ATM Re: Houghton Update

["Bill Cook" <atmj1@conceptsnet.com>]

In the Houghton in question, is the secondary holder attached to the front
element and allowed clearance through the second?
If not, this could be a problem?

Either way, what is the center thinkness if the elements?

When I started Houghtening - keying on work by professional designer, Robert
Sigler - he was kind enough to send me a design created with Code V. At that
time I was still trying to use the Mike Simmons program, IODP, and fighting
a loosing battle. I noticed that the CT of the second element was very thin.
This was probably done to save money on the lenses. However, working on
elements that are too thin is an invitation, in amateur circles, for
astigmatism. Mentioning my concerns to Robert, he agreed and, sent a new
design with much thicker elements. I have never recommended that amateurs
should try to build large Houghtons. However, I suppose that people who are
willing to work on a Houghton are willing to give more of themselves to make
a superior instrument. That being the case, a little extra thickness at the
outset can save a bunch of headahces in the end.

Please understand that all of this is spoken from text books, lens design
programs, and VARIED experiences. MY Houghton optics are now in their 7th
year of not being mounted. I will probably be the last on the planet to own
one because I can't get the time to put it together. VERY frustrating!

Kindest Regards,

Bill Cook
editor / publisher, ATM Journal