Object of the week 10th December 2023 - M79

M79

NGC 1904 Melotte 34

Lepus

R.A. 05h24m11.0s

Dec. -24°31'30" (2000)

Magnitude: 7.70

Size: 9.6'

Just as a break from the very faint targets that have come up of late on the OOTW
I have chosen the globular cluster M79 for this OOTW. I was slightly surprised that
it has not made it before. Discovered by Pierre Mechain in 1780. Mechain and Messier
saw it only as a fuzzy patch but about 4 years or so later in 1784 William Herschel
resolved it into stars with his 20 ft telescope and described it as a globular cluster
after observations with a larger telescope in 1806. M79 lies in the constellation of
Lepus. It is therefore a challenge to observe from my latitude of 52N as it is always
very low down. M79 lies about 41000 light years from us and perhaps 60000 from
the galactic centre.

Attachment 5298

M79 location (Our Galaxy)

As such it is one of the few globular clusters that is seen opposite
to the galactic centre. It is believed to have been stripped from the Canis Major
dwarf galaxy, although this is still up for debate. Recent observations suggest that it
is more likely to have come from the GAIA-Enceladus merger. This merger took
place about 11 billion years ago so M79 will be a very old cluster, perhaps of the
order of 12 billion years or so. The cluster has been around for long enough that
it is being disrupted by the interaction with the Mily Way and it sports a tidal tail.
Currently M79 contains perhaps 150000 stars packed into a globe about 118 lyrs
across. The core of M79 is very dense and it may have undergone a core collapse
process similar to that in M15. M79 does contain a large number of blue stragglers.


Attachment 5299

M79 Hubble Credit NASA/ESA

The concentration class of M79 is given as V (5) on the Shapley-Sawyer scale.
It should be visible as a fuzzy patch in binoculars from lower latitudes.
Observationally for me my last look with the 55cm was not able to resolve it into
stars as the transparency was poor and the object never rose above 15 degrees.
I was also possibly looking through some foliage ???? From lower latitudes of course
the object will be higher in the sky and therefore much easier to see and resolve into stars.

As always give it a go and let us know how you get on.

Hi, here's my observation from 1/12/2010: Messier 79 is a globular cluster in Lepus ; magnitude:7.8 ; size: 9.6' ; fairly bright, brighter central core, trail of stars eminating from the cluster. I used a 8mm Ethos at 238x with my 14.5 StarStructure f/4.3
Attachment 5300

With a 20" at 272x: "About a Class VI (really = V) globular. Can see a number of resolvable stars around the periphery. The core is bright and concentrated. Easy to find."

Picking one observation, this is using a 13.1" at 200x:

Contains an intense, 1' core that was mottled and partially resolved, particularly around the edges. The halo was easily resolved with several dozen brighter members peppered within the halo and around the periphery (~40 stars counted) although there were no dense knots. Surrounding the inner core (nucleus) is a dense ring of high surface brightness which was very mottled. In good moments of seeing this ring broke up into a swarm of additional stars. Located 40' ENE of HJ 3752, a striking mag 5.5/6.7 pair at 3.4" separation.

I am actually looking at this cluster right now from Chile using my 20" dob. My notes:

The cluster is at the zenith at the time of the observation. At 83x the edge is resolved and the core is compact. From there to 197x, 320x and 427x it gets resolved more and more with the core resolved at 427x. The cluster lies in a ring of stars with a string of stars running away from it pointing to a bright star. There are three spiral arm-like curls of stars that run out of the core. One of then ends in a string of stars perpendicular to the "arm". A very pretty cluster!

The GC is often a transparency tester for me at 48°N.

Under the last night rural sky I could pick up some mottling with my 6" and 84x and a direct visible faint star at the northern tip. I also noted the nice orange double star 0.6° SW.

Smallest aperture was my 8x30 binocular. I described the GC as a faint but clearly visible nonstellar diffuse patch

In my home country this object culminates only at low altitude and it’s hard to make out any detail. But on La Palma it was a splendid sight! It’s not the largest nor the brightest cluster among the Messiers, but fun because of the star chains around it and especially the one south (up in the sketch) of it, making it look like a pendulum. The almond shape of the cluster abruptly fades into a dark band on the SE side. The core is compact, could not be fully resolved and shows a notch as well on the SE side. (side note: this sketch was made with an active volcano less than 20 kilometres away, it rained ash particles on my telescope)

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