52 replies to this topic

[Skipper_52]

Hi all. Years ago I had a Meade refractor but sold it because it was useless near Chicago. I did learn a lot from it however. I just purchased a setup from an auction but am having a hard time finding the model #. I've enclosed pictures of it hoping someone can help me. I know it's a 6" reflector. The equatorial mount with clock drive is an older mount and I'm thinking it's missing the 'feet/base' which I could build or maybe purchase them from someone. There are no fine adjustment cables or gears for mounting them which upsets me. Can anyone identify these for me and tell if if there was/is a gear set I could attach to it and maybe the value of the mount. Is there a manual available for the 6" Meade reflector?

I'm a draftsman for Harper College in Palatine, Il which has an observatory. I was thinking I might get some help here too.

I appreciate the help.

Skipper

[MistrBadgr]

Hi Skipper,

I am not sure about the mount, etc., but you might want to consider turning the optical tube into a Dobsonian. There are some pretty good instructions for making a mount out there. You would just have to modify the plans for your size and focal length. What you have looks like maybe a six inch f/8 scope. That should make a fine planetary rig as well as general purpose scope. A Dobsonian mount that size would be fairly easy to move around and set up.

By the way, welcome to the forum!

Bill Steen

[Skipper_52]

I decided to build a azm mount for my 90x1000mm spotting scope on a Meade Field Tripod. Can anyone tell me what rpm's the declanation plate needs to be? I guess I could use a dc motor and put a pot on it but I'd like to be close at the start. I believe it's about .25 deg per min.

[Skipper_52]

Well I took your advice Bill and am building a DOB. But I modified the designs I saw and put bearings in the carriage mount. I also rigged a fine adjustment system for both axis. I'm building the base adjustment now. The base has a 12" lazy susan bearing in it on a 24" base. I was afraid of 'play' but once the weight got on it it rides smooth as silk. I'll post the base adjustment assembly as soon as I'm done. I had cataract surgery the past 3 weeks and finally got to the point where I could play again. Comments are welcome.

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[MistrBadgr]

Looks like you are well on your way to completion! That is a really good looking rig that is quite a bit different than a standard Dob mount. I am interested in the adjustments you have built into it and how it works out for you. Consider building yourself an eyepiece rack and mounting it between the altitude crank and the altitude bearing, right where they would be in easy reach.

Bill Steen

[Skipper_52]

The rack/shelf is being built. It will be attached to the outside and the support arms. Funny I didn't think about that until a few days ago. You forget the small stuff.

If you can zoom in on the photo you can see the simple string attached to the pulleys on the forward shaft. I tried it tonight after assembly and the adjustment is fine enough. I will however replace the string with braided stainless cable. We use to use it for fishing on downriggers. It's flexible enough to wrap around the pulleys.

I could figure out the ratio but I know I'm able to move it less than 1/8 degree by hand. I'm going to create a video of the assembly when I'm done. The base adjustment will be capable of 1/8 degree or less.

I'm 61, a retired carpenter (hurt) and landed a job at Harper College as the Physical Plant Draftsman. I had taught myself Autocad over the years so it's easy to design things. I'm cutting the pieces on a cnc router I designed and built. Here's a pic. It makes it a little easier to get precision pieces.

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[MistrBadgr]

That router is way too cool! No wonder your mount looks so good!

Bill Steen

[Skipper_52]

Thank you. Got the bugs worked out of the Base adjustment and it works. I'll mount it tomorrow and post some pics.

[Skipper_52]

Well I'm not happy with the way the pulleys worked. It did work but I was afraid of the line snapping. Tried braided stainless wire and it snapped from rubbing. Decided to go with a gear system. Cut the gears tonight. WIll send pics tomorrow. Oh yeah.. gears are out of baltic birch plywood.

[MistrBadgr]

You are definitely exploring new territory! This really sounds interesting.

Bill Steen

[d33d0gg]

Interesting indeed! Cant wait to see your final product.

[Skipper_52]

Got home from work and crashed. Won't be able to mount them tonight but here's 2 of the Alt gears. The large one will be mounted to the telescope carriage and the pinion to a 1/2" shaft. 12:260 gear ratio gives me about 16 degrees per turn. At this ratio I can move the scope from horizontal to vertical in a few seconds.
I decided that if I put another set of reducuing gears of 10:80 on a swing arm I can get the gear ration down to 2:360 or 2 degree whcih will give me micro adjustments of 1/16 of a degree or less when needed. The small pinion's hole is .5". for a scale idea.

I know some people think the wood for gears is a bad idea but Baltic Birch is extremely strong. You can't get the teeth to flex at all with your fingers and there probably won't be more than 3 lbs or force against the whole assembly when balanced. And ... when you can cut them yourself you say a fortune.

[MistrBadgr]

That is just really slick!

Bill Steen

[Skipper_52]

Got all the gears cut and trial tested it. It works flawless. So.. with the fine adjustment disengaged I get 22 degrees per revolution of the lower wheel. When you drop the fine adjustment gear down to engage it you get 2 degrees per revolution. I easily adjusted a digital angle gauge in 1/10 degree increments. I don't have the wheel for the fine adjustment yet.

Tomorrow I start the RA wheel and mount the base adjuster.

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[MistrBadgr]

That is pretty amazing!

[Skipper_52]

Disassembled it to machine the holes in the base for the RA mount. Screwed up the paper template for the RA disk. Pictures explain it. A few more pieces, pointer, eyepiece shelf, legs for base etc and I can paint. Should be pretty accurate.The RA disk is 14" in dia.
I bought a .00 digital angle finder that I can zero and will mount it to the carriage for Alt readings.
The auction came with a Meade 1000mm x 90mm lense that I will mount to the top of the carriage for photos.
Pictures never seem to upload in order. Should probably do them one at a time.

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[MistrBadgr]

That really looks great! Later, if you decided to motorize the mount, I think it would be rather easy for you. However, you might not have a need for that, unless you want to do astrophotography with the scope.

Bill Steen

[Skipper_52]

Sigh.. Screwed up again. I did'nt want the RA I wanted the Azm scale.

Thanks for the compliments Bill.

[Skipper_52]

Maybe someone can answer this one for locating stars using manual setting circles.. A RA circle will only work if you have an equatorial wedge.. correct? And Alt/Azm circles will only work if you know the current coordinates of the object based on your local time .. correct?

[MistrBadgr]

Alt/AZ coordinates will work if you know your physical location and time, as well as the position of the object you want to see. I know that AstroPlanner will calculate these values and I am sure other programs can as well. I believe people have come up with programming in the past for programmable calculators. I would not be surprised if there was not an app for some phones that can do that as well.

Bill Steen