Many of
us have heard of the constellation Sagittarius in the austral skies, but
Sagitta is an unknown constellation for many amateur astronomers. Even I can’t
remember where it is located in the sky and it is difficult to trace in
polluted skies because it has no star
brighter than 3rd magnitude.
Discovered
in 1745, M71 is a dim and loose globular cluster located in Sagitta, right
between Aquila and Cygnus, two birds that govern the summer skies. The best way to find M71 is to star hop from
the 1st magnitude star Altair , the eye
of the Eagle (Aquila). From there, trace a line to the star Sadr in Cygnus and
in the first third of that line you will be close to the area where the
globular should be. To the west of the
glob, there is an a unique asterism that looks like a tiny arrow made by four
stars: 9 Sge (Mag 6.20), HIP97818 (Mag 7.65), HIP97840 (Mag 8.30) and a fourth
one of magnitude 9.10. If you see it,
you can‘t miss M71.
It is
visible with binoculars under moderate light polluted skies (Surburban skies). It looked like a ghosty patch next to the
asterism decribed below. In fact, one has to use some averted vision to see it.
It does not show a definite core, but the whole surface has the same low
brightness. I have seen it with my telescope at 100x. Even at such magnification on 6” of aperture,
it looked like a nebular smudge with
about 10 dim stars in it.
Sumer is
coming soon so it would be a good time to plan on catching M71!
Clear
skies,
LG
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