Possible occultation of HIP115195 by Uranian Ring

PTS

Hi,
I received this message from David Dunham.  There is the possibility of a mag. 11.5 star being occulted by a Uranian ring on Nov. 07, 2008.
Anyone interested in observing this event?

PTS


Message to Bill Keel, Univ. of Alabama, about a Uranian
ring occultation late this week that may be of interest
to observers in Australia, N.Z., Asia, and the western
Pacific Ocean.

Bill,

      Thanks for this.  The star Feige 110 is also HIP 115195,
mag. 11.5, at J2000 RA 23h 19m 58.4s, Dec -5 deg. 09' 56".
Bianca, a 42-km satellite of Uranus, will occult the star between
12:50 and 12:59 UT in the Southern Ocean south of Australia and
New Zealand, but if there is a 1-sigma north shift, the path
would pass over populous North Island (NZ) and Victoria and
southwestern Western Australia.  But the chances are small;
the max. duration is expected to be 4 seconds.  Dave Herald
found this event over a year ago, and it is in IOTA's
prediction system.

      But you are also right that the star will be briefly
covered by at least the outer epsilon ring of Uranus.  Both
that event, and the occultation by Bianca, will be hard to
observe since at the time, the faint star will be less than
2" from the edge of the 5th-mag. planet; the occultation will
take place south of the planet, at about PA 170 deg. (so if
you can block the light of the planet with a bar in the
focal plane, orient the bar roughly east-west).  An occultation
by the epsilon ring should be possible from most of the
hemisphere facing Uranus, including New Zealand, Australia,
Indonesia, most of Asia (the Sun will be setting near the
Ural Mountains, and in Afghanistan), Japan, Taiwan, the
Philippine Islands, and the western Pacific Ocean, including
Fiji, Samoa, Guam, and Kwajalein.  With the glare from
Uranus, which might be decreased by using a near-IR filter
with a pass band near 8900 Angstrom units (a methane absorption
band will make Uranus darker there), it's unlikely that we'll
be able to obtain a signal-to-noise ratio good enough to learn
new information about the rings.

David

At 11:20 PM 11/2/2008, you wrote:
>I was struck tonight, while calibrating a new filter, to have trouble
>recognizing the field of the standard star Feige 110. On closer
>inspection, when I noticed faint companion objects to the brightest
>thing in the field and saw that the coordinates were close to the
>ecliptic, light started to dawn - Uranus is currently within 5
>arcminutes of the star. That figures - one more in my long list of
>late discoveries. Anyway, I had a quick look with Guide and notice
>that the limb passes only 1" N of the star on November 7. Are people
>planning to look for the ring occultations at this high inclination?
>
>Reards,
>
>Bill Keel
>(who still can't believe that with a whole hemisphere to pick standard
>stars from, he managed to pick up a nearby planet...)
>
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