It was Jay Freeman who gave me the idea of observing all the Messier objects with each instrument that I own. It's turned out to be a very useful habit. It gives me an excellent sense of the instrument's capabilities, while also reinforcing my memory of where each object is, what it looks like, and how to find it. Ideally, I'd like to be able to find every Messier object with every instrument at every level of light pollution by memory — though that's obviously a utopian goal that can only be approached, never completely realized.Ever since purchasing my 15×70 binoculars, I've been reminded of Jay's comment that 70-mm binoculars are the easiest instruments for doing a Messier survey. They can be swiveled very quickly, yet they're big enough so that most of the Messier objects pop out instantly as soon as they enter the vast field of view — assuming that I'm under reasonably dark skies.
Last weekend was late first-quarter Moon, so I had to get up before dawn for deep-sky observing. I ended up chasing down all the early-winter Messier objects — the ones between RA 0 and RA 6 — in a few minutes using my 15×70 binoculars. Only when I was writing down my notes a couple of days later did I realize that this had completed my Messier survey with that instrument.After my quick scan, I went back to view each of the objects more carefully. And here's where one of the drawbacks of binoculars became painfully apparent. One of the reasons that I can find deep-sky objects so quickly with binoculars is that once found, the objects display depressing little detail. So I'm not tempted to linger over each object as I would be if using a telescope. There are a few star clusters (the Pleiades, for instance) that really sparkle at 15×, but they're the rare exceptions.
Still, there were a few pleasant surprises. For instance, I was able to make out the outer loop of the Orion Nebula — the one that's almost 1° in diameter, passing near Iota Orionis. That's not an easy target even in telescopes with significantly more aperture. It's a reminder that using two eyes is especially valuable for viewing subtle nebulosity.
I do finally understand why 15×70 binoculars are popular with some beginners, though. For simply tracking down deep-sky objects — as opposed to seeing detail in them — the combination of the binoculars' enormous field of view, straight-through pointing, and pretty-huge light grasp is hard to beat. That could avoid a lot of the frustration that many beginners experience.