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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Ultimate capacity yet portable mount: AP 2400GTO ?
      #4419423 - 03/01/11 03:39 PM

...as an intermediate mount between the 1200 (81 lbs) and the 3600 (205 lbs), something like a 130ish lbs Astro-Physics mount would be still transportable for a determined individual (RA-unit approx. 80 lbs as the heaviest part), and would handle loooong refractors, like an 8" f/20, or big & heavy imaging scopes, like the CDK 17 & 20.

Do you think there's a "gap" between the 1200 and the 3600 ?

Could Astro-Physics touch a market segment with a 130 lbs "2400GTO" mount ?


Regards,

Ralph


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LLEEGE
True Blue
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Reged: 03/03/05

Loc: Cloud-chester,NY
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419442 - 03/01/11 03:50 PM

NEAF is right around the corned. You never know what Roland will unveil. This topic was mentioned on the APUG but RC didn't have much to say on the matter. I wouldn't hold your breath.

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Peter in Reno
Postmaster
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Reged: 07/15/08

Loc: Reno, NV
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: LLEEGE]
      #4419458 - 03/01/11 03:57 PM

I wouldn't exactly call AP1200 portable and now you want a portable AP2400? AP1200 has a huge carrying capacity of 140 pounds. What monster scope do you want to carry and call it portable?

Peter


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Peter in Reno]
      #4419522 - 03/01/11 04:31 PM

Quote:

"What monster scope do you want to carry and call it portable?"

8" f/20 refractor, with a weight of approx. 50 lbs ("portable" for a single person).

50 lbs may sound "easy" for the 140 lbs - rated AP 1200, but because of the extremely long torque moment arm (OTA length is 14 feet (with dew cap), it will tax the 1200 severely.

Torque moment is identical for:

14 feet 50 lbs OTA
7 feet 100 lbs OTA
3.5 feet 200 lbs OTA (which is beyond the 1200's capacity)

Got my point ?


Regards,

Ralph


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M13 Observer
scholastic sledgehammer


Reged: 12/09/06

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419527 - 03/01/11 04:32 PM

Quote:

...as an intermediate mount between the 1200 (81 lbs) and the 3600 (205 lbs), something like a 130ish lbs Astro-Physics mount would be still transportable for a determined individual (RA-unit approx. 80 lbs as the heaviest part), and would handle loooong refractors, like an 8" f/20, or big & heavy imaging scopes, like the CDK 17 & 20.

Do you think there's a "gap" between the 1200 and the 3600 ?

Could Astro-Physics touch a market segment with a 130 lbs "2400GTO" mount ?


Regards,

Ralph




Sounds like the solution to a problem which doesn't exist.


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skybsd
Post Laureate
*****

Reged: 02/01/08

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419529 - 03/01/11 04:33 PM

Transportable? Even if one could find a way to modularize the mount into more portable components, you're still left with a 140lb scope to think about..,

I'd have thought that if one had the coin for a CDK20, its reasonable to think that one would already have been looking at the el Capitan to begin with

Regards,

skybsd


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: skybsd]
      #4419544 - 03/01/11 04:38 PM

M13, skybsd,

So what about that 8" f/20, 50 lbs refractor ?

The 140 lbs rating applies to short, compact scopes.

Example: I've seen a 30 lbs 6" f/17.5 D&G mounted on the AP 900 (rated for 70 lbs), and the owner remarked that the 900 was barely adequate in holding it stable enough. He suggested the 1200 would be more appropiate for that 30 lbs refractor.


Regards,

Ralph

Edited by dothead (03/01/11 04:39 PM)


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skybsd
Post Laureate
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Reged: 02/01/08

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419590 - 03/01/11 04:51 PM

Hello,

Quote:

The 140 lbs rating applies to short, compact scopes.




I think you misunderstand..,

The CDK20 (bare OTA) weighs 140lbs - even if you find a way to design your theoretical mount to be modular enough to have portable assembly components, you still have to find a way to manage carrying the CDK20.

Regards,

skybsd


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: skybsd]
      #4419629 - 03/01/11 05:08 PM

skybsd,

yes, you're right - the CDK 20 was an ill-advised example.

But still, what about that 50 lbs, 8" f/20 (my next scope project) ?

Re portability of the mount: for this 6' 3", 240 lbs guy, 80 lbs (as the heaviest part) is still manageable.

(Germany is the country of beer. A beer crate with 20 0.5 liter bottles weighs in at 19.7 kg = 43.4 lbs. I find it a not too big effort to lift two full beer crates together on a 30"-high table - so I consider it feasible for myself to handle a 80 lbs RA-unit).


Cheers,

Ralph

Edited by dothead (03/01/11 05:59 PM)


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M13 Observer
scholastic sledgehammer


Reged: 12/09/06

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419637 - 03/01/11 05:11 PM

Quote:

M13, skybsd,

So what about that 8" f/20, 50 lbs refractor ?

The 140 lbs rating applies to short, compact scopes.

Example: I've seen a 30 lbs 6" f/17.5 D&G mounted on the AP 900 (rated for 70 lbs), and the owner remarked that the 900 was barely adequate in holding it stable enough. He suggested the 1200 would be more appropiate for that 30 lbs refractor.


Regards,

Ralph




http://www.planewave.com/index.php?page=1&id0=1&id=2

Done.


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: M13 Observer]
      #4419708 - 03/01/11 05:41 PM

thanks for the link.

Yes, I've also considered the Planewave mount, but the single most heavy component is 96 lbs, which is just that little too much (compared to 80 lbs) which would make it non-transportable for me.

Another candidate I considered is the Mathis Instruments MI-500 mount ( link ), but again, 100 lbs for the polar cone component is those 20 lbs too heavy.

Same with the Knopf MK-70 mount (see Astrolumina): relatively inexpensive for it's capacity, extremely stable, but 220 lbs with two 110 lbs components - not manageable.

What make AP mounts so attractive is that they are designed for maximum strength and rigidity with minimum weight.
Mathis Instruments, Knopf, and I suspect also Planewave, didn't intend their mounts to be portable, so they did not minimize weight to achieve portability.

I therefore suspect that a 130 lbs AP2400 mount would exhibit the same strength and rigidity as the 200 lbs MI-500.


Well, maybe I should just pull the trigger and see how the AP1200 would handle the 8" f/20 refractor...


Ralph


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skybsd
Post Laureate
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Reged: 02/01/08

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419716 - 03/01/11 05:45 PM

Quote:

Well, maybe I should just pull the trigger and see how the AP1200 would handle the 8" f/20 refractor...




Just about the safest bet anyone can make these days

Regards,

skybsd


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Peter in Reno
Postmaster
*****

Reged: 07/15/08

Loc: Reno, NV
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: skybsd]
      #4419720 - 03/01/11 05:49 PM

Have you e-mailed Astro-Physics and asked if your 14 feet long scope can be handled by AP1200? They will be more than happy to answer.

Peter


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: skybsd]
      #4419728 - 03/01/11 05:53 PM

well, you're probably right.

Though this mount from German master engineer Manfred Mauz (technical chief of the mechanical department of Munich Observatory) is reported to have a phenomenal stability for it's weight class (88 lbs, two 44 lbs components).

Decisions, decisions...


Ralph


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Peter in Reno]
      #4419737 - 03/01/11 05:57 PM

Not yet.

The 900 is rated for up to 180 mm f/8 refractors, the 1200 for up to 206 mm f/8, the 3600 for up to 12" f/12.

Though I suspect the 1200 could handle a 10" f/12, and I know that at 3RF, a 15" f/12 D&G is mounted on the AP3600.

Another possibility would be the Parallax HD200C (105 lbs, breaks in two components).


Regards,

Ralph

Edited by dothead (03/01/11 06:02 PM)


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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419855 - 03/01/11 06:58 PM

Paramount ME is your best bet. The most efficient mounting on Earth. It weighs 87 lbs and it lifts 150 lbs. It is right now on sale for $12,500. It is a steal for anyone from the euro zone.

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skybsd
Post Laureate
*****

Reged: 02/01/08

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Alph]
      #4419912 - 03/01/11 07:21 PM

Quote:

It is right now on sale for $12,500. It is a steal for anyone from the euro zone.




Errr., Nope, nope , and..., no

Regards,

skybsd


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Alph]
      #4419944 - 03/01/11 07:39 PM

The question is, can we take the manufacturer's stated capacity as gospel ?
In the light that some are more conservative than others with their specs.

Don't want to stir a hornet's nest, but are there opinions if the Pm ME ("150lbs cap.") is as beefy as the AP1200 ("140lbs cap.) ?

As a purely visual guy, I don't like to use a labtop in the field (like the Pm ME requires).


Regards,

Ralph


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Peter in Reno
Postmaster
*****

Reged: 07/15/08

Loc: Reno, NV
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4419978 - 03/01/11 08:05 PM

Astro-Physics capacities are typically for imaging. So if you are a visual observer only, then you can easily increase the capacity to up to double their advertised rate. Ask Astro-Physics first.

Peter


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Alph
Carpal Tunnel


Reged: 11/23/06

Loc: Melmac
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: skybsd]
      #4420070 - 03/01/11 08:39 PM

Quote:

Quote:

It is right now on sale for $12,500. It is a steal for anyone from the euro zone.




Errr., Nope, nope , and..., no

Regards,

skybsd




Sure, but he does not have to use an european dealer.


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Keith Howlett
Pooh-Bah
*****

Reged: 03/06/07

Loc: Northumberland, UK
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4420254 - 03/01/11 10:05 PM

Quote:

The question is, can we take the manufacturer's stated capacity as gospel ?
In the light that some are more conservative than others with their specs.

Don't want to stir a hornet's nest, but are there opinions if the Pm ME ("150lbs cap.") is as beefy as the AP1200 ("140lbs cap.) ?

As a purely visual guy, I don't like to use a labtop in the field (like the Pm ME requires).


Regards,

Ralph




Hi Ralph,

You see quite a few 20 inch RCOS mounted on Paramounts and these weigh 163 lbs without cameras and accessories. I don't think I would get away with that on my AP1200 but I think it would cope with the advertised cat/cass type 140 lbs load. (It was loaded to this level by the previous owner with no ill effects.)

Cheers,

Keith


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skybsd
Post Laureate
*****

Reged: 02/01/08

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Alph]
      #4420656 - 03/02/11 03:16 AM

Quote:

Quote:

Quote:

It is right now on sale for $12,500. It is a steal for anyone from the euro zone.




Errr., Nope, nope , and..., no

Regards,

skybsd




Sure, but he does not have to use an european dealer.





Indeed - I don't disagree with you..,

But unless such a buyer is willing to be creative - they're stuck with SB's EU distributorship's pricing

Regards,

skybsd


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Keith Howlett]
      #4420706 - 03/02/11 04:58 AM

Keith,

many thanks for your reply.

The question is how a mount will handle not a heavy, compact, but a "lightweight", but extremely long OTA.

While going lightweight with a long OTA (I'll use Carbon Fibre as material) sounds a good idea as far as portability of it is concerned, this also decreases the OTA's inertia against torque forces, like wind - talk about surface to mass ratio.

Guess I have to do real sound calculations to get a better idea of the matter - or better still, mount the 8" f/20 CFK refractor OTA on an AP1200 of someone else's first and see how the setup behaves...


Regards,

Ralph


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Keith Howlett
Pooh-Bah
*****

Reged: 03/06/07

Loc: Northumberland, UK
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4422208 - 03/02/11 07:15 PM

Hi Ralph,

That's understood and it's a question for the good people at Astro-Physics. They are very helpful, it would be worth a phone call.

Cheers,

Keith


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Duncan Kitchin
Pooh-Bah


Reged: 12/16/04

Loc: Beaverton, OR, USA
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Alph]
      #4422674 - 03/02/11 11:10 PM

Quote:

Quote:

Quote:

It is right now on sale for $12,500. It is a steal for anyone from the euro zone.




Errr., Nope, nope , and..., no

Regards,

skybsd




Sure, but he does not have to use an european dealer.




I'm not so sure about that - buying from outside of Europe and having it shipped can be expensive - particularly if customs stop the package in transit (becomes more likely with large packages) and demand the payment of 20% VAT...

Regards & Clear Skies
Duncan


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RogerRZ
Whatta you lookin' at?
*****

Reged: 01/09/06

Loc: West Collette, NB, Canada
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: Duncan Kitchin]
      #4423402 - 03/03/11 09:49 AM

One also has to put himself in a mount manufacturer's shoes.

Is there a market for a mount that can handle an 8" f/20 refractor. I don't know how many are actually out there, and of them how many of them would spring for a $20000 mount?


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: RogerRZ]
      #4423818 - 03/03/11 12:53 PM

yes of course, nothing to be said against this.

But let's consider you own a CDK 20 at a private observatory.

The AP 1200 (capacity 140lbs) would struggle with this scope (140lbs OTA) and auxilliary equipment.

The AP 3600 (capacity 300+lbs) would seem to somehow be "overkill" for this setup.

The "AP2400" (capacity 200ish lbs) would be the ideal mount for this scope, and cost less than the 3600.


Regards,

Ralph


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wz2
Most Boring Astronomer...


Reged: 07/30/10

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4424572 - 03/03/11 07:12 PM

I don't think any manufacturer wants to proliferate mounts in this price/capacity range. There's just not a big enough market.

Plus you're talking "private observatory" and CDK20 class instruments. A CDK20 is $32k for the scope alone. What's a comparable aperture RCOS go for, $50k? With scope, mount, dome, etc you're easily looking at rigs in the $100k range +.

I suspect the price difference between a hypothetical "AP2400" and the AP3600 would be relatively immaterial to a player in this range. Hence, not much motivation for AP to market one.

Just my opinion.

Chris


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: wz2]
      #4424694 - 03/03/11 07:58 PM

so, the poor ol' 8" f/20 refractor...

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wz2
Most Boring Astronomer...


Reged: 07/30/10

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4424780 - 03/03/11 08:36 PM

Ralph,

Won't this 8" f/20 scope create quite the torque moment arm across your broad German shoulders as well? It will be at least 14' long I'm assuming. You're looking for a portable mount so I'm thinking the whole set up will be portable, including scope?

Chris

ps Been to Munich - drank beer at Oktoberfest (lots) - it was fun


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: wz2]
      #4424818 - 03/03/11 08:57 PM

will transport tube and lens separately... (get modular!)

shall be "movable" until I'll manage to build a home for it...

it can be done (see Ziggy's 9" f/15 Clark).

done too many tracks in Nepal and have seen the Sherpas strut their stuff...


Ralph

Edited by dothead (03/03/11 08:59 PM)


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wz2
Most Boring Astronomer...


Reged: 07/30/10

Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: dothead]
      #4424853 - 03/03/11 09:21 PM

Ralph,

Won't this thing also need a rather large (tall) tripod or pier to keep the focuser / eyepiece from scraping the ground?

Chris

Trekked Nepal myself. Flew into Lukla (before they paved the runway). I'm dating myself.


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dothead
scholastic sledgehammer


Reged: 08/13/08

Loc: Heidelberg, Germany
Re: Ultimate capacity yet portable mount: AP 2400GTO ? new [Re: wz2]
      #4425915 - 03/04/11 01:39 PM

yes - I'll go for a height-adjustable pier (ala Pier-Tech), offered by a local company (normally for industrial applications):

minimum height: 60"
maximum height: 100"

With the additional 15" height of the mount, the eyepice will be about 25" above the ground when OTA is pointed at zenith.



Regards,

Ralph

Edited by dothead (03/04/11 01:43 PM)


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