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The making of my minuture truss tube
A 4.5" F/8
I'v always wanted to build a truss tube telescope I was wanting to rebuild my 10"F/5
from the classic newtonian to a truss tube for the portability part of it ,And the older I get the the heavier it gets.So instead of that I decided to build a little one first I thought it would be good experience and a way to refresh the ATMer in me since the last scope I had built was in 1992.I knew I'd have to have some help on this as far as the math part went so I went to astromart and joined in on the forum and posted an ad there for the specs on a 4.5" F/8 scope.And with in hours I had two very knoweledgeable ATMers there who give me what I was looking for the spaceing of the optical train.The most important aspect of ATMing.And I'd like to thank Ralph and Rich for there sound advise which I followed cause I knew they knew much more than I did.The following pics and descriptions are short and brief I'v tried to cover as much as I could without confusing myself and trying to toss in alote of technical stuff.But building a telescope is not a nuts and bolt toss together item it takes alote of technical figureing to do,And if your going to grind your own mirror all the advise I'v seen says to start out small and work your way up to the bigger things.Maybe the the next scope project I do I might try may hand at a 6" mirror just so I can say I did it.
But that is another story.
The first thing I needed was the
optics after all you can"t build a scope with out knowing what to build
I placed an ad in astromart for a 4.25" to 6" reflector all or parts.Wanted to get something cheap to keep
the cost down.Within a couple of days I recieved a couple of offers and 1 was for a 4.5"F/8 primary
with a 1" diagonal and he would throw in a .750 diagonal with a 1.25" focuser and and a mead 5x24
finder scope all for the cost of $50.00 and he even paid for the shipping and within a short amount of time
I had my parts.Thanks Brian it was a very good deal for me and the parts were more than satisfactory.
Now I need some material to build
the parts to hold the optics.I went to my dads and gathered up some left
over oak lumber that was in the shed this come from my dads woods he had
cut the tree down and had it sawn up to make a nice supply of oak lumber
my kitchen cabinets are also made from this oak.
Since this lumber came from my home land this to will hold an appreciation for me.Some of the pieces including the side bearings and the end rings for the top cell and the bottom base board were made from oak ply wood for durabilty and to help easy the production of the scope I did'nt think the solid wood was a good choice for some of the pieces.
rocker box and the primary mirror box were both
made from the solid oak wood and some small slats were also used from this wood in the secondary
mirror holder cell this wood is hard hard hard!!!
I was concerned with splitting it while work with it but the drilling of the holes before sinking in the nails
it all worked out fine.I plained it down to about .625" thick to help keep the size and the weight down.
The inside of the primary mirror box was painted with a flat black enamel paint.The inside of the primary mirror box measures 7 5/8" square And the outside is 8 7/8" and measures 7 3/4" tall.
is the mirror cell for the primary it is 6" in diameter and this was
also painted the flat black.The mirror will have spacers placed under it the set on silicon pads then the
spacers will be removed after the silicon sets up.I equally spaced three 5/8" wooden dowles then cut
notches in them to align the mirror and it also helps to support the mirror.The pic does'nt show it but there is three T-nuts under the center cover for the push pull bolts
Page of the 4.5" F/8