Grazing Occultation by 361 Bononia timed Jan. 30/31
Updated: 2001 Feb. 01
Below is Roger Venable's account of this virtually unique
observation of a grazing occultation, with multiple events,
during an asteroidal occultation. Too bad it was so
cloudy in the Mid-Atlantic States region so that we couldn't
time any additional chords, and so far I know of no others.
An occultation by the same asteroid was also observed in
Ukraine last October, so I've appended that report at the
end.
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From: "Roger Venable"
Date: Thu, 31 Jan 2002 00:09:28 -0500
Subject: [IOTAoccultations] Asteroidal graze! and double star to boot!
Greetings, all.
I just returned from a trip to north Georgia to see the 361 Bononia
appulse to TYC 2495-00265. I saw a graze with six -- count 'em, SIX
-- events! Seeing was 5 (ALPO) and the star image was stable. As if
that weren't thrilling enough, the first event appeared to be a step
event, with a 0.3 second delay, and the first reappearance was
incomplete. I think the second reappearance was incomplete also, but
in the excitement I forgot to dictate a note on it.
Assuming this was the south edge of the path, the asteroid was about
a path-width south of the predictions -- unless it's a very long
asteroid. I'm reporting this here, now, because later, when some
other lucky observer reports an occultation on this appulse, it will
then be evident that my graze observation fits his observation. That
way, you know that I'm not making this up! It is ironic that I saw
this asteroidal graze so soon after Jeff Lackmeyer posted a message
about seeing a possible asteroidal graze with Amherstia in Florida a
couple weeks ago. David Dunham may recall that I requested a north-
edge path for the Amherstia appulse: I've been looking for a graze!
A 0.3-second step event with an asteroid moving at 27 arcseconds per
hour gives a maximum separation of the components of the star of
about .002 arcseconds. Maybe it's a very distant star. Or, the step
event could be my misinterpretation of a diffraction phenomenon.
Here's the data, which I'll report on the usual form to Jan Manek
soon: Asteroid: 361 Bononia. Star: TYC 2495-00265. Observer: Roger
Venable. Location (WGS 84 average of 5 readings >5 minutes apart):
lat. +34deg 08.307min, long -84deg 54.236min, elev 218m. About a
mile north of Elberton, Georgia, USA.
11" SCT, clock driven equatorial. WWV and tape recorder, voice.
2002 Jan 31. Nominal time of event 0136.6 UT.
partial dimming 0142:54.0
further dimming 0142:54.3 asteroid then just barely visible
half-brightening 0142:56.9
off again 0142:58.9
on again 0143:00.5
off again 0143:02.9
on again 0143:03.9
All these events were of a high degree of certainty.
Be still my beating heart! I'm getting too old for this type of excitement.
I haven't been so elated about an observation since comet Hyakatake's big
night.
Regards to all,
Roger Venable
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Return-Path:
Date: Fri, 26 Oct 2001 09:59:27 +0300
From: Buromsky
To: dunham@erols.com
Subject: occultation by minor planet
Dear D.Dunham,
We send your the observations occultations star HIP 44087 by the
minor planet 361 Bononia.
Observers:
Occultation of HIP 44087 by 361 Bononia
Location: latitude:50,35,17,3N long:029,55,14,2E Height=146m
2001 oct 24 23h 31m 51,4s UT - D
23h 31m 52,8s UT - R
Duration 1,4 seconds
Magnityde star: 9,01
Magnityde minor planet: 14,12
Telescope Type: Refractor f5
Aperture: 133 mm
Mag. x40
Mount: Alt-Az.
Atmosphere Transparency: Good.
Star image stability: Good
Temp: - 5 grad C
Best regards B. Skoritchenko.