Hi this is Graham from Jenham's Astro today we're going to look at the Sky
Watcher SCT focuser which costs about 120 pounds in the UK it's a crayford
design for telescopes which have an SCT thread so largely were talking about
Schmidt Cassegrain and also a few Maksutovs.
I bought the unit to use with a Skywatcher sky max 150 pro the latest versions of which have got the thread to
accept an SCT type focuser okay very similar focusers are available for
other Sky Watcher products the Sky Watcher Equinox range of refractors has
a very similar unit the main differences being the obviously the attachment of
the focuser to the telescope tube and also the amount of draw tube travel
so in this unit the travel on the draw tube is two point seven centimeters
whereas if you have a Equinox refractor you've got something like thirteen and a
half centimeters of focuser travel but you might need with a refractor
scope okay so what's it like
okay so the focuser weighs just over 1 kilo it's quite a chunky unit on the
back of an optical tube if we look underneath we can see here the the
thread for attaching the focuser to the back of the telescope we can also see
that we have an option to adjust the orientation of the focuser
relative to the back of the optical tube we turn it through 360 degrees and then we
can use this knob to lock the orientation that's quite a useful
feature if you're trying to position the focuser on the back of an existing scope
that may have always will have a existing focus or knob and you don't
want it to clash with the the new focuser
so the unit is designed to accept two inch accessories as you might expect and
it comes with a reducer which has a compression ring both the the 2-inch
barrel and the reduced one and a quarter sized barrel have got
compression ring fittings to grip onto the eyepiece or diagonal that you might
wish to use you can see that the focuser draw tube has a graduated scale up to
two point seven centimetres of travel there abouts quite useful if you think
that you might want to take a note of a particular focusing position but I'd
also say given that you are using it as a secondary focuser attached to
another attach to a scope that's got an existing focuser them potentially that
isn't terribly useful in reproducing a particular focusing position it's not as
useful as it would be on say a refractor draw tube okay so you've got a dual
speed focuser so you have one times and a tenth times speed so you can do fine
focusing and the mechanism seems pretty smooth
you also see underneath here that you've got a lock screw so you can lock the
focus there in a given position and also in the middle here you can see there's a
recessed allen key stop it here so that you can adjust the amount of focuser
tension that you have that you want and that's often a contentious point
with crayford focusers some people say that they slip so if we were to take a
DSLR put the crayford onto the camera then I guess you can see there that there is
no problem holding that sort of weight and adjusting in and out no sign of
slippage obviously if I was to reduce the friction by putting the allen key in
here there comes a point like that where the draw tube will slide that that's the
point of the having the friction control to adjust the tension so if we do that
back up again then we're back to the sort of focuser tension that we might
want when we're doing astrophotography or if you've got a heavy diagonal
eyepiece on the end of the year of the focuser
okay so what are my impressions of the Skywatcher SCT Craiyford? Well
overall I say it's pretty good this focuser sits towards the lower end of
the price range for replacement focusers and I think it's good value for money
you can easily spend three or four times the cost of this unit on a replacement
focuser and it's obviously entirely up to you to decide if you want to have
one of those higher end units it's easier to spend probably half the cost
of your telescope again replacing the focuser maybe that's the right
thing for you to do if you choose to go for unit like this I think it's pretty
sturdy you'll find it this unit like a lot of replacement focusers are quite
heavy so that kilo on the back of your scope you've got to make sure that
you're gonna get the benefit of the better focusing
capability that you expect because you've got to allow for the fact you put
this extra mass on the back of the scope Can you balance the scope, can your mount
cope with that extra kilo so take a into account this particular focuser itself
we've seen that the action is nice and smooth I've used a similar unit on
skywatching refractor we're no problems at all for visual and astrophotography
work nice coarse focus good fine focus control and useful features like being able
to orientate the focuser as we've seen it's a Crayford some are out of
fashion rack and pinions are on the scene again I'd say all we can really
judge is this particular unit does the job we've seen it hold a decent mass of
payload so a camera or heavy diagonal sort of thing you might have hanging off
the back of the the unit and I think it can cope with that without any real
problems so overall Crayford SCT from Skywatcher I'd say it's good
value unit, well put together, nice and smooth to use, worth taking a look.
OK I hope it's been useful thanks for watching.