NGC 5466

Globular Cluster

Bootes

R.A. 14h05m27.0s

Dec. +28°32'06" (2000)

Magnitude: 9.20

Size: 9.0'

Class XII

With astronomical dark now gone from my latitude until mid-August I am now restricted to
brighter objects such as globular clusters. I was surprised that my choice this month had
not been selected before for the OOTW. NGC 5466 is a globular cluster in Bootes first
discovered by William Herschel in 1784 who catalogued it as H VI.9. It is a loose class XII
cluster that is often thought of as one of the more difficult NGC globular clusters to find
because of its openness, beaten only by NGC 5053 in Coma.

ngc5466.jpg

It is thought to have joined our galaxy as part of the Sequoia merger about 10 billion
years or so ago. NGC 5466 has a stellar stream associated with it called the 45 degree
tidal stream which will be stars stripped from it due to passes through the Milky Way plane.
NGC 5466 is listed as about 51000 light years from the earth and about 52000 from the
centre of the Milky Way. As expected, given its age, NGC 5466 is very metal poor which
gives it a suggested age of about 12.8 billion years. The remaining mass in the cluster is
estimated to be only about 54000 solar. The tidal streams and mass make it very similar
to Palomar 5. It is suggested from modelling data from the GAIA EDR 3 survey that the
tidal stream from NGC 5466 may have been perturbed by the LMC. Given the habit by
imagers to rename everything apparently NGC 5466 is now also known as the Snowglobe
cluster. NGC 5466 is also unusual in that it contains a blue horizontal branch. Hubble did image
NGC 5466 in 2019 as part of a program to measure the motions of stars in Globular clusters
and to weigh the Milky Way

I find this cluster much easier to see than 5053 and it resolves into a graininess with the 15”
but is only a hazy patch with the Mewlon 210, admittedly from not ideal skies. Its appearance i
n my larger telescopes is similar to this Seestar image.

IMG_0685.JPG