New mount suggestions

[Rainer]

57 minutes ago, souls33k3r said:

there's a massive hype behind this mount and i believe for good reasons too. From what i've seen that CEM60 got a negative press in it's early days but then they sorted those issues out but then starting from mid last year (only going by CN threads because there's very limited knowledge around on SGL) i'm only seeing guiding issues and people ready to rip whatever hair they've got left on their head. I might be safe because i don't have any but nonetheless the issues are there. Not sure what's what now. 

What about all those happy guys with any mount brand ? They just do not post anything ...

From 100 messages one is positive and the rest is complaining and whining ...

[souls33k3r]

I absolutely agree with both Olly and Rainer.

@ollypenrice I think if i didn't want a step up from the NEQ6, i would've been happy just with that old mount. But i wanted to get better at this hobby and throwing money at it was surely one way to do it. I do realise there are other components but i'm working on each and individual cog one by one  of course whilst not breaking the bank

@Rainer i won't be lugging this new mount with any more than what i already have and that too with one scope at a time so i'm sure i'll be staying well within the capacity limits. Like i said, i will still be guiding (guidescope or OAG) so is EC version still a good choice? I want to venture in to the 10 minutes subs mark (moving from 5 minutes) but with also better guiding and low RMS values in arcseconds. I totally agree and like i said, you will read 100 horror stories and maybe just MAYBE one positive comment about it. 

[Rainer]

5 minutes ago, souls33k3r said:

Like i said, i will still be guiding (guidescope or OAG) so is EC version still a good choice?

Hi souls33k33r,

I would say yes and if you do not like just send it to me in Mexico ...

Again, encoders are not there for taking away the guiding in the way way as a car with an automatic lane reading and keeping from time to time needs to be corrected a bit ...

I am sending a guide ping every 15 seconds just to correct drift in RA as well as DEC and that is it ...

I am guiding through an OAG at 3203 mm focal length and my main interest are the Arp Galaxies ...

I am not guiding with PHD2 but with Sky Guide from Innovations Foresight.

PHD2 guides on one star. Sky Guide uses the whole frame of the guide camera ... More info below. I tested it for 60 days and that convinced me and yes even having encoders I do guide and if you want tog et into long exposure time like 10 min subs you will need to guide (even having encoders) as drift is going to ruin your images. I do 15 minutes subexposures on the faint fuzzies of Arp ... at an image scale of 0.476" arc seconds per pixel and guess what ... I do get round stars ?

www.innovationsforesight.com

https://www.innovationsforesight.com/education/full-frame-guiding-focusing/

Rainer

I know I am a strange moth between all those butterflies still thinking that encoders do make guiding unnecessary ?

[Jkulin]

Hi Ahmed,

You are reading far too much into past problems with the software of the CEM60 / CEM60-EC and as Olly mentioned these problems were old hat and someone of Olly's skill and knowledge advising that you should look closely at the iOptron would be enough for me.

People need to move on, I have spoken to many many people and always do my research and I wouldn't be after buying another one in the future if I was not satisfied.

Personally I wouldn't touch an NE6 compared against the iOptron and I had the AZ-EQ6-GT which are similar.

I bought the 120EC knowing full well about iOptron using real life purchasers to test their Beta's...not really a big deal because at the end of the day they listen and make amendments, I can't say the same about Skywatcher, do they listen...do they h3ll, if they did they they would have made all of their mounts belt driven without people having to buy a kit and modify them and they would have got rid of the back lash that most people have to mess with to get them to guide properly. And...they would answer their emails, and when I emailed their UK disty's firstly no one replied via email and when I called it was...doooh I don't know, not exactly scientific. The amount swarf inside the SW is not exactly endearing either, that's why people have to either do a Hypertune themselves or send them away to get done, I very much doubt anyone has ever had to send an iOptron away for hypertuning!

When users have good, frequently clear skies, issues with guiding are massively reduced, you are in the heart of light pollution and bad skies, so you need something that doesn't need faffing with.

I now endeth the sermon!!!??

[pete_l]

3 hours ago, Rainer said:

What about all those happy guys with any mount brand ? They just do not post anything ...

From 100 messages one is positive and the rest is complaining and whining ...

Yes, that is a big problem. The manufacturers don't seem to go any effort to promote or support their products. They just produce a bunch of marketing photos, some "loading" specifications that nobody trusts, and then toss their mounts over the proverbial wall to an unsuspecting audience. There seems to be no more engagement from the suppliers, they don't take part in any forums, address issues or offer forum-based support.

So given that vacuum, it is not surprising when rumour and gossip takes over.

[ollypenrice]

Regarding the extent to which unhappy owners are vocal or not I would add this: particularly in the case of expensive products, people having a lot of trouble sometimes keep quiet about it. This may be out of embarrassment at having made what they feel to be a bad choice or, perhaps more likely, they are anticipating the possibility that they may want to be selling it on...

Olly

Edited April 24, 2019 by ollypenrice

[SteveA]

20 hours ago, Rainer said:

www.innovationsforesight.com

https://www.innovationsforesight.com/education/full-frame-guiding-focusing/

 

Extremely interesting this...thanks for posting that link.

Steve

[souls33k3r]

Sorry about the late reply, just been bogged down with a lot of work this morning.

I completely agree with everything that @Jkulin, @ollypenrice & @pete_l had to say. I'm just trying to make sure i am going to be making the right decision but i do also know that we all have different experiences with the products we get in the end. Some are good and some are just painstakingly bad but before i embarked on the research journey, i've heard nothing but good stuff about their latest CEM60's and CEM60EC's .... but in my eyes it's always good to know about the potential issues rather than not knowing which might lead you down the rabbit hole.

I shall soon be pulling the trigger ... soon

[Hicks]

Has anyone owned or used both the CEM60 and CEM60-EC and compared the two as far as guiding performance? I've seen guiding stats from people who've owned one or the other, but not really much from someone who's had a chance to use both and compare.

Reading various threads it seems there's split opinion on whether the RA encoder is worth the extra cost over the CEM60 if you are guiding.

Isn't another consideration however,  the increased spec for PE from +-5" p-p to < 0.5" rms for 5 min. Which firstly raises the question, one says peak to peak, the other RMS and for "5 min". Are these two specs directly comparable?

If they're directly comparable and given that a sharp spike that was still in spec would be <0.5" and able to be guided out (depending on pixel resolution). Where as with the non EC a sharp spike could be up to 5" and still seen as in spec, although I've not seen anyone reporting anything like that bad, it feels like worth including in any decision?

One other question, the specs say "60 lb (27.2kg), exclude counterweight*" does that mean you need to consider the 21lb counter weight leaving 49lb for OTA/other gear,or that the 21lb counterweight can be ignored and the 60lb is available for OTA/extra counterweights? Would extra counterweights be counted towards the 60lb?

Edited April 24, 2019 by Hicks

[RolandKol]

I found one person, who has both, and does not see any difference in  terms of guiding... but he has not specified a lot... 

@vlaiv helped me with the last question about Peak to Peak error, but .... I had no reply, probably as I forgot to Tag/Quote him... Maybe you guys will be more lucky

https://www.cloudynights.com/topic/607897-cem60ec-or-cem120-no-ec/?p=9234049

Edited April 24, 2019 by RolandKol

[Rainer]

34 minutes ago, Hicks said:

One other question, the specs say "60 lb (27.2kg), exclude counterweight*" does that mean you need to consider the 21lb counter weight leaving 49lb for OTA/other gear,or that the 21lb counterweight can be ignored and the 60lb is available for OTA/extra counterweights? Would extra counterweights be counted towards the 60lb?

Hi,

As they say 60 lbs carrying capacity and that means 60 lbs carrying capacity excluding counterweight. Counterweights are extra 

You can put 60 pounds of equipment on top and put 60 lbs of counterweights on the counterweights shaft or even more depending where the center of gravity of your equipment is.

My mount CEM 120EC2 is specified with 115 lbs carrying capacity and I have 118 lbs of counterweights on it and no problem. but that does not mean that my equipment is also 119 lbs. My equipment on top is perhaps 105 lbs but due to the high center of gravity and the preferred way I put my counterweights for balance i get that combination.

In the image you can see from top to bottom 3x 12kg, 1x 8kg, 1x 6kg and 1x 4kg counterweights (those ugly golden pieces ? ) which adds up to 54 kg  ~ 119 lbs 

Clear ?

Rainer

 

[Rainer]

39 minutes ago, RolandKol said:

I found one person, who has both, and does not see any difference in  terms of guiding... but he has not specified a lot... 

Hi Roland,

Most people are likely somehow a bit lazy or do not want to disclose what they do.

Of course the result can be the same.

I only have EC2 mounts but from my former experience I can say.

With encoder you mainly correct for drift and atmospheric refraction over a long period and perhaps the one or other sum up of seeing and a bit of rest PE. In reality it is not PE but it is more a summing up of different error and that is what you guide out from time to time but mostly drift and atmospheric refraction.

Without encoders you add the PE for guiding out and that is compared to drift and Atmospheric refraction a quick changing error whereas drift and atmospheric refraction are a slow changing error and are constantly moving only in one direction. PE is moving backwards and forwards and even can have additional peaks or valleys overlaid over the sinusoidal curve.

There are plenty of images of uncorrected PE curves and corrected PE curves in Cloudy Nights. iOptron delivers with each of their mounts plots of your RA errors be it non EC and EC mounts.

Look at the images of the plots of my mounts.

Rainer

[cotak]

9 hours ago, ollypenrice said:

Regarding the extent to which unhappy owners are vocal or not I would add this: particularly in the case of expensive products, people having a lot of trouble sometimes keep quiet about it. This may be out of embarrassment at having made what they feel to be a bad choice or, perhaps more likely, they are anticipating the possibility that they may want to be selling it on...

Olly

Well iOptron's not so expensive unless you go to the CEM120EC and EC2. And there are people talking about issues with CEM120s.

I find that Astro-Physics owners are the ones who seems to keep the most quiet about their issues, and there are issues if you look at the Yahoo forums. I find it most interesting that some have spend a lot of money on their AP mounts with encoders, and then get no better results than people who have spent a lot less, who then tells everyone to buy AP. Often the reason stated is that they have zero issues with their AP mount and it resolved all their imaging woes. Personally, I have with my ieq45 pro a bout of issues at the start to do with backlash on DEC. After resolving it to the best the mount could do and figuring out the settings needed in PHD2 it has just worked. So I really don't understand the mental state of people who has issues on expensive equipment and tells everyone they don't have any issues.

Interestingly. A fair number of AP mount owners have come out saying that their AP mounts did not give them better results than mounts like AZ-EQ6 or EQ6s. And recently I have found that some of the same people who buys the high end mounts were throwing away 50% of their frames and calling it a good take rate. I know Olly has experiences showing the mesu doesn't lose any frames which to me is a much better measure of what's what than the marketing heavy but substance thin way some of the NA manufacturers seem to maintain their market share.

 

Edited April 24, 2019 by cotak

[cotak]

1 hour ago, Hicks said:

Has anyone owned or used both the CEM60 and CEM60-EC and compared the two as far as guiding performance? I've seen guiding stats from people who've owned one or the other, but not really much from someone who's had a chance to use both and compare.

Reading various threads it seems there's split opinion on whether the RA encoder is worth the extra cost over the CEM60 if you are guiding.

Isn't another consideration however,  the increased spec for PE from +-5" p-p to < 0.5" rms for 5 min. Which firstly raises the question, one says peak to peak, the other RMS and for "5 min". Are these two specs directly comparable?

If they're directly comparable and given that a sharp spike that was still in spec would be <0.5" and able to be guided out (depending on pixel resolution). Where as with the non EC a sharp spike could be up to 5" and still seen as in spec, although I've not seen anyone reporting anything like that bad, it feels like worth including in any decision?

One other question, the specs say "60 lb (27.2kg), exclude counterweight*" does that mean you need to consider the 21lb counter weight leaving 49lb for OTA/other gear,or that the 21lb counterweight can be ignored and the 60lb is available for OTA/extra counterweights? Would extra counterweights be counted towards the 60lb?

Well I was just using a ieq45 pro 2 weeks ago, and now I have the cem60ec so you can call it similar enough. The payload's the same: Edge 8 at 0.54" imaging scale. 

I get about 0.1-0.2" RMS improvements over the ieq45 pro over long runs, and my excursions are withing 1" vs the sometimes 2-4" previously. The biggest differences as stated before is I can use dimmer stars cause I can run at 5 seconds instead of 1-2 second exposures for guiding. I don't think I am done yet with the cem60ec in terms of what guiding precision it can achieve as I haven't really play with PHD settings or route my usb3 through the mount yet. While the numbers are somewhat meh, the resulting star shape is better on the CEM60EC than I have ever seen in the ieq45 pro. On the 45 yes it round but some frames will have slight elongation in RA. On the CEM60EC so far no frames have shown that.

The PE spec for the non-EC is P-P as that's the larger value. For EC versions the encoders keeps the excursions within +/- 1-1.5" max. And since those excursions of RA are momentary RMS is the better value. And of course the RMS value looks better for marketing as well haha. So the specs are not comparable but they don't need to be. I think the RMS version is better because that's what you are after in a real imaging session and if  your mount consistently goes over the claimed RMS limits (0.3 rms for CEM60EC  gen 2), you can challenge iOptron to fix it. Granted, 0.3 RMS spec is likely too tight already to really have a convincing argument to sent to iOptron when your local seeing likely puts it at a higher number.

All said, EC or no EC is a personal choice. You can achieve sufficient performance without EC to get very good images. The EC is just a bit of extra on top.

 

[souls33k3r]

I guess i'll ask the very noobish question then. I get that a non-EC will be able to achieve the level of precision on guiding that the EC has or potentially can achieve but so far i really haven't any evidence (a guide graph from a few mounts would be good  and if someone has a link to a few of these that would help) to suggest apart from theoretical that the EC will be better. 

But the question really is, will you have to tinker and worry less (settings or physical mount) with the EC mount to achieve the precision when compared to that of non-EC? 

[cotak]

Cem60ec first run.

Ieq45 pro on a very good night. Look at the responses to helm.

 

Ieq45 pro at the start of my relationship with it.

So yes you can get excellent results without encoders but maybe takes a while to learn all the kinks. With my ieq45 pro it needed fair number of tinkering with the mount. You could also say that the CEM design is better do require less tinkering. However the cem60ec seems to just works out of the box.

 

[pete_l]

ISTM that the RMS accuracy of the encoders will easily outperform the variation in star position due to seeing. The encoders should also correct for things like cable drag on the mount, too.

The effect of atmospheric refraction won't be corrected by encoders. We are told that +/- 45° from the zenith, this refraction is about 1 arc-min. as a worst case. So starting with an object 45° in the east and imaging until it gets to 45° west, that comes to 120 arc-sec movement from the theoretical position in 6 hours of imaging. On average, 1 arc-sec per 3 minutes of exposure. Though at the zenith there is none and it increases as the object is lower in the sky. Down to about 5 arc-min at the lowest practical limit for imaging. So if you rely on encoders for tracking, even with a perfect PA, you will still see some elongation if you take multi-minute exposures and target objects that are lower in the sky.

 

I think I've just talked myself out of buying a mount with encoders. How did that happen? ?

Edited April 24, 2019 by pete_l

[souls33k3r]

10 minutes ago, pete_l said:

ISTM that the RMS accuracy of the encoders will easily outperform the variation in star position due to seeing. The encoders should also correct for things like cable drag on the mount, too.

The effect of atmospheric refraction won't be corrected by encoders. We are told that +/- 45° from the zenith, this refraction is about 1 arc-min. as a worst case. So starting with an object 45° in the east and imaging until it gets to 45° west, that comes to 120 arc-sec movement from the theoretical position in 6 hours of imaging. On average, 1 arc-sec per 3 minutes of exposure. Though at the zenith there is none and it increases as the object is lower in the sky. Down to about 5 arc-min at the lowest practical limit for imaging. So if you rely on encoders for tracking, even with a perfect PA, you will still see some elongation if you take multi-minute exposures and target objects that are lower in the sky.

 

I think I've just talked myself out of buying a mount with encoders. How did that happen? ?

I hope you've not

My goal really is to get better guiding which should result in better eccentricity of the stars because the final image is all about how eccentric the stars are ... yes you throw away subs due to bad fwhm values, low SNR or bad seeing but the less eccentric the stars are, the better the resulting image will be. So isn't the EC version of the mount a bit better in that respect that right out of the box it's behaving better? The PHD graph can't mean anything but it's getting the lower RMS values we all long for isn't it?

[cotak]

I think the EC is producing better results than the IEQ45 Pro does on a good night, from the get go.

The IEQ45 Pro will toss in a few stinkers during an overnight session I either throw out if they are really bad or I let the sigma clipping deal with it for me. So far no such issues with the CEM60EC. And I haven't done anything with the 60 other then setting it up in my observatory. 

That said right all you got is one set of anecdotal example. So your experience might be different. The positive side I guess is few CEM60EC seems to be sold 2nd hand so there shouldn't be some huge issues with them. And again you are likely to find yourself happy with a non-EC. I just always wondered about them and since I could afford to get one, I did.

[pete_l]

2 minutes ago, souls33k3r said:

So isn't the EC version of the mount a bit better in that respect that right out of the box it's behaving better? The PHD graph can't mean anything but it's getting the lower RMS values we all long for isn't it?

Yes - better. But even with perfect PA and a rock-solid OTA, if you are ever going to take multi-minute exposures halfway down the sky (i.e. not near the zenith) then encoders alone aren't sufficient to correct for atmospheric refraction. You'll still have to guide. Though I take your point the guiding will only be  very light touch.

[souls33k3r]

6 minutes ago, pete_l said:

Yes - better. But even with perfect PA and a rock-solid OTA, if you are ever going to take multi-minute exposures halfway down the sky (i.e. not near the zenith) then encoders alone aren't sufficient to correct for atmospheric refraction. You'll still have to guide. Though I take your point the guiding will only be  very light touch.

Yes guiding will never be out of the equation and it was never going to be in the first but even so if the mount can achieve those very low RMS values with the EC version, it should really make a hell of a difference. The only question is, are encoders going to be up for the job with a heavy payload (20kgs) at higher FL and 10 minute subs at least with near perfect pin point stars?

9 minutes ago, cotak said:

I think the EC is producing better results than the IEQ45 Pro does on a good night, from the get go.

The IEQ45 Pro will toss in a few stinkers during an overnight session I either throw out if they are really bad or I let the sigma clipping deal with it for me. So far no such issues with the CEM60EC. And I haven't done anything with the 60 other then setting it up in my observatory. 

That said right all you got is one set of anecdotal example. So your experience might be different. The positive side I guess is few CEM60EC seems to be sold 2nd hand so there shouldn't be some huge issues with them. And again you are likely to find yourself happy with a non-EC. I just always wondered about them and since I could afford to get one, I did.

So you have the CEM60 on a pier or on a tripod? Because i think one way of (so far that i have seen) to get good RMS values from any mount is to have it on a pier (which by the way mine will be going up during this summer). I can stretch my limit but it will be a stretch if that is i am completely happy with it in the long run and it just performs as is. @Jkulin mentioned this as well and that has sit down well with me is that there has hardly been a reported case (in my knowledge) that someone had to send in their iOptron mount  (especially the CEM60's) for hypertuning so maybe it doesn't require any?

[Jkulin]

I was running my CEM60EC with about 18-19Kgs and it never flinched once, I truly believe that the capacity is as they stated 27Kgs or 60lbs for imaging.

[RolandKol]

it looks like DF had some CEM60s for tuning..

but I was not able to find CEM60-EC in the tuned list

https://www.darkframeoptics.com/page/mount-performance-charts

Edited April 24, 2019 by RolandKol

[Hicks]

When it comes to the CEM60 it was said that PPEC is (or should be) disabled when guiding. Seems to be a common suggestion with many mounts to avoid fighting. What about the CEM60-EC though? Are the corrections due to the encoder (RA only?) always applied? Or are they ignored when guiding or optionally disabled?

Edited April 24, 2019 by Hicks

[Jkulin]

21 minutes ago, RolandKol said:

it looks like DF had some CEM60s for tuning..

but I was not able to find CEM60-EC in the tuned list

https://www.darkframeoptics.com/page/mount-performance-charts

Hi Roland,

I would seriously doubt that DF have ever had a CEM60EC in for hypertuning, when I looked at your link they just said iOptron, maybe I missed something, and if I have then will stand corrected.

6 minutes ago, Hicks said:

PPEC is (or should be) disabled when guiding

I never disabled anything with mine, there was never any need.