Instruction manual

Don't be shy! If you're just starting out, here's the place to ask that first question

Moderators: joe, Brian, Guy Fennimore

Post Reply
Nicto
Posts: 4
Joined: Sat Sep 05, 2015 4:40 pm
Contact:

Instruction manual

Post by Nicto »

Hello -- my dad was given a Jessops 900114 telescope a few years back that he took out the box but then never used. It's now been passed down to his seven-year old granddaughter, who's expressed some interest. I've managed to assemble it but suspect we are missing a couple of parts, including a lens on the eye piece (there is one on the finder). I know it's an basic chain store instrument but we just want to see if we can get it to work. Does anyone happen to have a manual for it please? Tried Jessops without luck: found this online, which looks similar but wary it's not the same http://www.opticalvision.co.uk/documents/18.pdf -- does anyone know where I can get a Jessops manual? many thanks

brian livesey
Posts: 5389
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Re: Instruction manual

Post by brian livesey »

This reflector has a long focal length ( f.8 ), so it should be easy to line up the mirrors, if this is what concerns you. What other part, except for the eyepiece is missing? By the way, you really need at least three eyepieces to get a decent range of magnifications; zoom eyepieces are also available. Get the best eyepieces you can afford.
If you need to know how to set the mirrors ( collimation ), ignore the main mirror for now. First, remove the eyepiece and make sure that the small mirror looks like a circle ( not elliptical ) in the eyepiece focuser and that it's in the centre of the focuser. I use an old high-power eyepiece with the lenses removed, leaving a 3mm hole, and look through this at the mirrors when adjusting.
Now, look at the image of the main mirror in the small mirror. Is it concentric with the small mirror? if not, use the adjusting screws behind the main mirror to bring it concentric. Collimating an f.8 'scope is easy to do, once we've had a go.
brian

Nicto
Posts: 4
Joined: Sat Sep 05, 2015 4:40 pm
Contact:

Re: Instruction manual

Post by Nicto »

Thanks for this Brian, it's v helpful. I suspect a few other pieces are also missing; there also seems to be a hole in the casing of the join between the eyepiece support and the main body of the telescope, which may actually let light into the main body of the telescope. Which, even I as a complete novice, suspect is not a good thing. We may scout around for a new one instead. Are there any brands you would recommend for a few hundred pounds secondhand? V much just to see the stars and possibly features on the moon etc with young kids and seeing if that may inspire them.

brian livesey
Posts: 5389
Joined: Mon Jan 09, 2006 11:05 am
Location: Lancashire
Contact:

Re: Instruction manual

Post by brian livesey »

If children are involved, a refractor would probably be better than a reflector, as they tend to be more robust and don't need resetting like a reflector.
I'm no expert, but a 100mm/f.10 refractor would be okay; for example, the Russian Tal. There's also the Skywatcher range of refractors.
Last edited by brian livesey on Tue Sep 15, 2015 3:43 pm, edited 1 time in total.
brian

Nicto
Posts: 4
Joined: Sat Sep 05, 2015 4:40 pm
Contact:

Re: Instruction manual

Post by Nicto »

Thanks Brian, that is very useful. Will give it a goo and get back to you when I need more guidance!

Post Reply