I’ve had very little time and energy for my astronomy hobby for the past two years or so. It used to be that I’d take the telescope out at least two or three times a week, weather permitting. I logged my observations, worked my way through the Messier catalog, reported my observations of variable stars to the AAVSO (American Association of Variable Star Observers), and tried to observe occultations of stars by asteroids for IOTA (the International Occultation Timing Association). I was never the most accomplished of observers, but I was out there doing things.
Life gets in the way, though, and I’m a bit older than I used to be. So time and energy are not what they once were. Enthusiasm has taken a bit of a hit, too, for several reasons. For one thing, I only have modest astronomical equipment, which limits what I can see. For another, I live eight miles from downtown Baltimore, and the light pollution is horrible. That’s an even worse limitation on what I can see. I also have less interest in going out on cold winter nights than I used to, but that’s at least a seasonal problem. What I can, or rather can’t, see is the main issue.
Which brings me back the Messier catalog, one hundred and ten objects forming a list that began life as a collection of objects not to look at if you happened to be hunting for comets. Today, that list is a key focus for many amateur astronomers. Hunting for and finding Messier objects is one of the first things most amateur astronomers undertake. For some, drawing these objects at the eyepiece occupies many hours of observation, while others photograph them. There is even an activity known as the Messier Marathon in which an amateur astronomer attempts to locate all one hundred ten objects in a single (looooong) night of observing.
I’ve never tried the marathon myself, but I have revisited these objects time and again. The problem is, I can’t see them all. Some are too faint or diffuse to see using my equipment from my location, and I don’t typically get to travel to darker locations. I have tried time and again to spot these elusive objects, hoping against hope that with growing experience and maybe the luck of just the right conditions, I’ll be able to catch one. But that has never happened.
Until last night.
Last night I took the telescope out for the first time in a long time. I happened to be out when Saggitarius was hanging in the sky at the end of my driveway. It’s a fairly bright constellation, and it also boasts a special position in Earth’s sky: the center of our galaxy lies in that direction, so the band of the Milky Way is thickest and brightest as it runs through Saggitarius.
But from my house, not so much. From where I stand with my telescope, that direction happens to be roughly the direction of downtown Baltimore, so the skyglow is brightest there. Worse, there’s a streetlight in my face, glaring at me from across the street. The Milky Way is invisible here, and I can’t even see the stars of Saggitarius without blocking the streetlight with my hand.
As you might guess, if I point the telescope at anything in that direction, it’s generally a disappointment. An object in that part of the sky must be fairly bright for me to see it, so most of the Messier objects in that region are difficult or impossible for me to observe.
That doesn’t mean I won’t try. I looked for several of them last night, moving from Saggitarius gradually upward from the horizon until I came to M17, a nebula known as the Omega Nebula or the Swan Nebula (and one or two other names, depending upon who’s doing the talking). There are very few nebulae I can see. Because they are spread out over the sky, their light is diffuse and their surface brightnesses fairly low. They have to compete with the human-created skyglow, even in a telescope. There are only a handful of nebulae I can see without using a filter designed to block the wavelengths of light most typically associated with light pollution.
I have two such filters, one a relatively recent purchase. Last night, I installed that filter, pointed the telescope at M17, and looked. Amazingly, there was a smear of light, long and thin, across the view. At first I thought it was a reflection off the lens from the streetlight. I moved the telescope a bit. The smear moved with the stars! It was real!
After years of not seeing the Swan Nebula, there it was before me. I tried the older filter and discovered that I could indeed see the nebula with its aid, but it was much fainter. Had I not known exactly where to look, it’s possible I would have missed it, or at least wouldn’t have been entirely certain that I’d seen it. Returning to the newer filter, I reveled in the view for some time before moving on to other targets.
What you see at the eyepiece is never what you see in a photograph. For many people, the smudge of light that greeted my eyes last night would probably have elicited an underwhelmed response. But for me, after years of not seeing it, suddenly discovering the Swan was a real treat.