A Few Globular Clusters (part 1)

[mike.brightmore]

I was going to do a one night vigil on globs but the weather hasn't played ball. First tried to catch my second favourite GC - M3 (Canes Venatici) and the nearby M5 (Serpens) but they are now a bit too low in my murky western sky for meaningful observation.

So started with the best - M13 (Hercules). Using the keystone asterism M13 is not difficult to find and stands out clearly as a fuzzy, round non-stellar object in binoculars. In the telescope it was magnificent as ever with more stars being resolved with increasing magnification. (Looking at it I always think of the Arecibo message sent to M13 in 1974 from the refurbished Arecibo radio telescope. Wouldn't it be a sickener if the only reply we get back in 50,000 years time is an engaged tone.) Took a quick snapshot to show some of the structure (below). Amazing to think that this ball contains about a million stars. Distance 25,000 LY. Magnitude +5.8.

M92 (Hercules) - Up a bit, left a bit to the other globular in Hercules. Distinctly smaller and fainter than M13 but nevertheless a beautiful compact GC about 35k light years away.

M15 (Pegasus) - then to the Flying Horse, well placed in the Southern sky. Using the Great Square go the opposite way to that which leads to Andromeda. So starting at Markab (Opposite corner to Alpheratz or Sirrah) follow the dog-leg of stars to Enif and just continue a bit further to M15. This is a bright object and unmistakably a GC in binoculars. The centre looks very compact and could not be resolved into individual stars using the telescope. Distance 33.6k LY. Magnitude +6.2.

M2 (Aquarius) - Using binoculars all I had to do was left them follow gravity as almost immediately below M15 was the equally bright M2 globular cluster. In binoculars this looked similar to M15 and in the telescope also had a compact central core but not as collapsed as M15. Distance 37.2k LY. Magnitude +6.5.

TO BE CONTINUED with the lovely little M56 in Lyra, the Ophiucus globs M10, M12 and M14. In Sagitta M71 and the faint and distant NGC 7006 (135k LY) in Delphinus. Globs are great.

540px-Hercules_constellation_map.bmp

[Talitha]

Thanks Mike, your reports are absolutely charming. The images really enhance the text. Just a thought... considering the size and density of M13, i wonder how far apart the stars actually are. Can you imagine living on a planet inside of the cluster? Wow, talk about twinkle twinkle little star, lol.

[mike.brightmore]

Yes Carol, I often wonder. Also can you imagine what the Milky Way would look like from NGC 2419 - The Intergalactic Tramp / Wanderer. Just out of interest this is the message sent to M13 from Arecibo in 1974. Did you ever see the crop circle 'reply' we got in the UK?

[Talitha]

Looks like the graphics from an old, old, computer game.

?Crop circle reply? I haven't a clue.

[mike.brightmore]

The late Carl Sagan helped compose the Arecibo message and it does contain an amazing amount of information about Earth and humans. The joke reply appeared as a crop circle (they were rife at the time) in a field next to the Chilbolton Radio telescope (UK HQ of SETI) and referred to some silicon based alien race.