Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Mounts

Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | (show all)
OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: iOptron CEM60, not a rumor anymore. new [Re: Astronewb]
      #6200645 - 11/17/13 08:28 PM

Gday Paul

Quote:

Andrew, I have a feeling that the tried and true iEQ45 will be relegated to that role in iOptrons lineup?




Dunno.
If the beast has good encoders and motor control loops, adding AltAz ability is merely a bit of code
why not have both mounts with the same ability but different
tolerances and accuracy.
I could stop designing my Krof mount then

Truly interesting times coming in the next few years.

Andrew Johansen Melbourne Australia


Post Extras: Print Post   Remind Me!   Notify Moderator  
Stew57
Carpal Tunnel
*****

Reged: 05/03/09

Loc: Silsbee Texas
Re: iOptron CEM60, not a rumor anymore. new [Re: OzAndrewJ]
      #6200775 - 11/17/13 10:04 PM

How about adding a starsense like camera in the polar scope hole? Auto align with needing an ASPA routine. A stepper for the alt and one for the az and a mount that self polar aligns.

Edited by Stew57 (11/17/13 10:23 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Christopher Erickson
Carpal Tunnel
*****

Reged: 05/08/06

Loc: Waikoloa Village, Hawaii
Re: iOptron CEM60, not a rumor anymore. new [Re: Stew57]
      #6200817 - 11/17/13 10:37 PM

Quote:

It is still a GEM. Yokes have been used in a lot of axis supports in a lot of industries. The design while not common is of little ultimate interest to me. The interest is in the machine tolerances of gearing, encoder operation, and HC software implementation. This is what will separate it from the pack or make it just another so so choice among the others although it will look a bit different.




It is an English Equatorial Mount, not a German Equatorial Mount.

Amateurs have been talking about and using forks and GEM's for so long that they have forgotten about all of the other equatorial mount designs that exist. Most of the other designs (English, French, English Cross-Axis, Yolk, etc.) just aren't as popular. However many of the non-AltAz big scopes can be found with these other mount designs.

However congratulations to iOptron for trying to step out and be one of the leaders and innovators and just not another far-East follower.

I just wish that their electronics were a bit more powerful and user-friendly. And if you are going to build in USB, please do it with an FTDI chip! Or better yet, go back to RS-232 or forward to Ethernet-TCP/IP. Anything but *BLEEP*-old, problematic USB and its perpetual OS driver problems and inevitable driver obsolescence.


Post Extras: Print Post   Remind Me!   Notify Moderator  
cloudywest
member


Reged: 06/15/13

Re: iOptron CEM60, not a rumor anymore. new [Re: Stew57]
      #6200827 - 11/17/13 10:46 PM

Quote:

It is still a GEM.



No, not a GEM. Think about when the mount is at zero degree altitude, the payload and CW of a GEM is at the same side of the tripod, or the center of gravity is outside the tripod top, while the CEM60 at different sides and center of gravity at the top of the tripod.


Post Extras: Print Post   Remind Me!   Notify Moderator  
cloudywest
member


Reged: 06/15/13

Re: iOptron CEM60, not a rumor anymore. new [Re: Christopher Erickson]
      #6200833 - 11/17/13 10:51 PM

Quote:


It is an English Equatorial Mount, not a German Equatorial Mount.
Amateurs have been talking about and using forks and GEM's for so long that they have forgotten about all of the other equatorial mount designs that exist. Most of the other designs (English, French, English Cross-Axis, Yolk, etc.) just aren't as popular. However many of the non-AltAz big scopes can be found with these other mount designs.

However congratulations to iOptron for trying to step out and be one of the leaders and innovators and just not another far-East follower.

I just wish that their electronics were a bit more powerful and user-friendly. And if you are going to build in USB, please do it with an FTDI chip! Or better yet, go back to RS-232 or forward to Ethernet-TCP/IP. Anything but *BLEEP*-old, problematic USB and its perpetual OS driver problems and inevitable driver obsolescence.




It is not an English mount too. To me they are fundamentally different. CEM60 balances the system by putting the payload and counterweight at different sides, so the center of gravity can be always at the center of the tripod by adjusting the CW. I think it was why the CEM60 named, Center-balanced Equatorial Mount. English mount uses no counter weight and mounts the OTA in a fork. If we need to name their similarity, they both have a fork; however, the functions of the fork are totally different, one is part of the body providing altitude adjustment and supporting the DEC, the other is an OTA holder (same as most of Meade fork mounts.
Here is a description of English Fork Mount by Wikipedia.
The English mount or Yoke mount[6] has a frame or "yoke" with right ascension axis bearings at the top and the bottom ends, and a telescope attached inside the midpoint of the yoke allowing it to swing on the declination axis. The telescope is usually fitted entirely inside the fork, although there are exceptions such as the Mt. Wilson 2.5 m reflector, and there are no counterweights like German mount has.
The original English fork design has the disadvantage of not allowing the telescope to point too near the north or south celestial pole.


Post Extras: Print Post   Remind Me!   Notify Moderator  
psandelle
professor emeritus


Reged: 06/18/08

Loc: Los Angeles
Re: iOptron CEM60, not a rumor anymore. new [Re: Stew57]
      #6200836 - 11/17/13 10:52 PM

Quote:

How about adding a starsense like camera in the polar scope hole? Auto align with needing an ASPA routine. A stepper for the alt and one for the az and a mount that self polar aligns.




You know, I had asked about the possibility of something like this, but with simple encoders in the alt/az that synched with the GPS and a magnetic compass so one could just polar align that way.

I like your way better...I'm lazy.

Paul


Post Extras: Print Post   Remind Me!   Notify Moderator  
OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: iOptron CEM60, not a rumor anymore. new [Re: cloudywest]
      #6200848 - 11/17/13 11:02 PM

Gday CloudyWest

Quote:

It is not an English mount too. To me they are fundamentally different




I noted earlier and Chris also mentioned it in passing
that this is based on an "English Cross Axis Mount",
where the OTA isnt fitted in a fork, and there is an opposing counterweight.
The innovative bit is putting the counterweights outside the bearings
such that the mount can be miniaturised.

Andrew Johansen Melbourne Australia


Post Extras: Print Post   Remind Me!   Notify Moderator  
dvb
different Syndrome.
*****

Reged: 06/18/05

Loc: Vancouver, Canada
Re: iOptron CEM60, not a rumor anymore. new [Re: OzAndrewJ]
      #6200915 - 11/17/13 11:58 PM

The CEM60 weighs about 10 lb less than the EQ6/ (27 lb v 37 lb IIRC), with a greater carrying capacity. It only weighs 2 lb. more than the iEQ45.

For me, that could replace the EQ6 I use for my 10" and the iEQ45 I use for smaller scopes, into one mount.

Considering that it may also be closer to the EQ6 than to the iEQ45 in quietness, it is pretty tempting.

But, like the iEQ45, will the first hardware release require some "tweaking"?


Post Extras: Print Post   Remind Me!   Notify Moderator  
Dan Finnerty
sage


Reged: 09/11/11

Loc: Pasadena, CA
Re: iOptron CEM60, not a rumor anymore. new [Re: OzAndrewJ]
      #6200936 - 11/18/13 12:11 AM

Quote:

Gday CloudyWest

Quote:

It is not an English mount too. To me they are fundamentally different




I noted earlier and Chris also mentioned it in passing
that this is based on an "English Cross Axis Mount",
where the OTA isnt fitted in a fork, and there is an opposing counterweight.
The innovative bit is putting the counterweights outside the bearings
such that the mount can be miniaturised.

Andrew Johansen Melbourne Australia




I am in a pedantic mood and something about these references to the CEM being an English Equatorial design is starting to bug me.

Whether an English Yoke or an English Cross, the essential feature of the English design is that the telescope is suspended *between* two RA bearings. The cross design avoids the flaw of the Yoke design obstructing the view of Polaris.

If someone can show an example of an English mount design that does not have the RA bearings on either end I would appreciate it. Google does not know everything

As we all know, the German design cantilevers the Dec axis off the end of the RA axis, the entire weight of the OTA and counterweight is cantilevered off the end of the RA shaft. Not optimal for mechanical stability by any means, but with enough "beef" it has been an effective design for many years.

The CEM design is neither a GEM nor an English design. The OTA is cantilevered off the lower end of the RA axis unlike a GEM (or English), but the counterweight is cantilevered of the opposite end of the RA shaft thus counterbalancing the OTA in RA as well as in Dec. This counterbalancing along RA is THE essential feature of the CEM design.

I submit that cantilevering the OTA off the end of the RA shaft is a fundamental difference from the English design. By your definition Andrew, the GEM is just an English Cross with the cross moved beyond the upper RA bearing and the yoke bearings miniaturized. So why bother calling it a GEM?

Phew got that off my OCD checklist! Now I can cope again

[edited to change some really bad wording]

Edited by Dan Finnerty (11/18/13 12:20 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
OzAndrewJ
scholastic sledgehammer
*****

Reged: 11/30/10

Re: iOptron CEM60, not a rumor anymore. new [Re: Dan Finnerty]
      #6200952 - 11/18/13 12:30 AM

Gday Dan

Quote:

The OTA is cantilevered off the lower end of the RA axis unlike a GEM (or English),




Are we talking the same mount here???
The ZEQ25 matches the above description,
but the CEM does have the OTA mounted "between" the RA bearings???

Andrew Johansen Melbourne Australia


Post Extras: Print Post   Remind Me!   Notify Moderator  
dvb
different Syndrome.
*****

Reged: 06/18/05

Loc: Vancouver, Canada
Re: iOptron CEM60, not a rumor anymore. new [Re: OzAndrewJ]
      #6200996 - 11/18/13 01:38 AM

Sounds more and more like CEM means "Chinese Equatorial Mount" - Neither German nor English.

Post Extras: Print Post   Remind Me!   Notify Moderator  
Christopher Erickson
Carpal Tunnel
*****

Reged: 05/08/06

Loc: Waikoloa Village, Hawaii
Re: iOptron CEM60, not a rumor anymore. new [Re: OzAndrewJ]
      #6201001 - 11/18/13 01:44 AM

Quote:

Gday Dan

Quote:

The OTA is cantilevered off the lower end of the RA axis unlike a GEM (or English),




Are we talking the same mount here???
The ZEQ25 matches the above description,
but the CEM does have the OTA mounted "between" the RA bearings???

Andrew Johansen Melbourne Australia




Agreed.

I think Dan is referencing the ZEQ25 and not the CEM60.

The CEM60 has the weight of the optical assembly between two RA bearings, which is the fundamental feature of the English Equatorial Mount.

I guess we could call it modified English Cross Axis Equatorial Mount, since iOptron moved the counterweights to one end of the RA axis instead of directly-opposing the optical assembly.

I played with the prototype at ASAE and it looked very intriguing... until I spotted that it had stepper motors instead of servos. For me that's a show-stopper right there. Steppers use a lot-more current and give off a lot-more heat. Batteries don't last as long. Radiant heat is never a desirable feature of a telescope mount. Especially for imagers.

And steppers... step. And microstepping requires a lot more, steady current that makes them put out a lot more heat and discharge your batteries that much faster.

And not being able to track well-past the meridian would be a real show-stopper for my imaging.

I think I would take an IEQ45 over a CEM60 any time.

Of course, YMMV!


Post Extras: Print Post   Remind Me!   Notify Moderator  
AndreyYa
member


Reged: 12/05/06

Loc: Sunnyvale, CA
Re: iOptron CEM60, not a rumor anymore. new [Re: dvb]
      #6201023 - 11/18/13 02:13 AM

Hi Chris,

I'm not sure that stepping motors are so hungry... Orion Atlas and Sirius take less than 500ma 12v at tracking (or guiding), and less than 2A during 800x sideral rate slew.


Post Extras: Print Post   Remind Me!   Notify Moderator  
moligpy
member


Reged: 11/22/10

Loc: Santa Clara, California
Re: iOptron CEM60, not a rumor anymore. new [Re: AndreyYa]
      #6201038 - 11/18/13 03:04 AM

The specs of CEM60 Power consumption says:
0.6A(Tracking), 1.1A(GOTO)

It seems CEM60 does not drain very much power.

Edited by moligpy (11/18/13 03:05 AM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
freestar8n
Post Laureate
*****

Reged: 10/12/07

Re: iOptron CEM60, not a rumor anymore. new [Re: Christopher Erickson]
      #6201043 - 11/18/13 03:16 AM

Quote:

I guess we could call it modified English Cross Axis Equatorial Mount




There is no cross here (it's more of a Z), and the polar axis bearing is not split so the weight can swing through it. I think it is closer to a GEM than English. I'm pretty sure I have seen variations on this theme somewhere, but I can't find any - either by an ATM or commercially.

When it comes to judging a mount for how well it can autoguide, I mainly go by how well it actually autoguides.

It seems like the weight may be better balanced on the pier itself - but it would be torquing the polar axis. Not sure what the trade offs are.

A clear advantage for low latitude would be the ability to tilt the counterweight shaft out, away from the pier.

And using batteries for the counterweight - as an option I guess - immediately saves weight in what you carry to a remote site.

Frank


Post Extras: Print Post   Remind Me!   Notify Moderator  
ur7x
sage


Reged: 01/08/12

Re: iOptron CEM60, not a rumor anymore. [Re: Dan Finnerty]
      #6201333 - 11/18/13 09:52 AM

Quote:

The essential feature of the English design is that the telescope is suspended *between* two RA bearings. The cross design avoids the flaw of the Yoke design obstructing the view of Polaris.




If that is what an English EQ is "essentially", then it might help to point out that the CEM60 does in fact have two RA bearings, and the Dec arm (and the OTA) is suspended *between* them.

By your own definition, it is in fact a modified English Cross.

Of course we can all see that rather than having two massive (and offset RA bearing) they have compacted them (so elegantly that you actually missed one of them) and rather than off set the whole thing enough to clear a counter weight arm inside of the bearings, they moved the counter weight outside of the *yoke* bearing.

Not new at all, but very innovative. Since this seems to be the first time the English cross has been adapted for small portable scopes.


Post Extras: Print Post   Remind Me!   Notify Moderator  
dvb
different Syndrome.
*****

Reged: 06/18/05

Loc: Vancouver, Canada
Re: iOptron CEM60, not a rumor anymore. [Re: ur7x]
      #6201516 - 11/18/13 11:36 AM

I will be interested to see how, in practice, CEM60 deals with crossing the South meridian.

Much of my viewing involves such a crossing. With my gear, this is not a problem, as I have instructed the iEQ45 to ignore it, and the OTA is not in danger of striking anything.

But, if a mechanical flip is required, it could be annoying.


Post Extras: Print Post   Remind Me!   Notify Moderator  
andysea
Pooh-Bah
*****

Reged: 09/03/10

Loc: Seattle, WA
Re: iOptron CEM60, not a rumor anymore. [Re: dvb]
      #6201855 - 11/18/13 02:53 PM

I might be wrong but it seems to me that the mount design does not allow tracking much far past the meridian because the dec assembly would collide with the body of the mount itself.

Post Extras: Print Post   Remind Me!   Notify Moderator  
dvb
different Syndrome.
*****

Reged: 06/18/05

Loc: Vancouver, Canada
Re: iOptron CEM60, not a rumor anymore. [Re: andysea]
      #6201872 - 11/18/13 03:06 PM

The black box the dec cable probably plugs into looks like it would contact the larger RA bearing.

Post Extras: Print Post   Remind Me!   Notify Moderator  
andysea
Pooh-Bah
*****

Reged: 09/03/10

Loc: Seattle, WA
Re: iOptron CEM60, not a rumor anymore. [Re: dvb]
      #6201879 - 11/18/13 03:09 PM

I guess I am not understanding how the thing works because it looks like the entire DEC housing/wheel and everything would hit the body of the mount itself.
You're right tho, the black box would hit first.
I will wait to see one in action:)

Andy

Edited by andysea (11/18/13 03:11 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | (show all)


Extra information
26 registered and 46 anonymous users are browsing this forum.

Moderator:  Dave M, richard7, bilgebay, iceblaze 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 17210

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics