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Equipment Discussions >> Mounts

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Bluejay08
member


Reged: 09/29/09

Re: iOptron CEM60, not a rumor anymore. new [Re: orlyandico]
      #6211406 - 11/23/13 01:32 PM

I think the performance of a mount depends on not only the rated payload, but also the type of the OTA. What more matters is the torque along the RA (tube diameter) and/or DEC (tube length). A 20lbs 108mm dia. OTA will have a better stability than a 200mm OTA. Same for the counter balancing. A Short CW shaft with more CWs should gives more stability than a CW extension with less CWs.

So I believe payload rating of iEQ45 or ZEQ25 is real and probably simulated and tested, but to what degree?


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andysea
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Reged: 09/03/10

Loc: Seattle, WA
Re: iOptron CEM60, not a rumor anymore. new [Re: orlyandico]
      #6211417 - 11/23/13 01:37 PM

I would like to add that the rated payload is only one piece of the puzzle. A30lbs Cassegrain type scope will tax the mount a lot less than a 30lbs long refractor. This is due to the longer moment arm of the refractor.

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Bluejay08
member


Reged: 09/29/09

Re: iOptron CEM60, not a rumor anymore. new [Re: andysea]
      #6211426 - 11/23/13 01:40 PM

Yes, same for an extra long tube.

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Bluejay08
member


Reged: 09/29/09

Re: iOptron CEM60, not a rumor anymore. new [Re: andysea]
      #6211428 - 11/23/13 01:40 PM

Yes, same for an extra long tube.

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Mkofski
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Reged: 07/19/11

Loc: Greenfield, Indiana, USA
Re: iOptron CEM60, not a rumor anymore. new [Re: Bluejay08]
      #6211430 - 11/23/13 01:40 PM

Quote:

I think the performance of a mount depends on not only the rated payload, but also the type of the OTA. What more matters is the torque along the RA (tube diameter) and/or DEC (tube length). A 20lbs 108mm dia. OTA will have a better stability than a 200mm OTA. Same for the counter balancing. A Short CW shaft with more CWs should gives more stability than a CW extension with less CWs.

So I believe payload rating of iEQ45 or ZEQ25 is real and probably simulated and tested, but to what degree?




I think the length is a more important factor that total weight. A short heavy SCT or Mak may work fine at or above the rated weight. I've tried a 6 or 7 pound 50" long Newt and focusing was a bear. I don't believe it would have worked at all for AP and was hard to use for visual.

Mike


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Spacetravelerx
Pooh-Bah


Reged: 12/23/12

Loc: New Mexico
Re: iOptron CEM60, not a rumor anymore. new [Re: andysea]
      #6211431 - 11/23/13 01:41 PM

Quote:

I would like to add that the rated payload is only one piece of the puzzle. A30lbs Cassegrain type scope will tax the mount a lot less than a 30lbs long refractor. This is due to the longer moment arm of the refractor.





I guess it depends on the mount. This does not matter on the LX850. SCT, Long Refractor, stacked, flat, etc.

I hope with the CEM60, being heavier duty, this is not an issue.


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Bluejay08
member


Reged: 09/29/09

Re: iOptron CEM60, not a rumor anymore. new [Re: Mkofski]
      #6211441 - 11/23/13 01:47 PM

You may try to tighten the tension adjuster a little bit.

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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: iOptron CEM60, not a rumor anymore. new [Re: Bluejay08]
      #6211460 - 11/23/13 02:00 PM

I'm a bit confused - why is the CEM60 being compared to the LX850? They seem to be in a different weight category (LX850 max: 90lbs, the CEM60 max: 60lbs). Did I miss something?

Paul


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Spacetravelerx
Pooh-Bah


Reged: 12/23/12

Loc: New Mexico
Re: iOptron CEM60, not a rumor anymore. new [Re: psandelle]
      #6211471 - 11/23/13 02:04 PM

Quote:

I'm a bit confused - why is the CEM60 being compared to the LX850? They seem to be in a different weight category (LX850 max: 90lbs, the CEM60 max: 60lbs). Did I miss something?

Paul





Let me word it differently.

I would hope a mount that can handle 60 lbs should be able to handle long refractors with a camera train, an SCT, or even a dual side by side setup.

60 lbs load speaks "beefy" to me. The lighter class mounts indicate petite.

To me if the CEM60 has an issue with a long refractor I would be concerned. My guess is though it should not (or better not!).

Still, I would love to play with one


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andysea
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Reged: 09/03/10

Loc: Seattle, WA
Re: iOptron CEM60, not a rumor anymore. new [Re: Spacetravelerx]
      #6211472 - 11/23/13 02:05 PM

I think it actually matters to all mounts, it's just a matter of where that limit is.

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psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: iOptron CEM60, not a rumor anymore. new [Re: andysea]
      #6211616 - 11/23/13 03:11 PM

Gotcha. But I'm with andysea, I think length of moment arm matters to all mounts; it's just what the limits are.

From what I know of iOptron mounts, I figure the CEM60 probably does 60lbs visual max (meaning it isn't a 12foot long refractor), as my iEQ30 was fine at 28lbs with an ES 152 achro on it (for visual).

Then, depending on the weight distribution, I could see the mount doing up to 45lbs for AP. And I'm sure some adventurous types will push that higher. I'm going to try it out with a 35lb load this spring for AP; we'll see how it does. (And to pass the "test," a mount has to be rock-solid at that weight/configuration. I don't like to worry about that while I'm snappin' pics; too many other things to fret over).

Paul


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Mkofski
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Reged: 07/19/11

Loc: Greenfield, Indiana, USA
Re: iOptron CEM60, not a rumor anymore. new [Re: Bluejay08]
      #6211654 - 11/23/13 03:50 PM

Quote:

You may try to tighten the tension adjuster a little bit.




I'll give tht a try if the weather ever clears a bit. I don't have any plans to use the 50" Newt on the Z25, just did it as a test.

Back to the CEM60... I would expect it or any mount will have more problems with a very long OTA that is at the maximum weight rating foe the mount.

I don't have any experience with "premium" mounts and don't know if the ones in the $5,000 + price range will have the same problem. Anyone out there tried to mount a 60" refractor at the maximum weight of their mount? I supose that if your mount is rated at 90 pounds it may be harder to find a long OTA that would tax the mount.


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andysea
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Reged: 09/03/10

Loc: Seattle, WA
Re: iOptron CEM60, not a rumor anymore. new [Re: Mkofski]
      #6211680 - 11/23/13 04:13 PM

I own two of the so called high end mounts and I am certain that they would behave differently with long or short scopes that are near the payload rating. At least that's what the folks at astro-physics tell me.

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Spacetravelerx
Pooh-Bah


Reged: 12/23/12

Loc: New Mexico
Re: iOptron CEM60, not a rumor anymore. new [Re: Mkofski]
      #6211688 - 11/23/13 04:18 PM

Quote:

Quote:

You may try to tighten the tension adjuster a little bit.




I'll give tht a try if the weather ever clears a bit. I don't have any plans to use the 50" Newt on the Z25, just did it as a test.

Back to the CEM60... I would expect it or any mount will have more problems with a very long OTA that is at the maximum weight rating foe the mount.

I don't have any experience with "premium" mounts and don't know if the ones in the $5,000 + price range will have the same problem. Anyone out there tried to mount a 60" refractor at the maximum weight of their mount? I supose that if your mount is rated at 90 pounds it may be harder to find a long OTA that would tax the mount.





Probably a different way to word it is, anyone have problems putting long OTAs on mounts in the 60lb class range mount?

Though anticipated price wise wouldn't this mount compete with the CGE-Pro? CGE-Pro can go to 90 lbs, BUT the CEM60 is lighter weight and has encoders.

I guess the other competition in the CEM60 mount weight range is the Mach1GTO (both being lighter weight), with the Mach1 being twice the price. However with the Mach1 you get a very known quantity.

The CEM60s other competition might be the CGEM DX. Performance wise and weight wise the CEM60 looks like it wins. Cost wise the CGEM DX wins.

I guess I am trying to figure out the mount's competition and determine which long tube OTAs might cause the CEM60 trouble. My bet is the Mach1 and CGE-Pro should have no problems, however I highly doubt folks with those mounts would put a Newtonian on them. Does the CGEM-DX have problems with long OTAs?

I can say I put my 130mm APO, which is over 27 lbs and over 37" long with gear, on the LXD75 and I have no problems there. I have got to believe the CEM60 would handle this without any problems.

All this speculation...


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mclewis1
Thread Killer
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Reged: 02/25/06

Loc: New Brunswick, Canada
Re: iOptron CEM60, not a rumor anymore. new [Re: andysea]
      #6211734 - 11/23/13 04:42 PM

Quote:

I guess it depends on the mount. This does not matter on the LX850. SCT, Long Refractor, stacked, flat, etc.



Of course it matters with the LX850, it isn't immune from the laws of physics.

The CEM60 might be just fine for imaging with an SCT like a C11 but might also have problems with a similar weight 6" apo (30-35lbs 4' length). In the same way the LX is fine with a 14" SCT but would have problems with a 9" apo (80lbs, 7' length). In this type of comparison I would also assume similar focal lengths (focal reducers used on the longer fl SCTs).

In both situations the scopes are within the specifications of the mounts but the length of the scope and where the weight is concentrated has a profound impact on how effective a mount might be.

Manufacturers are going to put their best numbers in their mount ratings, but in general the smaller the mount the more aggressive the ratings will be so comparing the imaging capabilities of a 30lb mount will be different % wise than that of a 60lb mount vs. a 90lb mount.

A whole bunch of variables (focal length, weight, tube length, weather conditions/wind, amount and type of PE, autoguiding aggressiveness, pixel size, sky conditions, etc. etc.) all contribute to determining how effective a mount might be on any particular night. No one set of numbers no matter who publishes them is going to tell you the whole story.

Edited by mclewis1 (11/23/13 08:37 PM)


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Stew57
Carpal Tunnel
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Reged: 05/03/09

Loc: Silsbee Texas
Re: iOptron CEM60, not a rumor anymore. [Re: mclewis1]
      #6211829 - 11/23/13 05:32 PM

One can group the competition by capacity but I would rather group the competition by price. The capacity is just another attribute. How close one views the rated capacity as realistic depends on the manufacturer. Some are quite optimistic others are rather conservative.

For my future mount upgrade I am looking at the EQ8 and the CEM60. Real world testing will determine my choice.


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Wmacky
Carpal Tunnel
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Reged: 11/24/07

Loc: Florida
Re: iOptron CEM60, not a rumor anymore. [Re: Stew57]
      #6211906 - 11/23/13 06:07 PM

Quote:



For my future mount upgrade I am looking at the EQ8 and the CEM60. Real world testing will determine my choice.





Me too. And a Mach One (somehow) if they fail.


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EFT
Vendor - Deep Space Products
*****

Reged: 05/07/07

Loc: Phoenix, AZ
Re: iOptron CEM60, not a rumor anymore. [Re: Astronewb]
      #6211907 - 11/23/13 06:08 PM

Quote:

may require some rethinking of the old 60-70% rule for AP




No rethinking is needed. First off, this is not a rule but a range that many people have found to be applicable to the lesser cost, mass-produced mounts of standard designs. Second, the reason for the "rule" has nothing to do with the mount itself but the kindly-put, "over-optimistic" estimates of mount capacity used by some companies. Finally, there are mounts that are both designed and manufactured to actually carry the amount of weight that the manufacturers says they can carry (and even more sometimes). The difference is that these mounts are generally well above the $2000 price range. But the configuration of the load even matters on these mounts. If a manufacturer claims that a new design can in fact carry a load that is substantially greater than other mounts in its weight and cost class without the need for more precise engineering and manufacturing, then it is for them to show that this is actually the case or for the end users to find out the hard way whether or not the claims are true. As is often stated, extraordinary claims require extraordinary proof, but you never know when a new design might actually provide that truth even when history suggests it might not.


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cloudywest
member


Reged: 06/15/13

Re: iOptron CEM60, not a rumor anymore. [Re: Mkofski]
      #6212279 - 11/23/13 10:22 PM

[quote I don't have any experience with "premium" mounts and don't know if the ones in the $5,000 + price range will have the same problem. Anyone out there tried to mount a 60" refractor at the maximum weight of their mount? I supose that if your mount is rated at 90 pounds it may be harder to find a long OTA that would tax the mount.


Yes, "premium" mounts should also follow the rule of physics. Here is the description of AP Mach 1 on payload capacity:
Approximately 45 lb. (20 kg) scope and accessories (not including counterweights), depending on length. Recommended for: Astro-Physics and similar fast refractors up to our 160 mm f7.5 Starfire EDF, 8-11" SCTs and 6-8" Maks.
These are only guidelines. Some telescopes are very long for their weight or heavy for their size and will require a larger mount. Remember also that imaging requirements are more rigid than visual observation.


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Pinbout
Postmaster
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Reged: 02/22/10

Loc: nj
Re: iOptron CEM60, not a rumor anymore. [Re: EFT]
      #6212301 - 11/23/13 10:40 PM

Quote:

If a manufacturer claims that a new design can in fact carry a load that is substantially greater than other mounts in its weight and cost class without the need for more precise engineering and manufacturing, then it is for them to show that this is actually the case or for the end users to find out the hard way whether or not the claims are true.




maybe when they display the mounts, have it loaded to compacity and run some pec software and diplay it on a 42" flatscreen, no laptop, so everyone can see.

just for fun put a vid camera in the scopes and move the mount to see the dampening time when stopping the slews.


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