Gary Seronik.com

It's a refractor extravaganza in n Telescope Workshop this month as we profile a pair of nifty designs that utilize flat mirrors. While purists might regard it as heresy to introduce reflective elements into the refractor' s light train, others will recognize the practicality of a shortened tube or the ability to create interesting options. Richard Erich and Robert Ayers take different approaches to their telescopes, but both instruments are chock full of good ideas.

In Binocular Highlight I profile one of Sagittarius's less popular Messiers, M55. This is a terrific globular, but it's perhaps neglected because it lies so far south and so near one of the sky's most action-packed regions.

To find out what else is in the issue, visit S&T’s web site, www.SkyandTelescope.com.

Happy reading — and as always, your comments, questions, and suggestions are welcomed.
Gary

What could be finer than a total lunar eclipse viewed from the tropics?

I’m pretty excited about this and I think it’s going to be lot of fun. I’ve been asked to speak on the Cosmic Trails cruise that Sky&Telescope and Insight Cruises have put together. The cruise goes all kinds of really interesting places (including the Panama Canal, Costa Rica, and Aruba, to name but three) and runs from December 13th to 23rd this year. And on the night of the 21st we’ll get to see a total lunar eclipse from sea.

With the final modifications completed, the scope is at last finished. At least for now...

The balance issue detailed on Day 23 was eating away at me, so I broke down and decided to make the necessary modifications after all. I’m glad I did. The work wasn’t as bad as I feared, and the results turned out better than I expected.

Requiring only a few parts, this simple and effective setup provides stable images.

In my Telescope Workshop column in the August 2010 issue of Sky&Telescope, I wrote about how you can build my newest (and best) binocular mount. Presented here are some additional photos to aid you in constructing one.

As most readers know, one of my favourite ways to view the night sky is with binoculars. And to get the most out of your binos, you really need to mount them. I've finally come up with a binocular mount that I'm really happy with. It's not only easy to build, it works great! In Telescope Workshop this month I tell you how to put one together. I've posted some extra photos here to supplement the ones in the magazine.

In Binocular Highlight this month I profile the two Messier objects lying in Lyra, the Lyre. M57 is the well-known Ring Nebula, while M56 is an overlooked globular. Both can be seen in binos.

To find out what else is in the issue, visit S&T’s web site, www.SkyandTelescope.com.

Happy reading — and as always, your comments, questions, and suggestions are welcomed.
Gary

The old saying that less is more rings true for telescope magnification, but there are many factors to consider before choosing your ultimate wide-field eyepiece.

Low-magnification views of the night sky can be breathtaking. It’s only with low power that we can fully appreciate the splendor of the Pleiades, the foggy expanse of the Andromeda Galaxy, or the wispy filaments of the Veil Nebula. But if discussions on internet forums are anything to go by, there's a lot of confusion out there about how magnification, field of view, and exit pupils relate to each other. And without understanding these factors, you might end up shortchanging your telescope’s low-power capabilities.

Every crater tells a story. Usually, the broad outlines of the talke are familiar — a comet or an asteroid crashes explosively into the lunar surface and leaves a circular depression. But some craters have more elaborate stories to tell. My On The Moon column this month tells the story of Proclus.

For those of you unfamiliar with SkyNews, read on . . .

The Astroscan’s greatest strength is its bare-bones simplicity, which unfortunately also means it lacks adjustments for achieving optical alignment.

Edmund Scientific's Astroscan has been around since 1976. Its enduring appeal is at least partly due to its no-muss-no-fuss simplicity. You plop it down in its base, put in an eyepiece, and you’re good to go. The optics come factory aligned, so you never have to worry about collimation. Unless, that is, the mirrors go out of alignment. And since the Astroscan doesn’t have adjustments to correct this malady, you’re stuck. But are you really? For the brave (or, perhaps foolhardy), there is a procedure you can perform that will put the scope’s optics back into alignment.

My book, Binocular Highlights, has floated to the top of its category at Amazon.com. This is actually the second time since Amazon replenished their stock a few weeks back, so this ranking is no doubt partly due to some pent up demand. Still, it's nice to see. (For those of you unfamiliar with the book, you can look it over here at Amazon.com.)

I was recently interviewed for the Houston Astronomical Society’s newsletter GuideStar. I’ve been interviewed a few times before and have found that the quality of the resulting article depends hugely on the interviewer. Prep is everything. And in this case, Clayton Jeter was a real pro. His questions were thoughtful and interesting, and clearly the result of having done his homework.

The complete interview appears after the jump.

Solving the thermal management puzzle can be as simple as adding a fan to cool your telescope's primary mirror.

In Part 1 I described the cause and consequences of telescope thermals, now let’s see what can be done to cure, or minimize the problem.

The daylight social centre of our star party is the swimming pool. At night, the reclining lounge chairs accommodate binocular observers. (Nikon FE, Fuji Sensia 200 slide film.)

The 7th annual Costa Rica Southern Star Party ran from January 16th through 23rd this year. We usually have excellent observing conditions and clear skies, but this year was exceptional. Virtually every dark hour was free of clouds and rich with celestial rewards.

The secondary mirror holder and spider on my 12¾-inch truss-tube Dobsonian is made with scrap wood, a few nuts and bolts, and a stainless-steel ruler.

The curved-vane secondary mirror holders I use on almost all my telescopes never fails to excite curiosity. Most people know that the principal benefit of the curved spider is spike-free stars, but they often wonder if it really works. The “points” adorning bright stars in telescopes with straight-vaned spiders are diffraction artifacts that don’t seriously affect the image but do impose an aesthetic quality that may not appeal to you. Luckily, the remedy is easy to make, works like a charm, and can be retrofitted to virtually any reflector — commercial or homemade.

This simple, easy-to-build mount provides the perfect introduction to long-exposure astrophotography.

Round stars. That’s the difference between astrophotos captured with a camera that tracks the sky’s motion versus one that doesn’t. Traditionally you’d make a tracked photo by placing your camera piggyback on a telescope with a motorized equatorial mount. But that’s a lot of equipment to deal with if all you want are some nice-looking constellation portraits or a shot of a newly discovered comet — especially if you have to travel to reach your favorite dark-sky destination.

You can enjoy viewing the Moon with nothing more than a modest telescope equipped with a few eyepieces. Even binoculars can show a great deal. But to get the most out of your lunar explorations a few additional tools are a big help. Here are my picks of the best and most essential Moon goodies.

Recently I did a segment for the show SUPERnova, which is produced by the talented team of Tyler Gamsby and Shannon Hartley for the Royal Astronomical Society of Canada's Vancouver Centre. The results are viewable above.

This is episode #4. Be sure to check out the other shows too. All are very nicely done and have unusually high production values. SUPERnova is part of the Vancouver Centre's International Year of Astronomy outreach program.

Enjoy!

Gary

Have scope, will travel! This Dobsonian not only gives great views, it also fits into an airplane’s overhead storage compartment.

One of the best reasons for learning to build telescopes is that you can make instruments that perfectly match a particular observing need or circumstance. As an editor at Sky & Telescope, my “circumstance” happily involved a lot of travel, and as a result I found myself dreaming of a telescope that I could take with me as I zig-zagged across North America from one star party to the next. It seemed a shame to arrive under the dark skies of the Texas Star Party or Mount Kobau without a telescope of my own.

Every stargazer has a “first telescope” story. Here's mine.

Like many backyard astronomers, one question I get asked all the time is “When did you get interested in the stars?” The truth is, I can’t remember a time when I wasn’t drawn to the night sky. Maybe part of the reason was that my family lived on an orchard under a splendid, dark rural sky. For me, the stars were as much a part of nature as the birds in the trees and the bugs crawling on the ground.

Combining optical excellence with rock-steady views, Canon's image-stabilized binoculars are a stargazer's dream come true. But is one best for you?

For a long time, 7×50 or 10×50 binoculars were considered the best choice for stargazing. Such binos are relatively lightweight, inexpensive, and capable of delivering fine wide-field views of the heavens. But most people find that hand-held 10×50s represents the upper limit of the weight and magnification comfort zone. Models featuring higher magnification or more aperture require a tripod or dedicated binocular mount for steady views. Even 10×50s rarely work near their potential without support. Unfortunately, such devices ensure that an instrument much loved for its portability and convenience becomes encumbered with as much paraphernalia as a small telescope. Enter the image-stabilized binocular.

Too big, too small, or just right? Making sure your reflector’s secondary mirror is the correct size is a straightforward task.

The Newtonian reflector has many strengths, not the least of which is that it consists of just two elements: a precisely shaped paraboloidal primary mirror and a flat diagonal secondary mirror. Yet for all its intrinsic simplicity, confusion abounds when it comes to the optimum size of the diagonal. Many amateurs, and apparently even some telescope manufacturers, seem unsure as to how to choose the correct size for the diagonal. So how big should it be? That depends on several design parameters and some personal preferences.