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"Largest" Amateur Scopes?

Scubadude

By Scubadude
in DIY Astronomer

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Scubadude

Scubadude

Posted
Posted

Was idly surfing this afternoon, I noticed that Orion make a 50" dob! Got me wondering what was the largest scope in use/built by amatuers?

Also wondered if any amatuers where using segmented mirrors, (I guess 50" mirrors aren't cheap) whereas a bunch of 10" ones might be more affordable?

Does segmentation work on a small scale or it is only viable when you suppase what you can make a single mirror do?

(Largest I could find referance too was 42"- Dr. Erhard Hänssgen's 42 inch (107 cm) Dobsonian Telescope)

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John

John

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I'm not 100% sure if UK-based John Wall counts as an amateur but he built one of the largest refractors in the world - 30 inches aperture. It's a special folded design using a singlet objective lens and a corrector somewhere long the light path. Don't know if it still exisits:

post-12764-133877520262_thumb.jpg

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John

John

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Awesome how much would one of them cost

im gonna start saving up :D

A 20" Orion Optics (UK) dobsonian costs around £5,500. Just the mirrors for a 30" cost around £10,000 so a 50" ? - say £30,000 ? - probably more.

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russ

russ

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There's apparently a new revolution in amatuer telescopes on the way which will mean very large scopes not being overly big. Someone called Mike lockwood has come up with a 20" f3 dob, designed in collaboration with Al Nagler and i think the Starmaster guy. It has to be used in conjuction with the new Televue Paracor 2.

The focal length is only 1500mm for a 20" :D Pretty amazing. No ladder required! Will open the door for much larger models without silly focal lengths and climbing 12ft ladders in the dark.

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bish

bish

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I read about those 20" f3 dobs in a mag recently ('Astronomy' I think). They sound a great idea. I have to admit though that a small part of me (ie the show off part) would want a 20" scope to look huge - even if it means falling off a ladder!

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russ

russ

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I read about those 20" f3 dobs in a mag recently ('Astronomy' I think). They sound a great idea. I have to admit though that a small part of me (ie the show off part) would want a 20" scope to look huge - even if it means falling off a ladder!

Ah yes that's where i read it.....standing WH Smiths :D

I suppose the ladder is part of the attraction. I did see Linton's big Obsession at Salisbury SP but didn't go over for a look. Was worried about falling off the ladder, wrecking his scope and car in all one swift movement.

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kris h

kris h

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The focal length is only 1500mm for a 20" :D Pretty amazing. No ladder required! Will open the door for much larger models without silly focal lengths and climbing 12ft ladders in the dark.

That does sound amazing thats the only thing i dont like

about the giant dobs having to use ladders

if you find any pics in the future of these dobs plz post them :evil1:

clear skies

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John

John

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How big do the scopes get at Stargazing events here in the uk? Its enough to make me want to get myself along to one of them. :)

There was a David Lukehurst 20" dobsonian at the SGL5 star party last year and I managed to get a quick peek through it at M51 and M13.

Simply amazing views :evil1:

I had a bad case of aperture fever for weeks after that ....... :D

BTW David Lukehurst does a range of ultra portable large aperture dobs:

DAVID LUKEHURST

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Beano

Beano

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What sort of view would you get through them?

Say, with a 9", an image of Jupiter from them that is a good quality usually has Jupiter the size of around 75-90 pixels wide (on a pc screen). How big would an image of Jupiter look through a 1 meter one?

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Nexus 6

Nexus 6

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There was a David Lukehurst 20" dobsonian at the SGL5 star party last year and I managed to get a quick peek through it at M51 and M13.

Simply amazing views :evil1:

I had a bad case of aperture fever for weeks after that ....... :D

BTW David Lukehurst does a range of ultra portable large aperture dobs:

DAVID LUKEHURST

John, thanks for that link, I am really envious of you looking through a 20" dob and seeing M13, my personal favourite dso. It was the first one I observed with my 6se a few years back. I can see why you have had that terrible fever :)

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ollypenrice

ollypenrice

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We have a 20 inch f4.1 and based on this experience I personally would want to go for faster f ratio and keep the focal length down to 2 metres or less. If you just keep adding aperture and focal length your field of view keeps diminishing. This means you never do get to see M101 as a complete, bright spiral, nor M33 etc. You just get to see more and more fainter, smaller, galaxies in the same kind of detail as you saw familiar ones before the increase.

So that f3 scope seems to me to be a truly great idea.

As for ladders, no thanks! I welded up a wheeled steel platform for two, with handrail all around it. Yhis makes tracking easier (you rest your arms on the rail as you steer) and has a built in bin for EPs etc.

Olly

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Moonshane

Moonshane

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Ah yes that's where i read it.....standing WH Smiths :evil1:

I suppose the ladder is part of the attraction. I did see Linton's big Obsession at Salisbury SP but didn't go over for a look. Was worried about falling off the ladder, wrecking his scope and car in all one swift movement.

yeah, there's nothing more annoying than the imprint of a bloodied nose on your primary :D

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