Low Altitude Messiers

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.

Messiers in Sagittarius and Scutum produced with Stellarium
View of the Messier Objects in Sagittarius and Scutum produced with Stellarium.

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.

M16: the Eagle Nebula by ESO
Image Credit: ESO – Messier 16 (the Eagle Nebula)

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.

Binocular Messiers

You may remember way back in 2014 I wrote about Charles Messier and his list of comet-like objects. I also mentioned that I’d started tracking them down with binoculars, and that was a while ago, so what’s happened since?

I’m still working to my usual leisurely pace, but I’ve collected good observations of 60 of them now. This year would be a great time to finish this project since it’s the 200th anniversary of Charles’ death. The BAA are encouraging observers to complete a Messier Marathon, or at least view all the objects this year. Perhaps I will.

I’m basing my work on the Astronomical League’s Binocular Messiers Program that rate 102 of the 110 to be observable with binoculars. I’ve set the additional challenge to observe as many as possible from my north-west facing back garden. This is one reason why it’s taking so long to complete the project: some objects have a very short window of opportunity. That said, I seem to have managed a couple they don’t think I should be able to see, but I stand by my observations ;-), and having observed 58 from their list have 44 left to go.

Unfortunately most of those are pretty low in the sky from the UK. For example, I snagged M41 in Canis Major a few nights ago as it briefly appeared from behind the row of houses before falling into the trees, and all whilst standing on top of a wall peering through the undergrowth. On the other hand I couldn’t have done that with a telescope! I’m very glad that M41 is big and bright or the Industrial Estate light pollution would have rendered it invisible.

Image Credit: M41 by Digitized Sky Survey (DSS)
Image Credit: M41 taken from the Digitized Sky Survey (DSS) using Aladin Sky Atlas.

The upcoming galaxies of Virgo and Coma Berenices may cause some problems. I’ve observed all the brighter ones and have the trickiest to collect on a night of really good transparency. I’ll have another go at M108 and M109 in Ursa Major on that night too.

Then I’m down to the horizon huggers of Scorpio and Sagittarius below 25° altitude. I can’t think of anywhere around my house that they’re possible. Not the street outside, our front bedroom window, they’d probably be difficult from the roof. So I’ll have to start being mobile to mop the rest up, and perhaps that’s the time for a marathon?

Charles Messier’s objects

Charles Messier

Charles Messier was born in 1730, in France, and grew up to be a comet obsessed astronomer working in Paris. To be fair to Messier, most 18th century astronomers were obsessed with comets since discovery could bring fame and riches.

Whilst hunting for these bringers of wealth, Messier kept finding himself confounded by other objects that appear non-stellar, but lacked one of a comet’s defining features: they weren’t moving. Whatever they were, they weren’t what Charles was devoted to.

It’s curious then that Charles’s lasting claim to fame is the Messier catalogue in which he listed 103 ‘nebulae’ – a definition that included almost anything that wasn’t a comet or clearly stellar – with 7 more being added after his death.

The binocular observer.

The thing about these 110 objects that might look like comets, but aren’t comets, is that they were objects not to confuse with a comet and as such, in binoculars they’re generally not impressive. The main exceptions tend to open clusters due to their looser stellar nature. Even so, many fail to break the fuzzy blob mould even with the benefit of modern optics.

Perhaps binocular astronomers are getting a good impression of what Charles Messier saw when we’re looking at globular clusters in the 15x70s. They’re little more than faint fuzzy object with a brighter core… perhaps.

It’s noticeable that many of the best binocular astronomy targets were ignored by Messier completely, but perhaps it’s not a surprise.

The Double Cluster

With his goals in mind, he was hardly going to mistake the double cluster (NGC 869 and NGC 884) above for a comet. They neither display background nebulosity, nor appear as a nebulous object as so many globular clusters have a tendency to do in antique telescopes and binoculars.

So what’s the interest in Messier’s catalogue?

Observing the Messier catalogue with binoculars is mostly an exercise in finding things. Most of these objects stand out well from the stellar background with a reasonably dark sky; that’s why they’re on the list in the first place.

Finally, a pair of binoculars is very compatible with this activity. Many of the Messier objects are near the horizon from the UK as Messier was working further south. Additionally, dark skies can be hard to come by to finish off those faint galaxies. So to locate the lot you’ll probably need to move around, which is home turf for binoculars.

I might sound disparaging about Messier’s objects. He certainly had no interest in them, however some of them are really beautiful, even in binoculars, take M45 Pleiades for example. But to see many of them at their best you need a telescope.

Which is your favourite binocular Messier?

Beautiful binocular clusters

I’m chasing Messier objects with binoculars at the moment. To be honest most aren’t all that impressive, but whilst searching out these objects in Ophiuchus I encountered something fabulous.

I found a huge cluster of bright stars with an obvious profusion of faint stars forming the background field. It immediately struck me that after a lean time on Messiers this object was what binoculars were made for.

But I wasn’t done!

As usual I let the field wander around only to catch sight of an even more impressive cluster. This one wasn’t as big, that much was immediately evident, but it sported a bright band of stars from north to south through the middle of a rich cluster.

A quick look at my copy of Sky & Telescope’s Pocket Sky Atlas told me that what I had originally found was the open cluster IC 4756, and that I was now gazing upon the splendour of NGC 6633. Here’s an idea of what they look like provided by Carte du Ciel, but it’s nothing like the real thing.

Detailed view of IC4756 and ngc6633

The red circle around NGC 6633 shows a 4 degree field of view which is pretty modest for moderate power binoculars. My 15×70 binoculars have about this field, and my 10x50s give about 5 degrees. So you can see why these are such good binocular objects. First they’re a bright starry magnitude 4 to 5, and secondly they’re really big, I would guess at least a degree across.

They’re not particularly hard to find either. There are plenty of bright stars around to help and binoculars are great for star hopping. Here’s a sky map courtesy of Stellarium to help.

Finding IC4756 and NGC6633

You’re missing out if you haven’t seen these two, so if you’ve got a pair of binocular take a look before they disappear into the morning glare until next year.