Mount Frustration - Upgrade advice needed

[didwebringbatteries]

Hello,

and greeting from Lebanon (this will become important in a moment). I currently own two telescopes that I use for imaging: 80/480 triplet APO and 200/1000 newt, both with an ASI1600MM. My current mount, locally purchased, is a CGEM DX that does OK with a 1.6 imaging scale but terribly so with the 0.7 that the newt/asi combo gives me. The mount can reach a total RMS of .7 rarely, and never stable enough, that I end up dropping half my 60 seconds frames if I am lucky. A lot of troubleshooting went into the mount in the past year that I am now considering an upgrade, as I am almost sure I got a bad mounttaking into consideration:

• durability
• doesn't need maintenance
• has a good reputation
• can handle the current OTAs and possibly a C9.25 EdgeHD
• budget 4500 USD, plus or minus 1K

And this is why the location is important. Shipping in & out is rather expensive, and getting local help in fixing/tuning/maintaining/customizing is definitely out of the question. I am also terrible when it comes to mechanical handy work. My research is always taking me back to Avalon, for the above reasons. Mainly the linear one, because i don't mind a meridian flip, SGP does that automatically. I couldn't figure out major differences aside from that.

Few local fellow astrophotographers shipped skywatcher mounts from abroad and they are not having any problems, although I don't think that's going to last as long as the avalon given the internals. I, of course, can be very wrong.

What do you guys think? Am I being rational here? And is the price difference between the Avalon and Skywatcher worth it? Am I disregarding some other mounts in the price range?

[vlaiv]

Hi, and welcome to SGL.

I'm going to start off by saying that 0.7"/px is very high resolution to work with, and in all probability you won't be able to exploit it fully. Mind you, I'm fairly hung up on proper sampling and many others don't seem to be much bothered if they are oversampling - as I've seen people happily imaging at anything between 0.6 and 0.9"/px.

So my first advice, regardless of the mount choice, would be to explore and consider use of x2 binning in software for your subs for 1.4"/px when working with Newt and ASI1600.

This will also relax need for very tight guiding that only comes with very high quality mounts (general rule of the thumb is to have total guide RMS half of working resolution or less, so for 1.4"/px you'll need 0.7" RMS or less, while for 0.7"/px that needs to go down to 0.35" RMS or less - and that requires very good mount).

As for mount recommendation, only thing that I can say about Avalon is that I've read good things, but also that they are a bit "elastic" - which causes issues in the wind. I can suggest another mount in your price range that is worth considering - CEM60. Many people will recommend CEM60EC version (with encoders), but my view on the topic is that EC version is not worth price premium over standard one. Again, disclaimer - this recommendation comes from second hand experience and analysis. I've not operated CEM60 myself (nor seen one for that matter).

Hope this helps.

[ollypenrice]

The Avalon is a very good mount and mechanically is so well made as to give little likelihood of needing attention. Electronics can give trouble on any mount but you wouldn't need to send the whole mount back, just remove the electronics and replace those. They are accessible and easy to deal with. I would have kept mine but I was offered a second Mesu 200 and that is a better mount, though larger and more expensive. 

While I like the Avalon I think it is too close in price to the Mesu. I have two of these now and would not swap them for any mount on the market at any price.

Like Vlaiv I think the seeing will prevent you from working effectively at 0.7"PP even if you can get your guide RMS down to about 3.5" RMS.

Olly

[andrew s]

@vlaiv I don't  understand the point of binning the CMOS ASI1600 on capture as it is software binned and not on chip? Do you have a specific reason for the recommendation?

I use my ASI1600 at full resolution as it then gives me the most options for post processing.

Regards Andrew 

[vlaiv]

Just now, andrew s said:

@vlaiv I don't  understand the point of binning the CMOS ASI1600 on capture as it is software binned and not on chip? Do you have a specific reason for the recommendation?

I use my ASI1600 at full resolution as it then gives me the most options for post processing.

Regards Andrew 

Neither do I - that is why I always recommend binning in software - it just opens up more possibilities and avoids any problems with possible loss of precision.

Only real advantage of binning in drivers (although I'm not sure if it's done in drivers at all in this case, but rather camera firmware), would be download speed / fps and data storage on computer used for capture, however in my view these "advantages" are not sufficient to justify doing it like that in comparison with options available in software.

[pete_l]

2 hours ago, didwebringbatteries said:

I end up dropping half my 60 seconds frames if I am lucky. A lot of troubleshooting went into the mount in the past year that I am now

I get the impression you are taking short sub images without any form of autoguiding. If that is so, then autoguiding would be my first suggestion.

Apart from that, I agree with vlaiv's view regarding binning.

[fwm891]

3 hours ago, vlaiv said:

As for mount recommendation, only thing that I can say about Avalon is that I've read good things, but also that they are a bit "elastic" - which causes issues in the wind.

I've had an Avalon Linear and regretted selling it ever since. There was a lot of hype early on about the linear in wind - I can say that even with long focal length tubes I had no wind related problems when imaging and found the belt driven mount really accurate when guiding. #1 for Avalon Linear

[didwebringbatteries]

Thank you all for your feedback. I am actually guiding, but as I said earlier, I don't want to get into the short comings of my current mount.

From what I've seen while researching binning, that's there is a lot of debate and a lot favoring doing that after capture. That won't fix the not very rounded stars i guess though? I wonder how others are using this camera at 900-1000 focal lengths, I've never seen anyone binning or even mentioning it(referring to examples on youtube and some blogs). Here comes some not very researched questions: Do I do the binning in SGP while capturing and I can drizzle to recover the resolution? or do I do the binning in the end by resampling?

The Avalon is already stretching the budget, including around 300 euros for shipping and around 1000 USD for customs. I am very comfortable with electronics, it's the mechanical part that my brain refuses to accept. The Mesu 200 seems to be a great mount and I looked it up while doing my research, but the price/weight and that 100KG payload that I will never need brought me back to the Linear. My newt with the massive guidescope and everything plugged it, is around 16KG. If I ever get the 9.25, I will be using an OTA probably. So the 20KG Avalon AP limit is enough for my use.

 

[newbie alert]

With a rms figure like thst I'd expect you to have great guiding.... if you're getting drift showing in the stars but a good guiding rms id look for flex rather than a new mount, how are you guiding, piggy backed guidescope ? Should get far more than 60 secs especially with the frac unguided.. I have a cgem myself not too sure how the dx version differs.. 

Set it up and give everything a good wiggle and check for flex..focuser tube especially

[andrew s]

With usb3 and a CMOS camera (where you can't do on chip binning) I can't see any reason to bin other than during image processing after capture.

Binning then trying to recover the resolution is just plain wrong.

I have a scope with over 2m focal length with an ASI1600 and don't bin. 

Regards Andrew 

[didwebringbatteries]

2 hours ago, newbie alert said:

With a rms figure like thst I'd expect you to have great guiding.... if you're getting drift showing in the stars but a good guiding rms id look for flex rather than a new mount, how are you guiding, piggy backed guidescope ? Should get far more than 60 secs especially with the frac unguided.. I have a cgem myself not too sure how the dx version differs.. 

Set it up and give everything a good wiggle and check for flex..focuser tube especially

Alright, more details about my issues, although I was trying to avoid turning this about my CGEM DX problem. I know my CGEM is under performing, it works, but it has many issues. RMS is between 0.6 and 2.2, same setup, same seeing, same everything. It is never stable enough to image with the newt. I do end up dropping half my newt frames, while APO at that scale they usually survive. It is not supposed to be this bad, but in my case it is. The RA housing has two bolts that are loose and cannot be tightened. I am under the impression this mount had a previous life somewhere and was shipping and sold as new here. Something is wrong with the internals. I have a friend that dismantled the mount for me, and every screw was a pain to deal with: rust, wear, etc... I will continue working on the CGEM in the hopes of getting it performing better, but I have been suffering with it for over a year now and I want to move to something that would give me some peace of mind.

Not the most cost efficient route, but I am not willing to sink money into the CGEM. That's why I am here, to see what you guys have experienced with the Linear and if you have better suggestions in that price range or lower. I want to do this right this time,  and the forums are my only source of support.

[souls33k3r]

CEM60 and CEM60-EC have been getting good reviews. Do not overlook these mounts.

I'm in the market for a new mount as well but just can not justify the cost of an Avalon right now ... or ever!

[newbie alert]

1 hour ago, didwebringbatteries said:

Alright, more details about my issues, although I was trying to avoid turning this about my CGEM DX problem. I know my CGEM is under performing, it works, but it has many issues. RMS is between 0.6 and 2.2, same setup, same seeing, same everything. It is never stable enough to image with the newt. I do end up dropping half my newt frames, while APO at that scale they usually survive. It is not supposed to be this bad, but in my case it is. The RA housing has two bolts that are loose and cannot be tightened. I am under the impression this mount had a previous life somewhere and was shipping and sold as new here. Something is wrong with the internals. I have a friend that dismantled the mount for me, and every screw was a pain to deal with: rust, wear, etc... I will continue working on the CGEM in the hopes of getting it performing better, but I have been suffering with it for over a year now and I want to move to something that would give me some peace of mind.

Not the most cost efficient route, but I am not willing to sink money into the CGEM. That's why I am here, to see what you guys have experienced with the Linear and if you have better suggestions in that price range or lower. I want to do this right this time,  and the forums are my only source of support.

I hear where you're coming from and agree with you as my cgem is under performing..never been totally happy with it and feel my avx was a far better mount, now lost my faith in celestron.. 

No doubt in my mind that the Avalon is a seriously good mount..Are you on a fixed pier or are you setup and pack down type of imager?...lots of other mounts to choose from around that price point and all far exceed what your achieving now..

Good luck with whatever you choose

[vlaiv]

5 hours ago, didwebringbatteries said:

Thank you all for your feedback. I am actually guiding, but as I said earlier, I don't want to get into the short comings of my current mount.

From what I've seen while researching binning, that's there is a lot of debate and a lot favoring doing that after capture. That won't fix the not very rounded stars i guess though? I wonder how others are using this camera at 900-1000 focal lengths, I've never seen anyone binning or even mentioning it(referring to examples on youtube and some blogs). Here comes some not very researched questions: Do I do the binning in SGP while capturing and I can drizzle to recover the resolution? or do I do the binning in the end by resampling?

The Avalon is already stretching the budget, including around 300 euros for shipping and around 1000 USD for customs. I am very comfortable with electronics, it's the mechanical part that my brain refuses to accept. The Mesu 200 seems to be a great mount and I looked it up while doing my research, but the price/weight and that 100KG payload that I will never need brought me back to the Linear. My newt with the massive guidescope and everything plugged it, is around 16KG. If I ever get the 9.25, I will be using an OTA probably. So the 20KG Avalon AP limit is enough for my use.

 

Thing with binning is about trying to match pixel scale to actual conditions - after (or during) the capture if scope and camera are not properly matched - in case of over sampling.

Due to host of factors we get what is essentially a blurry image (seeing, guiding/tracking, scope aperture to name a few). There is mathematically backed sampling rate that is needed to record an image that is blurred without loss of any detail - simply because detail is not there - it's been blurred out by mentioned factors. If you go higher (finer) resolution (more pixels per arc second) - you will not loose resolution. You won't gain it either by virtue of finer recording - because detail is not there - it's been blurred out.

What you will loose however is SNR. More you spread signal over pixels - each pixels gets less of it, and SNR drops. In AP it is all about SNR - you want to maximize it for given imaging time. Point of properly choosing sampling rate (even if it involves binning afterwards) - is to maximize SNR for wanted level of detail, or in case of optimum sampling - all the detail available.

If you bin to get to optimum resolution and then drizzle - no point in doing that - drizzle is used in case where you are under sampling - meaning there is detail to be recovered.

Many people want to see larger image of the target and they are happy with over sampling, but in reality there is no more detail in such image than in smaller one that has been scaled up (computer can't "invent" true additional detail, and if you enlarge image it will simply look blurry when viewed 1:1 - meaning 1 image pixel for one device pixel).

Binning is very similar to resampling - you reduce number of samples in each case and you improve SNR. However, there is difference between the two (as there is between different resampling methods - binning is in fact one of resampling methods). Binning has predictive SNR increase - it increases SNR in the same way stacking does - you are "stacking" adjacent pixels in fact. Resampling works differently - and usually provides less SNR increase. However regular binning is adding something called pixel blur. Because it acts in the same way as having larger pixels, and pixels have surface - that creates a small blur. Resampling has less of this blur (depends on resampling type - bilinear has about same pixel blur as binning, trilinear a bit more I think, while advanced resampling methods have less). There is however way to bin your data so that no pixel blur is added - and that is the best way to do it as it provides the most benefit and no drawbacks.

Best way to bin CMOS sensor data is to bin your subs after calibration and prior to stacking.

A lot could be written about binning, and it is fairly complex topic - but that does not mean it should not be used.

 

[andrew s]

Personally I think binning is a very crude way to improve S/N in an over sampled image. There are better techniques which can be exploit the over sampling e.g approaches based on wavelets or convolution, to reduce noise. If the noise is truly random the over sampling pushes its frequency higher, away from the lower resolution image, making them simpler to separate. 

I am planning to try some of these on my over sampled spectra but I think PI has implemented some  of these methods for images.

Regards Andrew 

[didwebringbatteries]

2 hours ago, souls33k3r said:

CEM60 and CEM60-EC have been getting good reviews. Do not overlook these mounts.

I'm in the market for a new mount as well but just can not justify the cost of an Avalon right now ... or ever!

I've seen mixed reviews when it comes to iOptron, similar to what you see for Celestron products, especially the AVX. But what drove me away from them, is the apparent need to be very careful around them or they break. I recall the example of carrying the setup without offloading the mount first. Second point is that some people had to return their mounts for some defects, this is not something that I want to go through. If I lived in Europe or Northern America, I would definitely not get an Avalon, as durability and/or lack of maintenance won't be a priority. I don't know, I might be putting a lot into Avalon's marketing point of being maintenance free for internal components. I really can't do anything about a mount that comes with a defect or fail after few months.

2 hours ago, newbie alert said:

I hear where you're coming from and agree with you as my cgem is under performing..never been totally happy with it and feel my avx was a far better mount, now lost my faith in celestron.. 

No doubt in my mind that the Avalon is a seriously good mount..Are you on a fixed pier or are you setup and pack down type of imager?...lots of other mounts to choose from around that price point and all far exceed what your achieving now..

Good luck with whatever you choose

That's my direction now, as far away from Celestron as one can be. I usually image from my balcony in the city, and occasionally drive to my relatives rooftop and less occasionally (but want to make it more frequent) to an hour away darker site. There are no plans for a fixed pier any time soon (not in a decade at least)

[souls33k3r]

13 minutes ago, didwebringbatteries said:

I've seen mixed reviews when it comes to iOptron, similar to what you see for Celestron products, especially the AVX. But what drove me away from them, is the apparent need to be very careful around them or they break. I recall the example of carrying the setup without offloading the mount first. Second point is that some people had to return their mounts for some defects, this is not something that I want to go through. If I lived in Europe or Northern America, I would definitely not get an Avalon, as durability and/or lack of maintenance won't be a priority. I don't know, I might be putting a lot into Avalon's marketing point of being maintenance free for internal components. I really can't do anything about a mount that comes with a defect or fail after few months.

That's my direction now, as far away from Celestron as one can be. I usually image from my balcony in the city, and occasionally drive to my relatives rooftop and less occasionally (but want to make it more frequent) to an hour away darker site. There are no plans for a fixed pier any time soon (not in a decade at least)

I completely agree with your reservations. I'm sure what you read were a few years old reviews but iOptron have tightened up their game and in the last 2 years they've been proving nothing but really good mounts.

[ollypenrice]

I still think that, from a reliable mechanical engineering point of view, you won't beat the Avalon. It is CNC machined from solid with hefty and high quality bearings running in a clean, dry environment. Very, very convincing.

The tension on the belts can, I'm told, be adjusted so the variability in reports of how the mount behaves in wind may be down to adjustment. Mine was a little elastic and I sold it to a friend with that out in the open. He adjusted it and it is now fine, he says. (It was still very good as I was using it.)

Olly

[Andyb90]

I’ve been very happy with my Linear. It’s extremely well built and very manageable to carry. I set up and tear down each time so that’s important for me. The guiding performance is also excellent. So far I’ve not found I needed to adjust the belt tension. As a note of caution if you do go for the Linear and you are buying new the mount manual states: 

“Never modify the tension of the belts (by dedicated screw), these are set in the factory and any unauthorized change will void the manufacturer’s limited warranty .”

[vlaiv]

@ollypenrice and @Andyb90 what sort of guide RMS are we talking about with Avalon?

I'm wondering because it uses same stepper motors and electronics as EQ6 platform, but I don't know what one step translates to in terms of arc seconds. In my view, steppers and their resolution is one of the limiting factors on SW mounts, or rather tendency of steppers to miss step when doing micro stepping - this is for DEC axis, RA is dynamic so miss steps will not have that much impact, but DEC needs to be stationary and any seeing or wind can create need for small correction and that in turn can be a problem if miss step happens - over correction or under correction with need for second correction and so on, eventually limiting how stable DEC axis is and in turn having impact on total RMS.

[cotak]

13 hours ago, didwebringbatteries said:

I've seen mixed reviews when it comes to iOptron, similar to what you see for Celestron products, especially the AVX. But what drove me away from them, is the apparent need to be very careful around them or they break. I recall the example of carrying the setup without offloading the mount first. Second point is that some people had to return their mounts for some defects, this is not something that I want to go through. If I lived in Europe or Northern America, I would definitely not get an Avalon, as durability and/or lack of maintenance won't be a priority. I don't know, I might be putting a lot into Avalon's marketing point of being maintenance free for internal components. I really can't do anything about a mount that comes with a defect or fail after few months.

That's my direction now, as far away from Celestron as one can be. I usually image from my balcony in the city, and occasionally drive to my relatives rooftop and less occasionally (but want to make it more frequent) to an hour away darker site. There are no plans for a fixed pier any time soon (not in a decade at least)

You do realize that all mount makes have a reject/failure rate? Even the venerated Mesu has examples where they needed some care.

You are just not going to find anything out there that guarantees free from failure in the mechanics.

The iOptron fragility is in my opinion only 50% true. The design for CEM is somewhat questionable but in reality it's only a risk for a narrow windows in setup and tear down. And for someone who's not prone to mistakes the risks is quite low. And they sold many copies if the risk is that high you'd see lots of stories of problem but you only see a few and mostly with the ZEQ25 due to the unfortunate way the spring tension was design there. The spring tension issue doesn't exist in any subsequent CEM mounts.

I know you say you are not mechanically inclined but  mounts are mechanical devices and as I mentioned above even the best can have issues, so you might want you make your peace with the idea of doing work on your mount. In that case if you can accept it iOptron tends to be very open to sending parts for owners to do their own work, saving you big bucks in shipping. It's one of the major reason I stuck with them as in Canada any warranty service for other brands would often require quite expensive shipping to the USA.

 

[cotak]

4 hours ago, vlaiv said:

@ollypenrice and @Andyb90 what sort of guide RMS are we talking about with Avalon?

I'm wondering because it uses same stepper motors and electronics as EQ6 platform, but I don't know what one step translates to in terms of arc seconds. In my view, steppers and their resolution is one of the limiting factors on SW mounts, or rather tendency of steppers to miss step when doing micro stepping - this is for DEC axis, RA is dynamic so miss steps will not have that much impact, but DEC needs to be stationary and any seeing or wind can create need for small correction and that in turn can be a problem if miss step happens - over correction or under correction with need for second correction and so on, eventually limiting how stable DEC axis is and in turn having impact on total RMS.

I view concerns about steppers as nothing more than wive's tales. Sorry, but that's how I feel about that line of thought.

I think that because DC servo motors are still going to be limited by the resolution of the control electronics, which will likely be PWM based for most non-luxury mounts and with motion control using low resolution encoders. And in many cases used spur reduction gears with fair bit of slop. So in the end does that gain you any real advantages over a stepper system with belts? I personally think that the result is a wash between the two approaches. 

[ollypenrice]

7 hours ago, vlaiv said:

@ollypenrice and @Andyb90 what sort of guide RMS are we talking about with Avalon?

I'm wondering because it uses same stepper motors and electronics as EQ6 platform, but I don't know what one step translates to in terms of arc seconds. In my view, steppers and their resolution is one of the limiting factors on SW mounts, or rather tendency of steppers to miss step when doing micro stepping - this is for DEC axis, RA is dynamic so miss steps will not have that much impact, but DEC needs to be stationary and any seeing or wind can create need for small correction and that in turn can be a problem if miss step happens - over correction or under correction with need for second correction and so on, eventually limiting how stable DEC axis is and in turn having impact on total RMS.

The Avalon stopped using the EQ6-derived motherboard and handset some time ago. I don't know where the present motors come from though. Personally I think this is a shame because I found they worked fine and the spares were cheap and available anywhere. My RMS was usually around 0.5" under guiding, Our EQ sixes manage this at their best but don't do so predictably or consistently.

3 hours ago, cotak said:

You do realize that all mount makes have a reject/failure rate? Even the venerated Mesu has examples where they needed some care.

You are just not going to find anything out there that guarantees free from failure in the mechanics.

The iOptron fragility is in my opinion only 50% true. The design for CEM is somewhat questionable but in reality it's only a risk for a narrow windows in setup and tear down. And for someone who's not prone to mistakes the risks is quite low. And they sold many copies if the risk is that high you'd see lots of stories of problem but you only see a few and mostly with the ZEQ25 due to the unfortunate way the spring tension was design there. The spring tension issue doesn't exist in any subsequent CEM mounts.

I know you say you are not mechanically inclined but  mounts are mechanical devices and as I mentioned above even the best can have issues, so you might want you make your peace with the idea of doing work on your mount. In that case if you can accept it iOptron tends to be very open to sending parts for owners to do their own work, saving you big bucks in shipping. It's one of the major reason I stuck with them as in Canada any warranty service for other brands would often require quite expensive shipping to the USA.

 

Ioptron (I can't do with their daft capitalization!) can expect the public to be cautious given that the company pumped out too many unsatisfactory products in the early days and carried out many quick revisions. Problems with the original spring loading of the 45 mount should have been discovered prior to production. I think it's important for the community to send a clear signal to all manufacturers:  Don't do your beta testing on us! Is it time to forgive Ioptron? Perhaps it is.

Olly

 

Edited May 11, 2019 by ollypenrice
Typo

[cotak]

4 hours ago, ollypenrice said:

The Avalon stopped using the EQ6-derived motherboard and handset some time ago. I don't know where the present motors come from though. Personally I think this is a shame because I found they worked fine and the spares were cheap and available anywhere. My RMS was usually around 0.5" under guiding, Our EQ sixes manage this at their best but don't do so predictably or consistently.

Ioptron (I can't do with their daft capitalization!) can expect the public to be cautious given that the company pumped out too many unsatisfactory products in the early days and carried out many quick revisions. Problems with the original spring loading of the 45 mount should have been discovered prior to production. I think it's important for the community to send a clear signal to all manufacturers:  Don't do your beta testing on us! Is it time to forgive Ioptron? Perhaps it is.

Olly

 

Well they are sort of done their beta now if you look at their product lines it is now evolution rather than revolution, so at this point likely to be fewer issues. However, just as with Cars it might be prudent to wait 1-2 year on any new model of mounts. It might be that the mechanics is fine but there's value to letting braver souls figure out all the particulars of any model if one's not adventurous. 

In the end I am very aware that they are a mass market business and all the potential issues that comes with it. And also how a beginner could attribute their issues to equipment rather than seeing the big picture.

My ieq45 pro was admittedly a problem child when I first received it.

• It didn't have the latest RA board to allow for the electronic balancing routine to be used, which iOptron quickly rectified by sending me an updated board.
• There was a lot of mechanical mis-adjustment. This part took better part of 1 year to sort out through just learning about the mount. Luckily the ieq45 pro design is very work friendly so overall I think I gained a good understanding how it is supposed to work and in the end was worth the effort.
• The original worm was badly machined and this and the old RA board makes me wonder if I got a copy that was on the shelf for a while. iOptron eventually agreed to help replace it at 50% cost. This for many would have been a deal breaker, but I'd remind those that the ieq45 pro has no PE spec, plus actually the mount guided just fine with a massive 60" of PE. In fact the replacement worm only did better by about 0.1-0.2 rms.
• I also fell down into my basement with the mount and tripod in one unit. No damage except to the rubber feet of the tripod, and sprained my ankle. So it's tougher than it looks. And this one was all my fault but in the end made me realize that I don't want to setup each night and resulted in my ROR which looks amateurish but works well.

So a lot of people would look at what i wrote and wonder why I kept the mount and still have a positive view of ioptron. Well they provided good support and were fair and reasonable to deal with. And the ieq45 pro ended up in a state that guides everynight around 0.5 RMS total. This is performance that requires no adjustments from me once dialed in be it -25C out or +40. So I was pretty happy to keep using them.

 

 

Edited May 11, 2019 by cotak

[Datalord]

On 10/05/2019 at 11:01, didwebringbatteries said:

Alright, more details about my issues, although I was trying to avoid turning this about my CGEM DX problem. I know my CGEM is under performing, it works, but it has many issues. RMS is between 0.6 and 2.2, same setup, same seeing, same everything. It is never stable enough to image with the newt. I do end up dropping half my newt frames, while APO at that scale they usually survive. It is not supposed to be this bad, but in my case it is. The RA housing has two bolts that are loose and cannot be tightened. I am under the impression this mount had a previous life somewhere and was shipping and sold as new here. Something is wrong with the internals. I have a friend that dismantled the mount for me, and every screw was a pain to deal with: rust, wear, etc... I will continue working on the CGEM in the hopes of getting it performing better, but I have been suffering with it for over a year now and I want to move to something that would give me some peace of mind.

Not the most cost efficient route, but I am not willing to sink money into the CGEM. That's why I am here, to see what you guys have experienced with the Linear and if you have better suggestions in that price range or lower. I want to do this right this time,  and the forums are my only source of support.

I have had similar pain with a CGX and ended up ordering a ASA DM85, which is quite a bit more than your budget. But I very seriously considered a CEM120EC as a cheaper alternative. In your case, I'm absolutely sure I would buy the CEM60EC.