Re: [ATM] materials and lenses

["Bob May" <bobmay@nethere.com>]

A lens will be a bit more difficult than a mirror because you, first of all,
have 4 surfaces to grind and polish up rather than the 1 of the reflector
telescope.  In addition, the curves need to be close to the desired ROC, a
lot more than the typical several inches that most mirrors get done to.
Finally, you need to insure that there is no wedge in the two surface of a
lens as this will do nothing but be a prism which will fatally affect the
lens' performance.
The easy part is that the surfaces are going to be spherical and a bit of
turned edge won't hurt as that will be under the mounting of the lenses.
Newport is a bit fluky in that they do sometimes have orders get lost in the
various parts of the company.  When they do get something out, it is
generally of professional quality.  The refractor kits are worth the money
although the telescopes that get made from the kits are only average in
quality as the glasses used are not the best choices but rather cheap
glasses that will provide the typical average performace in a scope.  Then
again, more exotic glasses will drive the price up drastically.
Bob May
http://nav.to/bobmay
bobmay@nethere.com
NEW! http://bobmay.astronomy.net


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