British Astronomical Association
Comet Section
2013 Campaign - 2P/Encke
This
year sees comet 2P/Encke's 62nd
observed return to perihelion since its discovery by Mechain in 1786.
The orbit is quite stable, and with a period of 3.3 years apparitions
repeat on a 10-year cycle. This year
the comet is well seen from the Northern Hemisphere prior to perihelion, which
is in late November. The comet
brightens rapidly during September and could be visible in large binoculars by
the end of the month. It crosses
from the evening to the morning sky through October and will sink into the
morning twilight by mid November, when it could be 6th magnitude.
This magnitude may however be optimistic as observations from the
SOHO
spacecraft in 2000 showed that it suddenly brightened after perihelion, by 
which time it will be at a poor elongation.
A possible explanation for this behaviour is that Encke has two active
regions, an old one with declining activity, which operates prior to perihelion
and a recently activated one present after perihelion.
There is, however, little evidence for a secular fading in the archive of
BAA observations of the comet, and the observations are consistent with no
change. The
comet is the progenitor of the Taurid meteor complex and may be associated with
several Apollo asteroids. This
suggests that on occasion it may outburst, though nothing major has been
detected to date.
The
comet is the focus of a Section campaign for 2013.
Visual
observers
-
Try
and obtain accurate magnitude estimates for as long an arc as possible.
Please use the magnitudes given on the charts that are available on
the Computing Section web page. These
observations will allow me to compute another point for our secular
magnitude graph. Submit observations in ICQ format.
-
Observe
Taurid meteors between October 23 and November 14.
CCD
observers:
-
Try
and obtain comparable magnitude estimates to those of the visual observers using the
technique developed by Roger Dymock,
particularly when the comet is out of visual range. Submit
observations in ICQ format.
-
Use
the Aprho technique to reveal possible minor outbursts. It is
important not to claim an outburst on the basis of isolated observations.
-
Monitor
when the ion tail first forms, and how it and the dust tail develop.
-
Image
conjunctions - the comet passes close to open cluster NGC 2281 around
October 1. There is also a
conjunction with 2012 S1 (ISON), but this occurs when too close to
the Sun for viewing.
Astrometrists
Published by Jonathan Shanklin. Jon Shanklin - jds@ast.cam.ac.uk
This
year sees comet 2P/Encke's 62nd
observed return to perihelion since its discovery by Mechain in 1786.
The orbit is quite stable, and with a period of 3.3 years apparitions
repeat on a 10-year cycle. This year
the comet is well seen from the Northern Hemisphere prior to perihelion, which
is in late November. The comet
brightens rapidly during September and could be visible in large binoculars by
the end of the month. It crosses
from the evening to the morning sky through October and will sink into the
morning twilight by mid November, when it could be 6th magnitude.
This magnitude may however be optimistic as observations from the 
which time it will be at a poor elongation.
A possible explanation for this behaviour is that Encke has two active
regions, an old one with declining activity, which operates prior to perihelion
and a recently activated one present after perihelion.
There is, however, little evidence for a secular fading in the archive of
BAA observations of the comet, and the observations are consistent with no
change. The
comet is the progenitor of the Taurid meteor complex and may be associated with
several Apollo asteroids. This
suggests that on occasion it may outburst, though nothing major has been
detected to date.