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Severe case of Aperture Fever

Started by DOTrevino , Nov 16 2012 10:08 AM

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25 replies to this topic

#1 DOTrevino

Vostok 1

topic starter

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Joined: 16 Nov 2009

Posted 16 November 2012 - 10:08 AM

I watched this last night in the local news. Quite a severe case.

click here

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#2 JayinUT

I'm not Sleepy

Posts: 6,142
Joined: 19 Sep 2008

Posted 16 November 2012 - 10:40 AM

I dropped off some mirrors for Carl at Nova this last summer with a friend and saw this out at Steve's garage. It is truly an amazing thing Mike and Steve are doing here. Here's wishing them all the luck in the world in getting it done and if they need some local help there's a group of us that would love to help. I will say, what an ATM project!

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#3 star drop

The Cardinal

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Posted 16 November 2012 - 10:43 AM

Aperture fever indeed!

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#4 csa/montana

Den Mama & Gold Star Award Winner

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Posted 16 November 2012 - 10:52 AM

Jay, if Mike is not a CN'r; maybe he would care to join, and share his experience of the builds!

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#5 mwt

Sputnik

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Joined: 15 Feb 2012

Posted 16 November 2012 - 04:07 PM

Wow....how do you calculate the size of the secondary??

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#6 GpB311

Mariner 2

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Joined: 29 May 2012

Posted 16 November 2012 - 04:38 PM

Id pay just to look through it for a minute.

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#7 Tim Gilliland

Viking 1

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Joined: 28 Mar 2009

Posted 16 November 2012 - 04:48 PM

Id pay just to look through it for a minute.

+1

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#8 skyward_eyes

Vendor - Sky-Watcher USA

Posts: 5,460
Joined: 12 Dec 2006

Posted 16 November 2012 - 06:12 PM

Haha I know him. His been working a long time on this. Truly a follow your dream story

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#9 TileArt

Sputnik

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Joined: 13 Sep 2012

Posted 16 November 2012 - 10:19 PM

I'd love to look through that just once.

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#10 Ed D

Aurora

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Joined: 30 Apr 2010

Posted 17 November 2012 - 08:57 AM

If he mounts this behemoth on a tractor trailer, like he did with his 'smaller' scope on the pickup truck, it would probably make it the ultimate grab and go!!!

Ed D

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#11 Starry eyes

Vostok 1

Posts: 150
Joined: 30 Apr 2010

Posted 17 November 2012 - 11:31 AM

So this is where that 70" is now. Actually the 70" blank is a Corning Pyrex that was cast as part of the scaling up process that culminated in the 120" Shane Telescope and the 200" Hale. It was originally made for a spectrograph, then found it's way to Tasmania where it languished until the late eighties when it was acquired by group 70. It had a sizable sagitta cast by bricks. It also had about a 1:6 thickness to diameter ratio so is a bit heavy. We always wondered about the cool down time!

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#12 Seldom

Surveyor 1

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Posted 17 November 2012 - 01:23 PM

Anyone have an idea what the focal length is?

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#13 csrlice12

ISS

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Posted 17 November 2012 - 02:05 PM

I'd say that goes a little beyond Amateur Astronomer. Is he looking to adopt? I'm available, I don't eat much.

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#14 BigC

Fly Me to the Moon

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Joined: 29 Sep 2010

Posted 19 November 2012 - 10:46 AM

You do realize that once you looked through the 70 inch ,nothing smaller will be acceptable ?!

Some years ago,several lucky amateurs were able to view with the 100 inch -forget just where I read about it. But moons of Jupiter were describes as orbs,not disks.

Wonder if there are any more of those spy mirrors available ?? :question:

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#15 Edward E

Surveyor 1

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Posted 19 November 2012 - 10:47 AM

At 70", if it was an f3 that would mean a minimum eyepiece height of 19 ft!

I would love to look through the scope but not climb the ladder to the eyepiece!

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#16 csrlice12

ISS

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Posted 19 November 2012 - 10:50 AM

You could go to the Military surplus auctions...they're always selling unneeded stuff; like rolling staircases/ladders they use for aircraft maintenance.....Portable, no, but neither is a 70" scope....

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#17 Seldom

Surveyor 1

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Posted 19 November 2012 - 11:58 AM

At 70", if it was an f3 that would mean a minimum eyepiece height of 19 ft!

I would love to look through the scope but not climb the ladder to the eyepiece!

Maybe he's got something in mind like Herschel's 48" scope, or Lord Rosse's "Leviathan of Parsontown". Also, IIRC the blank wasn't silvered (aluminized). I wonder where he can get that done?

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#18 coopman

Cosmos

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Joined: 23 Apr 2006

Posted 19 November 2012 - 12:39 PM

I hope that he has a structural engineer checking the framework that he is building to support the mirror. I would not have a good feeling if I were "winging" this part of the scope design.

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#19 csrlice12

ISS

Posts: 34,128
Joined: 22 May 2012

Posted 19 November 2012 - 12:41 PM

Theres an old radio telescope for sale in South America I believe. Maybe coat that thing with a mirror surface with the objective lens in orbit???? :lol:

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#20 Dave Mitsky

ISS

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Joined: 08 Apr 2002

Posted 19 November 2012 - 01:51 PM

Is it a parabolic or hyperbolic primary mirror? Aren't spy satellites equipped with variations of the Ritchey-Chretien Cassegrain design or three-mirror astigmats?

Dave Mitsky

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#21 FirstSight

Duke of Deneb

Posts: 17,409
Joined: 26 Dec 2005

Posted 19 November 2012 - 04:18 PM

There's a paradox for even the most avid amateur astronomer:
- the larger the aperture, the brighter and deeper the objects you can see BUT:
- the objects at the edge of visibility won't be any brighter than the objects that were at the edge of visibility in aperture several inches smaller AND there will be at least as many objects that are beyond the range of the current larger aperture scope you have as were beyond the range of the several inches smaller aperture scope you had before.

Not only that, but in darker skies than you have, you could see just as bright and deep with your smaller aperture scope than you can in your less dark skies with your larger aperture scope.

MORAL(s): aperture rules, but the size of the kingdom it rules is limited by how dark the skies are it's used under; also, there's always a swarm of galaxies and clusters that are just over the boundaries of your averted vision, no matter what aperture you have or how dark your skies.