Secondary school telescope building project

[ajwraith 10]

Hi there

I've got 15 students for 2 hours every fortnight. I wanted to give them an introduction to astronomy and help them to build a Dobsonian telescope. I was working on the idea of using a 200 primary mirror but they are so expensive. I do have a budget but it's only £450.

Recently I've been thinking of buying a 150 scope from eBay and recycling the mirrors and eyepieces from that for the project.

Anyone got any ideas or advice?

Andrew

[Capricorn 224]

8" miror set on Astroboot for £140 at the moment, also a 114 mirror set for £30.

Could get both.

On mine it is the first row of bits that appear on the screen.

http://www.scopesnskies.com/AstroBoot

[JamesF 17,610]

There's an 8" mirror set (primary including the cell and spider with secondary) on astrboot at the moment for £140.

James

[JamesF 17,610]

My turn to be too slow

James

[keithatrochdale 182]

Hi Andrew and welcome

It might help if you add where you are to your profile, you never know, somebody locally might be able to help you with parts.

[Capricorn 224]

James, we both thought of the same place.

Also they have the flex tube tubes for a scope, looks like they have taken one apart for some reason and are selling off the individual items.

[JamesF 17,610]

Could be that it was damaged during shipping and they're just selling off the bits.

James

[ajwraith 10]

Thanks very much for this. I'll also update my profile.

I'm in Bingley, West Yorkshire.

[username 57]

Brand new skywatcher 8" f6 primary for 149 euros from teleskop service, link below

http://www.teleskop-express.de/shop/product_info.php/info/p5492_Skywatcher-parabolic-newtonian-main-mirror-200---1200-mm.html

[JamesF 17,610]

Brand new skywatcher 8" f6 primary for 149 euros from teleskop service, link below

http://www.teleskop-...---1200-mm.html

You'd definitely want the correct size flat to go with it though, even if you make the vanes and support.

James

[username 57]

You'd definitely want the correct size flat to go with it though, even if you make the vanes and support.

James

Indeed you do!!

The best thing I've seen for calculations that may be of interest for the OP is this web page below

http://stellafane.or...b/newt-web.html

It will throw up warnings for oversize or undersize secondaries. Teleskop service sell a large amount of secondary mirrors too under the accessory section.

Also the stellafane.org website in general will tell you lots about building telescopes

Edited July 15, 2012 by username

[ajwraith 10]

Do these type of things come up often?

[JamesF 17,610]

Do these type of things come up often?

astroboot is astonishingly random, to be honest. I think it's just a way for SnS to get rid of stuff they have lying about that would otherwise get thrown in a skip. A while back they seemed to have absolutely loads of 76mm mirror sets. I did see a 130mm mirror set a while back but they didn't know if it was the spherical or parabolic mirror. Since then there haven't been that many that I was aware of, but I don't check it every day. Mostly I use it for cheap bits I want to carve up for something else.

James

[umadog 364]

Could be worth contacting some local astro societies. Often members have old kit to sell and they may be prepared to sell it for a lower price to local amateur. I see this a lot on the mailing list for one of my clubs. Last week a guy gave away a dented 8" Dob OTA with optics (scope was damaged in the storm that ripped through Washington DC recently).

[Ganymede12 361]

My school doesn't do anything like this!

Out of curiosity, how do you intend to show your pupils anything through it?

[steppenwolf 6,694]

I know this may seem completely off the wall but one telescope and 15 students is a poor ratio! How about buying two Sky-Watcher 150P Dobsonians and strip the OTAs down to their component parts so that the students can re-build them and the bases (which come flat-packed) in two teams. This is within your budget, will keep more students occupied and will make it easier to ensure some good observing time than working with just one telescope.

[Peter Drew 11,085]

I have a 8" primary mirror about F8 and suitable flat that I would be happy to donate, the mirrors are of unknown origin and the primary would need realuminising.

[Odd Thomas 122]

Peter, you are a gentleman.

[ajwraith 10]

Thanks for all of this.

I bought 200, 130 and 114mm mirror kits from astroboot. I paid £210 for all three kits. I'm also over the moon with the offer that Peter has made and although I work in Skipton I live close to his location.

It's an enrichment activity that I decided to offer in my school. I'm also Assistant Headteacher there. We are doing this project from September on Wednesday afternoons, so by the time scopes and mounts are made it should be going dark earlier. I'm also planning for the kids to take them home at times.

I'm also in contact with Keighley Astronomical Society and I've visited their area at Keighley College http://www.starcentre.org/

Thanks for all of the excellent suggestions. I'll also make good use of the calculator tool.

Andrew

[JamesF 17,610]

Sounds like it should be fun. SnS/Astroboot can be a bit slow at times. I've you've not received the mirrors in a week to ten days I'd give them a phone call to chivvy them along.

James

[jamespels 190]

Andrew, a subject close to my heart... I am part of the team that runs (or would if we had any time) Peak District Dark Skies and one of our objectives is to support science education in the region through astronomy. I also run the Peak Star Party (Oct 19 - 22) and am setting up a workshop with one of the UK lens companies to give people the chance to grind their own lenses. We will fund / part fund a number 4 - 6" mirror grinding kits (sorry it's a bit vague - still working on the details) but there is nothing stopping you contributing a little extra to get a larger blank.

Drop me a PM if you're interested with the number of students involved and I'll see what we can do.

Obviously it will mean you still need to build the dob bit but nothing stopping you from starting that earlier on.

James.

[ajwraith 10]

They texted me today saying that they will deliver tomorow.

Thanks again

[JamesF 17,610]

Blimey. I've never had that sort of service from astroboot. They'll be putting the prices up to cover it

James

[ajwraith 10]

Hi James

I was planning to make the mirrors too but I thought it may be a bridge too far. How much would it cost us to make our own 6 or 8 inch mirrors? Would you be able to offer us support? I would not know where to begin!

[jamespels 190]

Give me a few days and I'll try to get some prices fixed... should be a bit lower than list price but I can't see how much just yet!

James.