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What's the largest size amateur dob available?

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#1 robininni

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Posted 14 June 2013 - 08:49 PM

Just curious. I know Starmaster makes 30". What's the biggest that wouldn't be some special abnormal custom order?

You know, such that one could purchase the structure for it from one of the usual places and one of the usual suspects would make the mirror?

Thanks,

Rob

#2 nevy

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Posted 14 June 2013 - 09:04 PM

I know a bloke called Nasa whose got a quite big one in space.

#3 robininni

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Posted 14 June 2013 - 09:06 PM

I know a bloke called Nasa whose got a quite big one in space.


Hence I put the following line in the original post:

You know, such that one could purchase the structure for it from one of the usual places and one of the usual suspects would make the mirror?

:foreheadslap:

#4 plyscope

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Posted 14 June 2013 - 09:09 PM

web page Normand Fullum telescopes :cool:

#5 nevy

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Posted 14 June 2013 - 09:20 PM

I know a bloke called Nasa whose got a quite big one in space.


Hence I put the following line in the original post:

[i]You know, such that one could purchase the structure for it from one of the usual places and one of the usual suspects would make the mirror

:foreheadslap:


Oi , it was a joke ha ha , we'll I thought it was funny. :grin:

#6 Pinbout

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Posted 14 June 2013 - 09:23 PM

Starstructure makes the smallest rigs for the largest mirrors with the horizon series. Up to 40".

#7 Mike B

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Posted 15 June 2013 - 01:04 AM

Oi , it was a joke ha ha , we'll I thought it was funny. :grin:

Isn't that the scope that came with defective optics from the start?... had to fitted with after-market corrective lenses? You want somethin' like that from the usual supplier?

:poke:

I think i'll be stickin' with the "usual" amateur suppliers- thanks.
:lol:

#8 nevy

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Posted 15 June 2013 - 07:12 AM

Oi , it was a joke ha ha , we'll I thought it was funny. :grin:

Isn't that the scope that came with defective optics from the start?... had to fitted with after-market corrective lenses? You want somethin' like that from the usual supplier?

:poke:

I think i'll be stickin' with the "usual" amateur suppliers- thanks.
:lol:


Obsession perhaps :lol:
Before I get poked with another stick , I may need to clarify that this is another joke :grin:

#9 kfrederick

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Posted 15 June 2013 - 07:46 AM

I am getting a meter blank soon I hope I think think that is the new big .

#10 Pinbout

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Posted 15 June 2013 - 08:11 AM

did you get it anealed?

#11 turtle86

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Posted 15 June 2013 - 09:02 AM

Just curious. I know Starmaster makes 30". What's the biggest that wouldn't be some special abnormal custom order?

You know, such that one could purchase the structure for it from one of the usual places and one of the usual suspects would make the mirror?

Thanks,

Rob


I'd contact Starstructure and Mike Lockwood.

#12 Fred1

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Posted 15 June 2013 - 02:42 PM

Just curious. I know Starmaster makes 30". What's the biggest that wouldn't be some special abnormal custom order?
...
Thanks,

Rob


I think going beyond 40" might, to some, be considered "some special abnormal custom order" so if you're looking to consider what the "biggest" normal is, then, IMHO perhaps 36" is the limit for normal. FWIW, I have first hand information from someone who was investigating such sizes. He posed many inquiries to owners of such, all of whom reportedly claimed one-man set-up, but when my friend actually saw them setting up, none of the owners of these large scopes set up these enormous scopes by themselves. YMMV.

ps: If you are considering going REALLY BIG, then you MUST see these scopes in person, even those in private observatories that never transport anywhere. I spent some time with Tom Clark's 42" when he was still in Chiefland. These are not scopes designed for the faint of heart.

#13 Astrojensen

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Posted 15 June 2013 - 03:10 PM

Take a look at this: http://www.cruxis.co...e/scope1070.htm

I would think more than twice before attempting to get something that monstrously huge.


Clear skies!
Thomas, Denmark

#14 robininni

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Posted 15 June 2013 - 03:24 PM

Take a look at this: http://www.cruxis.co...e/scope1070.htm

I would think more than twice before attempting to get something that monstrously huge.


Clear skies!
Thomas, Denmark


Ha, yeah, that's too big to not be stationary in an observatory in my opinion!

Rob

#15 UmaDog

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Posted 15 June 2013 - 03:28 PM

The great thing about Hänssgen's scope is that it doubles as an RV: at the end of the night he can cover the mirror, tilt the OTA upright, and go to sleep curled up in the mirror box. As you can see, though, he keeps this bedroom rather messy: http://www.cruxis.co..._InTrailer9.jpg

#16 gatorengineer

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Posted 15 June 2013 - 04:05 PM

There are 50s running around now, you can check Mike Lockwoods site. There are probaby ten or more 40's out there some of which have a long history, JMI, and Swayze come to mind, that have been around for 20 years or so.

Budget trailer size are what becomes limiting.... I think much above 30 your enter a new class of massive, generally permanent scopes...

#17 jpcannavo

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Posted 16 June 2013 - 03:43 PM

Rob,
What are you thinking...!

#18 robininni

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Posted 16 June 2013 - 03:54 PM

Rob,
What are you thinking...!


Haha! Just asking! :)

#19 JayinUT

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Posted 16 June 2013 - 05:29 PM

I talked with Mike Lockwood in the spring and voice mail with Mike about a 36 inch dob. Still looking at it but it will be fall before I can move forward with it (stuff happens when you own some farms you lease out and have to do some replacement of equipment).

Anyway, Mike Clements is building and is almost done with his 70 inch reflector which is out at Steve Dobbs home/land. Here is a link to a post in February on that from my blog.

#20 turtle86

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Posted 16 June 2013 - 08:01 PM

Take a look at this: http://www.cruxis.co...e/scope1070.htm

I would think more than twice before attempting to get something that monstrously huge.


Clear skies!
Thomas, Denmark


I think a scope that size would be fine in a permanent observatory, but I'd definitely think twice about trying to transport one. I'd also think twice about using a scope that size for solar observing, as shown in one of the pics. I'd be concerned that with the tiniest flaw in that solar filter, one's face would melt like a candle as in that scene from Raiders of the Lost Ark.

#21 Astrojensen

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Posted 17 June 2013 - 02:28 AM

The problem with a scope this size is that an observatory is going to be incredibly expensive, simply because of the huge size and amount of material needed for its construction, not to mention the machinery and hours needed.


Clear skies!
Thomas, Denmark

#22 Jason D

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Posted 17 June 2013 - 02:40 AM

Those who can afford a 70" reflector should not have any problem affording an observatory ;)

#23 Astrojensen

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Posted 17 June 2013 - 03:04 AM

I'm not so sure about that. We do tend to want to maximize aperture and totally forget everything else.

Also, making the scope portable and not needing an observatory can suddenly either cut the total price in more than half or almost double the available cash you can spend on aperture.

No matter how we look at it, observatories are expensive. And in many places, they require permittance and must follow building regulations, adding complexity. A domed observatory for a 40" f/5 scope is massively huge, the size of a normal family house.


Clear skies!
Thomas, Denmark

#24 careysub

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Posted 17 June 2013 - 03:17 AM

I have thought that if you want to make a really huge Dob that it should be housed in a permanent observatory along the lines of the MMT on Mt. Hopkins:

http://www.hposoft.c...ry/ModelMMT.JPG

The entire structure rotates with the telescope (although the outer structure is isolated from the telescope mount) with clam shell doors covering the entire front. This allows a fixed elevator chair mechanism to provide easy seated viewing.

This could work even if the telescope itself is designed to be "mobile" (has wheels and can move). It would be rolled into the observatory and then secured rigidly in place.

#25 careysub

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Posted 17 June 2013 - 03:21 AM

But you need a place to keep the giant mobile telescope anyway.

To some extent this is an unavoidable expense.

And you need to move it if it is to be really mobile - a huge trailer and a big truck, or else a U-Haul moving van, or similar.






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