RE: Re[2]: [ATM] Hello list,some basic question for a new Dobsonian builder

["Alan Scott" <alanne1956@hotmail.com>]

I see your point about mold.  I actually live in Albuquerque New Mexico, so 
when people say "mold", we think you are speaking another language, or 
talking about some other country or something.  I think I read about mold in 
some book, somewhere.  :-)

On the other hand, I would think that a Sono tube would have the same 
issues.  I kind of remember seeing sono tubes used for telescopes somewhere 
before.

I do think that carton banding material will make a better secondary.  
However, it is probably slightly more complicated.  I guess my point is that 
many materials can be used, and will create a pretty good spider.  Or, a 
better way to say it is that there are many, many ways to skin most cats in 
ATM and end up with a good scope.  A masonite spider can be created with a 
dull knife and a bit of glue.  And, it makes a very functional spider.

Surprisingly, the scope with the masonite spider that I have looked through 
has BEAUTIFUL images.  There are no big defraction spikes that I noticed.  
It is painted flat black, so maybe that helps.  I will look closer next 
time, however.

alan

>From: Richard <cnc@cncservo.co.uk>
>Reply-To: Richard <cnc@cncservo.co.uk>
>To: "Alan Scott" <atm@atmlist.net>
>Subject: Re[2]: [ATM] Hello list,some basic question for a new Dobsonian 
>builder
>Date: Fri, 8 Apr 2005 17:45:58 +0100
>
>Hi Alan,
>
>Friday, April 8, 2005, 5:10:03 PM, you wrote:
>
>AS> I have seen this scope, using masonite, in action, and the Masoninte 
>works
>AS> very, very well.  I would disagree with the statement that it is asking 
>for
>AS> trouble.  You could probably put 10 pounds onto this spider, yet it 
>only
>AS> needs to hold ounces.
>
>Sure, but it's going to change your scope's collimation as the
>humidity changes and as temperature changes (and even as mold
>grows in it). I can't think of a less suitable material. Worst
>of all is it's thickness which is going to cause bad
>diffraction. Why not just use the free carton banding metal ?
>
>--
>
>Best regards,
>  Richard
>
>
>
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