It’s time for another open cluster, and in truth I’ve built myself a bit of a backlog. The issue is that I’m too lazy to scan my drawings in a timely fashion. That’s my excuse and I’m sticking to it. This time I’ve chosen to turn my telescope, with pencil in hand, on M103 (one of Charles Messier’s objects) in the constellation of Cassiopeia for the second time this season. The first was with my ST-80, but I felt that 44x magnification didn’t to it justice.

I’ve finally made a start on the open cluster observing programme I talked about in… February this year! It seemed sensible to start with an easy one because I was determined not just to observe and classify, but to produce a sketch too. The chosen target was Stephenson 1, which is also known as the Delta Lyra Cluster. As you’ve probably guessed, the delta Lyrae visual double – and many would say that is enough reason to take a look – plays a key role in the structure of this open cluster.

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!

Navigating to open clusters with a red dot finder is difficult. Many are some distance from a visible bright star – bright is magnitude 4 or more around here – and an Alt-Az (Altitude–Azimuth) mount is next to useless without an optical finder under these conditions. When double star hunting I usually prefer my Equatorial mount, and I think it’d be the best tool for the open clusters program too. Heavy though it is, once aligned it’s much easier to find your way around using the slow motion controls for RA (Right Accession) or Dec (Declination) whilst looking through the eye piece.

You may remember that I announced my intention to complete the open cluster program this year. Well we’re a couple of months in and a few things are clearer to me now. And that year’s seeming short than I’d expected. When is a group of stars a cluster? As a relatively new observer I’m used to open clusters like M37 which, courtesy of Stellarium, looks something like this. Open Cluster M37 in Stellarium They’re pretty obviously a cluster of stars aren’t they, so no problem there, even I can find that as long as I’m looking at the right one.

This is my third year as an astronomical observer, and I’ve decided the time has come to kick off a few projects aimed at improving my practical skills. Observing open clusters. The Astronomical League have some fantastic material and programs that are available online, even to non-members. I wish British astronomical organisations were more like their American counterparts (a discussion for another day). Anyway, the program that’s caught my imagination is the Open Cluster Observing Program which provides a list of 125 objects from various catalogues, most of which I’ve never encountered.