Sky Sketcher's Post Mortem 8

Sky Sketchers Post Mortem: "M10 and M12 Twins in Ophiuchus"

Part 1:

There is definitely no shortage of globular clusters to observe in the night sky, with the best of all residing in the far south. That is not to say that the notthern regions of sky do not have their little "gems" as well. Though most of us Southern Hemisphere observers are privy to the vast heavenly riches that abound in the antipodean skies, and gladly torment our poor northern cousins.

There is still a handfull of choice items that northern skies have that are unique. For instance, observing M-31 overhead is something that I have always wanted to do. Same with the vast Virgo cluster of galaxies and the unique "whirlpool galaxy". Albeit though I would not swap any of these objects for any of our "Jewels of the south", not even for the small magellanic cloud, (even if they came as a package). I hope some Americans read this article, they must be frothing at the mouth by now, nah, nah, nah. Anyway enough of this. As I was saying some of the northern objects are quite unique in their own right, and the two objects I chose for this article are the lovely globulars M-10 and M-12. Two objects that look decidedly similar in appearance.

Observing these items is a soothing experience. Both of these objects were discovered by Charles Messier in 1764, Messier was unable to resolve the objects into stars, and alas was not privileged to a wonderful sight. M10 is of around magnitude 7, with stars of around mags 11 to 15.The original distance of M10 was derived by H.Shapley at around 33.000 light years. Although modern studies suggest it may be closer than the great M13 in Hercules.

M12 is a globular that appears in the eyepiece to be a touch more compressed than M-10, with a sprinkle of nice, contrasting brighter stars. I used 126x mag on these globulars which was just nice as it resolved the clusters with a certain crispness, though not completely. M12 lies somewhere between 16,000 to 24,000 light years away and has a magnitude of around 8 and a diameter of 10'. The stars vary from mag 11.0 down. Both objects are choice small scope items and increase in grandeur with larger scopes.

Part 2:

The August new moon weekend at Wiruna proved reasonably productive. Friday night though was clouded out completely which left Saturday and Sunday to get in some observing. Saturday night was clear all night long, but alas torrential dew made life a misery. However I did manage to get in a few sketches and a bit of casual observing before tossing in the towel. Sunday night was the best and produced a very enjoyable observing session which lasted till 3.45 AM when my back went stiff and my bum became numb.

ESO 137-G10, ESO 137-G8 and ESO 137-G6:

This was my main target of interest. I noted this galaxy cluster while reading an article in "Sky and Space" by David Frew. Being a bit of a 'softy' for galaxies I thought I would give it a shot and was pleasantly surprised with the region being strewn with stars it was a nice contrast to see three fuzzy blobs come into view at 172X. As far as I can tell the three galaxies visible are ESO 137-G10, ESO 137-G8 and ESO 137-G6. Further scanning of the area will show a few other faint galaxies but I concentrated on the three objects just mentioned. I would recommend anyone with a medium to large scope, give this interesting cluster a look.

NGC 134 & NGC 131:

Two distinct edge on spirals in the galaxy hunters heaven of Sculptor. NGC 134 is a bright well defined galaxy with a vivid core and a very compact appearance. NGC 131 appears to be a minute copy of its much larger counterpart and wether it is gravitationally linked to NGC 134 I cannot be sure, but I doubt very much as visually it appears much more distant. NGC 131 has a bright central region and its overall brightness is not much less than NGC 134.

NGC 7793:

NGC 7793 is a large practically face on spiral galaxy, its core is much brighter than the rest of it, which emanates in a soft featureless glow. Almost egg shaped in appearance, photographs taken from very large telescopes show that the spiral structure of the galaxy is very patchy and not well defined, which probably leads to it being fairly uniform in overall brightness. In the 16" at 126X this galaxy shows little detail but I would say it is around 5' in length and very ghost like in appearance.

PK 329 -2.1:

PK 329 -2.1 is a lovely little ring shaped planetary in Norma which I spied in Uranometria and thought was worth looking at. At 126X with the use of the OIII filter this object was quite well defined, its ring structure was not uniformly bright but it is easily visible and should be quite easy locate for those interested in tracking it down. I hope some of you take a look at a few of these objects mentioned next time your out observing.

Clear Skies.