So what can you REALLY see when you point a fifty or sixty millimeter scope skyward?
Which is to say a whole heck of a lot more than you may have been led to believe by the nay-sayers and those addicted to aperture, the ones who will lead you down the road to financial purgatory faster than a speeding photon disappearing into a black hole. Not that I’m not fond of a bit of aperture. Many a night finds me parked behind the long white tube of a five inch or six inch refractor, or occasionally an eight inch SCT.
But —- the purpose of these tours is to demonstrate that the heavens hold an abundance of stellar wealth which is visible in small apertures. Many are the lonely objects just waiting for a sixty millimeter lens to pay them a visit. So think of this as your chance to provide some visual comfort to a distant collection of forlorn photons.
Greg is covering similar territory with his DSC-60 posts, which can be found by clicking on the green “DSC-60” tab at the upper right of the home page, as well as by scrolling down to “DSC-60 Project” at the bottom of the “Select Category” window on the left side of the home page. I’ll provide a link to those posts as we go if I’m covering the same territory. The primary difference is these 50mm/60mm tours will focus on a small area of the sky — usually a single constellation — and provide four or five stars that you can observe easily over the span of thirty minutes to an hour. I’ll go back over some stellar territory that either Greg or I have covered previously at larger apertures, and I have a few locations in mind already that have yet to be scrutinized by either of our pairs of probing eyes from the eyepiece side of a telescope objective.
So think of this as a spur to practice grab ‘n go astronomy with these small-apertured scopes, which are ideal for quick observing sessions. Between the DSC-60 series and this series of tours, we hope to get one message across loud and clear — there are countless stunning sights to be seen in apertures of fifty and sixty millimeters!
I’ve been thinking about a series of this sort for some time, and finally was prompted to get going with it when a new double-sided mount arrived on my doorstep from the albion shores of distant England. The mount is called the Sky-T, made by Synta, which currently is not available in the U.S. So by the time it reached my Oregon address, it had a few miles on it, but was otherwise unscathed. It took a few adjustments to get it working properly, but once I got that squared away, I found I had the ideal platform for mounting a 50mm scope and a 60mm scope side by side.
Which leads us to the scopes.
There doesn’t seem to be a lot available in the way of 50mm refractors, apart from finder scopes. Swift made an excellent 50mm scope many years ago, which rarely comes up for sale on the used market, and I believe Tasco sold a 50mm at some time in the distant past, which is also seldom seen among the ads for used refractors. And Stellarvue has offered their 50mm finder as a stand-alone refractor, dubbed the Lil Rascal. It’s short focal length makes it better suited for use as a finder, as opposed to a double-star splitter, but since you can swap eyepieces in it at will, it merits consideration. I was fortunate enough to come across a 50mm f/10.8 Zeiss on Amart, so I grabbed it quickly, and have been very pleased with it. The views are crisp, bright, and mouth-wateringly sharp.
The 60mm scope we’ll use for these tours is one I put together from various parts. The lens is an 800mm focal length Carton in a silver aluminum cell, which I mounted in a white aluminum tube. That cool black lens hood is a yogurt container with the bottom cut out of it that fits around the aluminum cell like your frosty hand in a warm glove. The final touches were a 1 1/4 inch Antares rack and pinion focuser and a 10×30 Celestron finder, which is the same one that comes with many of Celestron’s smaller scopes, including the six inch SCT. I’ve found that particular version has a field of view which is bright enough that I can see the crosshairs outlined against a dark sky — a rather rare trait, but I’ve got several of them, and all of them have that uncanny talent — and you can frequently find them on the used market for about $25.00. I believe the lens and cell cost another $25.00, the tube was somewhere around $10, and the focuser was about $45 — and the full container of yogurt was about three bucks. That all comes to right at $108 — not bad for a great little 60mm scope.
And that brings us to eyepieces.
We’re only going to use four for these tours: three Televue Plössls — 20mm, 15mm, and 11mm — and an old orange-lettered, magical 7.5mm Celestron Plössl. We’re not attempting to ferret out faint photons and elusive secondaries trapped at 200x in the glare of shimmering diffraction rings — that’s done better with larger apertures. The idea here is if whatever we’re chasing can’t be seen in the 7.5mm eyepiece, then it’s out of range for the purposes of this tour. If you want to torture yourself with dim views at 200x, I’ll look the other way. That’s not to say it can’t be done in a 50mm or 60mm scope — I’ve done it more times than I can count — but my eyes have always rebelled at the visual torment I was forcing on them. You won’t be able to resist trying it, anyway, so there’s no need for any encouragement from me. 😉
But the intent here is to see what can be seen in scopes of small aperture at reasonable magnifications — and without investing a fortune in eyepieces. I like the Televue Plössls, but GSO or Meade or Orion Plössls will do just as well, as will University Orthoscopics, or the older Celestron Orthos which can frequently be found on the used market — or just use whatever you have on hand. You can even mix up the brands and types — nothing is carved in stone here.
This series is also written with the beginner in mind, or at least those without a lot of experience at the eyepiece. So I’ll categorize each star we look at as easy, intermediate, or difficult. Some will fall into two of those categories for various reasons, which will be explained as we go along. And I’ll even include a few observing tips for a nominal fee — free!
In fact, I’ll throw in one tip right now. Unless you’re one of those rare people — and there really are a few of them — who can observe from a standing position and remain absolutely motionless over the eyepiece, sit down and make yourself comfortable! It is absolutely amazing how much more you can see when you’re comfortably seated at the eyepiece. A chair with an adjustable level seat is the best investment you can make — it will literally have an astronomical effect on your observing enjoyment. You’ll see things from a seated position that you’ll never catch the first glimpse of when standing up. An excellent example of that is the Polaris secondary, which is discussed in the second tour in this series.
And if position angles and celestial directions make your head spin and cause chronic spatial dislocation, you might want to read Greg’s post on the subjects here. Some time invested in reading it slowly and carefully, and going back over it a second and third time — or at least until you have a good grasp of its contents — will make your time under the stars many times more enjoyable and rewarding than it would be otherwise. Without a basic acquaintance of celestial directions and motion, you’re likely to feel like you’ve been dropped into the middle of a large city at night with no map.
So enough of the introductory information. Put on a coat, grab your scope, and let’s get going.
Oh — don’t forget your Star Splitter hat.
You’ll never get the hang of this without that hat. 😎
Tour number one starts ………………… here!