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No problem; I think it best, and certainly least expensive, to keep it simple Joel Send a noteboard - 25/01/2010 09:12:20 AM
Two basic things up front that you may already know, but definitely should before going further:

Magnification=scope focal length/eyepiece focal length.

So you want tubes with high focal lengths and eyepieces with low ones.

For deep sky objects especially, light gathering is the limiting factor, NOT magnification. You can always get a more powerful eyepiece (up to a practical limit; shortest commercial focal length I've seen is a 2.3mm that runs about $50 last I checked) but every time you increase the mags you're reducing the amount of light getting through, until you have a highly detailed image of pitch blackness. Since deep sky objects are already so faint that most require time lapse photography, aperture is our primary consideration (from the way you spoke above I suspect you know this, but want to be VERY sure. )

WARNING: Never view the moon at high mags, and never view the sun at all, even with a filter, unless you're tired of viewing ANYTHING!

Sometimes you can get the edge of a partially full moon at ~200X or so, but if it's all moon anything >100X is tempting fate. We sold a solar filter and I thought of using it once, until our manager reminded me that mass produced objects HAVE been known to be flawed in ways undetectable--until used, when they become blindingly obvious, in this case literally. If you must do it, use your camera; it may not be cheap to replace, but it CAN be replaced. And again, I know you're not an idiot, but some things I don't trust to chance (also, it's a public forum. )
Thank you for the information.

I noticed that there is a big price break at around $1500 and I certainly want to stay below that, but I wouldn't mind spending $1200 and I see that there are a lot of good telescopes in that range.

Quite welcome; I'm perhaps TOO willing to talk scopes. :<img class=' /> There are many good scopes in that range, yes, and unless you want a career in it I see little cause for more. Eight inch Schmidt-Cassegrain is my goal, and even if I could afford more I doubt I'd get it. For the money, going to 9.5, or 11, isn't THAT big an improvement, and while you can get bigger scopes, the decimal moves quickly, as you note. Back when I still sold them the biggest thing Celestron sold commercially was a 14" SCT with the works, and if you had $20k you didn't need, it could be yours in 6-8 weeks. Design is a bigger factor for the first one or two scopes you get than anything else, so it's important to decide if you want a refractor, a reflector, or a catadioptric (of which I think the Schmidt-Cassegrain is best, but the Maksutov is smaller and cheaper--in every sense. )

IMHO, you should go reflector on a budget unless you care about image orientation (astronomers don't, of course) and if you've got the cash to spare always go catadioptric, because it combines the best aspects of both reflectors and refractors, resulting in a scope that can produce several times the magnification of a similar sized reflector or refractor, and most commercial ones are fitted with some form of photographic aberration correction:

http://en.wikipedia.org/wiki/Catadioptric_system
For me there are several considerations:

1. I DO want to have a nice digital camera affixed somehow to take pictures of what I find and observe.

Sadly, I'm not as conversant on what digital cameras require; I didn't own one until Christmas (thank you, Maht. :)) You MAY be able to use them with a standard T-adapter and I want to say you can, but I'm not sure. A quick googling seems to confirm what I suspected, however: While some T-adapters may not be designed for digital cameras, there are plenty that can accommodate both digital and standard 35mm SLRs, so you should still be able to pick up 1) a T-adapter and 2) a T-ring to fit the camera to it for <$60. This Amazon link:

http://www.amazon.com/ScopeTronix-Digi-T-Digital-Eyepieces-Requires/dp/B0001YA9MY

(Not a direct link, but should get you there. )

offers the option of buying one or both of the required pieces, and also shows how they fit together on the scope; I'm not sure if you need the T-RING or just the T-adapter for a digital (you do for 35mm SLR) but you don't need more than that.
2. I need a good refractor lens due to urban light interference.

IMHO, you need a scope powerful enough to deliver what you want but still small enough to be semi-portable so you can throw it in the backseat and get away from light pollution. ;) That's another reason not to get a hideously expensive SCT that weighs 70 lbs. before you add the tripod. However, another good option is to get a kind of "shield" that goes around the far end of the scope and cuts a lot of glare; it won't help for glare at 10k feet though. Most refractors make at least a token attempt at this in front of the lens; reflectors are arguably DESIGNED with it, since the light passes the length of the tube before it hits a mirror, and light without a Pro Bowl safety-like angle won't make it to the mirror. Light pollution shouldn't hurt your contrast and detail much, but it can wash out your images entirely. Inability to resolve desirable light is one thing; having it overwhelmed by undesirable light quite another.

All Schmidt-Cassegrains have lenses; in fact, what makes them superior is 1) the Schmidt correction plate that removes aberrations formerly common in photographs and 2) that they combine both the refractors lenses and the reflectors mirrors, meaning a much shorter tube has a much longer focal length than either standard reflectors or reflectors. For example, my own 4.5" Newtonian has a focal length of... 917mm, IIRC, which is also the length of the tube (I'd bet money they made it exactly a yard, but anyway.... ) The Nexstar 5 is 2/3 size but has just over twice the focal length. In fact, I once had a customer who called all over TX looking for something to put on her balcony, and our manager assured her we had it, so she drove 200 miles only to find that the Wide Angle scope she wanted (Firstscope-80WA in the book) wasn't there, only Firstscope-80 (longer tube, normally good, but not for her. ) She THANKED ME for pointing her to the Nexstar 5, which, while three times the price, fit her balcony perfectly, with the same size, thrice the focal length and nearly twice the aperture of what she initially wanted. Funny tangential story I'll tell ya about that one some time; moral is "Never work for morons. " Actually, I only told her about the Nexstar to apologetically explain it was the closest we had to the $400 scope she wanted, and she decided on the spot to buy it, so the real moral is "Never assume you know what the customer wants. "

I recommend all Celestrons SCOPES (their eyepieces, IMHO, suck huge hairy donkeys) but I strongly suspect you're going to end up with an SCT anyway, so I see no sense in dropping a few hundred on JUST a refractor first (and dropping a few thousand would make Baby Copernicus cry. )
3. I DO want to observe deep space, if possible.

Honestly, I only just now realized how strongly deep sky aperture correlates with penis length:
<4.5" NO ONE wants to see,
6" is the minimum most DEMAND,
8" it starts being lots of fun and
>11" is probably wasted on anyone but a pro.

That amuses me no end, but don't let that fool you, 'cos in my experience it's dead on for telescopes. Eight inches will give you nice views of many things, and going bigger won't improve that much unless you go a LOT bigger. This is true in general of all designs, though you can get some pretty large but still affordable Dobsonian scopes because it's just a Newtonian tube on a swivel and a rotating base. Of course, it's hard to do tracking with a stick on a wheel, and if you don't time lapse 90% of the deep sky might as well not be there.
Obviously, a first step would be to plot planetary movement, lunar cycles and other similar things by using the methods outlined in the book reviewed. I'm also going to be doing the "low-tech" things such as building a simple sundial, etc. However, once I've done that I do want to start looking deeper into space.

If by "track" you mean plot on a chart, then a basic reflector like a Dobsonian should work, and probably as well as a refractor in any location. If you want to track them with the scope for photography or just convenience, you'll need the equatorial mount at a minimum, or a built in motor on a fork mounted scope. If, like me, you don't want to buy a half dozen scopes in your life, and know you're committed to deep sky viewing, your best bet is to bite the bullet and get the SCT now: You know you're going to, ultimately, and anything you buy in the interim is just inflating whatever that final cost will be.
When I read about telescopes, though, there are so many features I feel as though I'm buying a car but don't know how it works at all...I see things and wonder if the specs are the equivalent of "4-cylinder engine" or "V8 fuel-injected"...I just don't know.

Yeah, and I'd estimate fully half of it is bells and whistles designed for people who want to see the universe but have to label their shoes "left" and "right. " Celestron, Meade and (ugh... ) Orion make plenty of money off of those people; you and I don't need to further enrich them. ;) You don't need V8 fuel injection to go the grocery store, nor if you can make a DIY nitro rig in your garage (though the cops do prefer you use the V8 fuel injection. ;))

Honestly, if it were me (and if I weren't leaving the country to get married in six months it already would be... ) I'd say:

8" motorized SCT with tripod for stability, can be found in that $1000-$1500 range (the C-8 booked for $1200 new, but it's discontinued; you can still find them on EBay for $500, but caveat emptor)
T-adapter and possibly T-ring, ~$30-$60
camera, either 35mm SLR or digital; I can't quote you a price 'cos cameras ain't my area
a good star chart (the books with coordinates, not the little wheel you spin) that can be viewed by redlight, $15
a redlight (obviously) to protect your night vision while reading charts (in a pinch you can jerry rig this with a flashlight and something translucent and red) $10 and
a decent range of eyepieces, preferably Plossls or Kellners; they tend to be easier on they eyes when using them, and provide some correction for any distortion. Price varies widely from $50 for a set of basic ones to a hundred or more for something like the 2.7mm focal length Plossl I've always wanted (lowest focal length I've ever seen on the market. )

Camera's the only thing you can't get for <$100, and all but the lenses and T-adapter and T-ring can be had for <$20. If you've got the camera you could probably do the whole thing for <$1500, though you may have to shop around a bit (if you trust EBay you can probably do the whole thing for $600-$700. ) Sadly, you can go blind looking for a NEW Celestron 8" SCT that doesn't say "with patented Nexstar technology" somewhere in it's description, which is Celestron-speak for "you're about to pay a machine $500-$1000 to think for you. " Don't get me wrong, it's handy, especially if you're time pressed: Turn it on, it asks you the date, time and latitude, then it whirs around to the eastern horizon and asks you to fine tune it until some start that should be near the horizon is centered. Then it whirs around to the western horizon and does the same thing; from then on your telescope is calibrated until you turn it off: Type in what you want and it'll go straight there, and track it. That's pretty freaking neat, but if you can read a starchart and have fifteen minutes it's not worth hundreds of dollars. Anyone who can set a(n analog) clock can do it themselves (and, indeed, the earliest worm gear equatorial motors were essentially just clocks. ) Even if you DO have the cash... well, I'd rather have the 11" aperture instead if I'm gonna spend the money anyway. ;)

There are other optional toys; Celestron and Meade both sell colored eyepiece filters individually and in sets that will reduce some of the light getting through in exchange for accentuating detail (yes, Mars is red; most people want to see more than a big red circle. :P ) One nice but non-essential thing to have is a Barlow lens; they're small magnifiers, usually <5X on which eyepieces can piggyback, turning a 50X eyepiece into a 150X (Meade makes a very sturdy and compact 3X Barlow that's WORLDS better in both performance and design than the 2X that came with my scope; freaking thing's TWO PIECES, making it as stable as Cybil on crack. ) These can also usually be had for $20-$30, and if you go on EBay you can probably find one for <$10.

Another option I've never explored is a truss design you'll sometimes see in magazines. It's a bare bones but HUGE Newtonian; usually it's not even enclosed, just two big mirrors at opposite ends of a truss. The downside is you can't do all the tracking stuff; the upside is you can put a 30" aperture scope in your backyard for a couple grand. Not for the beginner though, IMHO.

I'm 95% certain this is the best way to go, and usually has the SCT designation (that's the primary one Celestron uses, and, obvoiusly, stands for "Schmidt-Cassegrain Telescope" )

http://en.wikipedia.org/wiki/Schmidt-Cassegrain_telescope

If you look at the diagram, assuming you haven't already done that much homework, you can see light first passes through a lens (like a refractor) then to a mirror at the rear, then BACK to a small secondary mirror in the center of the lens (like a reflector) then back down to the rear of the tube again and through the eyepiece. It's both a good and bad thing: Every time the light hits a mirror or lens you get more mags, but lose some light, and of course anytime you have a secondary mirror you'll lose a little of whatever's dead center in the field of view (however, the parallax of things in other GALAXIES makes this negligible, and because the mirror's in a lens you don't have to deal with the spidervanes on a reflector. ) That's the "Cassegrain" part; the "Schmidt" part is the Schmidt corrector plate for photography. Another option is the Maksutov, which does a very similar thing in a slightly different way, and usually has a bit shorter tube (great for portability) but always has a narrow field of view (this is bad. )

http://en.wikipedia.org/wiki/Maksutov_telescope

You may want to hit some star parties before you buy so you can compare the high end scopes in the field. There are various ones at various places and various times around the country, most always at a decent elevation in the middle of nowhere, and people come from around the country, sometimes around the world, with just about every telescope you can imagine. To borrow your car analogy, it's like a car show in many ways: People with more dollars than sense show up and show off; they'll not only LET you use their scopes there, they ENCOURAGE it. You can wander around all night from the guy viewing M31 in his 14" Mak to the guy looking at the Orion Nebula in his 20" SCT to the guy looking at the Pleaides in his 50" home made truss. You can also incidentally compare the advantages and disadvantages of each such telescope. ;)

End of the day I think you'll come back to a fork mounted motorized SCT with charts, camera adapter and lenses.

Sigh... if I weren't on medical leave for a dislocated shoulder I'd be VERY tempted to go out now; suddenly I see either my scope or the sky everywhere, and while it has it's downsides, one real upside of living in BFE is that it's fantastic for astronomy. On a clear night (which this is) you can see the Milky Way pretty well. Which reminds me: NOTHING makes glare like a full moon; if the moon is full and not just setting or rising, either enjoy looking at it or pick a different night.

Yikes, I really could go on like this forever; maybe I should just stop there until/unless you have more specific questions. I went with the 4.5" equatorially mounted Newtonian because it was our best (the Nexstar 5 wasn't out yet) but soon realized it was the most efficient buy without going SCT; you CAN do deep sky with it (just not much) and larger relecters are really just a poor mans SCT, IMHO. Next one I buy will be the 8" SCT, and it'll almost certainly be the last as well. That won't be cheap, but it's a helluva lot cheaper than buying a new telescope every couple years and winding up the same place for a lot more cash.

I really think refractors are overpopular though, so encourage astronomers to be wary of the pure refractor. No, they don't have a secondary mirror in the way, but Meade and Celestrons offerings obstruct very little vision (usually near single digit percentages) and, again, for deep sky objects the parallax is, well, astronomical, so it's not as big an issue as for, say, Jupiter. They do have sharper images, but other designs offer so much more light gathering for so much less money I don't think it's worth it. I'll illustrate it thus:

You can actually see Griffith Observatory from my best friends house, and when I visited summer before last we went, standing in line two hours for less than a minute viewing Saturn through it's 12" refractor. I could probably buy a modest house for what that thing would cost new (though maybe not in L.A. ) but, while I don't know what eyepiece they had in it, I've gotten better views with my 4.5" reflector in my backyard. If I can beat something that costs a year or twos income, for two weeks pay (at $6/hr, no less) maybe the refractor isn't the best bang for your buck. ;) However, in line with what I said above, there were about half a dozen SCTs set up outside ranging from 6" to 11" but unfortunately we were close enough on time (can't view before sunset, and the place closes at 9, I think--this was summer, mind) we didn't get a chance to look.

In retrospect I think this may have been a tactical error. It's too bad you don't live out there; we also went by Mt. Wilson (and Palomar; if I ever get to Yerkes I'll have seen all three of Hales biggest scopes, which were, in succession, the largest on earth from ca. 1890 until Keck) and learned you can basically "rent" a half night with a few friends on their 60". Granted, by "rent" I mean "donate a couple grand to the observatory" but still... 60" telescope! :)

You may want to bounce some of this off moondog, too; he knows the hardcore astronomy a little better than I, and knows photography better as well (95% of what I know about photography I learned solely to apply celestial photography, and have yet to apply. )
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Retrospective of What I Think We Both Want
This message last edited by Joel on 25/01/2010 at 09:16:11 AM
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If you can, try to get an 8" (or larger) aperture Schmidt-Cassegrain from Celestron. - 24/01/2010 11:18:05 PM 1361 Views
Wow...that's a lot of information. If you don't mind, I have a few questions. - 25/01/2010 04:20:40 AM 1002 Views
No problem; I think it best, and certainly least expensive, to keep it simple - 25/01/2010 09:12:20 AM 1114 Views

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