Porrima split - documentation pic 20080531 - 1 attachment

A small documentary style image showing the newly enlarging split of
Porrima A-B (gam Vir) now at around 1". Porrima B is now again becoming
accessible by small telescopes. This binary split is discussed in Alan
MacRobert's S&T note on page 68 of the June 2008 issue.

http://gallery.utahastronomy.com/mai...2_itemId=11377

Porrima was only at 38 degs alt at my op and seeing was Pickering 1 or
2. Because of this, an asthetic image was not possible. 83 short
0.125"
exposures where taken of the atmospheric speckle pattern. The two best
images showing the split and the two components are included in the
posted image.

Visually, at 564x with a 16" apeture, Porrima AB, in moments of still
air, appeared as figure-8 pattern or a just-touching kiss split, using
Haas's 2006 split nomenclature.

My computed split of 1.4" has a high degree of uncertainty and, due to
observation error, is not in consistent with the S&T article predicted
separations of 1.0" on April 20th, 2008, increasing to 1.1" on Sept.
15th. It is not consistent with the 6th Orbit Catalogue ephemeris split
(rho) values of 0.91" for 2008 increasing to 1.168" in 2009.

The WDS 6th Orbital Catalogue ephemeris plot of observations for Porrima
can be viewed at:

http://ad.usno.navy.mil/wds/orb6/PNG/wds12417-0127r.png

The entry for Porrima in the WDS 6th Orbital Catalogue references
neither the ids gam Vir or Porrima. Search the catalogue using the
alternative id STF1670AB.

Alternate designations for Porrima include: gam Vir 29 Vir WDS12417-0127
STF1670AB ADS8630 HD110379

Peace - Kurt

WDS 6th Orbit Catalogue:
http://ad.usno.navy.mil/wds/orb6/orb6frames.html




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