Date   

Re: Small mount was Recent encoder discussion on CN

Roland Christen
 

I guess if you need just an imaging mount with no clutches (no way to use manually without power), it can be very small and light weight.
A universal mount like the Mach2 or 10-Micron has more components than a non-clutched mount like the MYT or Rainbow mounts.
A non-clutched mount without encoders would be slightly less weight, and less cost, but will always require aggressive guiding.
A non-clutched mount with just an RA encoder to eliminate the periodic error would be medium cost and light weight.

There are a lot of permutations and possibilities, and it would depend on what you want to do with this mount. Some people just want a light weight mount that they can haul out from the basement to the driveway, put a scope on it, put an eyepiece on it and do a Moon Cruise or examine the planets. They don't need encoders or PE correction. Others want one as small as possible for airline travel and may or may not want to guide. Others want a precision universal mount that they can do anything with, but must have low weight because their back hurts. The possibilities are endless.

Low cost, medium or high cost. Medium weight low weight or ultra-low weight. Low tracking performance, medium or ultra-high performance. Clutched or non-clutched - universal or targeted. Single encoder or dual absolute encoders.

Pick any 3 out of 5.

Rolando



-----Original Message-----
From: alan.dang@...
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 2:46 pm
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN

And not just older people, but young enthusiasts who just want a lighter no-fuss mount that more easily travels when going on a group road trip where you have limited space for the Astro gear along with clothes and other travel essentials.

A real question is what is the smallest mount that would work with a AP105 and have encoders?  You might not save production cost over a mount that handles a C11 or AP130EDT — but if the mount is dramatically smaller or lighter, it could be interesting.

--
Roland Christen
Astro-Physics


Re: Small mount was Recent encoder discussion on CN

Christopher Erickson
 

For me, a super-compact, super-lightweight, super-rigid, super-tight, and super-accurate AP mount sporting strain wave gears and abs encoders would be the ultimate portable killer imaging mount.

And price wouldn't be a priority if it met all my requirements.

My name would be on the waiting list within seconds.
 
"My advice is always free and worth every penny!"

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


On Fri, Feb 26, 2021 at 11:37 AM Christopher Erickson via groups.io <christopher.k.erickson=gmail.com@groups.io> wrote:
I bought a Rainbow Astro RST-135 because AP currently doesn't have a compact mount that matches the size and portability of my Stowaway.

My overriding passion is for solar eclipse travel and occultation travel, two activities that don't require long exposures and extreme tracking precision and my 1100GTO and Mach1 are just way too much hassle for me for airline travels. The RST-135 and Stowaway fit solar eclipses perfectly, and the RST-135 and C11 with Hyperstar fit occultation travel perfectly.

But I have to say that now I have the RST-135 I have learned the value of super-lightweight portability. It is so much easier to get out and go for casual stargazing with buddies than with my bigger setups. I may only be 63, very strong and in good health, but even my Mach1 is often more of a handful than I want to haul out for an evening's casual stargazing on short notice. The RST-135 is so lightweight and compact that my entire mount kit, plus Pelican case is only 35 lbs. And that even includes a carbon-fiber tripod.

I am really enjoying my RST-135 but I would sell it in a hot minute if I could buy a compact AP mount for my Stowaway instead.

Abs encoders would be cool but not required by my applications. However I wouldn't balk at the extra cost for them. Personally I would want servos over steppers for a whole-multitude of reasons, although I understand that steppers are quite a bit cheaper than precision servos. Servos have way lower power requirements and consequently give off way less heat. For me that also means less battery capacity to haul around.

Maybe call it the Mach-10, for how light and fast it will travel the world with me.

However my favorite name for it would be the AP Intrepid. Fearless, nimble traveller and adventurer.

"My advice is always free and worth every penny!"

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


On Fri, Feb 26, 2021 at 10:46 AM <alan.dang@...> wrote:

And not just older people, but young enthusiasts who just want a lighter no-fuss mount that more easily travels when going on a group road trip where you have limited space for the Astro gear along with clothes and other travel essentials.

A real question is what is the smallest mount that would work with a AP105 and have encoders?  You might not save production cost over a mount that handles a C11 or AP130EDT — but if the mount is dramatically smaller or lighter, it could be interesting.


Re: Clutch Knobs vs. the Gearbox Release Levers

Roland Christen
 


"Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage."
If you have your mount set up, try this little experiment:

1) Send the mount to Park3.
2) while holding the rear of your scope, release the RA gearbox lever.
3) now let go of the scope.

Did the scope suddenly move? I bet not. Notice how stable the scope is even with the gears fully released. Even if it was unbalanced it would not move, unless you begin to swing the scope a bit from the Park 3 position. You can now manually move the axis to the horizontal position to do fine balance. once that is finished, return the mount back to Park3 position.

4) Now re-lock the gears with the lever only 1/2 way to the full lock position. Gently rock the axis back and forth by a very small minute amount until you can hear the gears engage naturally. Once they do, you will not feel any motion as you apply a tiny amount of pressure back and forth. When you feel no motion, turn the lever the rest of the way to fully locked position.

5) With scope still in Park3, release the DEC gearbox lever. Did the scope suddenly move? I bet not, and again note how stable the scope is, even if it was not perfectly balanced.
6) Now move the Dec axis to the Park2 position (horizontal). In this position you can do a fine Dec balance.
7) move the scope back to Park3 position and lock the lever in 2 steps as above.

Do this with your Mach1 mount in order to get a feel for how things should be done to prevent any kind of problems with the gears if you have unbalanced load. If you really don't know how badly out of balance you are, you can get pretty close to balance by loosening the clutches and doing a rough balance first. Once you have done that, you can do a fine balance by taking the gears out of mesh. You won't have to worry about wild swings when the axes are disengaged.

Roland Christen

-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 2:19 pm
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

Hi Rolando.

Thank you for your response and it is very good to hear you do service your mounts after the sale. Like I said, I don't mind spending the money for a world class mount, but I need to know that if the mount ever needs to be serviced and it is beyond my skill level that I can send it back to AP get it serviced. 

Also, thank you for explaining a bit more what it takes to damage the gears and for letting me know that I should only be using the gearbox release from Park 3. It is probably in the manual somewhere, but I never knew that the gearbox release should only be used in Park 3. This is great to know. 

Regarding my my Mach1, yes, I have felt the gears rake across teeth when I engaging the release lever a couple of times, but I have never forced anything. This was mainly a problem when I first got the Mach1 and I had a 11" EdgeHD OTA fully loaded with imaging gear, which required over 60lbs of counter weights. Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage. Of course, I did not know I should only be using the release levers from Park 3 which probably made the situation worse. That said, I never force it to engage, so maybe the gears are still OK. If memory serves me correctly, I think I only ever had this happen on the DEC Axis so based on what you told me I should still be OK even if I did slightly damage the gear. George sent me a note asking me to send him a screen shot of my guiding for 7 mins with aggressiveness set to zero. He seemed to indicate that he would be able to tell if the worm gear has been damaged based on this. Are there any other techniques to check if the worm gears have been damaged? I would like to check both Axis just to make sure they are OK.

The Mach1 was my first mount, so I made a lot of mistakes over the years as I learned how to use this type of mount. Now I need to clean up my mistakes and fix any issues so that I can get many more years of service out of the mount. Plus if I ever sell the mount I don't want to pass on a damaged mount to someone who then might blame AP for issues caused by me. The current plan is for the Mach1 to become my portable mount once the 1100 show up. I want to be able to do solar imaging and I found out recently that imaging the sun from inside a dome is a bad idea due to the sun heading up the dome during the day. So the Mach1 will make for a perfect platform for my Lunt solar scope that I can setup out in the yard away from any radiant heat sources. 

Thanks again for all your help and support.

Andrew J



--
Roland Christen
Astro-Physics


Re: Small mount was Recent encoder discussion on CN

Christopher Erickson
 

I bought a Rainbow Astro RST-135 because AP currently doesn't have a compact mount that matches the size and portability of my Stowaway.

My overriding passion is for solar eclipse travel and occultation travel, two activities that don't require long exposures and extreme tracking precision and my 1100GTO and Mach1 are just way too much hassle for me for airline travels. The RST-135 and Stowaway fit solar eclipses perfectly, and the RST-135 and C11 with Hyperstar fit occultation travel perfectly.

But I have to say that now I have the RST-135 I have learned the value of super-lightweight portability. It is so much easier to get out and go for casual stargazing with buddies than with my bigger setups. I may only be 63, very strong and in good health, but even my Mach1 is often more of a handful than I want to haul out for an evening's casual stargazing on short notice. The RST-135 is so lightweight and compact that my entire mount kit, plus Pelican case is only 35 lbs. And that even includes a carbon-fiber tripod.

I am really enjoying my RST-135 but I would sell it in a hot minute if I could buy a compact AP mount for my Stowaway instead.

Abs encoders would be cool but not required by my applications. However I wouldn't balk at the extra cost for them. Personally I would want servos over steppers for a whole-multitude of reasons, although I understand that steppers are quite a bit cheaper than precision servos. Servos have way lower power requirements and consequently give off way less heat. For me that also means less battery capacity to haul around.

Maybe call it the Mach-10, for how light and fast it will travel the world with me.

However my favorite name for it would be the AP Intrepid. Fearless, nimble traveller and adventurer.

"My advice is always free and worth every penny!"

-Christopher Erickson
Observatory Engineer
Summit Kinetics
Waikoloa, Hawaii


On Fri, Feb 26, 2021 at 10:46 AM <alan.dang@...> wrote:

And not just older people, but young enthusiasts who just want a lighter no-fuss mount that more easily travels when going on a group road trip where you have limited space for the Astro gear along with clothes and other travel essentials.

A real question is what is the smallest mount that would work with a AP105 and have encoders?  You might not save production cost over a mount that handles a C11 or AP130EDT — but if the mount is dramatically smaller or lighter, it could be interesting.


Re: GTOCP4 Control Box

Tom Blahovici
 

Hi
Here you are.  This routinely works no issues down to -20C.  Actually the only issue is my darks are at -20 and should be set to -25 on these cold days.
You can see the NUC, which is an I5, bought last year so it is pretty current.  There are also two Goldenrod heaters, two desiccant chambers a IR webcam and Thunderbolt to 10G network adapter.
In the box under the unit, there is the IOT power strip, the power supply for the setup, network hub and Anderson power pole box. There is also another GoldenRod heater.
The pier is mounted to a concrete block 3" in diameter and six feet deep.
All comes down in the summer so my wife can enjoy her garden.
Tom


Re: Small mount was Recent encoder discussion on CN

Bob Benamati
 

As someone who's become very pysically limited by handicap over the recent years, this is exactly what I've been holding off and hoping for in order to get some observing "independence" and flexibility back! I would certainly be a buyer.

Un-mounting the main scope from the 900GTO just to run my FSQ, and/or tearing apart the 900 from the pier in the obs. in order to go offsite to image is just not possible for me anymore. 

And ~20lbs would be a perfect weight that I can actually manage and setup unassisted!

BB
 








Sent via Verizon Wireless

On Feb 26, 2021 11:57, "Roland Christen via groups.io" <chris1011@...> wrote:
I'm thinking more along the lines of older people who can't lift 40lb of mount any more, but could set up a smaller mount that weighs between 10 and 20 lb. The idea of the encoders was to eliminate doing PE correction. With a high resolution small scope and the tiny pixel cameras that can record 1.5 arc sec stars, the last thing you want is to have tracking variations over short time periods that measure 10 to 20 arc seconds. Yes, you could guide at rapid fire rates, but that's just more gear to take along.

As an example, last night I shot a huge number of 30, 60, 90, 120  second exposures of the core of M42 with the Mach2 encoder mount. I did not guide or model, simply let it gather data over a 4 hour period. The mount was just polar aligned with my usual techniques. The average FWHM of the stars was between 1.5 and 1.8 arc seconds. Total drift was around 30 arc seconds for the entire period ( 0.13 arc sec per minute). Although I used my CCD camera, a modern CMOS camera with a 120 second exposure can capture a lot of data. Perfect for a fun weekend camping trip where you set up the scope, let it do its thing while you enjoy friends around a campfire.

Rolando

-----Original Message-----
From: Bill Long <bill@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, Feb 26, 2021 9:47 am
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN

For visual use, wouldn't encoders be way overkill? 

For imaging mobile space is a serious concern, especially if you have a smaller car or when it is a family outing as well. Mount, counterweights, tripod, camera, wheel, guide accessories, imaging computer, cabling, backup supplies, tools, etc. Making the mount smaller and lighter helps a lot. Smaller and lighter tripod helps as well.

Taking imaging gear on a plane isn't really a need for me now, which is why the RST135 isn't in my gear herd yet. The AP400AE would be awesome and would work with all of my scopes except for the two big iDK scopes which I wouldn't likely take on a road trip anyhow.

For solo trips where the space is all mine to use, then my other mounts are fine. But boy would a nice light more compact mint be wonderful to have!


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Elenillor <elenillor@...>
Sent: Friday, February 26, 2021 5:38 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN
 
I will put in my 2 cents on this. Back in the day I put my name on the list for a 400 as I wanted a smaller mount to go with the 600E. I wound up with a Mach1 as the 400 was superseded by the larger mount and very glad I have it.
 
Still in the search for a smaller option I got a DM6 shortly after they were introduced. It was rarely used, and I eventually sold it.
 
The DM6 excursion taught me that the mount head is only a small part of the 'kit' that needs to be transported for portable observing. Having a small head really made no difference in ease of transport, setup or takedown. I am only visual, photographers have another whole set of 'kit' to deal with that is independent of the mount head. As a result I see no reason to make any tradeoff for a small head.
 
I assume an updated encodered 400 would be only a little less cost than and a Mach2. Would they sell in numbers big enough to justify it's development is a good question. That was apparently answered when the 400 was discontinued.
 
As an aside for grab and go I have a TEC110 F5.6 on a gear headed tripod. I take it in an out of the house almost daily for quick solar or night time viewing.  Also a SKY90 with a smaller tripod for suitcase travel.

John

On Thu, Feb 25, 2021 at 08:16 PM, Roland Christen wrote:
If we ever decide to design a smaller portable mount, what would be most desirable? What's missing in the panoply of mounts today? Before you answer, I have in my right hand a 400 mount that weighs 12lb without the base. It has a precision gear set and can be fitted with absolute encoders that would allow it to track at sub-arc sec levels. I daresay that this mount can easily swing a C11 or a 140 refractor. Is there a reason for such an animal?
 
Rolando

--
Roland Christen
Astro-Physics


Re: Small mount was Recent encoder discussion on CN

alan.dang@...
 

And not just older people, but young enthusiasts who just want a lighter no-fuss mount that more easily travels when going on a group road trip where you have limited space for the Astro gear along with clothes and other travel essentials.

A real question is what is the smallest mount that would work with a AP105 and have encoders?  You might not save production cost over a mount that handles a C11 or AP130EDT — but if the mount is dramatically smaller or lighter, it could be interesting.


Re: Clutch Knobs vs. the Gearbox Release Levers

Andrew J
 

Hi Rolando.

Thank you for your response and it is very good to hear you do service your mounts after the sale. Like I said, I don't mind spending the money for a world class mount, but I need to know that if the mount ever needs to be serviced and it is beyond my skill level that I can send it back to AP get it serviced. 

Also, thank you for explaining a bit more what it takes to damage the gears and for letting me know that I should only be using the gearbox release from Park 3. It is probably in the manual somewhere, but I never knew that the gearbox release should only be used in Park 3. This is great to know. 

Regarding my my Mach1, yes, I have felt the gears rake across teeth when I engaging the release lever a couple of times, but I have never forced anything. This was mainly a problem when I first got the Mach1 and I had a 11" EdgeHD OTA fully loaded with imaging gear, which required over 60lbs of counter weights. Keeping the mount perfectly steady while engaging the gearbox release was a challenge at times and this is when I remember feeling the teeth raking across the worm more than once before it would fully engage. Of course, I did not know I should only be using the release levers from Park 3 which probably made the situation worse. That said, I never force it to engage, so maybe the gears are still OK. If memory serves me correctly, I think I only ever had this happen on the DEC Axis so based on what you told me I should still be OK even if I did slightly damage the gear. George sent me a note asking me to send him a screen shot of my guiding for 7 mins with aggressiveness set to zero. He seemed to indicate that he would be able to tell if the worm gear has been damaged based on this. Are there any other techniques to check if the worm gears have been damaged? I would like to check both Axis just to make sure they are OK.

The Mach1 was my first mount, so I made a lot of mistakes over the years as I learned how to use this type of mount. Now I need to clean up my mistakes and fix any issues so that I can get many more years of service out of the mount. Plus if I ever sell the mount I don't want to pass on a damaged mount to someone who then might blame AP for issues caused by me. The current plan is for the Mach1 to become my portable mount once the 1100 show up. I want to be able to do solar imaging and I found out recently that imaging the sun from inside a dome is a bad idea due to the sun heading up the dome during the day. So the Mach1 will make for a perfect platform for my Lunt solar scope that I can setup out in the yard away from any radiant heat sources. 

Thanks again for all your help and support.

Andrew J



Re: Clutch Knobs vs. the Gearbox Release Levers

Bill Long
 

You could order a grease kit and service your mount. In the process of doing that you remove the gearboxes and spend some quality time with the worm, wheel, and reduction gears. If anything is awry, you will no doubt see it. If not, your mount is now well greased up and ready for action. Two birds, one stone! 


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Andrew Jones <andjones132@...>
Sent: Friday, February 26, 2021 10:27 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers
 
Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J


Re: Clutch Knobs vs. the Gearbox Release Levers

Roland Christen
 


I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves.
I don't know where you got that information, but that's totally wrong. Of course we service our mounts.

As far as raking the gears when releasing them, it might cause an issue with guiding in RA because it would affect the periodic error during sidereal tracking. The Dec axis doesn't track, so any tooth damage would probably never show up during normal tracking and guiding. If it's just a minor amount of damage, the gears repair themselves during normal slewing to the point where nothing is affected. They lap themselves in if the damage is minor.

Major damage occurs when the user forcibly jams the gears back together when they are not aligned tooth top to tooth bottom. In other words, the tops of the teeth are jammed together and crush each other. The best way to re-lock the teeth of the worm to the worm wheel is to 1) always do it in Park3 position, both RA and Dec, and 2) move the lever half way and let the gentle spring pressure push the teeth back together while gently rocking the axis back and forth a slight amount until the worms mate fully. Then gently turn the lever the rest of the way to fully lock them in place.

In the case where the worm teeth have been crushed, there is no other fix than replacing the worm gears.

Roland


-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 12:27 pm
Subject: Re: [ap-gto] Clutch Knobs vs. the Gearbox Release Levers

Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J

--
Roland Christen
Astro-Physics


Re: Clutch Knobs vs. the Gearbox Release Levers

Andrew J
 

Hi Rolando.

Let's say that I did damage the worm gears on my Mach over the years by using the gearbox release levers. I know there has been times when I felt the gear rake across the worm gear before it fully engaged. I also know that have been having issues guiding on my DEC Axis. The mount is on a permanent pier in a dome and I recently verified both the PEC and my polar alignment using PemPro so I should not be having guiding issues. Which makes me suspect that I may have damaged my DEC Axis worm gear. Does AP offer an inspection/repair service for their mounts? Can I send the mount in to be inspected and serviced if needed?

Not only is this question important for getting my Mach1 fixed, I just put down my deposit for the 1100 GTO AEL with accessories and weights plus a 10" ATS Pier. Combined this is north of $20K. Which I am ok with as I know I am buying a quality mount that should last 20 - 30 years. That said, before I spend this kind of money I need to know that if I have issues with the the 1100 like i have with my Mach1 that I that I can send it to be serviced. I got a note back recently that indicated you don't service your mounts. That if repairs are needed the customer will need to perform the repairs themselves. I need to get confirmation that you do service your mounts after the sale. 

Thank you.

Andrew J


Re: Small mount was Recent encoder discussion on CN

Bill Long
 

Yes, that would be a very real use case for it. There is certainly an appetite for such a mount. 



From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Roland Christen via groups.io <chris1011@...>
Sent: Friday, February 26, 2021 8:57 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN
 
I'm thinking more along the lines of older people who can't lift 40lb of mount any more, but could set up a smaller mount that weighs between 10 and 20 lb. The idea of the encoders was to eliminate doing PE correction. With a high resolution small scope and the tiny pixel cameras that can record 1.5 arc sec stars, the last thing you want is to have tracking variations over short time periods that measure 10 to 20 arc seconds. Yes, you could guide at rapid fire rates, but that's just more gear to take along.

As an example, last night I shot a huge number of 30, 60, 90, 120  second exposures of the core of M42 with the Mach2 encoder mount. I did not guide or model, simply let it gather data over a 4 hour period. The mount was just polar aligned with my usual techniques. The average FWHM of the stars was between 1.5 and 1.8 arc seconds. Total drift was around 30 arc seconds for the entire period ( 0.13 arc sec per minute). Although I used my CCD camera, a modern CMOS camera with a 120 second exposure can capture a lot of data. Perfect for a fun weekend camping trip where you set up the scope, let it do its thing while you enjoy friends around a campfire.

Rolando

-----Original Message-----
From: Bill Long <bill@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, Feb 26, 2021 9:47 am
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN

For visual use, wouldn't encoders be way overkill? 

For imaging mobile space is a serious concern, especially if you have a smaller car or when it is a family outing as well. Mount, counterweights, tripod, camera, wheel, guide accessories, imaging computer, cabling, backup supplies, tools, etc. Making the mount smaller and lighter helps a lot. Smaller and lighter tripod helps as well.

Taking imaging gear on a plane isn't really a need for me now, which is why the RST135 isn't in my gear herd yet. The AP400AE would be awesome and would work with all of my scopes except for the two big iDK scopes which I wouldn't likely take on a road trip anyhow.

For solo trips where the space is all mine to use, then my other mounts are fine. But boy would a nice light more compact mint be wonderful to have!


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Elenillor <elenillor@...>
Sent: Friday, February 26, 2021 5:38 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN
 
I will put in my 2 cents on this. Back in the day I put my name on the list for a 400 as I wanted a smaller mount to go with the 600E. I wound up with a Mach1 as the 400 was superseded by the larger mount and very glad I have it.
 
Still in the search for a smaller option I got a DM6 shortly after they were introduced. It was rarely used, and I eventually sold it.
 
The DM6 excursion taught me that the mount head is only a small part of the 'kit' that needs to be transported for portable observing. Having a small head really made no difference in ease of transport, setup or takedown. I am only visual, photographers have another whole set of 'kit' to deal with that is independent of the mount head. As a result I see no reason to make any tradeoff for a small head.
 
I assume an updated encodered 400 would be only a little less cost than and a Mach2. Would they sell in numbers big enough to justify it's development is a good question. That was apparently answered when the 400 was discontinued.
 
As an aside for grab and go I have a TEC110 F5.6 on a gear headed tripod. I take it in an out of the house almost daily for quick solar or night time viewing.  Also a SKY90 with a smaller tripod for suitcase travel.

John

On Thu, Feb 25, 2021 at 08:16 PM, Roland Christen wrote:
If we ever decide to design a smaller portable mount, what would be most desirable? What's missing in the panoply of mounts today? Before you answer, I have in my right hand a 400 mount that weighs 12lb without the base. It has a precision gear set and can be fitted with absolute encoders that would allow it to track at sub-arc sec levels. I daresay that this mount can easily swing a C11 or a 140 refractor. Is there a reason for such an animal?
 
Rolando

--
Roland Christen
Astro-Physics


Re: Recent encoder discussion on CN

Roland Christen
 


So when I am moving the mount it will never be perfectly balanced.
No need to perfectly balance an 1100 mount.  5 lb out? Pfffft. 10 lb out, well that may require a bit of balancing.

Rolando


-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 10:54 am
Subject: Re: [ap-gto] Recent encoder discussion on CN

On Fri, Feb 26, 2021 at 08:37 AM, Roland Christen wrote:
"Why would you ever release the lever to reposition the mount in the first place? Do you have a permanent setup such as a remote observatory system? In that case I cannot ever see why the mount would be moved manually. Do you have a temporary setup which you tear down after every session? In that case why would you care about knowing absolutely where the axes are pointed, since you will be starting off fresh anyway? Just loosen the clutches and place the mount in a known park position and start the session from there."
 
Rolando

Hi Roland.

Yes, my Mach1 is on a permanent pier in an Explora-Dome in my backyard. I have it setup so that I can image from the house and almost never have to go to the dome when imaging, However, I have a lot of other stuff one the mount like, focus controllers, dew heater controllers, USB hubs, etc. which I am always trying to refine the setup. When I am working on stuff during the day I will often reposition the scope so I can reach certain things easier. As you know with refractors, they will never be in balance unless they are in their imaging configuration with the focuser set to close to focus and the dew shield out. I don't put everything out in it's imaging configuration if I am just working on the mount or switching out other components. So when I am moving the mount it will never be perfectly balanced. I try to have a good hold on the OTA before I release the gearbox levers, but it can still move a bit. 
 

--
Roland Christen
Astro-Physics


Re: Small mount was Recent encoder discussion on CN

Roland Christen
 

I'm thinking more along the lines of older people who can't lift 40lb of mount any more, but could set up a smaller mount that weighs between 10 and 20 lb. The idea of the encoders was to eliminate doing PE correction. With a high resolution small scope and the tiny pixel cameras that can record 1.5 arc sec stars, the last thing you want is to have tracking variations over short time periods that measure 10 to 20 arc seconds. Yes, you could guide at rapid fire rates, but that's just more gear to take along.

As an example, last night I shot a huge number of 30, 60, 90, 120  second exposures of the core of M42 with the Mach2 encoder mount. I did not guide or model, simply let it gather data over a 4 hour period. The mount was just polar aligned with my usual techniques. The average FWHM of the stars was between 1.5 and 1.8 arc seconds. Total drift was around 30 arc seconds for the entire period ( 0.13 arc sec per minute). Although I used my CCD camera, a modern CMOS camera with a 120 second exposure can capture a lot of data. Perfect for a fun weekend camping trip where you set up the scope, let it do its thing while you enjoy friends around a campfire.

Rolando

-----Original Message-----
From: Bill Long <bill@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, Feb 26, 2021 9:47 am
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN

For visual use, wouldn't encoders be way overkill? 

For imaging mobile space is a serious concern, especially if you have a smaller car or when it is a family outing as well. Mount, counterweights, tripod, camera, wheel, guide accessories, imaging computer, cabling, backup supplies, tools, etc. Making the mount smaller and lighter helps a lot. Smaller and lighter tripod helps as well.

Taking imaging gear on a plane isn't really a need for me now, which is why the RST135 isn't in my gear herd yet. The AP400AE would be awesome and would work with all of my scopes except for the two big iDK scopes which I wouldn't likely take on a road trip anyhow.

For solo trips where the space is all mine to use, then my other mounts are fine. But boy would a nice light more compact mint be wonderful to have!


From: main@ap-gto.groups.io <main@ap-gto.groups.io> on behalf of Elenillor <elenillor@...>
Sent: Friday, February 26, 2021 5:38 AM
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Subject: Re: [ap-gto] Small mount was Recent encoder discussion on CN
 
I will put in my 2 cents on this. Back in the day I put my name on the list for a 400 as I wanted a smaller mount to go with the 600E. I wound up with a Mach1 as the 400 was superseded by the larger mount and very glad I have it.
 
Still in the search for a smaller option I got a DM6 shortly after they were introduced. It was rarely used, and I eventually sold it.
 
The DM6 excursion taught me that the mount head is only a small part of the 'kit' that needs to be transported for portable observing. Having a small head really made no difference in ease of transport, setup or takedown. I am only visual, photographers have another whole set of 'kit' to deal with that is independent of the mount head. As a result I see no reason to make any tradeoff for a small head.
 
I assume an updated encodered 400 would be only a little less cost than and a Mach2. Would they sell in numbers big enough to justify it's development is a good question. That was apparently answered when the 400 was discontinued.
 
As an aside for grab and go I have a TEC110 F5.6 on a gear headed tripod. I take it in an out of the house almost daily for quick solar or night time viewing.  Also a SKY90 with a smaller tripod for suitcase travel.

John

On Thu, Feb 25, 2021 at 08:16 PM, Roland Christen wrote:
If we ever decide to design a smaller portable mount, what would be most desirable? What's missing in the panoply of mounts today? Before you answer, I have in my right hand a 400 mount that weighs 12lb without the base. It has a precision gear set and can be fitted with absolute encoders that would allow it to track at sub-arc sec levels. I daresay that this mount can easily swing a C11 or a 140 refractor. Is there a reason for such an animal?
 
Rolando

--
Roland Christen
Astro-Physics


Re: Recent encoder discussion on CN

Andrew J
 

On Fri, Feb 26, 2021 at 08:37 AM, Roland Christen wrote:
"Why would you ever release the lever to reposition the mount in the first place? Do you have a permanent setup such as a remote observatory system? In that case I cannot ever see why the mount would be moved manually. Do you have a temporary setup which you tear down after every session? In that case why would you care about knowing absolutely where the axes are pointed, since you will be starting off fresh anyway? Just loosen the clutches and place the mount in a known park position and start the session from there."
 
Rolando

Hi Roland.

Yes, my Mach1 is on a permanent pier in an Explora-Dome in my backyard. I have it setup so that I can image from the house and almost never have to go to the dome when imaging, However, I have a lot of other stuff one the mount like, focus controllers, dew heater controllers, USB hubs, etc. which I am always trying to refine the setup. When I am working on stuff during the day I will often reposition the scope so I can reach certain things easier. As you know with refractors, they will never be in balance unless they are in their imaging configuration with the focuser set to close to focus and the dew shield out. I don't put everything out in it's imaging configuration if I am just working on the mount or switching out other components. So when I am moving the mount it will never be perfectly balanced. I try to have a good hold on the OTA before I release the gearbox levers, but it can still move a bit. 
 


Re: Small mount was Recent encoder discussion on CN

Dale Ghent
 

On Feb 26, 2021, at 09:46, Frost David <frosty5@gmail.com> wrote:

I would love a smaller mount of this size and quality. It was what I wanted when I signed up for the Mach2 honestly. Something lighter and portable but still with great accuracy and same APCC/CP4 or 5 functionality.

This is why I recently purchased a Rainbow Astro 135. It weighs around 7 pounds and can easily be lifted out and setup on my tripod fully assembled in two minutes. For quick solar and nighttime use for those of us that do portable imaging, it’s fantastic. But the accuracy is nowhere near that of an AP mount. It physically can’t be. But for short focal lengths it works.
Yeah, I bought an RST-135 for mobile imaging on weekend trips and plane ride. I put a CFF 92mm f/6 frac on the top of it and it works exceedingly well, with the main parts of the setup split between a Nanuck roll-aboard hard case and ThinkTank Photo Shapeshifter backpack. On planes, the hard case with scope and imaging stuff goes in the overhead, the RST, laptop, and cables in the backpack go under the seat in front of me, and the tripod and power supply is in checked baggage. I haven't yet travelled to a place where there's no AC power for it and covid has nix'd travel for now, so I have some time to figure out a LiFePO4-based portable battery system that doesn't bust the airline rules regarding lithium batteries. The limit is watt-hours per battery, per person. It's me, my wife, and kid, so I can max out the usage by allotting everyone their own battery.

The thing that makes the RST-135 such a killer travel-friendly scope is its harmonic drive which obviates the need for counterweights for reasonable loads. As we know, counterweights can be half the mount's weight, or even more, so removing them from the picture makes airline transport such an easier task to contemplate.

So far I've taken the ensemble on 1 international flight (to central Mexico) and 1 US destination (SF bay area). The customs folks at QRO airport in Mexico were curious and amused by the gear, but I'm used to the exercise with customs officers having carried a lot of photo gear around the world.


Re: Recent encoder discussion on CN

Andrew J
 

Hi Bill.

Thanks for the feedback. That is basically what I have been doing. I currently have a TEC 140 on my Mach1 and I try to balance the OTA with the focuser racked close to where it should be in focus. However, as soon as I move the focuser with a fairly heavy camera and FW attached, then it will immediately be out of balance. I always rack the focuser all the way and pull in the dew shield in when I am not planning on using the mount so that OTA is shorter and I can cover the scope easier for storage. In this configuration the mount will always be out of balance. Based on what I read the other day, I thought that Roland was recommending to use the clutches to reposition the mount when it is not fully balanced in order to minimize the risk of damaging the worm gear. For the Mach1, this seems to make sense as it does not have encoders and as long as I unpark the mount from a known park position then the mount will not get lost. What is not clear to me now, is when I get the 1100 with AEL encoders here in a couple months, should I be using the clutches when repositioning the mount in order to avoid having the mount get lost. Maybe I am misunderstanding, but Roland's post here seemed to indicate that using the gearbox levers is the preferred method for repositioning a mount with encoders. 

Of course, I can still use the clutches with the 1100 and do the same thing as I do with the Mach1 and just unpark from a known park position, but then it would seem I am defeating the point of having the encoders and having the mount always know where it is pointing. The post from the other day seem to indicate that using the clutches is always the best way to reposition the mount unless I need to do find balance. This discussion seem to recommend the opposite when using a mount with encoders. I just want to make sure I fully understand the difference between the two methods of repositioning the mount and the pros and cons of each method. If I am using a refractor the mount will only be in balance when the focuser is set to near the the focus position and the dew shield is out. If I am just working on the scope when I am not imaging I normally don't set it to its imaging configuration so it will always be out of balance when I am just working on the mount during the daytime. I actually think I may have damaged the worm gear on my Mach1 as I am having difficulty guiding on the DEC Axis and considering sending it into AP to get it inspected. I want to make sure I am 100% clear on this topic so I don't damage the 1100 with encoders while at the same time taking full advantage of having a mount with encoders that never gets lost. 


Re: Recent encoder discussion on CN

Roland Christen
 


Do you recommend using the gearbox release lever to reposition the mount if your mount has encoders?
The question was "does the ENCODER mount lose position when you move the mount manually?" The answer is YES, if you use the clutches, NO if you use the gearbox lever. Locking the clutches and using the gearbox lever makes the mount similar to a Paramount - in other words it becomes a clutchless mount. This would be the way to make a permanent remote observatory system where you always want to know where the axes are pointed.

Why would you ever release the lever to reposition the mount in the first place? Do you have a permanent setup such as a remote observatory system? In that case I cannot ever see why the mount would be moved manually. Do you have a temporary setup which you tear down after every session? In that case why would you care about knowing absolutely where the axes are pointed, since you will be starting off fresh anyway? Just loosen the clutches and place the mount in a known park position and start the session from there.

Rolando


-----Original Message-----
From: Andrew Jones <andjones132@...>
To: main@ap-gto.groups.io
Sent: Fri, Feb 26, 2021 9:44 am
Subject: Re: [ap-gto] Recent encoder discussion on CN

Hi Roland.
 
Thanks for this explanation. However, I am now a bit confused again. This discussion would seem to recommend using the gearbox release levers when repositioning the mount. However, I took away from the below response to my question the other day related to using clutches vs the gearbox release that I should almost never use the gearbox release except for fine balancing in order to not risk damaging the worm teeth on the mount. This post now seems to indicate that if you don’t want your mount to get lost that you should use the gearbox release if your mount has encoders. So now I am confused again. Do you recommend using the gearbox release lever to reposition the mount if your mount has encoders? Maybe I am making this more complicated then it needs to be…
 
 
“Use the clutches when you want to manually move the scope around the sky (example: for visual sweeping of the Milky way). Use the clutches for placing the mount manually to one of the park positions during startup if you have moved the mount from a previous setup. use the clutches to get a rough balance in the two axes….”
 
“Loosen the Gearbox Release Levers only with the scope in Park3 positions. Releasing them in any other position could cause the gear teeth to rake across each other and possibly damage the worm teeth. The result will be poor guiding. Damaged teeth are expensive to fix. Use this method only for fine balance. If you don't need to do fine balance, don't release the lever.”

--
Roland Christen
Astro-Physics


Re: Encoders in the Mach2 vs 1100

Roland Christen
 

The error in an encoder mount is not periodic, so there is no real "periodic" error. The error tends to be a single smooth sine wave over a 24 hour period.

Rolando



-----Original Message-----
From: Seb@stro <sebastiendore1@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Fri, Feb 26, 2021 8:22 am
Subject: Re: [ap-gto] Encoders in the Mach2 vs 1100

Thanks for the explanations Rolando. That clears it up a bit. Indeed resolution and accuracy are two different beasts...

What I was missing is the fact that the accuracy spec is for an entire revolution of the ring. I also had a somewhat hard time wrapping my head around the fact that the pitch of the ticks (or barcodes) is the same for any ring size (at 30 microns) and that its not giving any benefits in actual resolution (ticks per arc-sec). But reading further, I understood that the output resolution is not solely dependant on the mechanical aspect, but also on the encoding protocol used. 

So my understanding at this point is that even if the pitch is the same for every size of ring, hence giving more "barcodes" on larger rings, the readhead is nonetheless outputting a value that is limited by the characteristics of the serial protocol used (26 bits for the Mach 2, as you stated). 

I also understand that these figures of 0.16 and 0.12 arc-sec accuracy are theoretical and achievable only under hypothetical ideal conditions. 

From all this, should I also understand that the Mach2's stated native periodic error of 0.25 arc-sec (peak-to-peak) is also a per-hour figure or am I still missing some parts of the puzzle ? (Is periodic error the same as accuracy in this context with encoders ?)

Sébastien


De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Roland Christen via groups.io <chris1011@...>
Envoyé : 24 février 2021 19:41
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Encoders in the Mach2 vs 1100
 

I would have thought that a bigger ring gives more space to mark a higher number of "ticks", hence giving higher resolution and so accuracy...
Resolution is not the same as accuracy.

There are 2^26 individual addresses (67,108,864) that can be accessed in the RESA encoder, whether it is 75mm or 100mm. Therefore the resolution is the same for both rings.

The stated accuracy is a measure of how accurate the encoder is over a 24 hour period of revolution (360 degree total angle of rotation). For the 75mm ring, accuracy would be approximately +-3.82arcsec/24hr or 0.16 arc sec per hour of tracking. For the 100mm ring it would be 0.12 arc sec. per hour.

In reality one can never get the ring to have zero runout, so the practical accuracy will come in at perhaps +-0.5 arc sec per hour, more or less. So whether you have a 100mm ring or a 75mm ring, it makes no practical difference. Star motion due to atmospheric refraction will be an order of magnitude higher if you are anywhere but at the exact zenith.

The way the RESA works is not like any other encoder system. It does not read "ticks" the way an ordinary encoder does. It reads a barcode that is imprinted on the steel ring. The barcode is read over a fairly large circumference angle. The readhead is a miniature camera, not a photodiode that registers black and white tick marks. It's really quite revolutionary how it works, and it does work splendidly for telescope mounts.

Rolando




-----Original Message-----
From: Seb@stro <sebastiendore1@...>
To: main@ap-gto.groups.io <main@ap-gto.groups.io>
Sent: Wed, Feb 24, 2021 4:40 pm
Subject: Re: [ap-gto] Encoders in the Mach2 vs 1100

Hello Roland,

Your post made me take a quick look at Renishaw's spec for the Resolute extended temp encoder and I found two interesting observations (not related to the low temp version) which made me realize I'm probably missing something in my understanding of how the encoders actually works...

First, when we look at the following table, the "system accuracy" is increasing with the diameter of the ring (kind of opposite of what you stated earlier), which made sense to me since I would have thought that a bigger ring gives more space to mark a higher number of "ticks", hence giving higher resolution and so accuracy... So I assume the "system accuracy" of the encoder (which is defined as graduation + SDE by Renishaw) doesn't directly translate into the "tracking accuracy" of the mount.



Second observation, still looking at that table, the order of magnitude of that system accuracy seems to be more than ten-fold lower in comparison to the spec'ed tracking accuracy of the mount (+/- 3.82 arc-sec "system accuracy" for the 75 mm ring vs +/- 0.25 arc-sec "tracking accuracy" of the Mach2).

To explain these differences, my guess would be that some (gear/pulley) ratio somewhere does indeed make the tracking accuracy similar throughout the mount models and while at the same time increasing it by a factor of about 10X relative to the Renishaw's specs, but I wondered if there was more to it...

Am I lost in space ? 

Regards,
Sébastien


De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Roland Christen via groups.io <chris1011@...>
Envoyé : 24 février 2021 11:48
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : [ap-gto] Encoders in the Mach2 vs 1100
 
Hello Astronuts,

To clear up any confusion about mount encoders, both Mach2 and 1100/1600 use the same Renishaw RESA high resolution encoders. The main difference is that the ring diameter of the 1100/1600 mounts is 100mm, the Mach2 uses a 75mm ring. Resolution and accuracy is the same for all. The readheads are the same RESA readheads, except that they are matched to their respective diameters, so that the 75mm readheads cannot be used on the 100mm rings and vice versa.

Roland Christen
Astro-Physics Inc.

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics

--
Roland Christen
Astro-Physics


Re: Recent encoder discussion on CN

dvjbaja
 

Some thoughts on small, portable mounts.  The ultimate in portability and load carrying capability is the Rainbow Astro RST-135.  Not inexpensive, but innovative with lots of potential.  For short focus telescopes the odd periodic error curve from the harmonic drive is correctable with a small, separate guidescope.  Can be run in EQ, or Alt-az configurations.  I love alt-az for the convenience of operation, eyepiece placement, and the lack of the dreaded mount flip. It would carry a Stowaway with little effort and most likely a 130 f/6.  Another to consider is Rowan Astronomy Atl-az, which has all the machinist qualities of an Astro-Physics Mach 1, but in an Alt-az package for visual.  Soon to be motorized! It's actually about the size of an AP 400.   I love my AP gear, but look around, there are some very high quality products out there as alternatives as Roland and company consider their next offering.  

 BTW, as an American, I absolutely hate the flood of cheap Chinese mounts, telescopes, and CMOS astro-cameras on the US market.  They are good mounts and cameras overall plus very affordable for folks getting started. It would seem our American companies have had to counter the flood and go the high end premium route to maintain market share and profitability. As someone who has managed a $6B portfolio of desktop PC's across all price points, I understand this well.  It's a complex world.  

-jg


On Fri, Feb 26, 2021 at 5:34 AM weihaowang <whwang@...> wrote:
On Fri, Feb 26, 2021 at 11:16 AM, Roland Christen wrote:
If we ever decide to design a smaller portable mount, what would be most desirable? What's missing in the panoply of mounts today? Before you answer, I have in my right hand a 400 mount that weighs 12lb without the base. It has a precision gear set and can be fitted with absolute encoders that would allow it to track at sub-arc sec levels. I daresay that this mount can easily swing a C11 or a 140 refractor. Is there a reason for such an animal?

I love to see a portable mount from Astro-Physics. However, before you go ahead and design one, you may want to ask what kind of portability you are aiming at.

Portable with a car? Then I think Mach2 fits it nicely. Mach1 is even better I suppose, but there is a tradeoff in payload.

Portable for air travel? Then Mach2 is too heavy for that for most people. Even Mach1 may be too heavy. I think a compact design with 20lb of weight (including base and counterweight shaft) would be desirable for this. It will need a light-weight dovetail system.  The counterweight shaft needs to be thinner, and longer too, so people don't need to bring many heavy counterweights to the plane.  

For those who do this kind of portable imaging, do they need high-prevision absolute encoders?  I am not sure.  At least for me, I don't need.  A smooth PE curve with less than +/- 4" of amplitude will be sufficient for me (good enough for 5 minutes of exposures on 300mm lenses).  Even +/-8" would be acceptable if there is good permanent PEC.  The mount has to be rigid, in case the places we travel to is windy, but I think AP mounts are all good for this.  The polar scope may need some rethinking.  The current RAPAS may be a bit too bulky for such a small mount.  Finally, its power consumption needs to be as small as possible.

That's my wishlist for an air-portable mount.

Cheers,
Wei-Hao

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