Topics

Mach1 Capacity


patrim01@...
 

I am considering a tandem setup on my Mach1. When I add up the weight of all components that would mount on top of the head, i.e., including tandem bar, saddles and dovetails plus all that mounts above that it would total about 55 lbs. Would this overload the mount for visual use? I have to think not when compared to a G11 with a 60 lb capacity rating, but wanted to ask those who would know best. Thx.
Bill


Suresh Mohan
 

I image very comfortably with 12 inch Newtonian whose ota without rings is 30 kilos ie 66 pounds; pls note my place has no wind
Suresh


On Feb 26, 2014, at 7:31 AM, <patrim01@...> wrote:

 

I am considering a tandem setup on my Mach1. When I add up the weight of all components that would mount on top of the head, i.e., including tandem bar, saddles and dovetails plus all that mounts above that it would total about 55 lbs. Would this overload the mount for visual use? I have to think not when compared to a G11 with a 60 lb capacity rating, but wanted to ask those who would know best. Thx.

Bill


Mark Acker
 

I think the general consideration here is not so much the total weight, but the moment arm.  That is, if you have a shorter, heavier scope (or set of gear), that would be easier for the mount to handle than a really long refractor, for example.

To answer your question, 55 lbs is not too much for the mount, especially for visual.
 
Mark Acker


From: "patrim01@..."
To: ap-gto@...
Sent: Tuesday, February 25, 2014 8:01 PM
Subject: [ap-gto] Mach1 Capacity

 
I am considering a tandem setup on my Mach1. When I add up the weight of all components that would mount on top of the head, i.e., including tandem bar, saddles and dovetails plus all that mounts above that it would total about 55 lbs. Would this overload the mount for visual use? I have to think not when compared to a G11 with a 60 lb capacity rating, but wanted to ask those who would know best. Thx.
Bill




Keith Egger
 

I image with a 40 lb payload consisting of a SkyWatcher 190mm Mak-Newt and a piggy-backed Stellarvue 90mm triplet refractor using an 18 lb + 10 lb counterweight for a total weight of 90 lbs, and I get sub-arc second guiding with that setup. AP recommends 97 lbs total weight with counterweights. Sounds like Suresh is imaging with more weight than that, so I can't imagine you would have a problem with that weight for visual. 
...Keith


Donghun
 

Take a look at these comparison photos between G11 and Mach1GTO.
You can see Mach1GTO is more substantial mount even tough it is lighter.
I doubt that G11 will handle more than Mach1GTO.


patrim01@...
 

Thanks All. That's what I thought but wanted to ask to be sure. I am planning on mounting both my TEC200MC and TEC APO110 side by side this weekend. Both are fairly short in length so moment arm should not be an issue. But all together with scopes, accessories, saddles and plates, I expect to be 55 to 60 lb. 
Keith mentioned AP recommendation not to exceed 97 lbs with counterweights. Where does this come from? I have not see it in my manual or on the Mach1 website.
Regards,
Bill


George
 

Bill,

 

The Mach1 can hold the weight…you are not going to break anything; however, we do not recommend that weight.  We estimate capacity based upon an imaging setup.  Is there a reason that you need to put two scopes on the mount instead of swapping them out?  If there is wind at the star party, you will be less satisfied.

 

We never include counterweights in the capacity ratings of our mounts, just the payload going on the mount.

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-282-1513

Email:  george@...

 

From: ap-gto@... [mailto:ap-gto@...] On Behalf Of patrim01@...
Sent: Friday, February 28, 2014 12:41 PM
To: ap-gto@...
Subject: [ap-gto] RE: Mach1 Capacity

 

 

Thanks All. That's what I thought but wanted to ask to be sure. I am planning on mounting both my TEC200MC and TEC APO110 side by side this weekend. Both are fairly short in length so moment arm should not be an issue. But all together with scopes, accessories, saddles and plates, I expect to be 55 to 60 lb. 

Keith mentioned AP recommendation not to exceed 97 lbs with counterweights. Where does this come from? I have not see it in my manual or on the Mach1 website.

Regards,

Bill


Keith Egger
 

Bill, I can't remember where that came from - it's been in my spreadsheet so long that my memory is hazy. Given that, it's probably best to be suspect of that number. 
...Keith


Keith Egger
 

George, your response re not including CW limits means that 3 x 18lb CWs on the optional short (10.7") Mach1 shaft is no different than an 18lb plus a 5 lb CW on the 10.7" CW shaft + 9.5" extension (according to my spreadsheet both would be balanced), even though the former would put a total weight of 114.7 lbs on the mount and the latter a total weight of 90.3 lbs. Is that correct? Is that because the moment arm of the short shaft would compensate for the greater weight required to balance the OTA load? Or am I not understanding something?

...Keith


Gregory <fyrframe@...>
 

I currently use my Mach1 in a dual scope config. Using all AP components, I have a TMBSS 130mm f/7 with AP’s big finder scope and a green laser mounted next to a ES 102mm f/6.5 with it’s own finder scope including mounting rings for both. I also have an old SBIG ST7 CCD camera with it’s filter wheel. I use 4, 9.5 AP weights and with scope positioning on the head, I have found excellent balance. I also use the RAPAS.
 
The only issue of any concern is that I have had to tighten up both the DEC and RA gears twice in my 1 1/2 years of ownership.
 
I don’t know the total weight involved, but I wouldn’t hesitate to recommend a similar set up.
 
Gregory
Gig Harbor, WA.
 

Sent: Tuesday, February 25, 2014 6:01 PM
Subject: [ap-gto] Mach1 Capacity
 

I am considering a tandem setup on my Mach1. When I add up the weight of all components that would mount on top of the head, i.e., including tandem bar, saddles and dovetails plus all that mounts above that it would total about 55 lbs. Would this overload the mount for visual use? I have to think not when compared to a G11 with a 60 lb capacity rating, but wanted to ask those who would know best. Thx.

Bill


Keith Egger
 

Just a "back of envelope" estimate based upon the weights given on the scope websites would seem to put you in the same ballpark as my imaging setup - around 40 lbs. 
...Keith


George
 

Keith,

 

There is no email history attached to your email, so I don’t know what was talked about.  We state that the Mach1 capacity is 45 lb.  We base our recommendation for imaging systems.  That stated weight refers to the payload (scope configuration) placed on the mount.  It does not refer to, nor include, the counter weights which are used to counterbalance the scope…they will be what they must be.  Don’t think it to death…enjoy imaging!  <G>

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-282-1513

Email:  george@...

 

From: ap-gto@... [mailto:ap-gto@...] On Behalf Of eggerk@...
Sent: Friday, February 28, 2014 6:05 PM
To: ap-gto@...
Subject: [ap-gto] RE: Mach1 Capacity

 

 

George, your response re not including CW limits means that 3 x 18lb CWs on the optional short (10.7") Mach1 shaft is no different than an 18lb plus a 5 lb CW on the 10.7" CW shaft + 9.5" extension (according to my spreadsheet both would be balanced), even though the former would put a total weight of 114.7 lbs on the mount and the latter a total weight of 90.3 lbs. Is that correct? Is that because the moment arm of the short shaft would compensate for the greater weight required to balance the OTA load? Or am I not understanding something?

...Keith


Keith Egger
 

My query George is that if you only specify payload there are quite different configurations of CW that can balance that load - by my calculations there is a 25 lb difference between between how much weight you would need to balance with the 10.7" shaft versus the 10.7" plus extension (20" total length). So I take it that this difference doesn't matter even though the total weight of the payload plus CW is very different? I've often puzzled about this because I have the 10.7" and the extension - should I put extra weight on the short shaft (shorter moment arm) or should I use the extension (longer moment arm) and reduce the total weight required? Does it make any difference which strategy I use? 
...Keith


George
 

Keith,

 

Either way will work.  We are not talking about a major difference in moment arm, even though it is generally best to keep it shorter rather than longer.  The weight is not a concern since it is a balanced weight.  The mount’s bearings can handle many times that much weight. 

 

Regards,

 

George

 

George Whitney

Astro-Physics, Inc.

Phone:  815-282-1513

Email:  george@...

 

From: ap-gto@... [mailto:ap-gto@...] On Behalf Of eggerk@...
Sent: Monday, March 03, 2014 9:41 AM
To: ap-gto@...
Subject: RE: [ap-gto] RE: Mach1 Capacity

 

 

My query George is that if you only specify payload there are quite different configurations of CW that can balance that load - by my calculations there is a 25 lb difference between between how much weight you would need to balance with the 10.7" shaft versus the 10.7" plus extension (20" total length). So I take it that this difference doesn't matter even though the total weight of the payload plus CW is very different? I've often puzzled about this because I have the 10.7" and the extension - should I put extra weight on the short shaft (shorter moment arm) or should I use the extension (longer moment arm) and reduce the total weight required? Does it make any difference which strategy I use? 

...Keith


Keith Egger
 

Thanks for the info. 
...Keith


jimmyjujames
 


All AP mount's bearings can easily support many times the recommended maximum OTA weight.
It's the moment arm (moment of inertia) that you want to minimize.
The worm and worm wheel must overcome this moment of inertia.
The bearings are not a problem and can easily support many times the
 recommended maximum OTA weight.

AP Mounts are very robust and can handle either extreme as long as you
 do not go above the maximum recommended OTA weight.

Since you have your spreadsheet started

Add another column or row for Moment of inertia

The results might be counter-intuitive but shows

The lowest Moment of inertia is with the most amount of counter weights on the shortest shaft.

The largest Moment of inertia is with the least amount of counter weights on the longest shaft.

I use the third equation in the DEFINITION section (about a forth of the way down the page)

http://en.wikipedia.org/wiki/Moment_of_inertia

I=m*r*r

For ''m'' I use 18, 10 or 5
''r'' is the length of the counter weight shaft from the center of the RA axis to
 around the center(?) of each counter weight.

Balance and then calculate the moment of inertia for each counter weight
 and then add them together for a total for this configuration.

I have 40-50 pounds on the OTA side of my 900 and my calculated moment of inertia doubles
 when I change from most counter weights on shortest shaft to least counter weights on
 longest shaft (with no extension).

AP Mounts are very robust and can handle either extreme as long as you
 do not go above the maximum recommended OTA weight.

I personally use the most weights on the shortest shaft for the lowest moment of inertia.

Total weight is not a problem, the bearings can handle many times the
 maximum recommended OTA weight.
 Your balanced and the extra weight is not a problem for the bearings.

The moment arm (moment of inertia) is what you try to minimize.
Increasing above the recommended maximum OTA weight also increases your moment of inertia.

Your balanced and the bearings can easily support the total weight.

The moment if inertia must be over come by the worm and worm wheel.

As always, I may be wrong again.
Jimmy