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Re: (IAAC) Obj: Nu Draconis (Kuma) - Inst: 10x50 Binoculars
Matt,
Great report! Not sure if I have attempted to split this pair with my 10 x
50's, but if I can find a dry spot to lie down on, I will try it next time!
Oh, that is, if I can find it! My skies are quite bad here and Draco's
head, obvious in dark skies, is just a blank space in the sky!
Thanks!
Penny
-----Original Message-----
From: Matt Leo <Matt@acrcorp.com>
To: Internet Amateur Astronomers Catalog <netastrocatalog@latrade.com>
Date: Wednesday, June 03, 1998 1:25 PM
Subject: (IAAC) Obj: Nu Draconis (Kuma) - Inst: 10x50 Binoculars
:----
:
: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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