NGC2451, an open
cluster in Puppis Comments Northern observers should not be scared away -- this is a nice bright cluster, easily
visible from the southern US at the right time of year.
A map of the star field. Magnitudes are given without
a decimal point, e.g. 67 is to be interpreted as magnitude 6.7.
How to Find It
Starting from zeta Puppis, move a short distance toward pi. I have successfully observed the cluster even when the horizon was too hazy for Puppis to be visible with the naked eye; the unmistakeable asterism around Pi Puppis (see below) can be found by dead-reckoning from Canis Major, and from there it's only a short hop to Zeta Pup and NGC2451.
A favorite of mine, this is one of those broad clusters for which binoculars are really more appropriate than a telescope. What makes it unusually attractive is the contrast in color between the brilliant red star c Puppis in the foreground and the white members of the cluster, of which at least five are easily seen.
While visiting the region, a similar colorfest can be enjoyed in the garish red supergiant Pi Puppis and its three white neighbors.
60-degree field of view
Data (Janes, Duke, and Lynga, 1987) RA 07 45 dec -37 58 total V magnitude 2.8 NGC number 2451 Trumpler class II 2 m angular diameter 50' distance 315 pc age (Myr) 36 integrated B-V .56 observed stars 153 earliest sp. class B7 brightest star 6.0
Northern observers should not be scared away -- this is a nice bright cluster, easily visible from the southern US at the right time of year.
(c) Copyright 1998 Benjamin Crowell. All right reserved.
Photos from the Digitized Sky Survey, stdatu.stsci.edu/dss/dss_form.html
Sky maps created by Your Sky, www.fourmilab.com