Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

CEM60 or CEM60-EC

  • Please log in to reply
721 replies to this topic

#1 souls33k3r

souls33k3r

    Vostok 1

  • -----
  • topic starter
  • Posts: 131
  • Joined: 20 Apr 2016

Posted 23 April 2019 - 10:09 AM

Hi All,

 

Let me firstly apologise because i know this topic has been much talked about and people's ears have soared up but i'm in the same dilemma as i was when i first started. Well to be fair, i'm even more scared now :)

 

I had a perfectly well NEQ6-PRO mount which i sold just last week so am out in the market looking for a new mount. 

 

My budget is limited (£2500) and within this budget and in the UK market i'm limited to a very handful of mounts. 

 

1) NEQ6-Pro

2) EQ6-R 

3) CEM60

4) CEM60-EC

 

So thinking logically, i wanted to move up the scale so CEM60 was the obvious choice, but then i got introduced to the CEM60-EC mount. Don't get me wrong, i heard good stuff about both. 

 

The two scopes that will go on this mount are the SW Esprit 100 and C8. I've been guiding using a 60mm guidescope and will continue to do so for a little while longer until i can get the OAG sorted out. (i do have it, just need to get the focus done).

 

Whilst i was researching and finding more, i started to read up on the encoders and the horror stories with guiding. 

 

Is this still an issue or has the latest firmware addressed this issue?

 

I know the NEQ6-Pro is a beast of a mount and has served me well and caused me less issues than most of the mounts out there so i expect nothing but the same with the slightly higher price point mount now.

 

Thanks in advance


  • lonelyranger likes this

#2 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 755
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 23 April 2019 - 10:31 AM

The simple answer is if you are comfortable with guiding, and intend to continue doing it, then save the money and get the non-EC mount.  The end result of a well guided session is unlikely to be much different between the EC and non-EC mount.


  • psandelle, Gene3 and souls33k3r like this

#3 Destrehan Dave

Destrehan Dave

    Mariner 2

  • *****
  • Posts: 267
  • Joined: 01 Dec 2005
  • Loc: Destrehan, LA

Posted 23 April 2019 - 10:35 AM

Hi All,

Let me firstly apologise because i know this topic has been much talked about and people's ears have soared up but i'm in the same dilemma as i was when i first started. Well to be fair, i'm even more scared now :)

I had a perfectly well NEQ6-PRO mount which i sold just last week so am out in the market looking for a new mount.

My budget is limited (£2500) and within this budget and in the UK market i'm limited to a very handful of mounts.

1) NEQ6-Pro
2) EQ6-R
3) CEM60
4) CEM60-EC

So thinking logically, i wanted to move up the scale so CEM60 was the obvious choice, but then i got introduced to the CEM60-EC mount. Don't get me wrong, i heard good stuff about both.

The two scopes that will go on this mount are the SW Esprit 100 and C8. I've been guiding using a 60mm guidescope and will continue to do so for a little while longer until i can get the OAG sorted out. (i do have it, just need to get the focus done).

Whilst i was researching and finding more, i started to read up on the encoders and the horror stories with guiding.

Is this still an issue or has the latest firmware addressed this issue?

I know the NEQ6-Pro is a beast of a mount and has served me well and caused me less issues than most of the mounts out there so i expect nothing but the same with the slightly higher price point mount now.

Thanks in advance


Personal experience, I have the CEM60-EC, and it tracks and points like a dream. I consistently can do 2min unguided subs. It’s an awesome mount, but I can’t speak to guiding yet.

My buddy ‘Uncle’ Rod Mollise says you don’t need the encoders, and he’s the grand high pubah of all things telescope, so really if you are short on change, the additional cool $1G might be better instead.

BTW, if you are a road warrior, you may want to consider the newer CEM40.

YMMV

DD
  • souls33k3r and lonelyranger like this

#4 souls33k3r

souls33k3r

    Vostok 1

  • -----
  • topic starter
  • Posts: 131
  • Joined: 20 Apr 2016

Posted 23 April 2019 - 10:36 AM

Thank you Charles.

 

I do have a few follow-up questions from your above comment, when would i not be guiding? Also isn't the RA encoder supposed to correct the PE and supposed to be better?



#5 souls33k3r

souls33k3r

    Vostok 1

  • -----
  • topic starter
  • Posts: 131
  • Joined: 20 Apr 2016

Posted 23 April 2019 - 10:38 AM

Personal experience, I have the CEM60-EC, and it tracks and points like a dream. I consistently can do 2min unguided subs. It’s an awesome mount, but I can’t speak to guiding yet.

My buddy ‘Uncle’ Rod Mollise says you don’t need the encoders, and he’s the grand high pubah of all things telescope, so really if you are short on change, the additional cool $1G might be better instead.

BTW, if you are a road warrior, you may want to consider the newer CEM40.

YMMV

DD

Again the phrase "unguided" used. Seems like people are relying on the un-guided imaging after all :) 

 

But isn't the guiding supposed to be better with the EC version? 

 

No, i'm not a road warrior and don't tempt me to become one either :D



#6 scadvice

scadvice

    Apollo

  • *****
  • Vendors
  • Posts: 1365
  • Joined: 20 Feb 2018
  • Loc: Lodi, California

Posted 23 April 2019 - 11:25 AM

I have the CEM60 with the TriPier and love the mount. I also have to set up and tear down most sessions. However, if I had an observatory I might even consider the CEM120 without the encoders for about 500 usd over the CEM60EC. I personally think the iOptron  CEM is the next step up from your first two listed mounts.

 

Anyway, (As one who is bias for the CEM iOptrons mounts) I think once you get acclimated to the the CEM60 either in a EC or not you will be very happy if you go that route. 


Edited by scadvice, 23 April 2019 - 11:55 AM.

  • lonelyranger likes this

#7 gotak

gotak

    Vanguard

  • *****
  • Posts: 2062
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 23 April 2019 - 11:27 AM

Guiding works just fine. There are no issues unless your guiding causes the encoder and guider to fight and triggering oscillation.

Guiding is better with the EC because you are not going to be issuing pulses rapidly. You let the EC handle the fast stuff and just adjust for refraction and other movements.
  • Merc, ksouers and lonelyranger like this

#8 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 755
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 23 April 2019 - 02:47 PM

Thank you Charles.

 

I do have a few follow-up questions from your above comment, when would i not be guiding? Also isn't the RA encoder supposed to correct the PE and supposed to be better?

You would not be guiding if you chose to shoot unguided.  :)  Seriously though, there are situations where folks don't want to guide.  For example, if you are shooting shorter focal lengths where the image scale would be forgiving of a small amount of periodic error, and you don't want the extra weight of a guide setup.  In my case, where I drive to nearby dark sites with a CEM25-EC, I rarely use anything longer than 350mm, and most often shoot 200mm or less.  So for me, with the light-weight mount, and small equipment load, I shoot a lot of unguided stuff.  But with longer focal lengths, where the image scale would show even the small PE that the EC is capable of, guiding is desirable.  If I were shooting at 2000mm I would definitely guide.

 

Yes, the encoder does tame PE on the RA axis, and that can help to reduce the workload that a guide setup needs to deal with.  But in general, a standard CEM60 should not have such extreme PE spikes that guiding won't be able to handle the job, even without the encoder.  That's why the final result, the image you create (which is what matters, not the graphs you get from PHD2) is unlikely to be much different between EC vs non-EC mounts.  So while the EC mount should be technically superior when guided, in practical use it's a distinction I'm not sure will be noticeable in the final image.


  • starbob1, souls33k3r and dapalmer like this

#9 gotak

gotak

    Vanguard

  • *****
  • Posts: 2062
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 23 April 2019 - 04:04 PM

So in another forum someone compared not apple to apples a CEM120 vs a CEM40EC, not exactly the same as focal lengths are different. However, for what it's worth the CEM40EC achieved 40% better results.

 

I have seen similar improvements myself between the IEQ45 Pro and the CEM60EC so I do think it makes a differences. The real question is if it is enough to matter to you for the amount of $ different. 


  • souls33k3r likes this

#10 suvowner

suvowner

    Ranger 4

  • *****
  • Posts: 382
  • Joined: 22 May 2016
  • Loc: Arkansas

Posted 23 April 2019 - 08:47 PM

well the cem60-ec is over your budget, with your scope weights the cem40 should be enough, and you could afford the ec version...ec scopes need to be guided differentlly, those who understand this dont have issues.....



#11 whwang

whwang

    Mercury-Atlas

  • *****
  • Posts: 2836
  • Joined: 20 Mar 2013

Posted 23 April 2019 - 10:28 PM

So in another forum someone compared not apple to apples a CEM120 vs a CEM40EC, not exactly the same as focal lengths are different. However, for what it's worth the CEM40EC achieved 40% better results.

 

I have seen similar improvements myself between the IEQ45 Pro and the CEM60EC so I do think it makes a differences. The real question is if it is enough to matter to you for the amount of $ different. 

 

Do you mind sharing the link?  I wonder what 40% means.  If 40% means that the star FWHM is reduced by 40%, then it will worth at least one month of my salary.  If 40% means my auto-guider needs to issue guide commands 40% less frequently, then I would say it worths nothing.


  • premk19 and souls33k3r like this

#12 gotak

gotak

    Vanguard

  • *****
  • Posts: 2062
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 23 April 2019 - 10:32 PM

It's invitation only forum.

 

The poster said 40% reduction in Phd's reported RMS values.



#13 Chuckwagon

Chuckwagon

    Viking 1

  • *****
  • Posts: 755
  • Joined: 23 Jan 2008
  • Loc: Orem, Utah, USA

Posted 23 April 2019 - 11:00 PM

It's invitation only forum.

 

The poster said 40% reduction in Phd's reported RMS values.

Which is why I noted that the important thing is not the PHD2 results, but the final image.  Either the CEM60 or CEM60-EC is likely to guide well enough that for most people the limiting factor will be seeing.  As Wei-Hao points out, a 40% reduction in FWHM, the final image result, would be worth the expense.  But the warm fuzzy of getting .5" RMS vs .8" RMS in PHD2 isn't worth much if it doesn't show up in the images.  I'm certainly not against the EC mounts, I have one.  And I'm sure for some folks the improvement in guiding will be worth the investment, I just don't think most folks would see it. 



#14 gotak

gotak

    Vanguard

  • *****
  • Posts: 2062
  • Joined: 18 Sep 2016
  • Loc: Toronto, CA

Posted 23 April 2019 - 11:14 PM

Well whether you see it or not depends on a lot of factors the biggest one being your imaging scale.

 

So whether it's worth it is a per case basis. I don't think everyone needs or should get one. In fact often I think the best mount for a lot of people is the eq6. 

 

We are in agreement there.



#15 nxda

nxda

    Mariner 2

  • *****
  • Posts: 252
  • Joined: 17 Mar 2015
  • Loc: Bluffton, Indiana

Posted 23 April 2019 - 11:38 PM

well the cem60-ec is over your budget, with your scope weights the cem40 should be enough, and you could afford the ec version...ec scopes need to be guided differentlly, those who understand this dont have issues.....

How do the EC mounts need to be guided differently? Are you saying guiding a non-ec is different than an ec? I don't at all believe this to be true so i'm very curious as to why you say that?

 

Will


Edited by nxda, 24 April 2019 - 12:28 AM.


#16 nxda

nxda

    Mariner 2

  • *****
  • Posts: 252
  • Joined: 17 Mar 2015
  • Loc: Bluffton, Indiana

Posted 24 April 2019 - 12:23 AM

So I own a 60-EC.... close to 5 years now I think, and it has been a fantastic mount for me. My guiding is generally under .3". Now i'm imaging at 700mm. I can't speak to what will happen at 1600 on your C8. 
 
This is what I believe you get with an EC model. Flexibility. Some nights trying to guide is just a nightmare because the skies aren't cooperating. When that happens I just shut PHD down and go unguided. With good PA, i'm comfortable out to 5 minutes on exposures. In theory, your images should be better because the mount is tracking better and therefore when guiding PHD is doing less work. 
 
I am not certain I've ever heard of a conflict with the encoder and guiding that created issues. Not sure where you saw that. I've been very active in the forums over the years about this mount and that's a new one for me. I'll just say, if in the past there was issue it doesn't exist today. 
 
In general I am a fan of iOptron. I am sure the non-ec is also a very good mount. I don't regret spending the extra $$ but I probably would have been happy without the encoder too.
 
My most recent guide graph
 
Good luck with your decision!
Will
IMG_5955-C.jpg

  • NMCN, StarMike8SE, jpbutler and 3 others like this

#17 whwang

whwang

    Mercury-Atlas

  • *****
  • Posts: 2836
  • Joined: 20 Mar 2013

Posted 24 April 2019 - 01:05 AM

It's invitation only forum.

 

The poster said 40% reduction in Phd's reported RMS values.

 

Thanks.  Unfortunately this is not what I am hoping for.

 

In my experience, on the same mount of mine with exactly the same setup, the night to night variation in PHD2's rms values can be 40% or even more, even though the final images have similar FWHM.  There are many factors that contribute to the PHD rms (seeing, wind, tracking accuracy etc).  Some of these factors can make a difference in the final image and some hardly can.  PHD rms is very useful, but not necessarily for judging performance of two different mounts.

 

I have used some entry-level mounts whose PE is large enough and fast-oscillating enough that every detail in guide setting can make a difference in the final image FWHM.  On such mounts, help from the encoder EC can be crucial. But I am not sure if CEM60 falls in this category.


  • souls33k3r likes this

#18 suvowner

suvowner

    Ranger 4

  • *****
  • Posts: 382
  • Joined: 22 May 2016
  • Loc: Arkansas

Posted 24 April 2019 - 01:21 AM

How do the EC mounts need to be guided differently? Are you saying guiding a non-ec is different than an ec? I don't at all believe this to be true so i'm very curious as to why you say that?

 

Will

https://www.cloudyni...ith-my-cem60ec/

 

 

you need to use longer than usual exposures and minmov 



#19 souls33k3r

souls33k3r

    Vostok 1

  • -----
  • topic starter
  • Posts: 131
  • Joined: 20 Apr 2016

Posted 24 April 2019 - 12:05 PM

Sorry for chipping in a bit late, had a busy day at work.

 

Very interesting comments from everyone.

 

The goal really is to get better guiding which should result in better eccentricity because the final image is all about how eccentric the stars are ... yes you throw away subs due to bad fwhm values or bad seeing but the less eccentric the stars are, the better the resulting image will be.



#20 suvowner

suvowner

    Ranger 4

  • *****
  • Posts: 382
  • Joined: 22 May 2016
  • Loc: Arkansas

Posted 24 April 2019 - 12:54 PM

Sorry for chipping in a bit late, had a busy day at work.

 

Very interesting comments from everyone.

 

The goal really is to get better guiding which should result in better eccentricity because the final image is all about how eccentric the stars are ... yes you throw away subs due to bad fwhm values or bad seeing but the less eccentric the stars are, the better the resulting image will be.

having a mount that is very well behaved has got to almost always be a good thing.........an encoder will always do this over the same mount without the encoder..........so if you can afford the encoder i think it is a no brainer to get it......i like that the encoder is there doing its thing taking care of pretty much all of the periodic errors, automatically and in real time without me having to do anything, then you really just need the guiding to take care of the polar alignment error and any potential non periodic error.......i love imaging with my c8 hyperstar without guiding, because i have the encoder i can do this. I am a lazy astronomer so I think the encoder is worth it, the easier it is to get setup and going the more likely i will do it..........


Edited by suvowner, 24 April 2019 - 01:01 PM.

  • Merc and souls33k3r like this

#21 spokeshave

spokeshave

    Vanguard

  • *****
  • Posts: 2091
  • Joined: 08 Apr 2015

Posted 24 April 2019 - 01:37 PM

Just to add some general thoughts on encoder mounts for consideration. I got a CEM120EC about a year ago. My intent for the single-axis encoder mount was not to image unguided. It was to improve overall guiding. My previous mount - a CGE Pro - was an excellent mount. It consistently guided at about 0.50" or below on both axes. The problem was that the DEC guiding error was always less than the RA error. The RA guiding was always fighting the periodic error and even though the PE was small, the reactive nature of the guiding meant that it was always behind the curve just a bit in RA. So even though the overall guide error was very good, because there was more error in RA, there was always some eccentricity. For short focal lengths, the eccentricity was not always obvious, but at long FL like with the EdgeHD 14 at 3910mm, the eccentricity was obvious. 

 

With the EC mount, there is virtually zero periodic error. As a result, the errors in RA and DEC guiding are always virtually identical. So although I am still guiding, my guiding is now very good in both axes and just as importantly, the error in both axes is essentially the same. To me, that is the real value of an EC mount. 

 

Tim


  • souls33k3r likes this

#22 souls33k3r

souls33k3r

    Vostok 1

  • -----
  • topic starter
  • Posts: 131
  • Joined: 20 Apr 2016

Posted 25 April 2019 - 04:39 AM

Appreciate you all giving your thoughts and making me understand this a bit better.

 

I'll be honest here, i'm really liking the sound of the CEM60 with encoders right now. Seems to me a no brainer but of course at a cost but then i have the opportunity to start fresh after selling my NEQ6-Pro mount and now i'm slightly wiser than what i was when i initially bought that mount. As much as i'd like a Mesu, it's just too weighty and secondly way out of the budget and lastly the over kill of the payload which i will never have. If  they have something smaller for a lighter payload, it would've gone for it but since there isn't, CEM60-EC is winning the race.... so far.



#23 suvowner

suvowner

    Ranger 4

  • *****
  • Posts: 382
  • Joined: 22 May 2016
  • Loc: Arkansas

Posted 25 April 2019 - 10:31 AM

Just to add some general thoughts on encoder mounts for consideration. I got a CEM120EC about a year ago. My intent for the single-axis encoder mount was not to image unguided. It was to improve overall guiding. My previous mount - a CGE Pro - was an excellent mount. It consistently guided at about 0.50" or below on both axes. The problem was that the DEC guiding error was always less than the RA error. The RA guiding was always fighting the periodic error and even though the PE was small, the reactive nature of the guiding meant that it was always behind the curve just a bit in RA. So even though the overall guide error was very good, because there was more error in RA, there was always some eccentricity. For short focal lengths, the eccentricity was not always obvious, but at long FL like with the EdgeHD 14 at 3910mm, the eccentricity was obvious. 

 

With the EC mount, there is virtually zero periodic error. As a result, the errors in RA and DEC guiding are always virtually identical. So although I am still guiding, my guiding is now very good in both axes and just as importantly, the error in both axes is essentially the same. To me, that is the real value of an EC mount. 

 

Tim

imaging at 3910mm is about as demanding as it gets.....since the cem 60 and 120 are based on the same type of design that is a huge endorsement of its capability.  the price/performance ratio of the cem-ec mounts is really really hard to beat. 


  • souls33k3r and lonelyranger like this

#24 jpbutler

jpbutler

    Apollo

  • *****
  • Posts: 1100
  • Joined: 05 Nov 2015
  • Loc: Edison, NJ

Posted 25 April 2019 - 11:23 AM

 

So I own a 60-EC.... close to 5 years now I think, and it has been a fantastic mount for me. My guiding is generally under .3". Now i'm imaging at 700mm. I can't speak to what will happen at 1600 on your C8. 
 
This is what I believe you get with an EC model. Flexibility. Some nights trying to guide is just a nightmare because the skies aren't cooperating. When that happens I just shut PHD down and go unguided. With good PA, i'm comfortable out to 5 minutes on exposures. In theory, your images should be better because the mount is tracking better and therefore when guiding PHD is doing less work. 
 
I am not certain I've ever heard of a conflict with the encoder and guiding that created issues. Not sure where you saw that. I've been very active in the forums over the years about this mount and that's a new one for me. I'll just say, if in the past there was issue it doesn't exist today. 
 
In general I am a fan of iOptron. I am sure the non-ec is also a very good mount. I don't regret spending the extra $$ but I probably would have been happy without the encoder too.
 
My most recent guide graph
 
Good luck with your decision!
Will

 

Looking at your phd2 settings, you seem to ignore the standard advice of longer exposure intervals and higher minmo values.

Can't argue with your results or 5 years of experience.

 

John



#25 nxda

nxda

    Mariner 2

  • *****
  • Posts: 252
  • Joined: 17 Mar 2015
  • Loc: Bluffton, Indiana

Posted 25 April 2019 - 12:26 PM

Looking at your phd2 settings, you seem to ignore the standard advice of longer exposure intervals and higher minmo values.

Can't argue with your results or 5 years of experience.

 

John

John,

 

I am no guiding guru... honestly what you see here is where I have landed after simple trial and error. They are not really informed settings. The only thing I play with now is exposure time... generally 2-5 seconds and it seems to work for me. I am certainly curious how others approach guiding with similar setups? 

 

Will




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics