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Equipment Discussions >> Refractors

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rolandlinda3
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A True Light Travel Scope--Possible?
      #6178188 - 11/05/13 09:01 PM

I recently posted a thread asking about candidates. I got excellent comments as I reviewed the bidding again. My requirements for travel are this: light weight (don't need a significant tripod), reasonably wide field, and preferably 80mm in aperture. As someone noted on my other thread, I had posted positive comments as we employed an Antares 80 (f/6) overseas, and used it with a desk mount. It is essentially a short tube refractor. I will tell you, however, the weight of this class is about 1.5 - 2 times what it needs to be, which drives other parts of the issue (like tripods). And, most of the short tubers have a fixed dew shield or one not easily taken on and off easily/quickly.

There are expensive options, but I am not looking for pristine optics...just average with decent field and light weight. I tried to C90 and their are some small cassegrains or Maks that might work but using these in the field with a wide variety of users is a real problem when the focal ratio is f/10-13. I have a problem with that restricted FOV as well.

So, I have on hand and readily use a Stellarvue SV80 FM2 finder scope. It is not designed as a travel scope. But why not? So I wrote them. This is how I put it....

I need a 3 pound scope (it is 2.5 pounds). I need FOV for my use and the use of lots of newbies in far away places or even close to home. Why not change the optics (it actually makes the optics easier to produce) so instead of a 3.75 focal ratio we have a 5 or 5.5. Take the fixed dw shield and make a way for it to come off easy. Put a short piece of Vixen bar on the bottom instead of just treating the mating piece as a finder scope. Voila! Travel Scope! Less than 3 pounds, a rotating back, decent field...

I have not heard back. This kind of solution (for any vendor willing to fill the niche) gives you a modest performing refractor, very light weight, and it could fit on anything from a desk mount to a light tripod to stick. With 2 EPs and a diagonal you have a whole kit.

I wonder why someone does not do it? SV has the tube already. It is light and strong. Someone makes it. And, in the end, you also have a beginner scope that is very competitive but lighter than the standard 80 short tube designs.

So, I am interested to see if they hear me. I mentioned that my other thread got 600 looks in 48 hours. I think the market is there, but who am I? Just a user with a need.

In the meantime, I am taking my SV80 FM2 and making it my travel scope. It is cheaper than the short tube designs and vastly lighter. It is 1/4 the cost of the expensive options.

What do you think?


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178200 - 11/05/13 09:07 PM

Here is the link if you want to see scope and then go to the specs of what I am using as a temporary travel scope: http://stellarvue.com/f80.html

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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178396 - 11/05/13 11:22 PM

Quote:

What do you think?




Roland:

This is what I think:

The Orion ST-80 was mentioned several times in the previous thread. It seems like it fits your needs perfectly. The OTA is under 3 lbs, it's 80mm F/5, the dew shield slides off easily. They are rugged. It comes with a pad to mount the scope on a tripod. The barebones OTA is $120.. what is there not to like?

Jon


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core
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Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6178441 - 11/06/13 12:05 AM

Quote:

Quote:

What do you think?




Roland:

This is what I think:

The Orion ST-80 was mentioned several times




+1

It's already been available for many years, fits the criteria you've spell out, and priced right so that you won't have a fit when you loose or break one. Buy used, they are even cheaper. Celestron had one years ago (spotter version), orion has 2 versions of a 80mm short-tube, ioptron has them in several colors with tracking mount, and I'm sure there are many other generics out there.


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Derek Wong
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178583 - 11/06/13 02:40 AM

If you don't want a short tube 80 and have a strict weight requirement, you almost have to spend more money. Many of the nice refractors have bigger focusers and the 80mm ones are usually 6# or more. The lightest travel refractors are the Borgs - good optics, and break down into several pieces. You have several choices depending on price and aperture:

71mm fluorite - $1200 with a couple of extras
77 ED - $895 for OTA
89ED - $1395 for OTA

Borg stuff comes up for sale on Astromart at times and sells for a reasonable discount. I think the 77ED would be good for your needs.

The Borg fork mount is very light but is not the smoothest thing in the world. There will be a mount called the Free Turn 1 from Half Hitch mounts that will be 3.5# and only $395. Later, the company is thinking of making an even lighter mount.

Derek


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TONGKW
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178647 - 11/06/13 05:05 AM Attachment (40 downloads)

Here is my solution for a travel scope set up weighing about 10 lb total.
The refractor OTA weighing 3.25 lb. is made from the lens in cell from my William Optics 72 FD. I make a new tube with a simple helical focuser in place of the stock tube and 2-speed focuser.
A small Vixen guide mount with slow motion control on both axes (1.25 lb).
A Sirui T-1005X photo tripod (2.5 lb).
A 6x30 fincer, diagonal and 2 eyepiece (3 lb).

K W TONG
C8+CG5 GT, TSA102+HEQ5 PRO, MK67+Voyager, NexStar 6SE, C5+Mizar K, WO ZS80FD+Kenko NES, Megrez 72FD+Kenko KDS, Mini Borg 50, PST


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t.r.
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Re: A True Light Travel Scope--Possible? new [Re: TONGKW]
      #6178717 - 11/06/13 07:48 AM

What exactly is the little Vixen mount with slo-mo's? Where can it be purchased?

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TONGKW
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Re: A True Light Travel Scope--Possible? new [Re: t.r.]
      #6178733 - 11/06/13 08:06 AM Attachment (16 downloads)

I somehow call it “Vixen guide mount” though in the catalogue it is called “Item 3562. Piggyback Fine Adjustment DX”
http://www.vixenoptics.com/acc/indiv/3562.html

It is very stable when supporting my little refractor but it has limited travel in both axes. I have to build a simple “elevating platform” for it out of two pieces of aluminum angle.


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Eddgie
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178823 - 11/06/13 09:15 AM

The field curvature on these fast finders is pretty extreme.

If you care about wide field viewing with modern wide field eyepices, you may find that at f/3.75, it is impossible to keep the entire field in sharp focus, and that the outside will be so far out of focus that even excellent eyepieces will show astigmatism.

This is why the vast majority of finders are only really suitable as finders. You dont' really need your finding stars in perfect focus and in the vast majority of them, they won't be.

But that is not the supplied eyepieces doing it, it is the horrendus field curvature of the scope itself.

There used to be a samll Petzval you could get. Maybe William Optics or something. Much flatter field.

So, consider the field curvature carefully.

My own advice is that unless you are willing to take the risk on re-sale if it does not work out, you may want to find something with a bit slower focal ratio.

Or maybe not. Lots of people have told me over the years that they only care about performance at the center of the field, and if you are in that camp, then this small fast refractor may be perfect for you.


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6178902 - 11/06/13 10:05 AM

You are right, Jon. It is the closest thing to the Antares I used and almost the same weight. With diagonal and EP added plus a couple rings...it's 3.8 pounds plus a couple added. That puts it out of reach, however, for most light tripods. Outside of that, these are great.

I just happen to already have the FM2, and some of its features are unique that would be helpful. The scope with its diagonal and an EP are less than 3#. If I could get the vendor to buy into a couple changes, it would would further increase its suitability.

We use C8s a lot for outreach and training. So our FM2 ends up doing double/triple work. It is already set up for light/quick adaptation to scopes if not used separately. In our case, this helps.

Other options, as discussed on the other thread, are available, but the prices go up very fast. If you were with me going to some of these places, price and weight drive the train. It has to walk where I go, be put up in a hurry, and if its use incurs damage or I pass it to others, it has to be replaced without major financial cost. The Antares was a little to heavy but the price was right; the ST-80 falls in the same class.

It may sound minimalist, but some places we go, hardware is really scarce. And, when it is around, it might get used for something else. When you have a light system (meaning around 3#, you can actually mount a scope with one standard ring and attached the ring to a handle...the handle is bolted with enough friction to a board...you have just made a two axis manual mount. I have done this because the cost and size of a tripod (even a light one) plus the scope to faraway places gets out of control real fast. And, as previously said, the tripod is attractive hardware for lots of other things.

These are the sorts of things we work through when we go places. However, for schools and villages, if they actually make the little homemade mount, they "own" the solution and want to protect and keep it. So there is method to this kind of approach.


Edited by rolandlinda3 (11/06/13 10:22 AM)


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Stephen Strum
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6178944 - 11/06/13 10:31 AM

One version of the ST-80 has a vixen rail attached to the optical tube, so rings aren't needed. Orion still lists it as 3.8 pounds, the same as the one with rings, but perhaps someone can chime in if the weight is actually less than that. Perhaps it might be closer to 3 pounds. Plus, if you take the dew shield off and instead use a piece of black foam or poster board or something and a rubber band for a dew shield you would probably save several more ounces. Maybe someone can weigh a stripped down version like that.

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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6179061 - 11/06/13 11:43 AM Attachment (25 downloads)

Quote:

You are right, Jon. It is the closest thing to the Antares I used and almost the same weight. With diagonal and EP added plus a couple rings...it's 3.8 pounds plus a couple added. That puts it out of reach, however, for most light tripods. Outside of that, these are great.




I am not quite sure where you are getting your numbers.. I happen to have four ST-80s, I just weighed three of them with diagonals, all three were within an ounce or two of 3.0 pounds.

For a photo tripod, the included mounting blocks are effective. As far as rings, you only need one ring, not two.. My favorite ST-80 has a two inch focuser, I work it at 200x on doubles, one ring is plenty stable...

An ST-80 has a real focuser and a very reasonable focal ratio that is workable at higher magnifications. I use them as loaners on lightweight photo tripods and they work and certainly are at F/5 are far more capable than an 80mm F/3.75 finder, I have one of those.. as Eddgie says, field curvature is nasty and at moderate to higher magnifications the CA is devastating.. but I guess you probably know that.

Jon

(Photo of Ioptron ST-80 fitted with Orion focuser on Fairfax $10 garage sale, 3.0 pound tripod, it all works and weighs 6 lbs total)

Jon

Edited by Jon Isaacs (11/06/13 11:43 AM)


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desertlens
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6179522 - 11/06/13 03:49 PM

I'm using the scope shown for my super portable option: a 60mm SV finder on a monopod. It's true that an ƒ3.75 finder will have significant field curvature but some eyepieces are helpful. Naglers and ES82s seem to have a complimentary FC that is very corrective. The 14 and 18mm ES82s are especially nice. Orthos also do well since I suspect they sweep much of the problem under the field stop. The setup in the photo gives me 9x and a TFoV of 4.66º. It is also very flexible with EP choices and filters. The setup weighs about 4.2# including the monopod. Due to hand held issues, the monopod limits me to about 18x (a 12.5 ortho) but I'm OK with that.



Edited by desertlens (11/06/13 04:07 PM)


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jrbarnett
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Re: A True Light Travel Scope--Possible? new [Re: Eddgie]
      #6179900 - 11/06/13 07:53 PM

To me even more problematic than the FC is the almost non-existent diffraction limited depth of focus with such scopes. We're talking microns that can be counted on our fingers and toes. Good luck with that, using a cheap focuser such as is often shipped on such OTAs.

- Jim

Edited by jrbarnett (11/06/13 07:55 PM)


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Derek Wong
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Re: A True Light Travel Scope--Possible? new [Re: jrbarnett]
      #6179918 - 11/06/13 08:09 PM

While you are using the finder, you can look for a Borg 77 Achromat. They are uncommon on Astromart but sell for $250-$350 and are likely to be substantially lighter than a short tube.

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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: jrbarnett]
      #6180048 - 11/06/13 09:39 PM

Quote:

To me even more problematic than the FC is the almost non-existent diffraction limited depth of focus with such scopes. We're talking microns that can be counted on our fingers and toes. Good luck with that, using a cheap focuser such as is often shipped on such OTAs.

- Jim




The depth of focus at F/3.75 is about 30 microns. To get a good focus, that does require a top notch focuser. But really, with an 80mm F/3.75, focusing would be done for individual colors, not the entire spectrum.

One thing about an F/3.75 scope, if you are using a 1.25 inch focuser, optical length of the drawtube plus the diagonal can only be about 4.5 inches, otherwise the drawtube cuts into the light path. Since a 1.25 inch diagonal has an insertion length of about 3 inches, that means a 1.25 inch Drawtube..

My University Optics 80mm finder is F/3.75 and setup to focus with an RA diagonal. It had a short focuser but it was long enough that the effective aperture was only 60mm.

Jon


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Rich
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Loc: Seattle
Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6180271 - 11/07/13 12:54 AM

How about this option? Specs say 3.5 lbs total including mount and tripod. Only 70mm, but at F5.7 could be better than 80mm F3.75. I do not own one so can't give first hand experience with it.

My 80mm Stellarvue NH weighs about 8+ lbs just for the OTA, so I have wanted to get a much lighter setup for hiking or other high mobility activities.

http://www.telescope.com/catalog/product.jsp?productId=102397&gclid=COTGi...


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CarlDD
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Re: A True Light Travel Scope--Possible? new [Re: Rich]
      #6180404 - 11/07/13 06:33 AM Attachment (16 downloads)

Hi Roland
I use a Borg 77 Achro as a travel scope. Instead of a tripod, I travel with a Car Window travel mount and improvise. The attached photo is the Borg 77 equipped for Solar H alpha. The improvisation was a locally purchased G Clamp.


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jrbarnett
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6180833 - 11/07/13 11:36 AM

$40 with tripod and backpack.

http://www.bhphotovideo.com/bnh/controller/home?O=&sku=681818&Q=&...

$63 for a little more aperture in the same basic set-up.

http://www.amazon.com/Celestron-21035-70mm-Travel-Scope/dp/B001TI9Y2M

It might be interesting to try one of these and see if it would work for your purposes. If so, you could almost afford to drop-ship a half dozen or so to the nearest larger city/town and have spares in-country to take into the bush. You could actually afford to leave them when you depart, which might be appreciated by your outreach guests.

Regards,

Jim


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desertlens
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Re: A True Light Travel Scope--Possible? new [Re: jrbarnett]
      #6181214 - 11/07/13 02:41 PM

Quote:

...even more problematic than the FC is the almost non-existent diffraction limited depth of focus...




Jim makes a valid point here. One of the things I like about the 60mm SV finder is the "slow" thread of the helical focuser which helps a lot in this regard.


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: desertlens]
      #6181350 - 11/07/13 03:57 PM

Great posts everyone. I might try some of these ideas when I accumulate some more funds. By the way, the SV 80 finder is like the 60...it has a helical focuser. I am really not so set on the 80 FM2, so don't think I am not willing to try something, but it is a decent focuser that is "tied" to the diagonal...that is set on the rear piece of the tube that is easily rotatable. There is no "draw tube" in a classic sense. In any case, it is a convenient arrangement.

The Celestron travel scope that Jim mentioned looks good, and I am not familiar with it. I know the tripod is junk and pieces a plastic, but if the optics are average and I can point the thing, that means a villager "outback" can do it. Don't know how tough it is and amazon reviews are generally from non-regular observers, so I cannot read to much into the ratins. Does look like a possibility.

Several have suggested things below 80. While I would like to look at the little 70 travel scope, one reason I don't go much below 80 is because we get better bang for the buck by simply using an affordable binocular. You have to think in terms of schools and way out there. It's not a straightforward decision in developing regions: do you want a 60-70 refractor or a 8x42 binocular? Our kits generally have both a small refractor and a binocular. If I could take only one and I am really cramped, we usually opt to take 8x42 binoculars (bushnell H2O) or even 7x35 (bushnell Falcons), 68 and 25 dollars respectively. Serious observers in the developed areas usually laugh at this, but they generally don't go where we go...and usually don't understand the local limitations. Believe it or not, this solution works when a scope can't be shipped in, and still covers a lot of ground.

Thanks again, all. BTW, Stellarvue did get back to me but no real revelation. Their lighter weight 80 is nice and would fit the weight class of the short tube designs; their optics are very good. The price is much higher, however. For me in this nice developed calm region with money, it's fine like many others. In the backwoods in the Philippines and Uganda...nope.


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terraclarke
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6181411 - 11/07/13 04:31 PM

I too vote for the ST80. I had the Orion one for years. I sold it when I got my AT72ED because that became my new travel scope, but even though the Orion had a larger aperture, it was considerably lighter. It used to easily fit in a suitcase and was light enough it didn't shift around. It gave great views too. The most bang for the buck of any telescope I have ever owned. Actually, I kind of regret selling it.

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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: terraclarke]
      #6181997 - 11/07/13 11:07 PM

I hear you. And the others. Probably will get one in any case. Same thing happened to my wife and me with a C8. We eventually put it in service in a Philippine school, but turned around and bought one for ourselves...then two for our little home-based ministry use. One will go to Mexico and we use the other for training. Reasons are similar to the refractor story: its portable; lot of aperture with light weight; easy to replace (for that size), and an ideal scope for the next level after beginners with a little refractor. It ends up being the primary scope for a school or community...but they go back to a little refractor for more constant use by students. The ST80 will probably be our choice since the Antares 80 is getting harder to come by.

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MooEy
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6182160 - 11/08/13 01:31 AM Attachment (12 downloads)

did someone mention borg?

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munchmeister
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Re: A True Light Travel Scope--Possible? new [Re: desertlens]
      #6183132 - 11/08/13 02:58 PM

Quote:

I'm using the scope shown for my super portable option: a 60mm SV finder on a monopod. It's true that an ƒ3.75 finder will have significant field curvature but some eyepieces are helpful. Naglers and ES82s seem to have a complimentary FC that is very corrective. The 14 and 18mm ES82s are especially nice. Orthos also do well since I suspect they sweep much of the problem under the field stop. The setup in the photo gives me 9x and a TFoV of 4.66º. It is also very flexible with EP choices and filters. The setup weighs about 4.2# including the monopod. Due to hand held issues, the monopod limits me to about 18x (a 12.5 ortho) but I'm OK with that.






PMJI, but I love this idea, with the monopod. Might even be able to use the monopod with and ST80 or AT72ED.

Attaching a long cord/ string to the monopod, with something on the end that you can step on as you are using a monopod, can help a great deal with steadying a monopod and is a very cheap solution. I've used that with a camera on the monopod and it should work ok with a wide field scope. Of course, a light tripod works well.


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desertlens
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Re: A True Light Travel Scope--Possible? new [Re: munchmeister]
      #6183331 - 11/08/13 05:24 PM

I've tried the monopod with my SV70ED and it works pretty well at low mag. I do think that the helical focuser works better in this application. It's just more convenient and less "in the way". I suspect the OP needs a diagonal and a mount that will allow for more mag but thought I throw the idea out there anyway. I had an excellent session with it last night: the entire sword of Orion with an 18mm ortho and a narrowband filter (yummy). I have a narrow IPD and use this as an alternative to binoculars. I usually sit with it, shorten up the monopod and rest it on my seat for stability. The big advantage for me is the flexibility of the 2" helical focuser with eyepieces and filters.

Edited by desertlens (11/08/13 05:43 PM)


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: desertlens]
      #6200552 - 11/17/13 07:19 PM

We did get the little ST80 for evaluation, and we like the package. It is not quite as beefy as the Antares that we had and still use overseas, but it is lighter, a little smaller, the EPs (couple of Expanse EPs) are much better, the finder scope (8x40) is much better, and the price is right (less than 180 for the OTA, rings&dovetail, 2 EPs, finder scope, and a soft pack). Focuser is tight and smooth. I will test it tomorrow but I doubt it has an issue of any mention. Last, I can get it easily and replace it easily...part of our requirement. Thanks to those who kept suggesting it.

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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6201125 - 11/18/13 06:15 AM

Quote:

We did get the little ST80 for evaluation, and we like the package. It is not quite as beefy as the Antares that we had and still use overseas, but it is lighter, a little smaller, the EPs (couple of Expanse EPs) are much better, the finder scope (8x40) is much better, and the price is right (less than 180 for the OTA, rings&dovetail, 2 EPs, finder scope, and a soft pack). Focuser is tight and smooth. I will test it tomorrow but I doubt it has an issue of any mention. Last, I can get it easily and replace it easily...part of our requirement. Thanks to those who kept suggesting it.




Roland:

If you find that you have issues with the focuser, I can give you some tips on how to improve the action without too much effort..

These are wonderful for all around usage and actually make quite good spotting scopes for observing birds and wild life during the day.

Jon


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6204316 - 11/19/13 06:16 PM Attachment (15 downloads)

First, Jon, I will take any suggestions you have. It looks like the screws on the focuser can be tightened a bit to give a little more resistance, although mine seems fine right now.

Second, for anyone reading the thread, the ST-80A OTA "kit" that I got was tested last night. The picture shows the OTA kit on the Antares desk mount (we had an extra from the Antares refractor kits that we use overseas). As expected, it is a keeper for a quick and light scope. A couple foibles I found surprised me: the EPs that were included get mixed reviews. The 9 mm Expanse is OK, but the 20mm is just not right. I know the scope is fast, but the EP accentuates the errors unacceptably. A much better choice for EP (and smaller + lighter) is a typical Meade or Celestron 15 or 25 mm EP with a typical 50 deg field. The view is much better...whether terrestrial or astronomical. As you would expect, the field is really fine to about 2/3 away from center, then it gets a bit flaky. That said, it is much lighter than other 80s and tough enough to stand some abuse. This kit had a standard Orion star diagonal, which is OK. I also have an old erect-image diagonal, which worked just fine also. Weight for OTA stripped is 3.8 pounds but it is really 5+ when you add the rings/small Vixen-style bar, diagonal, and EP. The pack with it can pretty much fit everything.

Yes, we would recommend it to newbies rather than a "Walmart-special" variety of scope and it will serve our purpose "outback" and overseas. Consistent with my previous comments, I would not go for less than 80mm. I tested alongside of a 4 inch SV102ED (much better of course) because I wanted to see how the 20mm Expanse EP did with better optics. But the test also reminded me that 80 is about as little light gathering as I want, or I would use a binocular instead. That conclusion is not for everyone, of course, but it is appropriate for our range of use and application.

Thanks everyone. Go buy one if you have not. And, hang on to those "cheap" EPs with standard 50 deg field and any diagonals because they work with this little one just fine. The bare OTA price is well worth it, as others testified, and it's decently light.


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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6204326 - 11/19/13 06:23 PM

Roland:

Indeed, the Expanse series is manufactured by Synta, it's one version of the generic Synta 66 degree Widefield. There are four of them, the 20mm, the 15mm, the 9mm and the 6mm. I have owned them all, multiple examples of most.

The 20mm and the 15mm seem to be modified Erfles and like an Erfle, are quite poor in a fast scope but quite wonderful at F/13.. The 9mm and the 6mm are quite different. They are very similar to the TMB Planetary eyepieces (the varies pieces can be swapped between them) with a negative Barlow-like front section and a magnifying rear... that negative-positive design with Barlow-like front section makes for better correction in a fast scope.

Jon


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rolandlinda3
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Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6204677 - 11/19/13 09:21 PM

That is very helpful, Jon. We use C8s all the time at home or in outreach, so I will just use the 20 with the f/10s. Even at f/7 on the 102 is was not the best but sounds like it will do fine on the SCTs.

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core
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6204786 - 11/19/13 10:22 PM

imo a 8x40 finder is not necessary on the ST80, even more so when your criteria is "a true light travel scope", a 1.25" 32mm Plossl will give 12.5x and 4° FOV. A RDF would be much better suited for the ST80.

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Pete-LH
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Re: A True Light Travel Scope--Possible? new [Re: rolandlinda3]
      #6205182 - 11/20/13 07:19 AM Attachment (9 downloads)

Just a couple notes on my part.
I have been looking for a small scope to be both a finder and a wide field addition when using my SCT(s).

I found the SV Finders to be nice as finders but do have the issue with curvature.

I have gone to the Baader Vario (f/4.1) which seems to be better. It has a combination sliding tube RACI 45 deg diagonal and helical focuser. I have tried it with my TAK 1.25 inch diagonal and get great views with my TV 32 deg Plossl (6.2 deg , 8X) and 11mm Nagler (3.42 deg, 23X) and even higher magnifications. In the latter case I could only focus with the sliding tube but I plan to get the Baader diagonal with a helical Eyepiece focuser.

I have also used the older small fast SP series of refractors, in particular the 60S(f/8) and this gives very nice views. Now I have a Vixen 70S guide scope which is reported to be f/6 (I need to check this because all of the other S series scopes were f/8).

I sold the 60S in a moment of weakness.

I have checked both the Vario and 70S on a Camera tripod and I think they are great. I use the 70S with my C9.25.

I am looking for the Fluorite FL70S (F/8). If anyone is interested in a sale or trade please let me know. I think this was Vixens best series-even the R&P focuser.

The Baader Vario can be relatively expensive but I have considered The Tak 60C and Borg 71FL(Still considering) and it is less than half of these. The lens is made Zeiss. I bought mine used. One downside-The diagonal has an illuminator with ten brightness settings and there seems to be no low setting which I prefer. But the brightness of the image and the fine crosshairs make the illuminator no a necessity.

Here is a pic of both scopes.


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t.r.
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Re: A True Light Travel Scope--Possible? new [Re: Pete-LH]
      #6205213 - 11/20/13 07:58 AM

I had forgotten about the Baader Vario, that would be a cool travel scope as well me thinks! But, like the OP, I feel 80mm is about the minimum for most and I personally really like what happens at 90mm, which IMHO is the best compromising package of all!

Edited by t.r. (11/20/13 08:02 AM)


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curiosidad
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Re: A True Light Travel Scope--Possible? new [Re: t.r.]
      #6206015 - 11/20/13 04:18 PM

Televue 60 maybe ?
Regards.


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JKoelman
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Re: A True Light Travel Scope--Possible? new [Re: curiosidad]
      #6206562 - 11/20/13 09:49 PM

Quote:

Televue 60 maybe ?



Wish that gadget had a 2" focuser...


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JKoelman
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Re: A True Light Travel Scope--Possible? new [Re: JKoelman]
      #6206568 - 11/20/13 09:52 PM

Anyone who has experience with TS's RFT905? In essence an ST80 on steroids: 90 mm aperture, decent 2" focuser, retractable dew shield: http://www.teleskop-express.de/shop/product_info.php/info/p5616_TS-90-500mm-R...

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Kon Dealer
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Re: A True Light Travel Scope--Possible? new [Re: JKoelman]
      #6207081 - 11/21/13 08:27 AM

Yes- a Kson 102ED f/6 See this thread.
http://www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/6198675/page...

CF OTA weighs 5.7lbs and is under 21" long with dewshield withdrawn.


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t.r.
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Re: A True Light Travel Scope--Possible? new [Re: JKoelman]
      #6207147 - 11/21/13 09:03 AM

Quote:

Anyone who has experience with TS's RFT905? In essence an ST80 on steroids: 90 mm aperture, decent 2" focuser, retractable dew shield: http://www.teleskop-express.de/shop/product_info.php/info/p5616_TS-90-500mm-R...




THAT is a cool ST! Thanks for posting it. OPT looks like a dealer for Telescope Service...I have an interest in these small, portable, inexpensive scopes. 90mm to me, really is a sweet spot! I love comparing them and seeing what they are capable of. I play with them more than my larger scopes really due to work, time contraints, yada yada...oh, to be retired! I'll be inquiring with OPT!


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Re: A True Light Travel Scope--Possible? new [Re: t.r.]
      #6207199 - 11/21/13 09:41 AM

FYI Teleskop Service ships worldwide.

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curiosidad
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Re: A True Light Travel Scope--Possible? new [Re: nicknacknock]
      #6207233 - 11/21/13 10:05 AM

Hello,
Some time ago I read in a forum of astronomy any comments on the image you provided and apparently said they gave the best image of M42 of the telescopes there present, including an 8-SC "and some other newton 10", giving a mixed picture, clean, nickel .. like no other.
In the words of the author of the post. M42 the best he had seen ....
A greeting


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Pete-LH
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Re: A True Light Travel Scope--Possible? new [Re: t.r.]
      #6207316 - 11/21/13 10:50 AM

TR, Please post what you find out at OPT. I am interested as well.

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t.r.
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Re: A True Light Travel Scope--Possible? new [Re: Pete-LH]
      #6207796 - 11/21/13 03:43 PM

Ixnay the scope at OPTWAY!
Telescope Service accessories only due to trade agreements.


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nicknacknock
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Re: A True Light Travel Scope--Possible? new [Re: t.r.]
      #6208623 - 11/21/13 11:52 PM

As I mentioned, TS ships worldwide. Just take out the VAT from the price and you have your price before shipping.

Just email them as they are quite prompt in replying to queries. Bought some things from them in the last year. Quite happy with them..


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Re: A True Light Travel Scope--Possible? new [Re: nicknacknock]
      #6210263 - 11/22/13 09:10 PM

Just forego all this drama - buy a Questar.

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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: Glen A W]
      #6210374 - 11/22/13 10:14 PM

Quote:

Just forego all this drama - buy a Questar.




Not a good widefield instrument... same problems as the 90mm Celestron Mak.

Jon


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Glen A W
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Re: A True Light Travel Scope--Possible? new [Re: Jon Isaacs]
      #6210383 - 11/22/13 10:22 PM

You are right - I know he mentioned the Maks in the OP. I just couldn't resist. It seems the Questar pushers are a dying breed.

I have a cheap 4.5/500 reflector that seems about as good as anything for a cheap portable RFT. Somebody actually gave me five of them back when the economy was booming and the Chinese were flooding the market.


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Jon Isaacs
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Re: A True Light Travel Scope--Possible? new [Re: Glen A W]
      #6210390 - 11/22/13 10:27 PM

Quote:

You are right - I know he mentioned the Maks in the OP. I just couldn't resist. It seems the Questar pushers are a dying breed.




I had a feeling that you were not serious..

Jon


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