Any new EQ8 Reports?

[nmoushon]

Its been a while now since the EQ8 was released. At first there were several people noting bad gears and backlash issues which have been noted and taked about on several other threads. This last week the EQ8 finally made land fall here in the USA. The starting price is very inticing....especiall for the mount head only. At $3800. Since it is still very very new in the US there are no reviews yet. I was wondering if there has been any new news regarding the issues with the EQ8, the European version that is. Have those that had the bad gears/backlash get the issue sorted out?

I'm in the market for a new mount with that capacity and I'm currently on the fence between a used AP900 or a new HDX1100 (EQ8). Theres a $2700 difference in price between the two. The AP as has proven history behind it but the EQ8 has inticing new tech (encoders) and a price point that is just too hard to not look twice at. So I'm trying to figure out if the $2700 is worth the risk or not.

[perfrej]

Just read up on the specs.. The EQ8 has low res encoders. Still good, but...

/per

[nmoushon]

Just read up on the specs.. The EQ8 has low res encoders. Still good, but...

/per

You're a bid one sided on your 10Microns Per . Not every mount can have those awesome encoders and fit in my budget.  Maybe in 5 years the tech might be in my budget.

[perfrej]

Just sayin'...

They quote a resolution of about 0.12" which is for the stepper motors, meaning that the smallest step the mount can move is 0.12". The on-axis encoders have a resolution of 1.2 arc MINUTES. I am quite convinced that it may be an excellent mount but I am worried about the gear eccentricity that surfaced in a few of them. Find an example without the eccentricity and you have a winner, that's for sure.

/per

[ollypenrice]

What do you want these encoders to do? Per wants them to run a 'guiding' system based on mount feedback and a sophisticated sky model. But if you are aiming to be at the mount and to guide on the sky (is this the case?) then why the big encoder deal? I don't really get it. At this stage underlying mechanical integrity is the big player. Or so I'd have thought.

Olly

[nmoushon]

I guess I'm still a bit confused about encoders. I thought they improved the accuracy of the mount while guiding. Wouldn't everyone want that?

[ollypenrice]

I guess I'm still a bit confused about encoders. I thought they improved the accuracy of the mount while guiding. Wouldn't everyone want that?

I dare say encoders on the mount could help guiding (by which I mean guiding on a star) provided there is some way of making them do so. What ways exist? Maybe they could in principle enhance the feed-forward input of PEC or you could have a feedback loop as in Per's system where the encoders are read and their position fed to the mount for correction. But can this be done at the same time as receiving guiding input from stars? I don't know.

In cases where you are guiding on a star I don't see much guiding value in having encoders. They are handy for remembering park positions and providing accurate GoTo but  of themselves they don't automatically impact on autoguiding unless they can be made to do so. Surely?

Olly

[perfrej]

Olly is correct in part. If the periodic error of your mount is such that it is easily guided out then you do not need the encoders - if you want to stay by the mount during operations (or at least be very close to it).

Encoders attached to the main (final) axii of mounts obviously provide information as to the very precise position of the axis in question. If that information is somehow fed into the motor control then the PE virtually disappears. The motors are controlled using the information from the actual resultant movement of the axis.

Absolute? Well, if the encoders are absolute then the mount cannot get lost. There is no need for any homing of the mount, it doesn't care about power loss, you hitting the top of your refractor with a cricket bat (why, why would you do that?) or if you loosen the clutches and play propeller with it. At the moment of power on, the mount knows where it is. At least approximately, if by "approximately" we mean down to about 0.1 arc-second

Now comes the interesting part. If we apply some basic mathematics (that's maths, not math), well known such, to the movement of the mount we can factor out more or less everything that contradicts steady movement at a constant rate. Lets name a few:

• Atmospheric refraction (quite a bit as it turns out)
• Orthogonality errors
• Flexure caused by gravity
• Flexure caused by other factors (consistent ones)
• Polar misalignment

In order to get rid of these anomalies (or realities) we need to teach the mount what the problems are. We do this by repeatedly feeding the mount syncs that tell it how wrongly pointed it is. Many of them, say 50 or so. This can be automated or, as is the case with 10Micron mounts, performed easily with the handset (or automated, of course). The mount then needs to model these imperfections and assign them parameters. This is just like doing a curve fit by means of linear regression, like in Excel, but involves a more complex set of parameters.

The resultant "model" is thus a set of parameters to a mathematical equation used to compute where a certain sky coordinate actually is using your rig with its specific pointing and tracking errors. Most mounts that can do this do it with the aid of a PC on the side. Without turning this into a crusade for a specific mount, I can tell you that the 10Micron mounts are (to date) the only mounts that will do this on their own; all other mounts need a pc and external software. If this is a problem or not is up to the end user, but I, for one, find it very satisfactory to have it in my mount and not in the PC.

When the mount has a model and proper motor control using the absolute encoders there isn't much stopping it from tracking your object without guiding. Naturally, the mechanical quality needs to be on par with the encoders.

I currently have my bigger mount (a GM2000HPS) at a remote site in southern France. Apart from the fact that my focuser is giving me a hard time, the rig delivers consistent pointing and tracking. Please note that due to my drilling the holes in the pier top slightly off angle, my polar alignment error in Az cannot be corrected fully. Thus, I am currently running the mount with a polar alignment error of exactly 52.8 arc-minutes. Stars are round, though and I do not even have a guide camera mounted. If the darn field rotation wasn't so obvious no one would notice...

So, my fellow addicts, in response to the question of "who needs encoders", the answer is that once you try it you do not want to go back to not having them.

All the best,

Per

[nmoushon]

Thanks for the added explaination. So I plan on using a C11" Edge to do AP with. I also intend to have my obsy in my back yard so not going remote. I'm still relatively new to AP so planning on spending a good amount of time out there. At least at the start. What I would like is that go and find the object I intend to image, via goto or maual, and start up the programs and equipement to image manually. Start imaging and then either stap out an use my visual scopes to observe or if its too cold just head inside and let it run and do its thing and get me as many perfect subs as I can. I would love to strive to achieve at least 30min subs with my C11" Edge @f/10.

I want a setup that would prove to have as few potential problems as possible. I know theres things I can't control like clouds making me lose my guide star. So the unguided exposures via encoders sounds enticing because it eliminates any guiding problems. I would definately choose that option if I had the budget for the GM2000 but I would barely be able to scrape together enough to get the GM1000. So with that said would I be able to achieve unguided 20-30min exposures with a C11" Edge on the GM1000? I think it would be pushing the limits of the mount just because of size. So if I'm going to struggle with unguided imaging with my C11" Edge and have to resort to guiding then I would be best to save my money and get an AP900?

[perfrej]

C11 EdgeHD is 2.8m focal length. Achieving five minute subs with guiding using a premium mount will be a daunting task in itself. I suggest you start your AP experience with something that will not put you off, say a refractor of less than a metre of focal length and reasonably fast.

Now, as for encoders on the EQ8, they sport a resolution of 1.2 arc-minutes, or 72 arc-seconds. 10Micron uses encoders with 0.11 arc-seconds resolution, ASA even better with almost ten times that. So, the difference between the EQ8 excoders and the 10Micron ones come out at 655 times as inexact. The EQ8 encoders are going to get you the "never gets completely lost" functionality and may even gice you a few minutes of unguided imaging at 0.5m of focal length. Not good enough, but certainly good enough for guiding.

Unfortunately, my dealings with the 925 EdgeHD scope - with microtouch focuser - tell me that you simply cannot image unguided with an OTA like that. The flexure is not predicatable enough due to mirror flop and instability in the mounting. I sold that scope because it would simply not build a good model with neither of my mounts. A pity considering the quality of the optics!

Now, there is a bottom line somewhere in all this hot air emanating from me It talks of reasonable focal lengths, stable designs and reasonable mounts. The ideal setup if you do not want to guide and want to be able to grow would be a GM1000HPS, a good refractor, say a Takahashi or similar, and a good CCD. If you want to go into exciting new territory and don't mind being 100 per cent PC dependent, the ASA DDM60 may be a cool candidate. It does, however, have a rather steep learning curve and a few people have had problems getting it to home reliably in remote setups.

If budget is tight, I suggest an NEQ6 or the new AZEQ6 for the mount. Saves you a few bucks and gives you headroom for a good guide camera.

All the best,

Per

[nmoushon]

I'm not completely new to AP. Been imaging with my ED80 for 2 years now. I know thats a big difference than the 2.8m focal length of the C11 so I'm expecting a big learning curve there no doubt. I do want to image long focal length. That the whole point of me upgrading as I prefer imaging galaxies over nebula. I will be keeping my ED80 for wide field AP as I don't want to mess with a HyperStar but I will get a reducer also. I know C11 will be hard to guide but I do want to give it my best possible chance of getting to work. Maybe I'm hoping to much for the sub length at the full 2.8m but I'm going to strive for it as much as is possible. Thats what I want anyways...it might not even be possible.

[ollypenrice]

Great post from Per, as ever. But why throw out the baby with the bathwater? It really isn't that difficult if you don't get hung up on the technology as an end in itself. I guide? I don't guide? I don't care, in principle. I just want sub pixel accuracy. For me personally, sorting out an autoguider is 10x (or maybe 100x) easier than faffing around with the IT side of making these unguided wondersystems work. I'm 61 (in a couple of hours  )

and I like the objects out there. They are gorgeous. I love them!! As for all this garbage that I need to get in touch with them, well, I just want it to work and shut up. I spent two years imaging at 2.4metres with Yves' rig (ODK 14/Mesu Mount 200) and what did it do? It worked. Woo Hoo!!!!

EQ8 at 2.8 metres? WIth backlash a go-go? Not on my patch.

Olly

[nmoushon]

Great post from Per, as ever. But why throw out the baby with the bathwater? It really isn't that difficult if you don't get hung up on the technology as an end in itself. I guide? I don't guide? I don't care, in principle. I just want sub pixel accuracy. For me personally, sorting out an autoguider is 10x (or maybe 100x) easier than faffing around with the IT side of making these unguided wondersystems work. I'm 61 (in a couple of hours  )

and I like the objects out there. They are gorgeous. I love them!! As for all this garbage that I need to get in touch with them, well, I just want it to work and shut up. I spent two years imaging at 2.4metres with Yves' rig (ODK 14/Mesu Mount 200) and what did it do? It worked. Woo Hoo!!!!

EQ8 at 2.8 metres? WIth backlash a go-go? Not on my patch.

Olly

Happy early birthday Olly!

Thats what I want to. To get consistant subs to be able to work with. I was hoping that it could be possible with the unguided accuracy of the 10Micron but its looking like thats not possible, with my budget that is. I'm pretty sure I could get to what I'm looking at with guiding so at that point the 10Micron has lost its edge. So I think I'm still down to trying to decide between the EQ8 and AP900.

[Gasman]

Hi guys

Interesting post, forgive me if I`m completely barking up the wrong tree but isn`t NM just seeking a good, `accurate` and reliable mount for AP?. I just wonder when accuracy is `good` enough ?.For my own part after finally getting PHD and Lodestar to work with my NEQ6 the other evening I got 8x5mins subs of the SN in M82 placed on a 23 micron slit without touching the mount which I assume would equate to a single shot of 40mins if I had chosen to do that?? So with my Atik 314 having pixel size of 6.45 microns thats an accuracy within 3-4 pixels,how much more accurate would I need to be? would that even show in an image?(maybe it would I`m not an imager??). Even better after synching on it in Cdc the next night I did a goto and it placed the SN slap bang where it was the night before. I guess when SW get it right with the EQ8 they`ll have another winner!

Regards

Steve

[Earl]

Its always a minefield deciding on the mount you want.

My advice is buy once so as not to repent at leisure.

The better the mount the longer it will serve without going down the what if route, Id like a 10Micron but i dont think i can justify the cost in the following equation.

Environment (sub length ) taking into account accuracy guiding as a low local length vs sub quality.

I could say use an AP1600 when in reality an EQ6 will do the job just aswell.

Round and round......

[tferrari]

Anyone interested in long focal length AP must consider auto-guiding a necessary part of the process. It's unnecessary to try to acheive your level of guiding from the mount itself when inexpensive (relatively) hardware/software is specifically designed to pick up the slack.

[ChrisLX200]

Anyone interested in long focal length AP must consider auto-guiding a necessary part of the process. It's unnecessary to try to acheive your level of guiding from the mount itself when inexpensive (relatively) hardware/software is specifically designed to pick up the slack.

Just so. And there has been no mention of AO guiding - has this gone out the window now? Maybe I'm a bit out of touch with developments here.

ChrisH

[nmoushon]

Hi guys

Interesting post, forgive me if I`m completely barking up the wrong tree but isn`t NM just seeking a good, `accurate` and reliable mount for AP?. I just wonder when accuracy is `good` enough ?.For my own part after finally getting PHD and Lodestar to work with my NEQ6 the other evening I got 8x5mins subs of the SN in M82 placed on a 23 micron slit without touching the mount which I assume would equate to a single shot of 40mins if I had chosen to do that?? So with my Atik 314 having pixel size of 6.45 microns thats an accuracy within 3-4 pixels,how much more accurate would I need to be? would that even show in an image?(maybe it would I`m not an imager??). Even better after synching on it in Cdc the next night I did a goto and it placed the SN slap bang where it was the night before. I guess when SW get it right with the EQ8 they`ll have another winner!

Regards

Steve

This is what I'm trying to achieve. The topic has kind of wondered about off my original intent but still applies to me trying to pick a mount. My original intent was to try and find if there were any new data on the EQ8. To see if anyone has been able to do further testing or not as I'm currently trying to decide between a new US version of the EQ8 or a used AP900. As some of the above posts have stated they are on different level but the low price of  the EQ8 is keeping it in the running as long as it can prove to be a worth mount to carry a C11 for AP. At this time with its current problems that have cropped up I'm not sure its worth the gamble and thus me trying to see if there was any new info out or not. But it looks like there isn't much as I guess the weather has been pretty horrible lately over Britain. The 10Micron got thrown back into the mix because I mentioned encoders on the EQ8 while the AP900 doesnt have any. But Per and Olly help explain the difference above. 

The better the mount the longer it will serve without going down the what if route, Id like a 10Micron but i dont think i can justify the cost in the following equation.

Environment (sub length ) taking into account accuracy guiding as a low local length vs sub quality.

I could say use an AP1600 when in reality an EQ6 will do the job just aswell.

Round and round......

I would love a 10Micron also but I think I would need at least the GM2k to really suit my wants and thats just WAAAAAAAY out of my price range. Lovely mount but just not for me at this time. 

Anyone interested in long focal length AP must consider auto-guiding a necessary part of the process. It's unnecessary to try to acheive your level of guiding from the mount itself when inexpensive (relatively) hardware/software is specifically designed to pick up the slack.

Just so. And there has been no mention of AO guiding - has this gone out the window now? Maybe I'm a bit out of touch with developments here.

ChrisH

Oh I'm very well aware of the need for guiding especially at long FL. I only brought up unguided imaging in concurrence with the 10Micron be thrown back into the mix and its ability to do long unguided imaging. I would love to do unguided imaging with a C11 but that probably would require a mount equal to my entire years salary...before taxes lol.  As above it very doubtful I would be able to achieve unguided exposures more than a couple minutes (if that) even with a 10Micron. So because I would have to rely on guiding period the price (and encoders) of the 10Micron now are "useless" to what I'm wanting. "Useless" it terms of providing me with guided accuracy boost but has plenty of other features but they aren't worth the price. I intend to use my SBIG 2k with dual chip to try and guide. I also will be using an OAG if it becomes to hard to find a guide star. 

[ollypenrice]

The price of going unguided is quite high, both in terms of the dollars and the input of effort needed to get it going at long FL, so I rather agree with NM and Tyler. Unguided can be done at long FL, certainly. My (robotic) neighbours a couple of valleys away have ASA mounts which do this - after a prolongued struggle to get them to work. How long a FL the 10 Micron will manage is something I don't think we know - or I certainly don't. It's a good mount in other respects too, though, and beautifully made.

Good point about the Active Optics route, which does seem to have gone quiet. I've seen both the SX and SBIG versions working here and they were mighty impressive. One owner described his as a real pain to set up, though. Certainly worth a bit of homework, all the same.

There is a downside to the dual chip guiding system, I reckon. Of itself it is a great idea but the hassles are plenty; you have to orientate the chip to suite the guide star rather than the target. Is this going to be the orientation you really want? It means that reframing the object on a subsequent night takes a lot longer. Rotation is pretty tricky to realign.  And there is a danger of your flats being affected by rotation, so if you are moving between targets on a single night you may need separate flats for both. So when do you shoot them? (It all depends on how symmetrical your vignetting is. Dust bunnies should normally rotate with the camera.) I'm a great believer in being orthogonal to RA and Dec. Coming back to an image in the future is so much easier.

Great line from Earl, 'repent at your leisure.' I've done a fair bit of that over the years, especially with mounts! Three of them, in fact. The FL of a C11 will give plenty of opportuninty for repentence if you get it wrong!   

Olly

[nmoushon]

The price of going unguided is quite high, both in terms of the dollars and the input of effort needed to get it going at long FL, so I rather agree with NM and Tyler. Unguided can be done at long FL, certainly. My (robotic) neighbours a couple of valleys away have ASA mounts which do this - after a prolongued struggle to get them to work. How long a FL the 10 Micron will manage is something I don't think we know - or I certainly don't. It's a good mount in other respects too, though, and beautifully made.

Good point about the Active Optics route, which does seem to have gone quiet. I've seen both the SX and SBIG versions working here and they were mighty impressive. One owner described his as a real pain to set up, though. Certainly worth a bit of homework, all the same.

There is a downside to the dual chip guiding system, I reckon. Of itself it is a great idea but the hassles are plenty; you have to orientate the chip to suite the guide star rather than the target. Is this going to be the orientation you really want? It means that reframing the object on a subsequent night takes a lot longer. Rotation is pretty tricky to realign.  And there is a danger of your flats being affected by rotation, so if you are moving between targets on a single night you may need separate flats for both. So when do you shoot them? (It all depends on how symmetrical your vignetting is. Dust bunnies should normally rotate with the camera.) I'm a great believer in being orthogonal to RA and Dec. Coming back to an image in the future is so much easier.

Great line from Earl, 'repent at your leisure.' I've done a fair bit of that over the years, especially with mounts! Three of them, in fact. The FL of a C11 will give plenty of opportuninty for repentence if you get it wrong!   

Olly

The AO is very interesting and I wish I had the budget to put into something like that but I don't Maybe in the future once I recoupe the money I can upgrade my camera to one that has it.

I'm aware of the problems with the dual chip camera for guiding. I will be starting with it and will try to keep to the same orientations that you do Olly. Hopefully with 4 options I will be able to find a guide star. I will be keeping my current guide cam and will budget for an OAG just incase the dual chip prove to difficult to work with.

I definately don't want to be repenting or regreting. So I am planning on this being a FINAL setup. Unless I get a lot of money from some where. So that why I'm doing so much research and getting as many suggestions as possible. I'm ever leaning more and more towards the AP900.

[stephen_usher]

OK, seeing as I'm an EQ8 owner (not that the weather's allowed me to use it much recently) I'll chip in.

Backlash

• I only appear to have it in Dec and not in RA and it's manageable.

Other problems.

• Every time I power up after parking the scope I have to sync the encoders to a star (usually Pollux) and it will invariably be a few degrees out in RA, usually too far East of the star. Once this has been done the mount tracks and slews well.
• As with all Skywatcher mounts, the handbox doesn't have a battery backed clock, which is a right pain and puzzling as it's not rocket science and would add a piddling amount to the cost.
• A couple of weeks after I got the mount during the parking of the scope the Dec worm gear started squeaking as it turned. This only happened once and sounded like lack of lubrication.

On the whole, not too bad. Having said that comparing any astronomical mount to other engineered objects they seem to be poorly engineered in the round and a bit thrown together. i.e. engineered with a "that'll do" attitude rather than carefully thought through and well engineered.

[tony210]

Hi - I have had the EQ8 for 6 weeks now and have adjusted DEC to reduce backlash which is fine and none in RA either that I can notice - it is behaving well now with accurate slewing with EQMOD and good guiding with PHD -RMS 0.8 and 10minute subs with round stars- that and good load capacity and price mean I am very happy so far as a reasonable mount for imaging -Tony.

[ollypenrice]

Hi - I have had the EQ8 for 6 weeks now and have adjusted DEC to reduce backlash which is fine and none in RA either that I can notice - it is behaving well now with accurate slewing with EQMOD and good guiding with PHD -RMS 0.8 and 10minute subs with round stars- that and good load capacity and price mean I am very happy so far as a reasonable mount for imaging -Tony.

What's your focal length or pixel scale, Tony?  RMS 0.8 sounds pretty bad, to be honest. I run between O.3 and 0.6 but I'm always wary of comparing raw numbers.

Olly

[Sp@ce_d]

I feel your pain!

I think you have to weigh up what it's worth to you in money saved & time spent, getting which ever mount you choose running the way you want it. I guess it depends if you like spending a lot of time "tinkering" and maybe even making parts etc or whether you look at it as false economy and want it to work out of the box so you can get on doing what you bought it to do... imaging!

It isn't a light decision to make by any means, something you don't want to get wrong.

I came so very close (yet again) to ordering an EQ8 last weekend (when FLO's10% weekend discount was announced). However, I thought long and hard all weekend over it and (I think) sense prevailed, in that it is such a new product it hasn't (fairly) been given time to prove itself yet. Yes, the reports of "issues" with some of them have put me off otherwise I'd have one right now.. Until I'm happy they are fixed or there are viable workarounds or mods then I feel I should be looking elsewhere. That is my opinion based on personal experience of .. yes I'll mention it again, SW's QC and having to tweek & mod astro products. I think the EQ8 needs at least another proven year in the field before it can be compared properly.

Don't get me wrong, I'm not against SW products.. I have a few and I'm (now) very happy with them. I just don't fancy spending that sort of money wasting precious clear skies to be a beta tester this time when I want to just get on imaging.

I'm doing the same as you and about to invest in a long FL scope (probably a C9.25, a bit smaller) so I'm not sure how long I'll hold out on the mount.. the longer the better to save up a bit more to have a wider choice. I've surprised myself by managing half hour guided subs with the tripple shooter setup so I'll try it out on the EQ6 first to see how it works out anyway. Moving upwards in price, there's the Avalon's or Mesu to consider? 

But lets face it.. the reason we feel almost compelled to buy an EQ8 is because of it's price.. half of the nearest contender!  SW know what they are doing

[Earl]

Depending on my health, my mount is the last part of my puzzle and im not set yet either, 10micron or mesu maybe eq8