[ATMoB-discuss] Making a Dob vs buying a

[Siegrist, David]

Dave S. wrote

>I'm not sure
>even if I had the skill to grind a 10" mirror, that I could make a
scope,
>much if any cheeper than Mead is selling them for.

The other Dave S. replies

Grinding a mirror makes little economic sense for the sub-mario sized
optics most of us have.   We tell folks who come by the clubhouse 
essentially asking the same question that you grind a mirror because
you want to grind a mirror.  BTW, it takes virtually no skill to grind
a mirror (empirically determined).  It does take patience and
perseverance.

Building a scope:  depends on the quality.  You can make an Obsession 
quality scope with the parts from the following estimate:

For a 10" scope you will need:

1/2",3/4"  plywood    40?
Hardwood (truss)      20?
Screws etc.           30?
  - cell, rocker box, mirror box, truss holders
    can all be fabricated out of above


Truss tubes    40?  (not sure)
Mirror kit    $120   (plus $1/hr for at least 60 hours)
  Coating      $40
Tube           $20
Formica        $10  home depot
Spider         $40   ( free to $$$ range)
Secondary holder  $30 (free to $$$ range)
2.25" Secondary   $120  
2" Focuser        $125 (ranges)
Zero mag finder   $30

This estimate is about $650.  You can spend considerably more,
or you can spend considerably less.   If you can scrounge, hit
the swap tables at Stellafane, and are good at woodworking,
you could probably do a very usable scope $400.


We had several folks grinding, and polishing mirrors last
night at the club house.  Bernie K. poured a new lap.
We had folks outside trying to observe around the beautiful
but bright moon.  And we had the normal hangers-on providing
all kinds of valuable free advice about mirror and telescope
making.
 
Come by some Thursday evening (excepting the 2nd Thursday)
to find out more...

  /dave