Day 8: Going Round in Circles
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.
Continue reading “Telescope Making Diary: Week #2”
Day 15: Side Bearings
A finished pair of side bearings. The slots will serve as simple handles once attached to the mirror box.
Sometimes what seems like it should be a quick and easy operation, turns out to be unexpectedly complex. Making the side bearings from my scope was one such a case.
Continue reading “Telescop Making Diary: Week #3”
Day 22: Completing the 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.
Continue reading “Telescope Making Diary: Week #4”
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?
Continue reading “Beat the Heat: Conquering Newtonian Reflector Thermals — Part 1”
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.
Continue reading “Beat the Heat: Conquering Newtonian Reflector Thermals — Part 2”
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.
Continue reading “Houston Astronomical Society Interview”
Here is a listing of every article I’ve written for Sky&Telescope magazine up to the end of 2009. The index is in chronological order and gives the year, month, page number, department heading, and title. You can do a keyword search using your browser’s search function (activated by pressing Ctrl and F simultaneously) if you’re looking for a specific item.
Continue reading “Complete S&T Index from 1997 to 2009”
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.
Continue reading “How To Build A Curved-Vane Secondary-Mirror Holder”
On top of ol’ Smokey. A mix of cloud and smoke from forest fires made for spectacular sunsets, but hazy night time viewing at this year’s MKSP.
I made my 25th consecutive trip to the Mt. Kobau Star Party last August. Although there wasn’t much stargazing to be had this year, I still had a great time. Here are a few pictures of the event. Continue reading “Postcards from Kobau”
At 10:56 p.m. EDT on July 20th, 1969, Neil Armstrong set foot on the lunar surface. That small step really did represent a giant leap. Perhaps as a species, we’ll never again achieve anything quite so grand or monumental.
Continue reading “Apollo 11 On The Moon”