40 replies to this topic

[SilverLitz]

I just got the notification on the availability of a new AP1100.  What should I do?

 

Prior to the $1700 price increase, I was thinking I would get the 1st available Mach2 or AP1100, but the big price increase gave me indigestion.  So I flirted with the idea of a MyT, but its issues (crosstalk, only USB2 through mount, and poorly engineered computer board) made think that it may be frustrating to get to work properly.

 

If I could get the Mach2 within a few months at $9K, I would prefer it to the AP1100 at $9.7K or $15.3K w/ encoders.  But who knows when I will get notified on the Mach2 (got on list at the end of Nov2020).

 

Part of me wants to bite the bullet, and go whole hog for the AP1100 w/ encoders, assuming I would eventually want encoders, as AP would install them, make sure everything is adjusted properly, and save $1000 vs. adding on down the road.  Only if the encoders actually provide meaningful performance advantage for AP.

 

Questions:

 

What is the expected life span and reliability of the Renishaw readers?  (Hate to have $4-5K parts that only last for a few years on a 20 year mount.  This could drastically change the value proposition.)

 

If I keep my load to no more than 50#, in an environment that has good seeing (1.5" typ) and low wind, is there much to be gained by adding encoders to the AP1100?

 

With 50# load (or below) what are the expected performance differences between a Mach2 and AP1100 (w/o encoders)?

 

Suggestions?

 

I am 99% AP only, and my current scopes are Esprit 100 and EdgeHD925, with intention of getting a 120-140mm APO, and my cameras are ASI183mm-Pro and QHY268M (coming).  My current and only mount is a G11.

 

Thanks!

Edited by SilverLitz, 05 March 2021 - 04:00 PM.

[rockstarbill]

Ask these questions on AP-GTO.

The benefits of the encoders is clearly explained on their website. Only they can answer questions about longevity, etc.

The Mach 2 is too new for anyone to comment much on it versus the 1100 with encoders. The only single thing I can see is the Mach 2 will not get lost if you loosen the clutches and move it. The 1100 will.

[PeteM]

You will not get a call/email from A-P for a Mach2 in the next couple months. On AP-GTO they said that the 1600 are being machined currently and next on the notification system. Get the 1100GTO either with encoder or not. I am getting the non-AE 1100GTO mostly because I trust the tight guiding it can do and be well within any seeing I will encounter(Michigan). But it is nice to know I can add the encodersr later.

[rockstarbill]

You will not get a call/email from A-P for a Mach2 in the next couple months. On AP-GTO they said that the 1600 are being machined currently and next on the notification system. Get the 1100GTO either with encoder or not. I am getting the non-AE 1100GTO mostly because I trust the tight guiding it can do and be well within any seeing I will encounter(Michigan). But it is nice to know I can add the encodersr later.

Yes that is what I did and it worked out great in the end. The 1100 without encoders is no slouch though. If you keep your PEM curve fresh yearly it's performance is pretty darn close.

[JMW]

I choose to put the deposit down on the 1100-AEL. I was originally going to just get the 1100 before I researched more about the absolute encoders. I a current owner of the 900 for about 10 years.

 

The 1100-AEL will be my primary mount for the rest of my life and I am keeping the 900 for EAA in my light polluted and tree obstructed backyard observatory.

 

I am at the place where I can afford it because I am not yet retired and will enjoy it until I am no longer able to deal with it as age/health eventually limits me. My experience with the 900 and the sharing of accessories between the mounts will help reduce the total cost of owning the 2nd mount. 

 

I plan on selling a G11 with Gemini 2 and a C11 EdgeHD with accessories to offset a bit of the cost of the encoders. I have been using a f/4 10 inch newtonian for the last 4 years instead of the C11.

 

I suggest you decide which mount you would want to use for many years. Also decide if you have the ability to wait for the Mach 2 verses paying more but getting the 1100 or 1100-AE this year. I suspect you would not be notified for a Mach 2 mount in 2021. I read about people who didn't make the last run and got on the list by late April 2019. Astro-Physics will probably do a 1600 run after the 1100 run is complete. The Mach 2 run would probably start close to the end of 2021.

 

The 1100 without encoders is still an excellent and easily guided mount. The 1100-AE is probably able to withstand greater winds without deflecting the scope as much because of the larger diameter axis compared to the Mach 2.

Edited by JMW, 04 March 2021 - 11:58 PM.

[mmalik]

But who knows when I will get notified on the Mach2 (got on list at the end of Nov2020).

I am from Sep 2019 and I was told it will most likely be 2022 for me to get a Mach2. In short, get an 1100, they are being produced fast at this time and you'll have one in couple of months. Get encoded if you can afford. Regards

[JCT]

You will not get a call/email from A-P for a Mach2 in the next couple months. On AP-GTO they said that the 1600 are being machined currently and next on the notification system. Get the 1100GTO either with encoder or not. I am getting the non-AE 1100GTO mostly because I trust the tight guiding it can do and be well within any seeing I will encounter(Michigan). But it is nice to know I can add the encodersr later.

This was exactly my approach.  Figured I would start without encoders for awhile, master the mount and then decide.  Will be a big step up regardless.  

 

From what folks have said, adding the encoders is reasonably straightforward and if I decide I want A-P to do it I can ship it back.   My guess is that for me, no encoders will be fine for the foreseeable future.

 

Mine should arrive next week, looking forward to it.

 

JT

[rockstarbill]

This was exactly my approach.  Figured I would start without encoders for awhile, master the mount and then decide.  Will be a big step up regardless.  

 

From what folks have said, adding the encoders is reasonably straightforward and if I decide I want A-P to do it I can ship it back.   My guess is that for me, no encoders will be fine for the foreseeable future.

 

Mine should arrive next week, looking forward to it.

 

JT

Yes, you can send them the mount back if you dont want to do the installation yourself. They will charge you for the encoders AND the installation though. 

 

EDIT: Just want to be 100% transparent -- the install is easy. Do it yourself. 

Edited by rockstarbill, 05 March 2021 - 02:32 AM.

[base16]

Mach 2 is less desirable given the cost, capability, and wait time especially when there are alternatives (A-P or 10micron are both great options). Get the 1100 and you can always add the absolute encoders later if you want to save upfront costs.

Through the mount cabling.
Portable (disassemble)
Proven performance
Capacity for more equipment / future proof

[rockstarbill]

Mach 2 is less desirable given the cost, capability, and wait time especially when there are alternatives (A-P or 10micron are both great options). Get the 1100 and you can always add the absolute encoders later if you want to save upfront costs.

Through the mount cabling.
Portable (disassemble)
Proven performance
Capacity for more equipment / future proof

Hold on here. I have both of these mounts here. 1100 with AE and a Mach 2. Lets break down what you are saying into real world applications.

 

Through mount cabling

The 1100 has a very large opening that can allow for decent amounts of cables to be run through the mount. However, I use an Ultimate Powerbox V2. It needs one 12v power and one USB3 to be run through the 1100 for it to be fully functional. The Mach 2, has one 12v power and one USB3 run through it for me. So at the end of the day, for my use cases (many) this is a wash.

 

Portability

The 1100 axis do split which makes it a more portable unit, but that is diminished a bit by the weight of the two cases you will then place each axis into. While in singles they will not add up to the total weight of the Mach 2, they will use up more space than the Mach 2 would. So for raw weight for a single piece the 1100 wins, for less space used the Mach 2 wins. At the end this (to me) is a wash.

 

Proven performance

Astro-Physics as the maker of the product is what makes me say this is also a wash. The same Renishaw brand absolute encoders are used in both mounts. The Mach 2 has a sligh reliability advantage in the fact that it cannot ever get "lost." The 1100AE can, in a scenario where the clutches are loosened. Without the encoders the 1100 will lose to the Mach 2 due to the fact that the Mach 2 has NO PE and NO backlash, while the 1100 (with a PEM curve) will have sub-arc second PE per worm cycle, and a very small yet largely insignificant amount of backlash.

 

Capacity for more equipment / future proof

I am going to use AG Optical iDK's to talk about comfort with the largest telescope you can possibly put on either mount. On the Mach 2, I would say the 12.5" iDK would be the largest I personally would wish to place on the Mach 2. Likewise, on the 1100 the 14" iDK would be the largest I would personally do the same. I dont think "more" equipment is really the answer here, as neither of these scopes press the max capacity of either mount. So if you kept the imaging trains very heavy (i.e. PL16803's with CFW5's, Sagitta OAG, filters, etc) I dont think the "more equipment" is super relevant. It is quite obvious that a larger telescope would fit the 1100. Just look at the two mounts side by side, and that is apparent. If your goal in life is to get extremely large aperture telescopes, then you should probably avoid both of these and buy a 1600 and be done with it. As it is, the 1100 has a VERY SLIGHT advantage over the Mach 2. 

 

In closing on this, they arent drastically far from one another. The true advantage I think with the 1100 is that you can buy it and use it for a few years and then make an informed decision on whether you want to invest in the encoders or not. While that may end up costing more in the long run if you decide to get them, you will probably be so sold on doing so, that the extra $$ will be less of a concern and the added performance and capability will shine above that. Know that you only got penalized $1000 more dollars (based on the current "add-on" kit price) than if you had bought them with the mount. $1000 dollars today, is worth more than $1000 3 years from now. So -- in the end I think the 1100 without encoders is the best option for people. But not due to cabling, portability, performance, or capacity. 

 

TL;DR: The flexibility of the 1100 is why it is (IMO) a better option if you don't already own one.

[base16]

Hold on here. I have both of these mounts here. 1100 with AE and a Mach 2. Lets break down what you are saying into real world applications.

 

Through mount cabling

The 1100 has a very large opening that can allow for decent amounts of cables to be run through the mount. However, I use an Ultimate Powerbox V2. It needs one 12v power and one USB3 to be run through the 1100 for it to be fully functional. The Mach 2, has one 12v power and one USB3 run through it for me. So at the end of the day, for my use cases (many) this is a wash.

 

Portability

The 1100 axis do split which makes it a more portable unit, but that is diminished a bit by the weight of the two cases you will then place each axis into. While in singles they will not add up to the total weight of the Mach 2, they will use up more space than the Mach 2 would. So for raw weight for a single piece the 1100 wins, for less space used the Mach 2 wins. At the end this (to me) is a wash.

 

Proven performance

Astro-Physics as the maker of the product is what makes me say this is also a wash. The same Renishaw brand absolute encoders are used in both mounts. The Mach 2 has a sligh reliability advantage in the fact that it cannot ever get "lost." The 1100AE can, in a scenario where the clutches are loosened. Without the encoders the 1100 will lose to the Mach 2 due to the fact that the Mach 2 has NO PE and NO backlash, while the 1100 (with a PEM curve) will have sub-arc second PE per worm cycle, and a very small yet largely insignificant amount of backlash.

 

Capacity for more equipment / future proof

I am going to use AG Optical iDK's to talk about comfort with the largest telescope you can possibly put on either mount. On the Mach 2, I would say the 12.5" iDK would be the largest I personally would wish to place on the Mach 2. Likewise, on the 1100 the 14" iDK would be the largest I would personally do the same. I dont think "more" equipment is really the answer here, as neither of these scopes press the max capacity of either mount. So if you kept the imaging trains very heavy (i.e. PL16803's with CFW5's, Sagitta OAG, filters, etc) I dont think the "more equipment" is super relevant. It is quite obvious that a larger telescope would fit the 1100. Just look at the two mounts side by side, and that is apparent. If your goal in life is to get extremely large aperture telescopes, then you should probably avoid both of these and buy a 1600 and be done with it. As it is, the 1100 has a VERY SLIGHT advantage over the Mach 2. 

 

In closing on this, they arent drastically far from one another. The true advantage I think with the 1100 is that you can buy it and use it for a few years and then make an informed decision on whether you want to invest in the encoders or not. While that may end up costing more in the long run if you decide to get them, you will probably be so sold on doing so, that the extra $$ will be less of a concern and the added performance and capability will shine above that. Know that you only got penalized $1000 more dollars (based on the current "add-on" kit price) than if you had bought them with the mount. $1000 dollars today, is worth more than $1000 3 years from now. So -- in the end I think the 1100 without encoders is the best option for people. But not due to cabling, portability, performance, or capacity. 

 

TL;DR: The flexibility of the 1100 is why it is (IMO) a better option if you don't already own one.

 

I hope you enjoy both your mounts! We are discussing products that are crème de la crème so the differences are expected to be a wash.

 

42lb single piece vs 2 smaller pieces (16.5lb + 11.5lb) makes the 1100 more portable for me -- I'll know once I receive the 1100 :fingers crossed:. I typically keep my individual weights to the minimum as possible. I don't use those scopeguard/hard cases unless I'm shipping the equipment, so the effective weight of 1100 is (to me) much more desirable factor until I get a more permanent setup. Portable can also mean setup/tear down portable.. it's less straining to operate the smaller pieces vs 1 heavier piece.

 

And while I don't intend to buy a single component that weighs more than 40-50lb by itself, I do plan on experimenting with multiple components as I grow into this hobby where the weights of those components combined can be much higher.  The higher capacity (if/when needed in future) is a desirable trait for long-term expenses like this.

 

Through-the-mount USB is just another aspect that was relatively suboptimal about Mach2 for me. I think it's great that the Mach2 has _something_; which is better than not having USB & power through the mount. That said, if there was an Ethernet port on Mach2, it would have been more future proof/extensible than just a USB 3.0 & power cable. For most/all practical purposes the USB should be sufficient for the foreseeable future.

 

I agree that the differences are a wash, as you say it, and we can live with either of them for a while. But the fact is 1100 (especially without AE) is much more versatile & flexible & future proof and one of the best mounts available on the market now for the price & availability & capability.

 

The Mach2 has such a long wait time, most people are better off buying a 10micron if the capacity of Mach2 is not a major concern anyway. If you already have the Mach2 then the availability part is clearly not a concern, and the points mentioned above are not necessarily deal breakers. In essence, if you see my previous comment & this comment its the combination of cost, capability, and wait time which together make Mach2 less desirable given what's currently available on the market at this pricepoint.

[rockstarbill]

I hope you enjoy both your mounts! We are discussing products that are crème de la crème so the differences are expected to be a wash.

 

42lb single piece vs 2 smaller pieces (16.5lb + 11.5lb) makes the 1100 more portable for me -- I'll know once I receive the 1100 :fingers crossed:. I typically keep my individual weights to the minimum as possible. I don't use those scopeguard/hard cases unless I'm shipping the equipment, so the effective weight of 1100 is (to me) much more desirable factor until I get a more permanent setup. Portable can also mean setup/tear down portable.. it's less straining to operate the smaller pieces vs 1 heavier piece.

 

And while I don't intend to buy a single component that weighs more than 40-50lb by itself, I do plan on experimenting with multiple components as I grow into this hobby where the weights of those components combined can be much higher.  The higher capacity (if/when needed in future) is a desirable trait for long-term expenses like this.

 

Through-the-mount USB is just another aspect that was relatively suboptimal about Mach2 for me. I think it's great that the Mach2 has _something_; which is better than not having USB & power through the mount. That said, if there was an Ethernet port on Mach2, it would have been more future proof/extensible than just a USB 3.0 & power cable. For most/all practical purposes the USB should be sufficient for the foreseeable future.

 

I agree that the differences are a wash, as you say it, and we can live with either of them for a while. But the fact is 1100 (especially without AE) is much more versatile & flexible & future proof and one of the best mounts available on the market now for the price & availability & capability.

 

The Mach2 has such a long wait time, most people are better off buying a 10micron if the capacity of Mach2 is not a major concern anyway. If you already have the Mach2 then the availability part is clearly not a concern, and the points mentioned above are not necessarily deal breakers. In essence, if you see my previous comment & this comment its the combination of cost, capability, and wait time which together make Mach2 less desirable given what's currently available on the market at this pricepoint.

Good response here, Arvind.

 

The ethernet comment is somewhat valid but if you have a 12v 45amp connection you have plenty of juice to run a switch, etc. 

[WadeH237]

What is the expected life span and reliability of the Renishaw readers?

As Bill mentioned in post 2, the AP-GTO user group is a good place to ask this.

 

I would say that Roland has made two relevant comments on that user group.  He's mentioned a few times that he does not use the low temperature variant of the encoders, yet has not seen them fail in the Illinois winter.  He also made a mention some time ago that they'd never seen an encoder failure on an Astro-Physics mount.

 

Obviously, there could be a one-off failure at some point, but I get the distinct impression that the encoders are pretty robust.  In my case, I keep my AP1600 with encoders under a TG365 cover.  It's been outside almost all the time since I installed the encoders just over 3 years ago.  I don't worry about it.

[JCT]

Yes, you can send them the mount back if you dont want to do the installation yourself. They will charge you for the encoders AND the installation though. 

 

EDIT: Just want to be 100% transparent -- the install is easy. Do it yourself. 

Yup - I finally found a video that demonstrated what was involved, doesn't look too bad.  Figured that if it was an issue someone would have posted that by now!

 

Will spend the weekend configuring the new NUC-based imaging setup, finally migrating from the ASIair.

 

Best,

 

JT

[rockstarbill]

Yup - I finally found a video that demonstrated what was involved, doesn't look too bad.  Figured that if it was an issue someone would have posted that by now!

 

Will spend the weekend configuring the new NUC-based imaging setup, finally migrating from the ASIair.

 

Best,

 

JT

You and anyone else with new AP mounts, feel free to hit me up in DM's for help with anything getting set up -- mounts, models, etc.. Very happy to help the community out. 

[rockstarbill]

As Bill mentioned in post 2, the AP-GTO user group is a good place to ask this.

 

I would say that Roland has made two relevant comments on that user group.  He's mentioned a few times that he does not use the low temperature variant of the encoders, yet has not seen them fail in the Illinois winter.  He also made a mention some time ago that they'd never seen an encoder failure on an Astro-Physics mount.

 

Obviously, there could be a one-off failure at some point, but I get the distinct impression that the encoders are pretty robust.  In my case, I keep my AP1600 with encoders under a TG365 cover.  It's been outside almost all the time since I installed the encoders just over 3 years ago.  I don't worry about it.

I should have come and hung out with you when you were still here in Echo Lake, but I may move over to Cle Elum with the new 50/50 model they offer.  

 

Still kinda bummed I did not come seek you out, Wade. Maybe with my next house!

[WadeH237]

I should have come and hung out with you when you were still here in Echo Lake, but I may move over to Cle Elum with the new 50/50 model they offer.

 

Still kinda bummed I did not come seek you out, Wade. Maybe with my next house!

I feel the same way.  I knew that you were in the neighborhood, but only learned how close recently.

 

I'm pretty seriously introverted, so I never really got to know any of the neighbors in the 19 years that I lived there.  My wife is the opposite, so she's the one that maintains our social relationships.

 

If you do set something up in Cle Elum, we should be sure to fix that.

[SilverLitz]

Thanks for the responses so far!

 

I will end up going for the AP1100 instead of waiting (how long??? Daleen said at least 2 more runs) for the Mach2, even though the AP1100's capacity is overkill.  (I have zero appetite for mounting/dismounting an unwieldy 70#+ load, as this will be uncovered on my back patio.) 

 

I also expect the AP1100 is machined to tighter tolerances vs. the Mach2, as it designed to perform at a high level without the need of encoders.  My mind has an analogy of the sound of simpler Class-A audio amplifiers compared to much more complicated Class-AB with extensive feedback.  The feedback intensive Class-AB have much better specs, but the Class-A amplifiers sound MUCH better and realistic (I have actually built my own Class-A preamp and power-amps, and they sound very realistic).  The downside is the Class-A amplifier requires MUCH higher quality components, better power supplies, and more heat sinking.

 

My concern with reliability of the encoders is more with the read heads and not the encoder rings, as I expect the failure rate of the read heads would be an order of magnitude higher than the rings due to their electronic nature.  It also seems that the read heads are much more expensive than the rings.

 

I still do not have a good feel for the practical/realisable/tangible performance improvement to be expected w/ the AE version compared to the base AP1100.  I have read reports than base AP1100s guide as good as seeing allows, though I expect this assertion should be conditioned on the actual seeing conditions.  My seeing is better than most, w/ 1.5" typical and 0.7" on the rare good nights (Meteoblue est. for my location).  With my good seeing location, I expect that can actually realize resolution improvement down to ~0.4"/px, a level that I expect to image at for galaxies (EdgeHD925 & QHY268M).   At 0.4"/px scale and assuming guiding w/ and OAG, would the AE add a meaningful improvement?  Or is AE "gilding the lily"?

 

Daleen called me while I was in the middle of composing this reply, and I had her put me down for a new AP1100, as I do not want to wait 2 years for a Mach2.  She told me to expect September delivery.  I need to talk to George about deciding whether to go for encoders or not.

 

I plan on keeping my G11, to allow running 2 imaging rigs to make the most of the precious clear skies.  I will put the G11 on my LW tripod, and put the AP1100 on my FHD tripod beast.  I need George to explain whether I need attach the AP1100 to my FHD; do I need both the 119FSA and 119FP?  Does the combo 119FSA-FP work for the FHD and does it drop into the FHD's normal MA collar?

 

I know the encoders eliminate DEC backlash.  But, is DEC backlash a practical problem for the base AP1100?  DEC backlash does give me problems with my G11 from time to time, and is my main frustration with my G11.

 

I know the encoders will reduce RA PE to ~0.25".  What is typical PEC adjusted PE for the base AP1100?  At what image scales does this give problems?

 

I think I will go for the DOVEDV10 saddle, as I feel the wider clamp spacing of the DOVELM162 could give problems with my Esprit's after-market 7" dovetail plate; I want at least 2 clamps engaged.  With my G11's 8" saddle, the end of my Esprit's 7" plate extends ~0.5" past the front edge.  With the DOVEDV10 extra 1" on both sides of center, it should clamp in both the middle and end.  Does this make sense?

Edited by SilverLitz, 05 March 2021 - 03:07 PM.

[rgsalinger]

https://astromart.co...00-go-to-mounts may be of interest here. These do go fast. 

[Jeff_Richards]

https://astromart.co...00-go-to-mounts may be of interest here. These do go fast. 

There's a used 1600 AE there as well at an unbelievable price...

[dhaval]

There's a used 1600 AE there as well at an unbelievable price...

That looks fishy. I would be very careful about that ad.

 

CS!

[Jeff_Richards]

That looks fishy. I would be very careful about that ad.

 

CS!

Lol, I thought the same thing...

[rockstarbill]

Thanks for the responses so far!

I will end up going for the AP1100 instead of waiting (how long??? Daleen said at least 2 more runs) for the Mach2, even though the AP1100's capacity is overkill. (I have zero appetite for mounting/dismounting an unwieldy 70#+ load, as this will be uncovered on my back patio.)

I also expect the AP1100 is machined to tighter tolerances vs. the Mach2, as it designed to perform at a high level without the need of encoders. My mind has an analogy of the sound of simpler Class-A audio amplifiers compared to much more complicated Class-AB with extensive feedback. The feedback intensive Class-AB have much better specs, but the Class-A amplifiers sound MUCH better and realistic (I have actually built my own Class-A preamp and power-amps, and they sound very realistic). The downside is the Class-A amplifier requires MUCH higher quality components, better power supplies, and more heat sinking.

My concern with reliability of the encoders is more with the read heads and not the encoder rings, as I expect the failure rate of the read heads would be an order of magnitude higher than the rings due to their electronic nature. It also seems that the read heads are much more expensive than the rings.

I still do not have a good feel for the practical/realisable/tangible performance improvement to be expected w/ the AE version compared to the base AP1100. I have read reports than base AP1100s guide as good as seeing allows, though I expect this assertion should be conditioned on the actual seeing conditions. My seeing is better than most, w/ 1.5" typical and 0.7" on the rare good nights (Meteoblue est. for my location). With my good seeing location, I expect that can actually realize resolution improvement down to ~0.4"/px, a level that I expect to image at for galaxies (EdgeHD925 & QHY268M). At 0.4"/px scale and assuming guiding w/ and OAG, would the AE add a meaningful improvement? Or is AE "gilding the lily"?

Daleen called me while I was in the middle of composing this reply, and I had her put me down for a new AP1100, as I do not want to wait 2 years for a Mach2. She told me to expect September delivery. I need to talk to George about deciding whether to go for encoders or not.

I plan on keeping my G11, to allow running 2 imaging rigs to make the most of the precious clear skies. I will put the G11 on my LW tripod, and put the AP1100 on my FHD tripod beast. I need George to explain whether I need attach the AP1100 to my FHD; do I need both the 119FSA and 119FP? Does the combo 119FSA-FP work for the FHD and does it drop into the FHD's normal MA collar?

I know the encoders eliminate DEC backlash. But, is DEC backlash a practical problem for the base AP1100? DEC backlash does give me problems with my G11 from time to time, and is my main frustration with my G11.

I know the encoders will reduce RA PE to ~0.25". What is typical PEC adjusted PE for the base AP1100? At what image scales does this give problems?

I think I will go for the DOVEDV10 saddle, as I feel the wider clamp spacing of the DOVELM162 could give problems with my Esprit's after-market 7" dovetail plate; I want at least 2 clamps engaged. With my G11's 8" saddle, the end of my Esprit's 7" plate extends ~0.5" past the front edge. With the DOVEDV10 extra 1" on both sides of center, it should clamp in both the middle and end. Does this make sense?

The encoders reduce the PE to 0.25" over a 24 hour period of the wheel. Not 0.25" over the period of the worm. Get that part right please.

[SilverLitz]

The encoders reduce the PE to 0.25" over a 24 hour period of the wheel. Not 0.25" over the period of the worm. Get that part right please.

Bill,

 

I do not think your are correct, you are off by quite a bit, per A-P:

 

1600 and 1100: Accuracy is +- 3 arc seconds over the entire 24 hour, 360 degree rotation. +- 0.2 arc sec per hour typical accuracy.

[andysea]

Lol, I thought the same thing...

That was a scam. The photo used in the ad was Michael Sidonio's 1600.