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APM's largest mount too good to be true?

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#1 dddhgg

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Posted 29 July 2010 - 06:11 AM

While browsing APM's site I stumbled across their giant APM-GE 300 mount. It certainly looks imposing, but I wonder: 600 kg maximum telescope weight (visually) for "only" 23,700 euros? Too good to be true? As far as I know this capacity far exceeds anything else commercially available. For example, the OGS-190 lifts a mere 200 kg and costs somewhere near $150k.

By the way, for those who don't read German, here are the specs:

Axis diameter in RA and DEC: 140 mm exterior, interior 90 mm
Material: steel
Polar height: 0° to 90°
Drive: Steel friction gears 350 mm in diameter, with Servo motors
Net weight: 450 kg (560 kg if three counterweights are added)
Photographic telescope weight capcity: 400 kg
Visual telescope weight capacity: 600 kg
Gear error: less than 5", + - 2.5
Overload clutch on both axes
Delivery time: approx. 1 year

Included in delivery:
GE300 mount with motors and FS2 computer control
Friction gearbox
Counterweight bar
4 x 40 kg counterweights
Pedestal adapter.

#2 gnowellsct

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Posted 29 July 2010 - 03:56 PM

I think that mount is intended for c14s in portable applications.....

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#3 nemo129

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Posted 29 July 2010 - 04:41 PM

Greg,
You are a riot! Only "girly men" would use a lighter mount...because 450 kg to 560 kg is after all...quite portable! :lol: I hope to see the video on this as well! :bow:

#4 dddhgg

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Posted 29 July 2010 - 05:36 PM

Greg,
You are a riot! Only "girly men" would use a lighter mount...because 450 kg to 560 kg is after all...quite portable! :lol: I hope to see the video on this as well! :bow:


It's possible of course that someone added a few zeroes by mistake (or forgot a few decimal points). But if not, I'm still intrigued by the fact that for twice the cost (approx.) of say a Paramount ME you would get a mount which lifts about eight or nine times the weight.

#5 johnnyha

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Posted 29 July 2010 - 08:47 PM

The 600kg is for visual. If you're doing AP the limit is only about 900 pounds - I'll stick to my EM200 thanks. :grin:

#6 dddhgg

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Posted 29 July 2010 - 10:20 PM

But what commercially available scope weighs 900 lbs?

#7 nemo129

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Posted 29 July 2010 - 10:57 PM

Maybe something a research center would purchase? A larger RC?

#8 gnowellsct

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Posted 29 July 2010 - 11:42 PM

Maybe something a research center would purchase? A larger RC?


But as you get into these larger instruments it becomes more the rule that you put a field de-rotator on the scope's camera and track in alt-az....much as I love the GEM, once you get above a certain point, it's alt-az all the way.

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#9 Russ S.

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Posted 30 July 2010 - 08:11 AM

But what commercially available scope weighs 900 lbs?


Two 450 lb scopes?

#10 mayidunk

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Posted 30 July 2010 - 09:38 AM

That's a grab 'n go mount if I ever saw one! :whistle:

#11 Brian Risley

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Posted 01 August 2010 - 07:21 PM

"I think that mount is intended for c14s in portable applications....."

Got to see the video of you packing that mount into your car and another of you setting it up and lifting your C-14 on to it without a ladder! :roflmao:
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#12 Scopyfrank

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Posted 02 August 2010 - 04:37 AM

Greg,
You are a riot! Only "girly men" would use a lighter mount...because 450 kg to 560 kg is after all...quite portable! :lol: I hope to see the video on this as well! :bow:


After the hairy chested portable scope, here's the hairy chested portable mount.
:sumo: <--- he is not hairy chested btw.

#13 RichA

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Posted 02 August 2010 - 09:52 PM

Anyone remember Rand who advertised in Sky and Tel in the 1970's, they had scopes on trailers? Or Lorentz Systems? Still, AP is a mount company, not a scope company (as they say) and likely aim this at institutions, maybe the military

#14 dothead

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Posted 03 August 2010 - 06:40 AM

or wealthy amateurs link (scroll down the page): the 24 inch Cassegrain Telescope mounted on the K-140 mount (which is the same as the APM GE-300) weighs approx. 220 pounds, which leaves some weight margin with this mount (which is good for it's intended use as a purely Astrophotography instrument).

Another use for this huge mount would be big aperture, long focus refractors (long arm of force!): would Astrophysics' biggest mount, the "El Capitan", hold an 12 inch F/20 D&G without too much jitter (20 foot long OTA) ?
Or this puppy (11+ feet long 10 inch heavy duty (268 lbs) APO) ?

Or maybe an BIG, long focus Newton ?

Cheers,

Ralph

#15 Keithdrengen

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Posted 04 August 2010 - 10:00 AM

21" f12 apo, doesnt specify the weight though.
http://www.astroshop...00-cnc-ii-ota/p,8508
Have to copy and paste the link.

#16 dothead

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Posted 05 August 2010 - 06:18 AM

yeah, Markus Ludes' old dream! - though impractical except in the most temperate (=tropical) climate. He experienced too much thermal issues (in his observatory in Germany) even with his 12" APO (the huge lens didn't manage to track the falling nighttime temperatures and thus experienced too much sperochromatism).
The 21" APO was at one time commisioned to be installed at the premises of the ARGUS project (amateur astronomer club in Indiana), but the project was abandoned because of lack of funds.

Normally the rule of thumb in mounting refractors is that the lens diameter should not exceed 3 times the axis diameter of the mount. Example: the maximum for AstroPhysic's 1200 mount (3.35 inch shaft) is a 10 inch refractor, which complies with all empirical experiences.
Thus even the APM GE-300 (= Knopf K-140), with it's 140 mm = 5.5 inches shafts, would be insufficient to support the 21 inch F/12 APO. A 16 inch refractor would very likely be the limit!!!

Cheers,

Ralph

#17 dddhgg

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Posted 08 August 2010 - 02:52 AM

Normally the rule of thumb in mounting refractors is that the lens diameter should not exceed 3 times the axis diameter of the mount. Example: the maximum for AstroPhysic's 1200 mount (3.35 inch shaft) is a 10 inch refractor, which complies with all empirical experiences.
Thus even the APM GE-300 (= Knopf K-140), with it's 140 mm = 5.5 inches shafts, would be insufficient to support the 21 inch F/12 APO. A 16 inch refractor would very likely be the limit!!!

Cheers,

Ralph


I didn't know about this rule; thanks! Do you know whether there exist
some similar rules for shorter tubed telescopes (like RCs or fast newtonians). I'd guess their shorter lever arm and generally lower mass per inch of aperture means that you can push further in terms of aperture. Correct?

#18 dothead

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Posted 09 August 2010 - 04:50 AM

Kim,

of course there are no "hard rules", but for visual applications there is the general consensus that for "short-tube" scopes (tube length < 3 x tube diameter), the mass of the telescope's OTA should not exceed the mass of the equatorial mount's head (= mount without counterweights).
Of course this depends how well-engineered the mount is, and also how much wind there is.
For Astrophotography, there would be more stringent conditions to observe.

Best wishes,

Ralph

#19 dddhgg

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Posted 11 August 2010 - 06:08 AM

Thanks Ralph! I'll keep that in mind.

#20 Jerome Ni

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Posted 15 August 2010 - 05:22 AM

600 KG?Jesus&#65281; How big is the worm wheel&#65311;

#21 dothead

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Posted 16 August 2010 - 04:06 AM

no worm wheels used - this mount employs friction wheels of 14 inches diameter, so there are NO periodic errors...

BUT... those 600 kg would be much reduced if you'd want to mount a long-focus refractor. For example, a 16 inch F/20 D&G achromat OTA would weigh about 100 kg, but because of the long arm of torque would very likely be the limit even for this mount!






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