A Converted-StarBlast Travelscope

Converted StarBlast

This ultraportable telescope is ideal for outings in which stargazing is a “maybe” instead of a “definitely.”

Although I have a house full of telescopes, I still find myself dreaming up new ones that would be ideal for this or that situation. But that’s one of the real joys of learning to make telescopes — you can build instruments uniquely suited to a given application, limited only by your budget, skill, and imagination.
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Centre-Dotting Your Scope’s Primary Mirror

Collimated scope

There’s no getting around the fact that collimating your reflector telescope (Dobsonian or otherwise) is much easier when the centre of the primary mirror is marked with a paper doughnut. Thankfully, these days a good number of commercially made telescopes come with their mirrors pre-marked. But if your scope isn’t so equipped, don’t worry — the procedure for adding a centre doughnut isn’t difficult. In fact, the hardest part might be convincing yourself that you can take out the primary mirror without inviting disaster.
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Collimation Tools: What You Need and What You Don’t

Collimation tools

Aligning the optics of your reflector telescope is crucial for optimal performance — all the more so if you have a telescope with a focal ratio of f/5 or less. A good tool can make the difference between successful collimation, and an exercise in frustration that encourages you to settle for “good enough.” But selecting the right tool can be more confusing than actually using it. On-line discussions offer a bewildering array of opinions and experiences — some of which posted by people who make and sell the products they (naturally enough) recommend. So what do you really need to collimate your scope?
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Telescope-Making Books: The Good, the Bad, and the Unnecessary

ATM books

Although the internet can be a wonderful resource for first-time telescope makers, it can also be a source of great frustration. No matter what the topic, it’s possible to find completely contradictory advice. Far more dependable are good ol’ fashioned books — especially those that have stood the test of time.
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Exploring Low-Power Limits


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.
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How To Collimate An Astroscan


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.
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Telescope Making Diary: Week #1

Lance’s scope.

My dear fiend Lance Olkovick (a.k.a. Nanook of the North) observing Jupiter at dawn from Mt. Kobau with his 12½-inch f/5. The scope I’m building will be similar to this.

The nights are cooling down and the days becoming increasingly overcast and grey. That can mean only one thing: it’s Telescope Making Season again. And so, I’ve decided to tackle a project I’ve had in mind for some time now, namely, a rebuild of my 12¾-inch truss Dobsonian.
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Telescope Making Diary: Week #2

Day 8: Going Round in Circles

Routing a circle

Routing the hole for the top of the mirror box.

Cutting neat, tidy circles in plywood. This is where a plunge router really shines. And make no mistake — building a Dobsonian means cutting circles. In the case of my scope’s design, the first ones are for the tube ring and for the flange at the back of the tube, where it mates with the mirror box.
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Telescope Making Diary: Week #4

Day 22: Completing the Upper Tube

Complete upper tube

The scope’s upper tube all done. The gloss-black finish is achieved with Monokote.

With the mirror box done, it was time to move on to the comparatively straight forward job of finishing up the top half of the scope. This consisted of two tasks: giving the cardboard tube a protective covering and attaching all the hardware.
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