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