Where you from? You sexy thing (sexy thing, you). No, this post isn’t about hot and sexy telescopes. Well, okay, maybe just a little. That banner photo above is the new Skywatcher Skygate 18-inch truss tube dobsonian. They also have a 20-inch that looks the same, but the pictures I was able to find of it online weren’t quite as blog-worthy. The 20-inch can be yours for a paltry $7000; or in a goto version for a mere $8000. Below is the Explore Scientific version of the same-sized scope, at $8600, non-goto only.
Skywatcher advertises its 20-inch as the largest mass-produced dob on the market; to get anything bigger, you have to go to the specialty dob makers, like New Moon, Discovery, Teeter, Obsession, etc., and they’ll cost far more. Looks like it’s time for me to go back on Jeopardy already. So soon?
One more, because why not: my obsession since seeing it grace the pages of Sky & Telescope as a kid, the gorgeous and tiny Questar, a functional work of art that achieves optical perfection:
Okay, the point of this blog post isn’t to, ahem, tittilate your senses with pictures of hot scopes. No, it’s different than that. It’s to get you to bring your mind to bear on what you’re looking at to make the objects sexier, more interesting.
Most newcomers to astronomy have unreal, almost impossible expectations of what they’ll be able to see through the eyepiece of their new scope. Usually, this is based on having seen those stunning Hubble pictures for the past 25-odd years. Lately, it can also be because of the amazing pictures taken by amateurs. You can see these works of art posted daily on the various Facebook astro pages, or on sites like Astronomy Picture of the Day. For some, these high expectations can discourage them right out of the hobby.
Some objects do meet expectations. The moon is the prime example. With any kind of aperture, say 4 inches and up, you can get up close and personal and feel like you’re in orbit. The moon does not disappoint. The planets are a different story. The images you see will be far smaller than what you see in pictures, and the amount of detail will also be significantly less. But there is still detail to be seen, if your seeing conditions are good and you are patient for those rare few seconds every few minutes when the seeing gets even better. Those seconds can be magical, and you will see a level of detail that is similar to, but still much less than, the photos you see on the astro pages.
Open clusters, like the Pleiades, or the Hyades, or the Beehive Cluster, or any of the many other winter clusters (M35, M36, M37, M38, M41, M46, M47, M48) don’t need such mental gymnastics. Because stars are point sources of light, basically any sized scope 5 inches or larger will show you the most of the stars that make up almost any open cluster in the Messier Catalogue, and the cluster will look more or less just like it does in a photograph.
Even so, it can only enhance your viewing experience to know that, for example, the Pleiades are 444 light years away. I’m a history buff, so it’s interesting to me that the light that is arriving at your eyes left the Pleiades while Sir Francis Drake was circumnavigating the globe, a few years before the Spanish Armada and when Shakespeare began writing his plays, . It’s also interesting to know that the nebulosity surrounding them (like the Merope Nebula) is not leftover from the formation of the Pleiades, but just happens to be interstellar gas that the Pleiades have encountered on the path that they’re all moving along.
Globular clusters are similar to open clusters in meeting expectations, but not quite as good. A 5-inch scope will barely show a sprinkling of individual stars in M13, the Great Hercules Cluster. But an 8-inch scope will show plenty of them there as well as in a bunch of other brighter globs, too. That extra aperture gives many clusters – both open and globular – a more “filled-in” look. Apetures just a bit larger than that (10-12 inches or so) will make globs look like a pile of diamonds sprinkled on velvet. More aperture means more light, and more light means you can see dimmer stars in the cluster that a smaller scope just can’t deliver.
On the other hand, when beginners look at galaxies and nebula, things like Andromeda or Orion, they expect them to look like the pictures they’ve seen over and over again. And when they don’t, well, that’s just plain disappointing. Hell, even more advanced users like myself are often disappointed by the actual visuals that a larger scope will throw up, like my C9.25.
That’s because those pictures are – obviously – taken by cameras. My point being that a camera can gather light for minutes, hours, and even longer so that it can pick up dimmer objects and detail that your eyes simply are unable to while looking through the eyepiece. As a result, cameras can produce glorious pictures like this:
Instead, this is about what Andromeda looks like through a telescope with just your eyes:
You won’t see the details as shown in that first photo because your eyes do not work the way a camera does. Your eyes gather light for only a second or two at most, and that’s as far as they go. You won’t see any color, because the structures on your retina that detect color, the cones, need more light to activate them than these extended, diffuse objects can provide. (Stars and double stars can have color because their light is concentrated into a point source.)
You’ve gotta get up into the realm of 15-20″ telescopes, like the two at the top of this post, before galaxies start looking like spirals and dust lanes become readily visible. Note the word readily. If you look again at the second M31 pic, you can just barely see the dust lanes there. If you’re observing from insanely dark skies, you can get this level of detail while using a slightly smaller scope, say, 12″ or so, depending on your eyes and how many carrots you’re eating. Otherwise, in a smaller scope (4 to 8 inches) one galaxy will look very much like another – like a faint gray fuzzy smudge. This why they’re often referred to exactly in these terms, as faint fuzzies.
Disappointing, yes. But, but, but . . .
What you have to do is bring your mind into the equation, not just your eyes. It’s just like what you have to do after being married to the same person for 20 years. For example, our eyes will look at the big gray splotch (no, not your spouse) that is the Andromeda Galaxy, and go, “Okay, well, that’s definitely a big gray splotch, all right.”
But your mind will tell you that the Andromeda Galaxy is 2.5 million light years away, twice the size of the Milky Way and contains about a trillion stars, about five times as many as our galaxy. It will tell you that because of that great distance, the age of the light hitting your eyeballs is so old that the only people walking around here on earth when the light left Andromeda were australopithecines. It will tell you that Andromeda and the Milky Way are going to collide and merge about 4 billion years from now, and when they do, it is very likely that not a single star will hit another star.
If you take the time to learn about what you’re looking at, you will know that all galaxies used to be referred to as nebula. You’ll know that it was Hubble (the dude, not the scope) who was able to determine through photographs of Andromeda he took about 100 years ago, that these nebula were separate galaxies in their own right. He did this by calculating the first accurate measurements of the distance to Andromeda, placing it outside of the Milky Way.
If you keep going with this concept, right now in the spring sky, there are M81 and M82 – a pair of galaxies in Ursa Major that appear in the same field of view of a low to medium powered eyepiece. There’s also the Leo Triplet – M65, M66, and NGC 3628, which can also be seen in one view. And finally, there’s the grand-daddy of them all, Markarian’s Chain, starting with M84 and M86, and stretching for about a degree and a half through half a dozen other galaxies. When you start thinking about clusters of galaxies, 65 million light years away – almost exactly the time that the dinosaurs all bought it from that asteroid impact – things get very interesting, indeed!
It’s the same with the Orion Nebula. Yes, it’s the most glorious nebula in the sky. Pictures show it to look like this:
But it just doesn’t look like that through the scope. Not even close. This is what it looks like visually through a 5-inch scope, like my Mak, under suburban skies:
With my C9.25, it looks more like this drawing:
Again, it’s important to know what you’re looking at to make that view sexier and more meaningful. The Orion Nebula is a stellar nursery, where baby stars are born. It’s about 24 light years wide – almost 6 times the distance between our sun and its nearest neighbor, Proxima Centauri. The nebula is about 1344 light years away, meaning that the light that we’re looking at left there not long after Muhammad died after expanding the Muslim Empire, when the Chinese were inventing paper money and the water clock. The nebula was the very first deep space object of astrophotography, with Henry Draper being the first to take its picture in 1880.
The nebula is lit up almost entirely by that tight ball of hot, young stars (ahem) at the center, called the Trapezium. The stars in and around the nebula are only between 300,000 and 3,000,000 years old – absolute babies compared to everything else we see when we look up at the sky. These hot stars produce a huge amount of stellar wind, probably due to an overabundance of Mexican food. The stellar wind are streams of particles constantly leaving these stars in all directions. They’ve blasted out that notable hole or cave in the nebula, creating shock waves as they do so. These shockwaves, along with gravity itself, cause the interstellar gas to collapse, condense, with the result that other protostars begin forming.
Knowing about the objects you’re looking at, their distance, what they are, what that means, will get you beyond the merely visual and make all of these objects a lot sexier and a lot more interesting to observe. As for your spouse, you’re on your own there. Good luck with that.