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Showing posts with label Schmidt-Cassegrain. Show all posts
Showing posts with label Schmidt-Cassegrain. Show all posts

Thursday, December 26, 2019

Buy A Real Telescope!

There are two kinds of people: those who own an astronomical telescope - and those who want to own one!

If you're of the 2nd variety, you may not own a telescope on the grounds, that, "they're, just too expensive!" Well, some telescopes ARE too expensive! - like those, situated beneath state-of-the-art observatory domes on the summits of Mauna Kea, and Mauna Loa, in the Hawaiian Islands. Now, THAT'S too expensive; for most of us, anyway.

Believe it or not - there are telescopes on the market, that actually approach the optical quality, and sizes, of some of those gems of the tropics. And, there are some that DON'T! And, it's the ones that don't - that are the, truly, expensive items! I will stay clear of those kinds of "powerful", "600X"-type "mockeries", except to give a brief overview and tell you where they can most likely be found.

Orion StarBlast 4.5 Astro Reflector Telescope Kit.
Orion StarBlast 4.5 Astro Reflector Telescope Kit.

Certain kinds of telescopes, or, maybe more accurately, items that LOOK like real telescopes, that are marketed using high, but, ambiguous numbers - are likely to have the overall construction, as well as, overall usefulness, of a high-priced "toy". Although there are some rare exceptions, any type of optical instrument sold by department stores, or other chain store outlets, is likely to consist, mostly, of hype - and disappointment. Don't buy one. I could write a short book on my reasons for telling you that (maybe I will!) - but, not here.

There. That's that! Now, let's look at real, astronomical optical instruments that are available for the non-rich, amateur astronomer, or anyone else who wishes to acquire a well-made optical instrument, for other purposes, as well (I understand that "other" purposes exist - but, I'm not familiar with any of them!)


Orion SkyQuest XT8 Classic Dobsonian Telescope Kit.
Orion SkyQuest XT8 Classic Dobsonian Telescope Kit.

This will be short, and sweet, mainly because I only know of one telescope manufacturer which meets all, of what, I consider, the most important criteria: quality, price, available accessories, reputation, and general knowledge of telescopes - based on my experience and familiarity them: Orion Telescopes and Binoculars of Cupertino, California.

Because of the necessity of variety, and of combinations of variety - much of it aimed at the more advanced, "intermediate" amateur astronomer - Orion carries many types of telescopes, and telescope 'packages', which, I cannot possibly give decent coverage to here, so, before I briefly go over a few of their more 'general-purpose' telescopes, I'll just mention that, they also carry instruments for the advanced amateur, as well as, professional astronomer.

I will note here - NEVER buy a telescope, based on advertisements of "power". I think that statement should be embossed on every telescope's packaging, just above, "DO NOT USE TO LOOK DIRECTLY AT THE SUN". Any telescope, in theory, can provide high, even very high magnifications. That's not what you're interested in. Advertising a telescope by "power"-"magnification", is a marketing device. It's done, only because it can be, and it sounds so good. But, magnification is the least of your concerns; aperture - is a major concern. The cost is a close second.

Orion SkyQuest XX12g GoTo Truss Tube Dobsonian Telescope.
Orion SkyQuest XX12g GoTo Truss Tube Dobsonian Telescope.

There are a few, basic types of scopes: Refractors, Reflectors, and Cassegrainian, "folded" optics types. All of these come in a variety of aperture sizes. Refractors, typically, are in the smaller ranges, mainly because they are more expensive to make. Reflectors, come in small, medium, and large. Folded optics types, come in medium and large. My recommendation, for a beginner, is to purchase a reflector telescope of at least a 4-4.5-inch aperture, but that's because I'm partial to reflectors, and there, generally, larger apertures.

Here are three scopes from Orion, that I recommend for someone who has never before purchased a telescope, and/or, is a beginning-intermediate amateur astronomer. Prices are, as of their latest catalog.

  • StarBlast 4.5 Astro Reflector Telescope Kit: This is a 4.5-inch tabletop model, swivel-base, Dobsonian mounting, and is supplied with two eyepieces (for change of magnification) - 17mm and 6mm (26x and 75x, respectively). 0-power finder-scope. This model features an alt-azimuth dual-axis system for manual repositioning. Best suited for the beginner. Good for observing the moon, planets, and brighter deep-space objects.

  • Orion SkyQuest XT8 Classic Dobsonian Telescope Kit: An 8-inch "floor" model-style, Dobsonian mounting. Comes with 2x Barlow lens (doubling mag. of the eyepieces): 35mm and 25mm (34x, 48x, 68x, and 96x w/Barlow) and 0-power finder-scope. This model features an alt-azimuth dual-axis system for manual repositioning. Best suited for, beginner-intermediate. Good for observing the moon, planets, and dimmer deep-space objects.

  • Orion SkyQuest XX12g GoTo Truss Tube Dobsonian: This telescope is my personal "dream-scope". 12-inch aperture, computerized "GoTo" drive mechanism. Laser-based finder-scope. This model features the GoTo computer-automated drive. Stepper-motors, on both axes, and a hand-held computer controller, allow automatic repositioning of the telescope, based on controller input (keyed or voice). Includes 28mm and 12.5mm eyepieces and 2x Barlow (54x, 108x, 120x, and 240x). Best suited for intermediate-advanced amateurs. Good for observing the moon, planets, and harder-to-reach deep-space objects, such as distant galaxies.

I could continue down the list, as, there are other models in all of the classes I've mentioned, with varying degrees of accessory inclusion. All of the models mentioned here will be very good for observing a variety of celestial objects. Orion carries an entire line of accessories, from extra eyepieces, and solar filters, to planetary and deep-space digital CCD cameras and adapters. Your best bet, though, is to view their current, full catalog online, at telescope.com.

Unfortunately, they no longer provide a real, paper catalog! But, according to their associate, Rick, they will likely be back (as soon as people realize that, paper, is actually, a much faster, more intuitive browse than a screen!)

Dale Alan Bryant
Senior Contributing Science Writer
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Wednesday, May 22, 2019

The O-TEAM: A Thousand and One Nights

(Late - very, very late; one night in 1989...)

As one-third of that, one-time, an infamous trio of hard-core, dedicated, 'back-woods', 'MacGyver'-ish, observational astronomers: the 'O-Team' - Mike Petrasko, Muir Evenden, and myself, who's late-night and, sometimes, 'deep-freeze' telescopic adventures, back around 1989 (typically, in below-freezing temps) -- I would never, ever have believed that one day - our telescopes would be able to, practically, "take us by the hand", and give us a detailed, orated tour of the night sky - all by their artificially intelligent selves. Nope - that's the kind of thing that only happened in sci-fi films...

Moreover, how could any of us possibly have imagined, that, variable stars - those, peculiar stellar anomalies that are light-output, vary over periods of time, from about a few hours to several days, should turn out to be *variable* - because there were planets getting in the way! - by crossing the faces of those stars (as seen from our perspective)...of all things!!

Telescopes used by the O-Team on The Woods Hole Golf Course - Illustration by Dale Alan Bryant.
Telescopes used by the O-Team on The Woods Hole Golf Course - Illustration by Dale Alan Bryant.

Many times, over the "O-Team years", some 30-something years ago, I had made painstaking efforts at trying to capture such things, as, the North America nebula, or the galactic core in Sagittarius, on film, using a piggy-backed, 35mm SLR, loaded with Fujichrome 200, acetate slide-film. With a lot of patience, and, even more, practice, something like this could be gotten - in as short a span as 45 minutes - using the telescope, as a guide scope, during the exposure. I could never have imagined (not even in any of my wilder dreams) that, film - the conventional platform for photography, since its invention - the century, before last - would soon be replaced with the microchip capable of generating an equivalent image in 10-20 seconds - un-guided!!

Unfortunately: I have missed out - entirely - on the GOTO, computerized, Dobsonian-mounted telescope revolution: that is - the kind of amateur astronomical telescopes that are capable of repositioning themselves, by 'slewing' across the sky, via, computer-controlled, stepped servo-motors - to any celestial object in the heavens, using the celestial coordinates, right ascension, and declination - by converting them into their alt-azimuth counterparts - all on command!"...

I've never used one. In fact - I've never even SEEN one (at least, not 'in person').

No. My active days (or rather, nights) as an observational astronomer with the O-Team were the kind, where, in the cold months, you got dressed for the weather using three layers of outer garments, three layers of warm socks for your feet - wrapped over, with plastic trash bags to keep the warmth in under your boots - and, at least, one wool cap and a pair of mittens (mittens hold in heat better than gloves).

If you didn't look like you were ready to start training attack dogs - you were missing some clothing.

When you were finally ready - you disassembled your scope and packed it into the back seat, trunk, or bed of your vehicle, and - if you could, still, just slide into the front seat - you were ready to drive yourself, along with your gear, to one of your, very, best-kept secrets: a chosen, dark, secluded and, preferably, isolated observing site! (We actually had two sites that we frequented, but, one, in particular, was, by far, our preferred nocturnal "delinquency". You see: on many, many starry nights, you could find me, and my telescope (well - and, my truck!), and Mike and Muir, and their vehicles, perched on one of the fairways at the Woods Hole Country Club's plush, green carpet, of highly-manicured grass. To say that we were obsessed - well, that would be a really, really accurate statement...

On any, given, clear night, we would abandon the warm, blissful comfort of our cozy beds at around 12:00 midnight, and drive out to our, apparently, God-given observing station; or any party-cloudy night, for that matter - just in case. And if you've never seen the unlikely, ominous sight of a silhouetted Volvo, parked in the middle of a golf course in the middle of the night - before, well, you just haven't lived!

From our perspective, golf courses were built, and designed, for astronomers. They offer wide expanses of sky, and - serendipitously - are covered with a durable, and, surprisingly well-kept swath of grass - which, seems to run on, in all directions, forever! Now, what philanthropic soul had done this great service for science? (I never did believe in the rumors, that, they also used these green havens, for other, unimportant 'sporting activities', as well).

Here's how it usually went...

After arriving at the golf course, and, having driven, up, onto the fairway, you set up your scope and connected it, via, mini-jumper cables w/alligator-clips, to your vehicle's battery. This was to run the electro-mechanical clock drives, that, slowly moved the scope, in synch with Earth's rotation, across the sky to follow the particular celestial object you were observing. Muir used an 8-inch Celestron Schmidt-Cassegrain. Mike had an Edmund Scientific, 4.25-inch AstroScan, and I used an 8-inch Meade Newtonian reflector.

The next step was to set up the card table and lay everything out on it: a very good, laminated star atlas with reticle templates, a red-filtered, military-style elbow flashlight, eyepieces w/case, pocket shortwave radio, tuned to WWV (for timing anything you wanted to time) along with, Mrs. Holmes' home-made brownies, if you were fortunate enough - and pray that you didn't completely drain your vehicle's battery, by dawn. (There were actually statements, like: "Oh, well; if my battery dies, I'll just call a tow truck in the morning.", made, frequently...who cared?!)

Now, all this was usually set up near the frozen, ice-covered, first-hole putting green of the WHGC - regardless of winter, its threat of frostbite, or - of the threat of getting booted off the course by the local law enforcement. You see, we once (once?!) had a brief encounter with a police officer, who, was out on his rounds and, spotting, three, parked automobiles - in the middle of a golf course - had decided to drop by our private, highly-manicured observatory.

Having noted our three, rather large-ish, optical instruments, tables, chairs, ladders, and vehicles - electrical connections and all - the officer, slowly and cautiously approach our bunker, and asked, "What kinds of weapons", we were using to, obviously, protect ourselves against, the potential, horrors of the night sky. Naturally, we all-too-excitedly broke into a rather lengthy discourse about the myriad wonders - galaxies, nebulosities, etc., that we had seen that night, and offered him a view for himself; with such fervor and passion (which, he, apparently didn't share with us), that, he probably just couldn't wait to escape the bizarre situation.

Over time, they eventually learned to ignore us, entirely and, for the most part, we continued to have the WHGC, all to ourselves for our continuing, awesome onslaught of the universe, at large.

And that's how those days went.

But times have changed dramatically. Today, all this is done, remotely, with a laptop, or tablet, or even, smartphone - right from the comfort of your own bed!!

What will the next, 30-something years in amateur astronomy bring?.....

Dale Alan Bryant
Senior Contributing Science Writer
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