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Toy Store Refractor Alt-Az Mounts

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#1 E_Look

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Posted 09 July 2009 - 10:01 PM

Has anyone tried to improve or fix the wobbly alt-az mounts that most often come with those cheap 60 mm refractors?

I really wonder what kind of images I can get from their optics, if I can get the images to stop moving all over the place.

#2 gnowellsct

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Posted 09 July 2009 - 10:29 PM

I fixed the one that my wife had from her teenage years. It had been in the closet a long time. I advertised it on Astromart and tried to give it away in my club.

Finally I fixed it by putting it in the trash can.

A more serious answer to your query is that there are 60mm cheap scopes and 60mm cheap scopes. Some are so bad as to have plastic lenses, some not. But there are people who have played with them and the general view is that they do a lot better when they are remounted.

But that this is still not saying much.

Greg N

#3 E_Look

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Posted 09 July 2009 - 11:11 PM

Aw, come on. I kind of can't bear to part with it as it was the first scope I got a glimpse of Saturn and Mars (never mind the moon) with. It took quite a while, but when I finally figured out how to EFFECTIVELY focus with that nearly impossible to use focuser, that little breadcrumb sized image of Saturn blew me away! And, no, it doesn't have plastic lenses; they are glass. However, the two 0.965" barreled eyepieces, 12.5 and 4 mm, whatever their design, afford just about no eye relief, and I've just realized that the 4 mm is useless, as 118x is about as large a magnification as 60 mm (~2 5/16") can yield, and the 4 mm produces 175x.

Ah, back on topic- the worst part is that after the locking screw that holds the mount stem to tripod is tightened, the mount still wiggles (a lot).

So, to be slightly more specific, I was wondering if there were any modifications that could be done to it to minimize that rocking. As just about everyone knows, there are other problems with it, too.

#4 SkyscraperJim

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Posted 10 July 2009 - 09:48 AM

Orion sells a small GEM for about $100 (probably more than the scope originally cost) and you can get a 0.965"/1.25" diagonal to use 1.25" eyepieces. I also think you can still buy decent quality 0.965" eyepieces from some sources, but I'm not sure where.

#5 KWB

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Posted 10 July 2009 - 09:57 AM

Hi

Exactly what model scope do you have?

#6 oldtimer

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Posted 10 July 2009 - 10:23 AM

Was it the model that had the 4mm symetrical eyepiece and 3X barlow that produced 600X?

#7 E_Look

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Posted 10 July 2009 - 11:17 AM

Yeah... heh... the Barlow was useless, a plastic Barlow.

It's an old EduScience 60 mm aluminum tube refractor, with the plastic rack and pinion focuser. I've heard folks here complain about focuser slop; this focuser's track moves all over and cannot hold a position... for too long.

So, the mount and tripod is not all there is that is wrong with it, but the focuser I can adjust myself to, but inability of the tripod-mount interface to hold the OTA without shifting is basically impossible to ignore.

And until I can lick the mount issue, only the supplied eyepieces, or maybe the Plössls that came with my Orion scope can work, as the other EPs I own are TMB Planetaries and one Stratus, which is even heavier than the TMBs.

I'll bet the objective lens isn't too bad; if I use a "real" EP, I might be able to get a decent image with it.

I wonder if I can insert some kind of O-ring or some such to steady the mount in the tripod.

#8 gnowellsct

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Posted 10 July 2009 - 05:54 PM

Well then I would say get some mounting rings and put the 60mm on your FS152 or your C14. That would be very solidly mounted and lead to some good observing.

Honestly, these things are compromised in almost every which way, you're better off starting from ground zero. The other thing I noticed about cheap stuff is that it is designed to be cheap. That sounds silly. I have messed around with cheap stuff and discovered that when you try to attach it to high end stuff you often run into unforeseen problems due to the fact that the cheap stuff almost falls apart in the presence of uncheap stuff. So cheap stuff is designed not to be upgraded, in a sense. I ran into this issue on an old Newt which wasn't even that cheap.

Anyhow, I'm sure you can come up with something. For one thing you could glue the 60mm at a 45 degree angle, use some strong RTV. Now extend the tripod legs and bolt them so they can't close. Take some sturdy plywood and bolt the legs to the plywood. Now put the plywood on a three point suspension system, say with three car jacks, and tilt it to whatever part of the sky you want....

regards
Greg N

#9 Herenomore

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Posted 10 July 2009 - 09:38 PM

Has anyone tried to improve or fix the wobbly alt-az mounts that most often come with those cheap 60 mm refractors?

Yes. Tom Peters did and he came up with this:

Attached Files



#10 rutherfordt

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Posted 11 July 2009 - 08:56 AM

Try this link:

http://www.davetrott...e Telescope.pdf

#11 roscoe

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Posted 11 July 2009 - 09:56 AM

I replaced the altitude adjuster on one with a turnbuckle with long ends that I had around, added double nuts and rubber washers to the OTA bolts, and put a coke-can metal shim in the azimuth 'bearing' on one scope that passed through my hands.......all that made it slightly better........ Another repair was to find the balance point on the OTA, drill a hole, epoxe in a t-nut (looks like a cross between a washer and a nut) and mount it on a camera tripod. That worked pretty well. ( I took the focuser off first to empty the metal chips out..) There are lots of plans around for simple dob-type mounts that can be easily built to solve the whole problem, too.......

#12 tommyhawk13

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Posted 11 July 2009 - 08:42 PM

I have the eduscience 50mm, and saw the rings of saturn. It was the scope that I bought for the kids that got me in this mess.

I used some scrap aluminum from work to attach it to a camera tripod.
The bracket was screwed into the telescope tube, and it had a 1/4-20 hole tapped in the aluminum already.
Orion sells a plastic bracket just like it, but it's more fun to come up with something that works for free.

The camera tripod works great, just remember to have the handle facing away from you when you mount it. The tripod was a WalMart purchase, a simple Velbon, or something. No need to get a Manfrotto for this one.

A hybrid diagonal will






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