, so I decided I'd trace the dragon from tail to head, which at
my location rquires the use of binoculars.
--
Draco's head is a irregular trapezoid or kite shape, with Beta on the
right (at this time and season) towards Hercules' foot, Xi on the left
pointing to the dragon's body, Gamma at the bottom or tail of the kite
roughly in the direction of Vega, and Nu at the apex of the kite
roughly in the direction of the Big Dipper. At magnitude 4.9, Nu is
barely visible with averted vision at my suburban location. Curiously,
Xi was quite easily seen. By it's Greek letter Xi should be the
fourteenth brightest star in Draco as opposed to Nu's thirteenth, but
according to SkyMap 3.1 Nu1 is Magnitude 5 and Xi is magnitude 3.9.
--
As I located Nu, I noticed a smudginess which caused me some fussing
with the focus and diopter adjustment on my binoculars. I'm always
hoping that one day I'll be able to see some nebular object in
binoculars from my light polluted location! Once I got the things
adjusted, I was surprised to find that Nu was a very handsome double
star, which I confirmed with my book. The black space between them
was quite evident, in the 10x glasses appearing about the thickness of
heavy piece of paper like a telephone book cover held edgewise at arms
length. The stars themselves are very closely matched white pinpoints,
which at first led me to believe it was an artifiact of an unsteady
hand and overactive imagination. This occaisioned further fussing and
eventually leading me to lay down on my car hood to get a better
view. In all liklihood this pair would be easier to split in 7x or 8x
binoculars due to their greater steadiness.
--
Fussing with the binoculars, I found that it is very important to keep
a relaxed eye. Evidently, even slight tension in the eye distorts its
shape and focus. Trying to get a sharper view, I closed my right eye,
focused the binoculars, then closed my left eye and tweaked the
diopter. When I closed my right eye again, the view was out of focus.
I was not conscious of any significant tension in my open eye, which
is why I ended up climbing up on the hood of my car so I could support
my head and relax my neck. Then instead of closing each eye, I simply
placed my hand in front of the half of the binocular I wanted to
ignore, blocking the view. This way I was able to set the focus and
diopter adjustment so that as I switched from eye to eye the view
remained in sharp focus. After this procedure I could readily split
this star either lying on my back resting the glasses on my orbits, or
standing with the glasses handheld.
--
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