Low Altitude Messiers
By James
Back in February I noted that most of the remaining Messier Objects were too low to be seen from my back garden. Well I managed to fit an observing session in during one of our Society meetings to observe the Perseid meteors this August.
As it turned out it was cloudy most of the time, so very few meteors were seen, but during the early part of the night, before the Moon rose, I stuck my 10×50 binoculars on their monopod and pointed them low to the South in the direction of Sagittarius.
As you can clearly see there’s a lot to go at here! Unfortunately, even from this site trees obscured anything below the star Kaus Borealis marking the tip of the lid of the Sagittarius teapot.
I could get pretty close and that star was a nice bright marker, so I decided to begin with M22. It was immediately obvious to the East of Kaus Borealis and well clear of the trees. A large round fuzzy patch with no sign of resolving into stars. Just what you’d expect from a globular cluster in a pair of binoculars, or in fact in a small telescope. I panned to the West, but as expected M28 was not seen. It was obscured by the tips of those trees.
I was keen to bag the lowest of the objects on view, and typically enough the next target isn’t marked in the image above. I chose M8 (the Lagoon Nebula) which is that box below M20 and to the West of the last targets.
M8 was seen amidst a collection of brighter stars aligned east-west as a patch of nebulosity in direct vision. It’s nothing but a fuzzy patch which was about 7’x3’ in size when compared to the separation between the adjacent stars 7 Sgr and 9 Sgr. Truthfully, I suspect that I was primarily seeing the open clusters NGC6530/6523 forming within this emission nebula as they match the position of this patch.
M24 is an interesting target, and one made for binoculars. That’s because it’s the Sagittarius Star Cloud: a view through an interstellar dust cloud of the neighbouring galactic spiral arms. It’s a large and very obvious grouping of stars of various magnitudes, there’s nothing nebulous about this one! It spanned about ¼ of the binocular field of view, or about 75 arc-minutes, in its length and perhaps ⅓ of that in width (25 arc-minutes). It’s aligned roughly northeast-southwest.
I wondered whether I could find the open clusters in Scutum. Being the brightest M11 was the first on the list using the stars of Aquila as a signpost (Scutum isn’t very bright). To my surprise there it was as a modest sized, but bright condensation of stars. It was immediately obvious, but I couldn’t resolve an stars with the binoculars. I’ve managed to get a telescope on M11 from Home since and it’s a spectacular open cluster!
Down and to the West I sought and found M26 which was much smaller and fainter than M11. Definitely no stars to be seen in this one, and I haven’t viewed it telescopically yet.
I’d taken to starting my star hopping at M24 because it’s so obvious in binoculars, and fabulous to look at too. This time I noticed two more fuzzy patches to the northeast as the transparency improved.
The first spherical patch of nebulosity appeared above a convenient asterism allowing me to identify it as M18. Nebulous and unresolved I estimated it to be about 8 arc-minutes in diameter by comparison to the local stars separations.
Further to the North is a much more irregular patch in the right place to be M17 (the Swan Nebula). Again this was nebulous and unresolved. M16 (the Eagle Nebula) spotted as a nebulous patch around a coarse cluster of stars that formed a suitable pattern for a positive identification. No detail seen, but it’s clearly visible whilst not resolved. I estimated it to be 5 arc-minutes in size.
These two objects are star forming in that dust cloud mentioned earlier. Without it the whole area would be as star filled as M24! On the other hand we wouldn’t have objects like M16 to look at, even if it didn’t look like that in my 10x50s.
Finally for the night I found M25 easily spotted to the East of M24 as a coarse and sparse open cluster that did resolve fairly easily. A range of magnitudes leads me to assess it as a Trumpler class II2m open cluster.
And that was the end of a very good night’s work with the binoculars. Nothing I viewed that night was particularly taxing, many other Messier objects are much trickier. It’s a lovely part of the night sky and there are more to capture here, but I think that’ll have to wait for next year as time and the weather have not been kind.