Science | Skywatch with Bill Irwin

By Bill Irwin –

I stargaze, therefore I am.

With the holiday season coming, some of you might be considering purchasing a telescope or binoculars. Most equipment designed for nature watching can be used for stargazing, but the converse isn’t always true.

Field of view and magnification are the prime specs for binos and telescopes. In astronomy, many objects are faint and quite small, so light gathering and resolving power are major considerations.

The bigger the lens or mirror, the more light it picks up and the more detail it can theoretically present. Star images, being pinpoint, are one of the most stringent tests of optical quality, so a less than perfect optical figure shows image defects clearly. Seeing detail on Jupiter or Saturn demands good optics since the magnifications needed will be high. Astronomical telescopes, unlike spotting scopes or binoculars, do not give an erect image. This isn’t a big problem in practice

In astronomy, the mount for the telescope is very important. You can’t make out fine details if the scope jitters every time you touch it and you do have to touch it to focus.

There’s a really bewildering amount of equipment out there but the good news is a lot of it is quite good and some of it is incredible, but you do have to pay for the good stuff.

Equipment made in China is now very competitive, optically. The quality control can be spotty. A lot of it is resold by rebranders who have QC standards of their own, which helps.

The best stuff is still made in Japan or Russia in any volume. The manufacturers in the US and Europe make top quality stuff but they are usually smaller outfits, sometimes at the mercy of what they can get for optical materials, but nonetheless still at the very best quality levels.

The mechanical quality of the focuser is very important to your overall ease of use. It is one of the main mechanical interfaces between you and your scope and there is something to the feel of it like the old stereo amps with big, heavy, smooth-feeling volume controls.

If you plan to take pictures through your equipment, you can multiply all the above requirements considerably. Any shake or optical smear or colour error will be obvious with a camera.

I can’t really cover all the available types of telescopes in the space of this column, but if you PM me I can get more brand specific and talk about where I get my stuff.

Don’t forget, people still build their own scopes from cardboard sonotubes and pipe parts and even old ship porthole glass.

There are some nice choices in the smaller refractor types that would make excellent gifts as well as a good set of binoculars.

Oh yeah, the stars: what are they up to this winter? The Leonid meteor shower peaks on November 17 under moonless skies. It can be a spectacular display. The same applies to the Geminids on December 13/14.

We are going to lose Venus as the morning star this December but it will re-emerge in the evening sky as spring rolls around. But Mars is growing in the dawn sky as it heads for a close opposition next July. It’s always a thrill to get a good view of it as it is one of the only planets that presents a solid surface. It is also a very challenging observation for you and your equipment because it is so small and the air has to be very steady to get much detail. Jupiter and Saturn will sneak around the sun and become visible in the morning sky in the new year. Old friends returning to an observing stool near you.

In the meantime, while you’re debating what telescope to get, please get out and look at Orion rising in the east earlier and earlier. What a magnificent constellation! Red Betelgeuse and brilliant Rigel at the head and feet. Two of the biggest and most powerful stars in the sky and the three stars in the belt and the sword hanging down under the belt. That middle star in the belt is not a star; it’s M42, the Orion nebula. Just about any binoculars will show it. A stellar birthplace excited to glowing by four young hot stars. The real Saturday Night Live. Don’t forget, too, that Orion is constantly doing battle with Taurus the Bull to his right. Bullfights from outer space!

As usual, you can come right down to the arena here at the Bells Lake Observatory. Contact me at (250) 620-0596 or irwin8sound@gmail.com.

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