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Posts Made By: Charles Hakes

June 6, 2003 04:01 PM Forum: Equipment Talk

Porro Prism vs. 45degree erect Image

Posted By Charles Hakes
Porro prisms are like what is in most binoculars, so they have a straight-through view given by 4 internal reflections. The 45 degree versions use a single prism and, as the name implies, angle the light path by 45 degrees. Since both cause the light to go through lots of glass, both are primarily for daytime use. My guess is that a cheap 45 might perform better than a cheap porro (since it is only one piece of glass). Right now I am waiting on a 45 with a large clear apperture for daytime use with a 32mm Plossl (or 24 Pan when I can aford it). Most of the ones you get will limit the field of view somewhat (also true of the one porro I have used). I guess your preference would depend on how you want to hold your head when viewing. Hope this helps.

Charlie

July 16, 2003 04:03 PM Forum: Equipment Talk

Meade LX3 8" quatrz

Posted By Charles Hakes
Make sure it is not just a fuse. I use a schools LX200 that has something flaky on the board, so a fuse goes out every year or so. I don't know if the boards are similar to the LX3, but they may be.

Also on that same scope (maybe this is where the problem started) I replaced a single large capacitor. The old one had blown out (probably from voltage reversal) and the new one was from Radio Shack. Look closely at the board and see if anything looks like it got too hot.

Good luck,
Charlie

August 5, 2003 04:06 PM Forum: Telescope Making

Mirror packaging

Posted By Charles Hakes
I did that cut styrofoam trick and shipped a 16" cassegrain mirror set successfully. But I also cut the foam sandwich so it fit in a homemade 20x20x8 wooden crate. I then packed the crate inside a 24x24x12 cardboard shipping box with bubble wrap all around. The wood may be overkill, but I'll bet it could stand the 6' drop kick test. I shipped it FedEx ground.

I think the key with "optical" tissue paper is it just being lint free. my mirror came back, the cover was aluminum foil (which is also lint free). It was stretched to not touch the primary. This cover was also used on the convex secondary. Yes the aluminum foil could touch the surface, but I couldn't see any problems with that. (Actually it looked great.)

Good luck,
Charlie

August 5, 2003 04:17 PM Forum: Equipment Talk

Looking for a good 10” reflector that tracks

Posted By Charles Hakes
For about the price of one of those hefty EQ mounts, you could also consider a Dob Driver from Tech2000. I have one and like it for what it does.

Charlie

August 22, 2003 02:46 AM Forum: Equipment Talk

A really dumb question from a confused newbie

Posted By Charles Hakes
Also, make sure the tube is ballanced. Sometimes "from the factory" is only approximate, and it could be if things aren't ballanced enough that the motors aren't strong enough. The problem is usually with the tube mounting point. I use 4 oz. nails and velcro on one of my scopes, but I am sure there are prettier solutions.

Charlie

August 22, 2003 03:01 AM Forum: Equipment Talk

Mirror re-coating.

Posted By Charles Hakes
I have used this place a couple of times.

http://home.covad.net/~alcoat/

Very fast turn around and the mirrors look great.

Charlie

August 26, 2003 01:38 AM Forum: Equipment Talk

Mars again.. LOL :-) Contrast questions

Posted By Charles Hakes
I remember the polar cap as being much brighter... but that was a few weeks ago before the monsoon.

Charlie

September 15, 2003 09:34 PM Forum: Equipment Talk

Parabolic mirror coatings

Posted By Charles Hakes
I have had a 10" and a 16" mirrors coated here:

http://home.covad.net/~alcoat/al_2-2.htm

He did a really quick turn around on them and they look great. His coatings are not "enhanced" though, but some of these other posts have addressed why I didn't go with enhanced.

Charlie

September 21, 2003 02:15 AM Forum: Equipment Talk

Biggest Dob without a ladder

Posted By Charles Hakes
I have looked through a 30" f4 that didn't need a ladder. However, there was a rather large secondary and then a tertiary mirror that was at eye height. I thought the sharpness was OK, but the thing that struck me was seeing so many colors on Jupiter.

Charlie

October 1, 2003 02:07 PM Forum: Telescope Making

Stripped threads - help

Posted By Charles Hakes
Thanks for the replies all. I think I will look into the helicoil first - do you need any special tools for installing one? I have seen them already installed, but have never watched how they go in. I have used the 1/4-20 inserts you can put into wood, but I would be surprised if the same technique would work on aluminum. (BTW - why do they put threads in aluminum in the first place.?!)

Charlie

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