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[ATM] mounts
Ahhh,my favorite subject!OK if your all done groaning <G> I'll give the
quick tour of Ron's world of mounts.I like the Tennessee trott...oops!
Sorry,wrong mount!The thing is we who like taking pictures usually need to
go where the sky is clear of stray light.So it's a 20+ mile trip to darkest
where ever,set-up takes maybe an hour and then you get down to the task at
hand.Moving a 200lb plus mount is in the truss category.Ideally you get
some friends together and buy a plot somewhere that isn't prone to
vandals,and pour some concrete.At the very least you have 1 less piece of
hardware to lug.Having a mount there so all you need is the OTA plus acc.
is even better.Most of us aren't that flush.So it's back to having it both
ways.As described in another letter,large and heavy dampens out
vibration.Accuracy keeps your efforts on schedule.Since I'm a first
generation machinist stuck in the last century I always think in terms of
heavy metal.But I have finally come around to the idea of light mounts
with heavy properties.A GEM built from alum pipe say 3" in dia. for both
axis.Then use alum pipe welded at the 'T'.And then slipped into a polar
housing of the same material.The bearings of course lightly pressed onto
the shafts,(I'd use split collars as keepers).To simulate mass a large
auger is screwed into the ground before the field tripod is anchored to it
via a large turnbuckle.The idea being able to satisfy the need for low
vibration and high rigidity.If there was a way to fill all the empty spaces
with 10wt.synthetic oil,this could further dampen any vibration.Now this is
a very sketchy idea I must admit.From long experience,I know massiveness
and good design can do almost anything but move.Which can be a
problem.Especially if your trying to stuff this Palamor in the back of a
Tracker :-)!I would approach any design problem by asking what it is you
really need rather then free-climb such obstacles as weight,size and
expense.What you need is something that is reliable and doesn't shake.When
I build my own photo-grade mount,it will be on a permanent site.Then use my
friends 16"X60"CC South Bend lathe to make the mount.Probably from 3"
bushing stock.After seeing David Britz's rig, size of mount does
matter.Until I re-read the thread on this subject,it occurred to me how
important mass and accuracy is.Computers are great for tracking,but still
need something to work with.David's mount does just that.Check it out at:
http://home.att.net/~starastronomy/DavidB/index.html The BC photos show
good design and basic machining done well.I just wonder what kind of work I
could do if I took my Cave optics,and installed them into a real first
class OTA and battleship-grade mount.
regards,Ron
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