Occultation of iota Cancri by (411) Xanthe April 18 UT by Richard Nugent - New 2007 April 18, 21h UT

Tony George has determined the occultation light curve using Limovie

The very gradual events are due to the angular diameter of iota Cancri

From: Dunham, David
Sent: Wednesday, April 18, 2007 4:41 PM
To: 'Richard Nugent'
Subject: Diameter of iota Librae resolved

Richard, 

     Many thanks for your 4-megabyte video clip and the very 
interesting Limovie plot of the very gradual events.  Rather than 
play the video directly from the Web link, for most it will probably 
be better to download the file to your computer and play it offline. 
From the B and V magnitudes of this spectral type G5 star, the 
Warner relation computes that the angular diameter is 1.7 
milliarcseconds which, at (411) Xanthe's distance, subtends 3.6 km 
or 11 Fresnel diffraction fringes.  So the star's angular diameter 
clearly dominates over diffraction, and from your and the other 
video observations, plus the outline solution (will help determine 
the local slopes for the contacts on Xanthe that will be needed), we 
should be able to determine the star's angular diameter rather well. 

     David

-----Original Message-----
From: Richard Nugent [mailto:rnugent@wt.net]
Sent: Wednesday, April 18, 2007 3:52 PM
To: Dunham, David
Subject: Re: Iota Occultation Results from 22 km south

David, here's my 15 second video clip of the Xanthe event with the 
gradual D an R. No intensifier used, just the Watec 902 Ultimate on 
the trusty (not rusty) 4" Meade SCT. Also is a preliminary Limovie 
plot. Each white dot on the Limovie plot is a video frame. 

Richard

Harold Povenmire observed the occultation with a telescope visually 
at the same location.