SKY & TELESCOPE'S NEWS BULLETIN -- October 7, 1994

P/MACHHOLZ 2 (1994o)

Periodic Comet Machholz 2 is now in six pieces, as D was recently found split in two. You'll find it in the predawn sky near Regulus and the Sickle of Leo. SKY & TELESCOPE columnist John Bortle says Machholz 2 appears obviously double through a moderate telescope, as pieces A and D are much brighter than their siblings. Component A is magnitude 9.4 with slight condensation and a 2.5' coma. D is 10.1 with a diffuse 2' coma. Bortle notes this is the first comet in nearly 140 years to show fragments with distinct comas. Comet West did break apart in 1976, but its nuclei remained embedded in a single coma.

The following positions are for component A, given for 0 hours Universal Time and equinox 2000 coordinates. The D nucleus is located about 5 arc minutes to the north-northeast of A.

 
             R.A.      Dec.
             =============
  Oct.  8    9h 41m   +12.7 deg
  Oct. 10    9  46    +11.6
  Oct. 12    9  51    +10.5

P/BORRELLY (1994l)

Perhaps easier is Periodic Comet Borrelly, which rises about midnight about halfway between the bright stars Procyon and Betelgeuse. Bortle says Borrelly is very obvious, even in large binoculars, because its coma is strongly condensed with a stellar nucleus. He rates it magnitude 9.0 overall. Look for a short jet coming from the east side of the nucleus. Here are positions for 0 hours Universal Time:

 
             R.A.      Dec.
             =============
  Oct.  9    6h 40m   + 3.7 deg
  Oct. 11    6  45    + 4.5
  Oct. 13    6  50    + 5.3

MAGELLAN's GRAND FINALE

This week should see the dramatic conclusion to one of NASA's greatest success stories in planetary exploration, the Magellan orbiter. Beginning the 11th, engineers at the Jet Propulsion Laboratory will fire Magellan's thrusters and force the craft deeper into the upper atmosphere of Venus. Contact may be lost within a day thereafter, with a final destructive plunge coming on Thursday or Friday. Magellan has been orbiting Venus for five years, providing spectacular radar images of that cloudy world and, more recently, providing a sensitive probe of the planet's gravity.

A SPACE RECORD TIED

For those of you who enjoy trivia, as this is written there are 12 humans in orbit -- six on the current shuttle mission, and six aboard Mir, the Russian space station. That ties the record for the greatest population in space. The last time this happened, notes space sleuth Jim Oberg, was in July 1992. And the maximum likely -- either now or in the foreseeable future is 13, assuming some future shuttle carries seven instead of six.

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