Posts Made By: James Lehr Miler

October 20, 2011 04:39 AM Forum: Refractors

Dept store refractor mount DEC drive upgrade?

Posted By James Lehr Miler

You know all those import small refractors, the vintage ones, even new ones, all seem to have that stupid DEC sector drive which is mostly worthless and impossible to fix once broken or stripped out. Why can't someone come up with a retrofit device that can replace those that works well, is 360 degree turnable, clutched well and it's control cable does not always get in the way while working the controls at night???!!!!! I love those little refractors but I hate that stupid DEC sector drive!
Is there a way to come up with something better? Usually, those mounts are made out of cheepo pot aluminum and will break or snap off if monkeyed with too much.
Help me Augie-Ben-Doggie; your my only hope!

July 5, 2011 07:01 PM Forum: Reflectors

Help needed with Cassegrain assembly

Posted By James Lehr Miler

Hey!
Many years ago I had the same problem, so what I did is set up a simple optical bench using home made mirror cells out of plywood, bolts, wing nuts and compression springs, all found at ACE hardware. I also fashioned a mini one for the secondary and placed the whole thing on a board, which I cut in a slot along the middle of. Then I placed that whole arrangement on a GEM mount from 2 inch pipe parts so that I could "track" the moon. I tried to do all the positioning of the optics in daylight but failed miserably, so I had to wait until dark. One thing that would have helped was a very far off bright street light to zero in on.
Anyway, just by a bunch of trial and error I finally came up with the spacings. All the math in the world did not help one iota. I just monkeyed around with it until it all came into focus. Once I had the spacings set, I then bolted everything in place, measured everything, and built a tube assembly to fit it, at first using Sono tube which I later replaced with a fiberglass one.
The bottom line is that you just have to "play" with it all until you get what it is you want. If the optics get to a fairly good focus, but the images are crap, then the problem is with the optics alone. Altho mirror tilt and alignment may play a key role.
I am terrible with math, so I build my 'scopes by just playing around with things until it comes together. Over the years, I have a "feeling" of how it goes together and, just about always, it does. Yes, I screw up a lot, but I also learn. It is my hobby and my passion and my therapy.
I also try to build my 'scopes as something to look at as well as through.
So, you might try building a stage to just mess around with and who knows, maybe it will work! It did for me.
If you have a hard time visualizing what it is I am talking about, let me know and I could send you a drawing through snail mail or e mail.
Starman 1000

July 12, 2011 09:55 PM Forum: Antique/Classic/Vintage Optical Instruments

8" f4.5 Cave

Posted By James Lehr Miler

Dave,
Wowzers, man! Pretty 'scope! I wanna be first in line to buy it if you offer it up for sale. Need anything in partial trade? I've a bunch of stuff.
I wish I had the bucks (or a corporate sponsor) to put together a telescope museum that displays older equipment, and uses it all in a public setting. That has always been a dream of mine. I don't know why, but I just love old telescopes. Especially ones that are refurbished and look really good.
I live in Tucson, Arizona, and to this end, I am considering putting forth this concept idea to our local "Pima Air and Space Museum" [Google it]which deals mostly in planes of all kinds. They have a small space annex as well but it needs way more then what they present.
Nice job!!!
One atta-boy certificate!
Starman 1000

July 22, 2011 10:46 PM Forum: Antique/Classic/Vintage Optical Instruments

Unitron 4" Equatorial

Posted By James Lehr Miler

Try lowering the front leg of the tripod a bit. If I am not mistaken, it need not be perfectly level to polar align.
Or, maybe with a lot of effort, the bolt could be exchanged with a longer one, but I suspect there would be no room to do that.
Any chance you could provide a close-up shot for us to examine?