Posts Made By: Jack Day

Thick plate glass is a rare find these days. Dan Cassaro sells som 16" blanks that are 7/8" thick. He also has some 20" available in this thickness but even I would be hesitent to tackle it. Mind you my first mirror was a 14" out of 3/4" plate. Currently I am working on an 18.625" blank out of 7/8" plate but I would not be comfortable going any larger. The only problem with Dan's glass is that he is back logged a bit, and is currently trying to get caught up. If you are not familiar with the ATM resource page check it out at:

http://www.freenet.tlh.fl.us/~blombard/

Another option is to talk a local glass company into getting you some 1" plate glass. It is no longer made in the U.S. but is still able to be found. Up to a 20" mirror should be possible.

Jack

The one you were thinking of was on Steve Swaze's site.

http://home.europa.com/~swayze/spider/spider.html

Though he had some site problems and the picture is gone. Email him and I am sure he would send it to you. I have one and could take a picture too if need be.

Jack

Liberty Lake Eh...

Well from what I remember it used to be quite dark out there. Of course that was before they put in that lovely shopping center / Mall as you get off of I-90. Have you gone out to Starr Butte yet with the Spokane Astronomical Society? It is pretty dark there from what I can remember, though I was in the club when they still met at the gravel pit near Freeman Wa. Also there are several local star parties you could attend this summer... Table Mountian Star Party (July 25,26 & 27th) Near Ellensburg, Wa. Oregon Star Party I think nearish Bend, OR and Mt Kobau Star Party in Osoyoos B.C. just north of Omak / Tonasket / Oroville WA. and ending the season is the Orion Nebula Star Party again up on Table Mountian.

Good luck, and if you are ever in Wenatchee and want to go observing feel free to drop me a note.

Jack

Ed,

If you are going to give computer advice at least have him use the correct (Ok, More correct) utility. : ) At the command prompt type: fdisk and select the option to delete the current logical partition. Once deleted power off the PC. Upon power up insert a bootable copy of a Linux / FreeBSD / etc. Disk (CD or Floppy)and proceede to install new OS.

Clear Skies! And good luck Darren!

Well, at least you didn't advise him to get a Mac!

Hi Chris,

Just wanted to give you some info on Zambuto Optical and Zambuto mirrors in general. Your first question was:

>>Q: Is there really a big difference between say a Zambuto 10" mirror vs. a Meade or Orion 10" mirror?

There are some fundemental differences between mass produced mirrors and those done Done by Zambuto Optical.

First of all is the concept of annealing the mirrors pyrex substraight to remove all strain. All of the mirrors that come out of Zambuto's shop are tested for strain and striation before ever making it to a machine to be worked. In the past blanks not passing the anneal test would have been simply boxed back up and returned to the vendor. Currently Zambuto Optical is having their blanks custom annealed and this is no longer an issue. But why is this important and don't the Orion's and Meade's of the world do the same. Strain effects the ability of the glass to hold a stable shape while being figured and also will cause problems with the mirror's figure any time the glass is heated or cooled. And yes, others do have concerns about annealing, but a mirror that might be considered passable to them could still have failed in Zambuto's shop. In other words: If it shows any strain, it fails.

Striation: This is simply a case where when the Pyrex glass was melted it was not mixed well enough and leaves areas of different physical characteristics throughout the blank. One area may be softer than another, or expand and contract at a different rate than other parts of the mirror. Where a poorly annealed piece can be "re-annealed" the only cure for most striated glass is the local fire hydrant. Striated glass is nearly impossible to figure and even then the figure changes depending on the glasses mood on any given day. Continued in part II

Here is a better view of the business end:

Shoot! Great job! Of course ya could have had six if you would have just taken a picture of your feet!

LOL

Good Job!

Jack

You might also give this a try:

http://www.rustoleum.com/product.asp?frm_product_id=29&SBL=1

I have used it. As I recall it is close to Celestron Orange but a bit darker on color. Worked very well for me.

Picture of the adapters...

Thanks & Clear skies!

Hi Floyd,

I have been seriously considering some of the new Swan eyepieces. I have a 6" f/10 refractor, a C-8 (just bought yesterday), a 14" f/5.4 dob, and a 80mm f/6 refractor. It sounds like these would perform well on the 6" & 8", but I wonder on the f/6 and f/5.4.... please let us know how they look on your faster dob's when you get the chance. Also, didn't you try some of the Burgess 72 degree wide angles at some point? If so how do those compare?

Thanks & Clear Skies!

Jack