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Small multi-use refractor questions

Started by hemismith, 07/15/2005 07:51PM
Posted 07/15/2005 07:51PM Opening Post
OK, the age-old discussion again, but after reading what I could here I still have a few questions. Here's the scenario:

I would like a small refractor, not for astrophotography, but just for wide-field views, daytime use, and hopefully quick looks at the moon and planets. Alt-Az mount only. Airline portability is desired. Cost is a factor.

So here are the questions:

It seems the Orion 80 ED is the best all-around optical value, but it doesn't fit on an airline. So basically it appears we have the 80 mm SV and 80 and 66 WO options. The WO APOs are basically twice the cost of the "achros" (no more "semi" discussions here). I think the 80 APO is out of my budget. The 66 mm APO is just a little more than the 80 achros. I figure they could both probably be pushed to similar powers? I'm not sure how much color will bother me; FWIW I already have a v-block filter. The 66 could get by with a lighter mount. So: 66 Petzval (much cheaper), 66 APO, 80 Zenithstar, 80 Megrez, 80 Nighthawk, which shall it be?

Next, what kind of a finderscope, if any, should I get? Perhaps both a red-dot and small 6x30 on a dovetail mount? Do I really need one?

What kind of tripod/mount? I don't want to spend more than the scope. I guess daytime and nighttime have different needs, but a single one would be preferable. I assume I would need some kind of slow motion controls. I've heard the slow-motion heads for photo tripods aren't too great. How about Orion's AZ-3? It's probably not too good for daytime though -- does it have any kind of fast-motion option?

Thanks very much!

Posted 07/15/2005 09:12PM #1
My two cents:

Skip the finder. With such a small scope, and a reasonably low-power eyepiece, your FOV could easily be >4 degrees (maybe 6 or more).

Similarly, I'd skip the slow-motion controls. If the mount is reasonably smooth, they shouldn't be needed at reasonable magnifications.

For Astronomy:

I'd go for the larger aperture, if it otherwise fit my needs. 80 vs 66 mm gives almost 1.5x the light.

I don't know much about small mounts, but you should consider if a DSC like the compact Sky Commander can be fitted to it.

Allen
Posted 07/15/2005 09:12PM #2
So here are the questions:

It seems the Orion 80 ED is the best all-around optical value, but it doesn't fit on an airline.
----

It is my understanding that the ED-80 can fit as a carry on with a small amount of effort, the light shield needs to be taken off is all....

Jon
Posted 07/15/2005 10:56PM #3
I agree with the skip-the-finder advice, at least for now. Spend that money instead toward a wider angle eyepiece around 30mm. Even a decent plossl will give moderately wide views, wide enough to find things.

I have a TV-85 with one of their little 1x finders and I haven't replaced the battery in years. (Maybe I should sell it. Anyone interesed?) Learning to star hop is easy to learn, and a useful skill, even if goto is down the road.

For a similiar price as the Orion AZ mount, you can get a used vintage japanese equatorial mount on the astromart classifieds. It may take a few weeks but they show up. Eventually a better mount will become desirable.

The only thing wrong with censorship is [deleted].

Posted 07/15/2005 11:43PM #4
One scope does all is always a though call. A WO 66 Terrestrial pkg is probably a good deal at $295 if you're expecting to be doing mostly daytime viewing (since its complete with diagonal, eyepiece, and case; and is lighter for your small tripod). The 45deg diag may be a pain in the neck for stars/moon/planets, and the 66 won't be much in terms of light grasp. Of course the 80mm isn't too much better in terms of light grasp... The WO Megrez II 80 SD (WO says they may have a promo pkg on ZenithStar in Aug too... Megrez SD is slighter better optically, but ZenithStar is slightly nicer mechanically) is good at $599 if you're doing more astronomical viewing, since its complete with nice 90deg diag, ok finder, and case, but needs eyepiece. Of course, you might not like the 90deg diag or the left/right flip for terrestial viewing, so you may want to get a 45 deg diag also... Then of course the Orion 80ED is best optically, but lowest of all mentioned in terms of mechanics, but still with nice focuser, but you'll end up with a BIGGER scope, and will need to buy diag, case, etc... For low powers, a photo tripod such as Bogen 3021 or heavier with a fluid video head - 3126 or better is good. Of course, with the video head, you'll have to tighten the knobs quite a bit when scope pointed high and you'll have quite a bit of backlash at moderate to higher powers (40x - 100x)... You chooose. There is no PERFECT one solution!
Posted 07/15/2005 11:52PM #5
... for lower powers, a red dot finder is perfect... No finder is alright, as long as you have at least a 3deg field (4deg + even better; i.e. 15x - 20x with wide angle 65AFOV or better), otherwise it gets frustrating especially looking at the sky...
Posted 07/16/2005 01:21AM #6
Thanks for the responses and great advice and info; some good stuff to chew on.

I currently have a Parks Gold 30 mm Plossl and Lumicon 1.25 diagonal. The FOV with this will be about 4 deg with the 66 and 3.3 with the Zenithstar 80, a bit less with the others. I can't get much wider without going to 2", and at the time I bought those I couldn't justify a 2" setup. It sounds like it would be nice to have the wider field without a finder, in which case it may be worth getting a WO package that includes a 2" diagonal. I need a 45 deg diagonal as well though. I'll have to do research on 2" eyepieces to see if there's anything decent that's reasonably priced. Of course, all my filters are 1.25 as well though. One thing always leads to another in this hobby!
Posted 07/16/2005 01:49PM #7
Craig,

One option that hasn't been mentioned yet is the 100ED Borg. It's designed to readily break down for airline travel and gives extra aperture. Extra aperture can have a greater affect on crisp views than paying the extra $$ for a triplet.

Reviews of the scope have been quite good, and I'm thinking of picking one up myself.

Right now, I use a Stellarvue Nighthawk paired with a Unistar Light and love it. The small amount of CA doesn't bother me on wider views, though it can be a little distracting at high powers. The mount is smooth enough that slow-motion control is not missed. Equatorial mounts take up space, and take more time to set up, which makes less suited to 'grab and go' status.

-my two cents.

-David
Posted 07/18/2005 01:06AM #8
Thanks very much. Interesting options. I'll have to do some more research to figure out what the final cost will be for all of them. At any rate, it's clear that there is no such thing as a one-size fits all solution, at least not cheaply.

I have one follow-on question that I'll post as another thread.
Posted 07/18/2005 04:31PM #9
I'm surprised no one has mentioned the Orion 80mm short tube, which retails for $200 and is occasionally on sale for $150. I had one several years ago and sold it, but wish I hadn't as the stars were pinpoints. Contrast was very good (but not great) and it made a good daytime scope as well. I've read that putting a barlow in front of the diagonal can give you 110 to 130 power without the image breaking down.