Eq8 or CEM120

[Nigella Bryant]

Hi all, wanting some opinions on mounts. It will be the last mount I'll buy having turned 60 last year and retired. I currently run an OO12inch f4 Newtonian on a neq6. It's at the top of weight capacity for that mount at 20kg with guidescope, etc. I did rebuild and tune the neq6 with rowan belt mod, upgraded bearings on worm gears, added the upgrade counter weight bar plus weights. It is sweet as a nut and after two or even three star alightment puts the object within the field of view of my Canon 1000dm camera. I can also do unguided images for 45 to 60 secs which is enough in Mt light polluted sky. That's the background. 

Now I know my mount is way over capacity for imaging and in the next couple of years before I go into the heavens myself I'd like to own a 16inch VX f4 Newtonian. So I'm thinking of going for a new mount this year for keeps and  I'm looking at either an EQ8 or a CEM120. The cem120 would be at the top of my price range. 

I'd love opinions please. BTW, telescope is housed in an observatory a 2.7m pulsar dome. 

 

Edited May 12, 2019 by Nigella Bryant

[cotak]

If it's the last one why not go out with a bang?

I think in this contest the cem120 is the better choice just for the cable management alone. And the lack of backlash would be good too.

[Nigella Bryant]

1 hour ago, cotak said:

If it's the last one why not go out with a bang?

I think in this contest the cem120 is the better choice just for the cable management alone. And the lack of backlash would be good too.

That's what I was thinking, along with USB 2 and 3 connection, GPS and WiFi built in. Keep thought's coming, lol. 

[Jkulin]

I'm biased CEM120EC all the way

[Whirlwind]

Is this just for imaging of visual as well?  I ask because if you want a longer focal length of about 1600mm and it is just for imaging then why not say the VXL12"?  This would be less burdensome mount wise and aperture is less important (compared to visual) when it comes to imaging.  It's also not as costly so would allow more funds to be spent on the mount (which is always the critical part of imaging set up).  You are saving about £2k.  That could then go towards upscaling the mount (which might open up things like the MESU) and/or a cooled CMOS colour camera which would also likely improve your images.  If you are committed to going for this weight capacity the only other mount with this capacity and price range that I know of is the JTW OGEM but is relatively untested (the base version is similar to the CEM120 in price). 

On the other hand if you want a visual telescope as well then a 16" will work wonders and that changes your mount choices.

[Datalord]

I was very seriously considering a CEM120EC before buying an ASA DM85. But only the EC version. I think those encoders are worth it knowing all the trouble guiding can give you. (disclaimer: Still haven't tried imaging without guiding, but I spent a ton of money getting to that point...).

[Rainer]

On 12/05/2019 at 01:44, Nigella Bryant said:

I can also do unguided images for 45 to 60 secs which is enough in Mt light polluted sky.

Hi,

Why do you limit yourself to this exposure times ?

Rainer

[Nigella Bryant]

On 13/05/2019 at 01:37, Datalord said:

I was very seriously considering a CEM120EC before buying an ASA DM85. But only the EC version. I think those encoders are worth it knowing all the trouble guiding can give you. (disclaimer: Still haven't tried imaging without guiding, but I spent a ton of money getting to that point...).

My top price to spend is£3500

[Nigella Bryant]

1 hour ago, Rainer said:

Hi,

Why do you limit yourself to this exposure times ?

Rainer

Cus in light polluter skies more shorter image's stacked are better than less longer one's. I saw a convincing talk on this recently. 

[Nigella Bryant]

On 12/05/2019 at 19:54, Whirlwind said:

Is this just for imaging of visual as well?  I ask because if you want a longer focal length of about 1600mm and it is just for imaging then why not say the VXL12"?  This would be less burdensome mount wise and aperture is less important (compared to visual) when it comes to imaging.  It's also not as costly so would allow more funds to be spent on the mount (which is always the critical part of imaging set up).  You are saving about £2k.  That could then go towards upscaling the mount (which might open up things like the MESU) and/or a cooled CMOS colour camera which would also likely improve your images.  If you are committed to going for this weight capacity the only other mount with this capacity and price range that I know of is the JTW OGEM but is relatively untested (the base version is similar to the CEM120 in price). 

On the other hand if you want a visual telescope as well then a 16" will work wonders and that changes your mount choices.

I have considered the Ogem as it's only £150 more than a CEM120 but I'm weary as there's literally nothing out there about them, apart from their own Web page. I did email them asking for more information about the mount and all I got back was an obtuse reiteration of my question. "what would I like to know" da, a download on spec, a pdf brochure of an actual mount. Their website seems to contain mostly computer graphic simulations, etc. So I'm now weary about that. Wasn't a fantastic promotion of their mount. 

[Rainer]

11 hours ago, Nigella Bryant said:

Cus in light polluter skies more shorter image's stacked are better than less longer one's. I saw a convincing talk on this recently. 

Hi,

Understand and I guess it is all a question of what objects we do image.

I asked because I image from a suburban sky and make 900 second exposure time images.

I have two CEM 120EC2 and I would say it is the best investment ratio so far. 115 lbs carrying capacity (no counterweights included in that ratio, to added to it) for each US $ 6.998,00. No other mount brand has a carrying capacity including encoders for that  price.

The Plain Vanilla CEM 120 is US 3.998,00 which is also inbeatable.  You will not find a mount with this carry/price ratio. Perhaps the Skywatcher EQ-8 ?

OK the mount is out now for about 18 months but I know as having beta tested a lot for iOptron that the mount is ripe to about 95%. Mechanically the mount is very robust (OK, the USA market does not like injection molded parts) perhaps because they are not shiny and you have no bling bling moment 🤣

The base model CEM 120 ist I would say 99% ripe. iOptron Customer support is first class.

As you see I am very biased but also very satisfied with my two mounts and they carry a lot.

Rainer

PD Look where I am 😱

Edited May 14, 2019 by Rainer

[dph1nm]

So I have a 12" F4 Newt permanently mounted on an EQ8. It will *usually* do 45 sec unguided exposures at 1"/pix at any dec IF you train with PPEC. Without PPEC forget unguided on mine, as it has +/-6.5" periodic error and the EQ8 has a really fast (~3min) worm cycle. I have even had it do 2min unguided exposures at at 0.6"/pix at high declinations. However it can be temperamental, and it has an annoying habit that the  PPEC eventually stops working and has to be retrained (so much for "permanent") - no idea why it does this.

I think if I were buying now I would be very tempted by the CEM120, but it is more expensive than the EQ8 - and of course I have never used a CEM120 so it might have as many quirks as the EQ8!

NigelM

[Nigella Bryant]

On 14/05/2019 at 16:11, Rainer said:

Hi,

Understand and I guess it is all a question of what objects we do image.

I asked because I image from a suburban sky and make 900 second exposure time images.

I have two CEM 120EC2 and I would say it is the best investment ratio so far. 115 lbs carrying capacity (no counterweights included in that ratio, to added to it) for each US $ 6.998,00. No other mount brand has a carrying capacity including encoders for that  price.

The Plain Vanilla CEM 120 is US 3.998,00 which is also inbeatable.  You will not find a mount with this carry/price ratio. Perhaps the Skywatcher EQ-8 ?

OK the mount is out now for about 18 months but I know as having beta tested a lot for iOptron that the mount is ripe to about 95%. Mechanically the mount is very robust (OK, the USA market does not like injection molded parts) perhaps because they are not shiny and you have no bling bling moment 🤣

The base model CEM 120 ist I would say 99% ripe. iOptron Customer support is first class.

As you see I am very biased but also very satisfied with my two mounts and they carry a lot.

Rainer

PD Look where I am 😱

I'd only be looking at the non encoder at what I can afford but with guiding would that still be good if it's not 100% beta tested. I'm really taken with the Cem120. 

[cotak]

Guiding encoder mount has it's own challenges so if you want to be safe stick with the regular one and it should work almost a well. You only need the encoders if you are going for unguided (difficult) or long focal lengths and you want better stability.

[Rainer]

2 hours ago, Nigella Bryant said:

I'd only be looking at the non encoder at what I can afford but with guiding would that still be good if it's not 100% beta tested. I'm really taken with the Cem120. 

Hi,

As far as I can judge the CEM 120 Plain Vanilla is as troublefree as any other mount and as written ... where do you get that carrying capacity for that amount of money ... and believe me ... the mount is robust

https://vimeo.com/277888636

https://www.youtube.com/watch?v=KsHkzgjPYGA&list=UU-Y3S_VW6ek5nBOkoeiUZ_w&index=9

As you can see nothing breaks and NO, I did not loose the 2 Year Warranty by doing that 😱 or at least iOptron has not told me 🤔

So far I have not seen a video by somebody doing this with a so called " Premium Mount " like Astro Physics, ASA, 10micron, Paramount, you name it ... 😎

Rainer

Edited May 15, 2019 by Rainer

[alan potts]

I am not sure when but I am asking myself the same questions as you, as much as I feel the CEM 120 may be a better mount when pier or tripod is taken into account the EQ 8 works out the same as the mount head of the CEM, more or less., so this option is a fair bit more expensive. I have always been pleased, though not delighted with Skywatcher gear and feel I may go for the cheaper option, but then I get better and clearer nights here, and most likely more of them, it's difficult this one.

Alan

[cotak]

Cost is always going to be an issue unless you are independently wealthy, which I wish I was as then I don't have to work to do astronomy!

I ended up getting a CEM60EC in the end over the CEM120EC due to my ROR being too small to meaningfully use the capacity of the CEM120EC. And during that time I was tempted to save some money with various copies of used EQ8 being available locally. In the end though the times the EQ8 has mentioned in the same breath as backlash made me go with the CEM, which measures out to 25ms of backlash.

Again as said before the cable management is a good thing without much downside.

[DaveS]

52 minutes ago, Rainer said:

Hi,

As far as I can judge the CEM 120 Plain Vanilla is as troublefree as any other mount and as written ... where do you get that carrying capacity for that amount of money ... and believe me ... the mount is robust

https://vimeo.com/277888636

https://www.youtube.com/watch?v=KsHkzgjPYGA&list=UU-Y3S_VW6ek5nBOkoeiUZ_w&index=9

As you can see nothing breaks and NO, I did not loose the 2 Year Warranty by doing that 😱 or at least iOptron has not told me 🤔

So far I have not seen a video by somebody doing this with a so called " Premium Mount " like Astro Physics, ASA, 10micron, Paramount, you name it ... 😎

Rainer

I'm not sure the ASA software would allow you to do that, but in any case there are no gears, wheels, belts etc to break.

[Rainer]

14 minutes ago, DaveS said:

I'm not sure the ASA software would allow you to do that, but in any case there are no gears, wheels, belts etc to break.

... and good for the ASA mount owners like you, who do not have to worry about that, but as you know Mr. Murphy is out there and in the least thought moment he plays you a trick ...

There is no product which is 100% fool proof ...

You are right but the purpose was to demonstrate that the mounts are robust ... No more no less ... 

Also as there are many Urban Myths out there complaining about so called Mass Produced Chinese Mounts are rubbish and delicate ... specifically because they are not machined out of a block of Aluminum ...

BTW the CEM 120ECXXX are not a mass produced product ... but there is still the thinking of the people that anything made in China is MASS produced ...

 

[DaveS]

Oh, I'm not decrying the CEM120, just saying that the DDM mounts would probably be stopped from hitting those limits.

For what it's worth, if I hadn't bought the DDM mounts then the CEM would be at the top of my short-list. Mind you, having grown used to the utter silence with which the DDM slews, hearing gears whirring is a bit novel.

[Rainer]

2 hours ago, DaveS said:

Oh, I'm not decrying the CEM120, just saying that the DDM mounts would probably be stopped from hitting those limits.

For what it's worth, if I hadn't bought the DDM mounts then the CEM would be at the top of my short-list. Mind you, having grown used to the utter silence with which the DDM slews, hearing gears whirring is a bit novel.

Yes at 4° per second = 960X the CEM 120 is a bit noisy but at 512X ~ 2.13° you do not hear it anymore ...

Of course that is very annoying when slewing once per night to find the object to be photographed  🤣  for 4 o 5 hours and then another slew for parking 😱 ... a bit of fun must be allowed ...

Unfortunately the GoT speed can not yet be adjusted and is done always as 960X ... has been suggested to iOptron already ... 

 

Edited May 15, 2019 by Rainer

[Nigella Bryant]

20 hours ago, Rainer said:

Hi,

As far as I can judge the CEM 120 Plain Vanilla is as troublefree as any other mount and as written ... where do you get that carrying capacity for that amount of money ... and believe me ... the mount is robust

https://vimeo.com/277888636

https://www.youtube.com/watch?v=KsHkzgjPYGA&list=UU-Y3S_VW6ek5nBOkoeiUZ_w&index=9

As you can see nothing breaks and NO, I did not loose the 2 Year Warranty by doing that 😱 or at least iOptron has not told me 🤔

So far I have not seen a video by somebody doing this with a so called " Premium Mount " like Astro Physics, ASA, 10micron, Paramount, you name it ... 😎

Rainer

I'm 99% sure I'm going to press the pay button on the CEM120 which I think will be good combo for my 12inch f4 Newtonian and guidescope @20kg load and future proof if I decide next year to upgrade to a 16inch newtononian @32kg load. Thanks everyone who's chipped in, it's been very useful. 

[Rainer]

27 minutes ago, Nigella Bryant said:

next year to upgrade to a 16inch newtononian

Hi,

How long will that Newtonian be ?

Rainer

[Nigella Bryant]

An f4 I think 1558mm in length. 5ft 3in in old money I think. At the mo, my 12inch f4 is 1200mm or 4tf.

[Rainer]

1 hour ago, Nigella Bryant said:

An f4 I think 1558mm in length. 5ft 3in in old money I think. At the mo, my 12inch f4 is 1200mm or 4tf.

OH I see quite long telescopes and ehre the weight is not relevant but the moment arm and how much it acts as a sail ...

Maybe a Truss Newtonian and not a tube Newtonian ?