hi this is Graham from Jenham's Astro in this video i'll unbox and take a look at a
guide scope this is the BST starguider a 50 millimeter guide scope picked up
online and it cost me just under 70 pounds now I wanted to get another guide
scope basically because I've got a few telescopes that I wanted to try them out
in it in longer exposures than I normally do so I wanted to get another
guide scope I already got one guide scope which is this one which is a star
way 50 I've got this set up on my GT 81 and I did wonder whether I could just
buy a bracket to allow me to use this existing guy scope tube assembly on
another telescope so basically what I'm trying to do is connect two guys scope
up to it to a telescope using a finder scope bracket like this one here so I
looked at the cost of buying a bracket and basically there wasn't much
difference if I'd bought a bracket to use this existing guys go tube then I
didn't really save a great deal of money so it seemed like a good excuse to buy
another guys scope so in this video we're gonna open up the box and see what
you can get for not really very much money
okay so I've removed the rest of the packaging so we've got the Rings which
has a safe pretty lightweight core each of them has feels like they're maybe
they're plastic the these bolts certainly lightweight the Rings are
is metal and the bar the Rings are attached with a couple of bolts all
seems perfectly solid for the job whole assembly ways I think around 600 grams
the tube assembly here you can see it's got 50 millimeter guys go star guide
written on the sides quite smart nicely finished moving the lens cap hopefully
you can see I'll tilt in the right direction I even
just see a little tint there is a little bit of coating there on the lens it
looks green to my eye this is a f/3.2 unit so it's got a focal length of
162 millimeters I think so in theory it's gonna be useful for relatively
short focal length telescopes but I guess different people have different
opinions on what ratio you should have for a guide scope focal length versus
the main telescope focal length so certainly if I get on with this guide er
I'll try and use it on some longer focal length scopes and see how it performs so
looking down at the folks our end we've got series of screws so if I undo these
then we can see hopefully that the camera if it was attaching to their
guide scope that it's got brass compression ring there hopefully you can
see that therefore tighten it it says quite nice it's not gonna mark the
camera if I undo this bolt here you see that whole end of the guide
scope moves by maybe three and a half centimeters and then this nut is
tightening down the assembly so I guess this is the operating position of the
glidescope looking at the focuser we've got it's a helical focus so pointing the
the datum line you see the zero so as we rotate the folks then the torch II is
moving in and out nice and smooth nice clear graduations to find a given focus
position and then if we I guess tighten this screw here tighten that down then
the folks who doesn't move there's a little bit of play here in the ring but
nothing too significant I'd say doesn't feel like the actual
or tube is moving let me close it up again certainly first impressions yeah
pretty good call the adjustments you need looking
inside the tube
I'd say it's reasonably well darkened flocked perhaps or pulleys black paint
hopefully it'll do the job so next step is to hook it up and see that we can
reach focus and get a bit of an idea of the image quality okay so this is setup
we're going to use I put the star guide on to the finder bracket of my celestron
c90 and you can see with this kind of bracket you can fit the star guider
comfortably inside the bracket and the balance of the scope looks like it's
going to be okay and I've got my standard camera used for guiding ASI
120m see it's a color camera but I've never had any problems with it
guiding previously I'm just gonna have a look at the video from this setup and we
can just judge if we can get a good focus when we look at infinity okay so
we hooked up in a sharp cap looking at a distant tree on the horizon and this is
the first video feed from the camera so I'm gonna do now is to move the draw to
bit now initially I have the draw tube at full extension and that really didn't
work so firstly you can see that the draw too will rotate when the locking
screw is undone then that's approximately the position
for focus I think we've got the draw to you around half extended there around
fifteen millimeters on the three centimeter scale so if I lock down start
Ida the screw and now we can rotate the helical focuser in and out of focus and
hopefully it's clear that you can get a nice clean image somewhere around there
using the star guiding that's what else is there to say well if I lock down the
screw on the helical folks here and also on the draw tube then the whole assembly
is pretty tight it's certainly doesn't seem like the flexure is gonna be a
problem with this arrangement and then if I was to adjust one of the screws to
move the position of the star guide are relative to the c90 then you can see
it's very straightforward to align the star guider to the main scope or so also
to offset it if you need to to achieve a good guiding star
okay so BST 50-millimeter guidescope is a good value well I'd say that it is I
think we've seen that even though the construction is lightweight that you
we've seen you can adjust it well you can get a good focus and then you can
lock it down so that it's got a robust mounting which is really an important
feature if you're going to do water guiding you've got to remember that it
is a 50 millimeter f3 achromat so it's normal to see some color fringing when
you look at the video image and that really shouldn't be a problem for auto
guiding all of these guide scopes operate at a short focal ratio so I
think if you're looking for a low-cost guys scope they've run like this that
you can mount on your finder bracket then definitely give it a try
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