(IAAC) Obj: Aldebaran (alpha Tau) - Inst: 5" f/5 alt-az refractor

Observer: Lew Gramer
Your skills: Intermediate (a few years)
Date/time of observation: 1998 Sep 11/12 07:39 UT
Location of site: Lee, NH, USA (43.09838 N, 71.04206 W)
Site classification: Exurban
Sky darkness: 5.8 <Limiting magnitude>
Seeing: 7 <1-10 Seeing Scale (10 best)>
Moon presence: Stunningly present!
Instrument: 5" f/5 alt-az refractor
Magnification: 52x
Filter(s): None.
Object(s): Aldebaran (alpha Tau)
Category: Star.
Class: K5
Constellation: Tau
Data: mag 0.85  size 0.03"
Position: RA 04:36  DEC +16:31
This morning, I witnessed a lunar occultation of Aldebaran,
from the graze line in southeastern New Hampshire, USA!
I was on the SW quadrant of the intersection between Routes
125 and 152 in Lee, NH. The weather was Classic New England,
with rolling scud clouds that swooped in a half hour before,
and a crisp, clear INFURIATING frontline that came in just
10 mintues after, as I was breaking down for the night!
Add to these adventures a late-night speeding trap on Route
125! But I had the great fortune to run into a Trooper with
an interest in astronomy: I told him I was going to watch a
"grazing occultation", and before I could explain that, he
said "Oh!" and rushed me off with a warning and a wish for
clear skies... Very nice. ;>
As for the graze, I got to see three startlingly beautiful
events between scudding clouds: two ingresses with various
fade-out times, and one sudden egress. These alone made my
1AM alarm and 1.5 hour drive worthwhile!
But I also caught an even more startling event - a *fading*.
Not a DISAPPEARANCE, but a brief partial reduction of about
two magnitudes in Aldebaran during a clear moment! I am not
sure, but this seems to imply that a lunar feature occulted
a *portion* of the supergiant's 0.03" disk... unless it can
possibly be explained by some refractive effect from the
lunar limb?? Either way I (of course) don't have an accurate
enough timing to match this with a video system in operation
nearby... Though with a few hundred meters distance between
us, I wonder if the video camera managed to catch this!
At any rate, the gradual ingresses plus this bizarre fade made
me feel this was a log worthy of being submitted to IAAC! This
is the sort of subtle thrill that makes this hobby worthwhile.