Weekend Stargazer: November 20 – 22


Jupiter as seen in an 8-inch telescope at 300×.

This weekend is ideal for getting in some early season Jupiter observing. But why not wait until later in the year when it’s more conveniently placed in the evening sky? You certainly can, but there are three reasons why you might want to begin your Jupiter watch now.

In the December 2015 Sky & Telescope

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It's easy to overlook deep-sky treasures that aren't located near prominent landmarks. And that's a shame. Some very fine sights are found "out in the open." In this issue's Binocular Highlights column we look one such object, Andromeda open cluster, NGC 752.

Making a telescope can be quite a balancing act. Literally. Usually this involves heavy counterweights, but there's a way of avoiding them. In this month's Telescope Workshop column I highlight Ken George's nifty spring counterweight system.

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.

In the November/December 2015 SkyNews

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In this issue's On The Moon column, we go on a tour of Mare Humorum, a feature that often seems to be over looked. And yet, Humorum has a long list of fascinating details, including a wonderful floor-fractured crater and numerous wrinkles and rilles. You can easily spend a rewarding evening just exploring this one corner of the Moon.

For more about what’s in the current issue, visit SkyNews.ca

In the November 2015 Sky & Telescope

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It's hard for me to believe, but this month's Binocular Highlights column is my 200th. To mark the occasion, I decided to list my favourite binocular deep-sky targets.

In my Telescope Workshop this issue I profile a very interesting 10-inch f/7 planetary Dobsonian. What makes this scope noteworthy, apart from its impressive build quality, is that it's designed specifically for quick and easy setup at public observing events.

Twilight Lunar Eclipse

September 27 lunar eclipse

From the West Coast, the September 27 "blood," "supermoon" eclipse was simply a lovely twilight eclipse.

Review: Canon’s Image-Stabilized Binoculars

Canon 15x45s

Over the years I've tested virtually every affordable image-stabilized binocular on the market for reviews appearing in Sky & Telescope magazine. Canon is the clear leader where astronomy is concerned. The company currently offers six models, each with something to interest the backyard stargazer. Some of these binoculars are among the very best available for astronomy, while some are more general purpose.

Five Reflector Performace Killers

Reflector telescope front view

The Newtonian reflector is one of the most versatile optical configurations ever created. Whether homebuilt or commercially manufactured, a good Newtonian can rival the performance of any optical design.

Knowledge is power. The more you know about your Newtonian reflector’s potential and its pitfalls, the better equipped you’ll be to ensure it’s delivering peak performance.

No-Tools Telescope Collimation

Telescope front view

For optimum performance, precisely aligned optics are a must. Luckily, achieving this goal doesn't have to be difficult.

Most telescope users know that the only way to get every last drop of performance from a reflector telescope is to ensure that the optics are in good collimation. Here's a method that's simple and doesn't require tools or even a centre-dotted primary mirror.

Building the Outback Travelscope

Me at Uluru

Me, the Outback Travelscope, and a bloody big rock.
(Photo courtesy George Brandie)

When I was preparing to travel to Australia for a total solar eclipse and some dark-sky observing sessions in the Outback, I decided it was finally time to rebuild my 8-inch travelscope so that it could go into my suitcase and arrive safely at my destination.

Getting the Most From Astro Binoculars

Bino user

Binocular stargazing is full of surprises. Sometimes you stumble across a pretty cluster and wonder how you’d previously missed it. Other times, you hunt and hunt for a galaxy listed at 8th magnitude, only to come up empty handed. It’s enough to make you wonder — what makes one object a binocular standout and another difficult challenge? Compiled here are the five most important factors that determine whether or not a deep-sky wonder will turn out to be binocular trash or treasure.

Build This Simple Binocular Mount

Bino mount in use

Requiring only a few parts, this simple and effective setup provides stable images for detailed views of the night sky.

“This is the best binocular mount I’ve ever used!”

Those were the first words out of my mouth as I came indoors from testing my just-completed binocular rig. It’s rare that I build something that actually works better than expected, but finally I’d come up with a binocular mount that provides steady views, is easy to use, very portable, and simple to build. It was a good night.

A Beginner’s Guide to Collimation

Front view

I’ve been building and using telescopes for more than three decades and I’ll share with you a secret: collimating a Newtonian reflector is easy. So why does it seem so difficult when you’re just starting out? Probably because you’ve done your homework by Googling the subject and have read and re-read everything you’ve found. And now, you’re lost in a forest of information — some of it contradictory, some of it densely technical. Truly, sometimes less is more.

Build a Hinge Tracker for Astrophotography

Scorpius stars

This image of the Scorpius Milky Way was captured from Costa Rica with a DSLR camera and the simple hinge tracker mount described here.

If you have a DSLR camera and are interested in astronomy, you’ve probably considered dipping a toe into the astrophotography waters. But a camera is only part of the equation — for exposures longer than a few seconds, a tracking mount is usually necessary. Unfortunately, most suitable mounts are relatively bulky, or expensive, or both. But not the hinge tracker. It costs less than $10 to build, takes less than an evening to assemble, and requires no batteries. And best of all, you can put one together even if you’ve never built anything more complicated than Ikea furniture.

My Photo Web Site

FilmAdvance title

I invite everyone to check out my web site, FilmAdvance.com.
In addition to astronomy, photography is a big passion of mine. So, I started FilmAdvance.com as an outlet for my photographic explorations. There will inevitably by some astronomy related content posted there, but mostly it’s about seeing the universe through the lens of a camera, instead of the eyepiece of a telescope. Look in on it from time to time to see what I've been up to with my cameras and darkroom. Enjoy!

The Big Red One: My Optimized 6-inch f/9 Reflector

Big Red 6-inch f/9

Attention to detail is what separates a regular Newtonian reflector from one optimized for high-contrast performance. This 6-inch f/9 uses every trick in the ATM’s book to deliver superb planetary and deep-sky views.

This was the first telescope I made using my own optics. Like most telescope makers, I got started the easy way, by building Dobsonians with mirrors ground by others. But one day I got bit with the mirror-making bug. I blame my friend Lance Olkovick, our local club’s mirror-making ace. But why a long-focus 6-inch? At the time I was a hardcore Jupiter junkie and was convinced that a long-focus Newtonian would deliver excellent views of my favourite subject. I also wanted to prove a point.

Beat the Heat: Conquering Newtonian Reflector Thermals — Part 1

Newtonian thermal gradient

What you need to know when it comes to optimizing your scope’s thermal behavior.

Generations of backyard astronomers have debated why, inch-for-inch, the performance of a high quality refractor usually edges out an equal-quality Newtonian reflector. This disparity is most apparent when viewing low-contrast planetary detail — the images in a good refractors often have a touch more snap to them. Is there some intrinsic shortcoming in the design of the Newtonian reflector that makes this inevitable?

How To Build A Curved-Vane Secondary-Mirror Holder

Curved spider

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.

A Tracking Platform for Astrophotography

Tracker lead image

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.

Understanding Binocular Exit Pupils

Exit pupils

Do binoculars with small exit pupils really produce dimmer images?

One binocular specification that seems to generate more than its share of contradictory advice is exit-pupil size. I've often seen statements to the effect that you should avoid binoculars with smaller exit pupils because the view is “dimmer” than in models having larger exit pupils. But is this actually true, and more importantly, should it factor into your binocular selection?

Sizing Up the Newtonian Secondary

Secondary mirror

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.

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