hi this is Graham from Jenham's Astro this video is intended to save you a few
pennies if you've got a Celestron c90
telescope and you'd like to use it to do
some photography with a digital SLR it
can be a great way of taking pictures of
the moon for example. now you probably
worked out that you going to have to buy
some kind of adapter to connect
telescope to the camera and generally
there are two parts to to this sort of
adapter first part is called a T-ring
so here's an example of a T ring this
one is for a Canon digital SLR one side
you have an adapter that screws into the
body of the camera when you remove the
lens and on the other side you have a
standard thread now you can buy one of
these for a nikon camera sony can and
many types of camera that long as you
can remove the lens then it's worth
seeing you can find a suitable T ring
It's an inexpensive easy way to get hold of, no real problem there.
The issue can come if you search the web and you're looking for the second part of the adapter that
goes between the t ring and the
telescope. so you might find you come
across a unit like this so it's labeled
as you can see t adapter c90 and i think
what can say is that this t adapter
works with some models of telescope for
example the celestron nexstar  4se
but it's labeled C90 so you
think it's going to work with a celestron
C90. You'ld be wrong
so if we remove the accessories from the
back of the telescope so take off the
visual back the erecting prism and the
eyepiece then we can see the thread
that's on the back of the unit and this
would be the point where you expect the
t adapter to to screw onto the back of
the telescope so here we go here's the
adapter a see if it'll fit. it doesn't.
the threads are completely incompatible
okay so the c90 adapter maybe it fits
the old C90 so I've got one of those
here it is so this is the back of the
old C 90 and well it looks more promising
the thread looks like it possibly could
be the same and indeed if we attach the
T adapter it will thread onto the old
model of C90 so there we go
climbing up a bit squeaky so that is as
far as it will tighten the problem is
you can see there's play, so this
adapter isn't any good because you're
not going to have a rigid mounting
between the camera and scope so if you
wanted to use it you'd have to pack out
a spacer to remove that play. if you do
that some people report that you still
have problems and you can't focus the
scope at infinity
so overall I have say even though some
other users reported that there's C 90
Astros can use this adapter I have to
say in general it doesn't work with C
90s new or old okay so what do you use
in its place to connect the camera to
the scope well here's the rub. if you
remember we looked before at the visual
bat that comes with the new C 90 so here
it is
when you get your scope you attach it
onto this thread of the back
okay no problem and guess what there's a
thread on the back of the visual adapter
that looks a bit familiar well it turns
out that that thread is already the one
that you need to attach the T ring. so on goes the  t-ring along comes the camera
Bob is your uncle. So it works fine so
what is the moral of the story? I would
say if you bought a selection on C90
still a great scope you know a big fan
of this scope if you want to connect
your digital SLR all you need is the T
ring. You do not need to buy this adapter
it's a shame that it's got c90 written
on it because as far as I'm concerned it
doesn't fit and it's unnecessary so you
probably could be spending a few
pounds or dollars that you don't need to
spend but the good news is you can
connect the camera cheaply using just a
t ring and then you've got a good rigid
mounting between the telescope and the
camera and off you go okay I hope it's
been useful thanks for watching
you
