I am seeking help in field testing a magnitude chart between v7 and
v13 for NGC1647, an open cluster in the Taurus constellation, is
presented. The purpose of the NGC1647 chart is to provide a study
example for estimating limiting magnitudes suitable for large
binocular and small telescope users between m_v 6.0 and 13.4. NGC1647
is approximately 45 arcmins in diameter at a distance of 540 pc near
Aldebaran at J044608.4 +190437.4. At my observing location (Salt Lake
City, Utah), an extreme wet winter weather pattern has resulted in
about ten clear nights since October 31, 2003. NGC1647 is near its
zenith position. It does not look like this weather pattern is going
to improve any time soon. I would appreciate it if observers in other
locations might take a few minutes to field test this chart, time
permitting within your observing sessions.

The project homepage with supporting materials and a description of
how the charts where developed is at:


Several NGC1647 charts are available:

Star numbering system chart – star numbers, not magnitudes plotted

Direct view magnitude chart – for use with binoculars (81kb):

Even view magnitude chart – for use with Newtonian reflectors and
other scopes with an even number of reflections (81kb):

Odd view magnitude chart – for use with SCTs, small reflectors and
other scopes with an odd number of reflections (81kb):

NGC1647 area finder chart, including Aldebaran and nearby Cephid
variable SZ Tauri (12kb):

Regards, Kurt