http://www.skyandtelescope.com.au 49I
t looks like C/2013 X1
(PANSTARRS) will still be
the comet of chief interest for
Southern Hemisphere visual
observers during the month of July.
As we noted in the previous
issue, this comet passed perihelion
(closest point to the Sun) on April
20 at 1.31 astronomical units,
and passed Earth on June 21 at a
distance of just 0.64 a.u.
July, therefore, will see 2013 X1
pulling away from both Earth and
Sun and fading relatively quickly
— although if it lives up to its early
promise, it should remain a good
object for binoculars and small
telescopes throughout the month.
July begins with the comet in
the southern constellation Ara
and (from brightness parametersderived early this year) possibly
around magnitude 6.5 to 7.
During the first half of July, it will
move from Ara across the small
constellations Norma and Lupus,
reaching Centaurus on the 17th of
the month. It will remain in this
constellation for the remainder
of July, fading to magnitude 9
or thereabouts by the end of the
month.
If you’d like a little more of a
challenge, the returning short-
period comet 9P/Tempel will
come to perihelion (at 1.54 a.u.)
on August 2 and will be visible to
telescopic observers throughout
July as a diffuse nebulosity of about
magnitude 11 as it traverses Virgo.
Discovered by E.W.L. Tempel
at Marseille on April 3, 1867, thiscomet was considered ‘lost’ for
many years until improvements
in orbital computation methods
enabled it to be recovered in 1972
(actually confirming a suspected
image obtained by Elizabeth
Roemer at the previous return of
1967). Today it is best known for
having been the target of the Deep
Impact mission in July 2005. As
one of the small (but growing)
number of comets that have been
visited by spacecraft, it is of historic
interest and worth tracking down
forthatreasonalone.✦Sailing across the southern skies
Comet C/2013 X1 will be ideally placed for observation throughout July.
Comet C/2013 X1
(PANSTARRS) will
be well placed for
southern observers
during July, but you’ll
need binoculars or a
telescope to see it.DAVID
SEARGENT
has been
acomet
specialist for
more decades
than he’d like
to admit. His
latest book on
the subject,
Snowballs in
the Furnace,is
available from
Amazon.com“This comet was
considered ‘lost’
for many years.”