 The
Palomar globular clusters are by nature faint. Most are
visible only in larger amateur instruments and many are not visible
at all. As these clusters go, Palomar 2 is a showpiece.
Yet even in the largest of amateur instruments it appears as little
more than a round, very diffuse hazy spot.
Palomar 2 is
unique in several ways. How many other globular clusters do
you know of in Auriga? That's right -- there aren't any
others! Palomar 2 is an "outer halo" globular which
lies much father from the center of our galaxy than most. Most
globulars lie within 20,000 light years of the galactic center, but
Palomar 2 lies over 100,000 light years distant. Although not
the most distant known, Palomar 2 lies at a galactic longitude of
170o,
nearly in the opposite direction of the galactic center as seen from
our vantage point. Because most globulars lie much closer in,
they tend to be found in constellations such a Sagittarius and
Ophiuchus. When we look toward Auriga we are looking in the
opposite direction of the galactic center where few globulars are
found.
Another thing that
makes Palomar 2 special is that it lies near the plane of our galaxy
behind a veil of dust. If it weren't for the dust between us
and Palomar 2, it would appear over 1.2 magnitudes brighter.
If not for the intervening dust it probably would have been
discovered much earlier and perhaps given an NGC number.
In addition to blocking some of the light of the cluster stars the
dust also makes it look much redder. This is because more of
the blue light is blocked than the red, changing the apparent color
balance.
I had some difficulty
finding Palomar 2 in my 18-inch f/4.5 because, as with many obscure
objects, the coordinates I had were quite a bit off. I did
notice a round haze nearby and upon checking the DSS I discovered
that this was indeed the globular. Palomar 2 had long been
mistaken for a galaxy (MCG +05-12-01) so this may be how it is
plotted on your charts. It is also listed in the Guide Star
Catalog as the "star" GSC 02374-0153.
Once I was certain I
was looking at the globular I went back for a closer look. It
was visible at 97x as a very round hazy ball. I noted that it
looked "pretty cool" and that no stars were resolved.
Averted vision was necessary to see it clearly, but it wasn't that
difficult to see. At 270x it looked a bit like a faint
telescopic comet. I found very few visual observations
of this globular so I can only estimate the minimum aperture to see
it. Those with 12-inch or smaller scopes should have a try at
it. If you do glimpse it you can count yourself in a select
group.
Palomar 2 is about 3o
away from Iota Aur. The larger circle is a 6x30 magnifying
finder with an FOV of 5o. The smaller circle is the
eyepiece view circle drawn below. Zenith is down.
Above is the view in an 18-ich at
94x. The bright star on the right is below and to the left in
the finder view. |
