Is a CEM70 enough?

[AbsolutelyN]

My 250PSD is pushing my AZEQ6 mount to the limits and it often struggles to guide acceptably for even 2 mins so I'm looking at upgrading my mount. I'm trying to think long term as in I don't really want to have to buy another at a later date but I also don't want to spend a fortune on an overkill mount. 

It will be used with my 250mm Newtonian but in the future max weight scopes I can see it might need to handle could be a 300mm Newtonian or perhaps a RASA 11. 

The CEM70 seems to have a recommended weight for astrophotography of about  21kg (2/3rds of 31kg) which is fairly reasonable given with care you can push them a bit like I am currently doing. It won't be setup in an observatory but it will be semi-permanent so setup times for mount does not concern me as I only do it a couple of times a year. 

However my query is am I better simply saving and going for CEM120 or EQ8R? They are considerably more expensive so other than weight capability will they perform much better or is it diminishing returns?

Any thoughts really appreciated. 

[DaveS]

Mesu?

[AbsolutelyN]

12 minutes ago, DaveS said:

Mesu?

Unfortunately way out of budget. I think they are in region of £6k and ideally I’m looking for half that.

[vlaiv]

CEM120 or Mesu as higher end offering. Since Mesu is way out budget wise - then I guess CEM120?

[AbsolutelyN]

13 minutes ago, vlaiv said:

CEM120 or Mesu as higher end offering. Since Mesu is way out budget wise - then I guess CEM120?

Thanks, I infer from that the CM70 won't really cut it then. Better start saving. 

[vlaiv]

1 minute ago, AbsolutelyN said:

Thanks, I infer from that the CM70 won't really cut it then. Better start saving. 

There is one more mount that is in the pipeline and looks very much like iOptron offerings.

Not sure when it will be available, nor if it's going to be good budget option.

https://www.primalucelab.com/world/equatorial/skywatcher-cq350-pro-synscan-mount.html

although it does say that it is CEM60 replacement - so not much better than CEM70.

[AbsolutelyN]

2 minutes ago, vlaiv said:

There is one more mount that is in the pipeline and looks very much like iOptron offerings.

Not sure when it will be available, nor if it's going to be good budget option.

https://www.primalucelab.com/world/equatorial/skywatcher-cq350-pro-synscan-mount.html

although it does say that it is CEM60 replacement - so not much better than CEM70.

Thanks that's interesting. Is it a daft question to ask if the Celestron CGX-L is in any way comparable to the other mounts in same price range?  

[vlaiv]

3 minutes ago, AbsolutelyN said:

Thanks that's interesting. Is it a daft question to ask if the Celestron CGX-L is in any way comparable to the other mounts in same price range?  

I've looked at CGX-L when it came out - and for some reason I just did not warm up to it.

There is not much detail on how it performs (that I could find) - and to me, it looks more like 0.6" RMS mount than 0.3" RMS mount like iOptron CEM60/120.

Maybe it is just my imagination, but I classify mounts by their guide performance and CEM60/120 are 0.3" RMS class mounts. HEQ5/EQ6/EQ8 are 0.8" RMS (stock) or 0.6" RMS (modded). Mesu is 0.2" RMS range. I could be very much mistaken - but those are sort of figures that are in my mind when someone mentions those mounts.

For large aperture scopes it really is worth having mount at 0.3" RMS or below (of course - payload should be respected as well and it is always better to "overmount" then "undermount").

[AbsolutelyN]

2 minutes ago, vlaiv said:

I've looked at CGX-L when it came out - and for some reason I just did not warm up to it.

There is not much detail on how it performs (that I could find) - and to me, it looks more like 0.6" RMS mount than 0.3" RMS mount like iOptron CEM60/120.

Maybe it is just my imagination, but I classify mounts by their guide performance and CEM60/120 are 0.3" RMS class mounts. HEQ5/EQ6/EQ8 are 0.8" RMS (stock) or 0.6" RMS (modded). Mesu is 0.2" RMS range. I could be very much mistaken - but those are sort of figures that are in my mind when someone mentions those mounts.

For large aperture scopes it really is worth having mount at 0.3" RMS or below (of course - payload should be respected as well and it is always better to "overmount" then "undermount").

That's really interesting thanks. I was drawn to the EQ8 because I've used their support before which was ok but iOptron is totally new to me. Looks like it is the way to go for my budget.  

[david_taurus83]

I've not seen a CEM70 in the flesh but I did have an AZEQ6 and I would have lumped them together in the same weight class? Not sure you'll see the performance increase your looking for? I have the CEM25 and only have 6kg on it and balance is really critical. If its slightly out in Dec and RA it guides all wonky but get the balance just right and its great. I wouldn't like to try and balance a 250P on a CEM mount! The 120 might be better suited though. 

[CedricTheBrave]

I am in the same boat, currently with a NEQ6RPro and my new scope (which I always knew) is too big.

so I am deliberating on the CEM70 or the 120

So far I am erring on the 120 as the 70 will be on its limit for me.

so saving my pennies! (and waiting for stock)

also have to build my obsy first!! 

think I have gone mad

[oymd]

3 hours ago, AbsolutelyN said:

My 250PSD is pushing my AZEQ6 mount to the limits and it often struggles to guide acceptably for even 2 mins so I'm looking at upgrading my mount. I'm trying to think long term as in I don't really want to have to buy another at a later date but I also don't want to spend a fortune on an overkill mount. 

It will be used with my 250mm Newtonian but in the future max weight scopes I can see it might need to handle could be a 300mm Newtonian or perhaps a RASA 11. 

The CEM70 seems to have a recommended weight for astrophotography of about  21kg (2/3rds of 31kg) which is fairly reasonable given with care you can push them a bit like I am currently doing. It won't be setup in an observatory but it will be semi-permanent so setup times for mount does not concern me as I only do it a couple of times a year. 

However my query is am I better simply saving and going for CEM120 or EQ8R? They are considerably more expensive so other than weight capability will they perform much better or is it diminishing returns?

Any thoughts really appreciated. 

With such a LARGE and heavy scope like the 250PDS, I think you need to consider the moment arm as well.

It's not just that it's almost 15kgms, but due to it's diameter and length, it will act as a huge sail on a tiny boat.

I think that the CEM120 is the least you should consider.

And as the saying goes...there is no overkill mount...

[AbsolutelyN]

33 minutes ago, david_taurus83 said:

I've not seen a CEM70 in the flesh but I did have an AZEQ6 and I would have lumped them together in the same weight class? Not sure you'll see the performance increase your looking for? I have the CEM25 and only have 6kg on it and balance is really critical. If its slightly out in Dec and RA it guides all wonky but get the balance just right and its great. I wouldn't like to try and balance a 250P on a CEM mount! The 120 might be better suited though. 

You're right, I guess I was hoping something more affordable existed 🙂 

[AbsolutelyN]

44 minutes ago, CedricTheBrave said:

I am in the same boat, currently with a NEQ6RPro and my new scope (which I always knew) is too big.

so I am deliberating on the CEM70 or the 120

So far I am erring on the 120 as the 70 will be on its limit for me.

so saving my pennies! (and waiting for stock)

also have to build my obsy first!! 

think I have gone mad

I dread to think when these things will be back in stock ... I guess it leaves lots of time to save up. 

Edited April 20, 2021 by AbsolutelyN

[AbsolutelyN]

2 hours ago, oymd said:

With such a LARGE and heavy scope like the 250PDS, I think you need to consider the moment arm as well.

It's not just that it's almost 15kgms, but due to it's diameter and length, it will act as a huge sail on a tiny boat.

I think that the CEM120 is the least you should consider.

And as the saying goes...there is no overkill mount...

It certainly does act as a sail but given calm conditions you can get very good results with it even with a light weight azeq6. Lots of great points here, it's now very clear CEM70 is not up to it and CEM120 is needed. I think I was a bit taken in with the 32kg and hope that there might be a cheaper option.  Clearly not. 

Edited April 20, 2021 by AbsolutelyN

[AbsolutelyN]

Does anyone have any experience of iOptron support? For instance I needed to replace main board on my AZEQ6 a couple of years ago and it was very quick and easy to get a replacement from OVL. Never had any dealings with iOptron and can't say I'm impressed with their website. 

Edited April 20, 2021 by AbsolutelyN

[Neil27]

11 hours ago, AbsolutelyN said:

Does anyone have any experience of iOptron support? For instance I needed to replace main board on my AZEQ6 a couple of years ago and it was very quick and easy to get a replacement from OVL. Never had any dealings with iOptron and can't say I'm impressed with their website. 

The biggest key to great customer support is whom you buy from. There are many dealers out there in the market place and getting the right one can make or break any purchase when the s**t hits the fan. Having dealt with FLO, RVO and Modern Astronomy recently I have no hesitation in recommending any of these.

Regarding your mount, there’s an old saying that I’m sure you may be familiar, always get more mount than you think you need, and the mount is the key to a stress free time in this hobby. If I was you I would seriously consider the CEM 120, it has the carrying capacity, a fair reputation from what I have seen both sides of the pond. Another option would be to wait for a suitable second hand mount, there have been instances of Mesu mounts for around 3.5k, AP mounts for a little more, even EQ8’s for around for around 1.5 to 1.8k if you want to ‘fettle’ it.

Happy hunting and good luck.

[AbsolutelyN]

9 minutes ago, Neil27 said:

The biggest key to great customer support is whom you buy from. There are many dealers out there in the market place and getting the right one can make or break any purchase when the s**t hits the fan. Having dealt with FLO, RVO and Modern Astronomy recently I have no hesitation in recommending any of these.

Regarding your mount, there’s an old saying that I’m sure you may be familiar, always get more mount than you think you need, and the mount is the key to a stress free time in this hobby. If I was you I would seriously consider the CEM 120, it has the carrying capacity, a fair reputation from what I have seen both sides of the pond. Another option would be to wait for a suitable second hand mount, there have been instances of Mesu mounts for around 3.5k, AP mounts for a little more, even EQ8’s for around for around 1.5 to 1.8k if you want to ‘fettle’ it.

Happy hunting and good luck.

Thanks Neil. If buying new it will be with FLO as I know they will sort any issues. Good point on second hand. 

[newbie alert]

I own a cem60,  incredible mount , more than pleased.. I bought it when it was just on the release of the cem 70, I preferred the look, wasn't really that much info out there and only a handful of testing mounts that were showing pre-release.. when they did release the price to me just didn't add up.. cem60 were £1699, cam 70( basic model ) was £2350! I couldn't see where the extra £650 was other than a slightly different gear size,  black livery.. , think the basic cem 120 was £2550 at the time... for me the price just didn't add up... awesome mounts thou, won't take that away from them

 

[AbsolutelyN]

On 22/04/2021 at 07:11, newbie alert said:

I own a cem60,  incredible mount , more than pleased.. I bought it when it was just on the release of the cem 70, I preferred the look, wasn't really that much info out there and only a handful of testing mounts that were showing pre-release.. when they did release the price to me just didn't add up.. cem60 were £1699, cam 70( basic model ) was £2350! I couldn't see where the extra £650 was other than a slightly different gear size,  black livery.. , think the basic cem 120 was £2550 at the time... for me the price just didn't add up... awesome mounts thou, won't take that away from them

 

Yes it's a real shame about the price rises, wish I was 12 months earlier on this as its about 1k more now.

Comes down to CEM120 or EQ8-R. Wavering slightly towards the EQ8R despite all the advice to go with the CEM120 because I know I can get parts and support from OVL whereas the iOptron is an unknown quantity in regard to support for any issues that may occur over the years. Feels important as the mount will be permanently covered rather than in a observatory so less protected.  

[JSeaman]

I'm using an NEQ6 Pro with a 300PDS on and can do 10 minute sub so guess you have some other issues

That said I'm at the limits of the mount and I have been torn between EQ8 and CEM 120. I had settled on the 120 then found a bunch of people with ioptron issues. That said, it's easy enough to find a bunch of people that have issues with any astro equipment as it's a complicated set up at the best of times. Keep us posted on which way you go!

 

[AbsolutelyN]

25 minutes ago, JSeaman said:

I'm using an NEQ6 Pro with a 300PDS on and can do 10 minute sub so guess you have some other issues

That said I'm at the limits of the mount and I have been torn between EQ8 and CEM 120. I had settled on the 120 then found a bunch of people with ioptron issues. That said, it's easy enough to find a bunch of people that have issues with any astro equipment as it's a complicated set up at the best of times. Keep us posted on which way you go!

 

You're doing well to get 10 min subs with such a payload. I've managed about 5 mins and probably could get the odd 10 min sub but I can't consistently do it as very reliant on conditions.  I'd loose too may subs to even a slight breeze as I'm in quite an exposed location. So I tend to go with shorter 1 min exposure which has a far higher keeper rate. 

You can find great and awful accounts of both mounts, though finding it hard to find in-depth reviews/views of the EQ8R. I guess some of it is just the luck of getting a good copy just as it is with some camera lenses. 

Edited April 26, 2021 by AbsolutelyN

[JSeaman]

Yeah don't get me wrong it's right at the limit but with a RoR obervsatory I have a keep rate of about 80-90% so not too bad, I lose more to satellites than wind

Agree completely on the comment about good copies, I hope you find a good solution!

[AbsolutelyN]

31 minutes ago, JSeaman said:

Yeah don't get me wrong it's right at the limit but with a RoR obervsatory I have a keep rate of about 80-90% so not too bad, I lose more to satellites than wind

Agree completely on the comment about good copies, I hope you find a good solution!

You know perhaps an observatory would be a better investment .... thought I had go ahead for one the other day but permission has since been revoked. I'm fully exposed to the west unfortunately so the hope is heavy duty mount will reduce the impact of that. 

[JSeaman]

Honestly I wouldn't dream of running this set up without one. And as a bonus you don't have to polar align again, you can be up and running literally within a couple of minutes on a good night. I think wind makes for a challenge at the best of times with a scope but these Newtonians really do suffer from it, a dome is great if you can but I had to replace my dome with an RoR due to sheer size. I'd definitely ask permission again