Date   

Re: Concrete pier

Nick Iversen
 

How about poles made for retaining walls? Treated and designed to be placed directly in the ground. The local supplier guarantees them for 50 years. Cost under $100.


Re: Keypad 4.19.5 unsuccessful upload

midmoastro
 

disregard, looks like I am good.


Re: Keypad 4.19.5 unsuccessful upload

midmoastro
 

This may require a new thread but I was reading over the docs on this upgrade and trying to determine what version CP4 I have. My mount was delivered earlier this year, 2021, and in looking at APCC and connecting the AP2 driver, I see "VCP4-P02-10" in the top left hand corner. So it seems like I should be safe to upgrade, correct?
"Keypads that are used with GTOCP4 control boxes that have P02-01 firmware or later versions".


Re: APPM Model sanity check (suggestion)

John Upton
 

On Sat, Nov 6, 2021 at 02:35 PM, Ray Gralak wrote:
1) The Verify run keeps the active model on, while a normal run would have modeling off.
Ray,

   Thanks for that bit of information. The method I was going to try as documented above will not work since any existing model would have been turned off. I can use the same method so long as I check the Verify Model box, though. It is good to know that I was almost on the right track.

John


Re: APPM Model sanity check (suggestion)

Ray Gralak
 

Hi Linwood,

Or... am I just crazy to consider reusing a model after a tear down and reassembly?
You could do a simple test to find out! Specifically, you could do a Verify run in APPM with a much smaller number of points than your model. That is, a Verify run does not have to use the same points as your active model. When you do this, take a look at the measured pointing errors in the table that APPM creates in the verify run.

BTW, in case anyone is wondering, there are two main differences between a normal APPM run and a verify:

1) The Verify run keeps the active model on, while a normal run would have modeling off.

2) The Verify run will not replace your active model. That is, APPM won't ask to load it into APCC, and APPM will even warn you if you try to load a verify run.

Also, a verify run will probably be much less useful if you are checking a few Dec Arc rows, because it wouldn't take much longer to create new Dec Arcs.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of ap@...
Sent: Saturday, November 6, 2021 8:33 AM
To: main@ap-gto.groups.io
Subject: [ap-gto] APPM Model sanity check (suggestion)

The discussion on refreshing reminds me to ask this.

I set up and tear down nightly, but fairly precisely in the same setup (example: I usually land within 5' of polar
aligned after I put things together).

I have built a nice model of the sky, but for just time constraints (and I guide) I do not build a new model each
night, and because I worry the model is no longer good, I generally do not use one at all.

I know that APPM has a verify process, that will check each model point for consistency (presumably to flush
out equipment variability that may be invalidating it from run to run).

Would it be possible to have a similar process, perhaps a "model sanity check", which would take 10% (or
some specified number of model points), and check just those. The idea is to see if your model is still good
but in far less time than a complete verify run (which basically takes the same time it would to build a model).

I am not sure how to interpret it, but some kind of correlation calculation could tell you if it looks good or bad,
and is worth using. The idea is spending 10 minutes to validate a fairly large model rather than 60-90 minutes
to build a new one.

Or... am I just crazy to consider reusing a model after a tear down and reassembly?

Linwood


Re: APPM Model sanity check (suggestion)

John Upton
 

Linwood,

   I also set up anew each night (for the most part). I understand exactly your concerns with using an old model. I have not tried it out yet but think I will try this soon -- the night or two.
  • Build a small (normal for me) model of maybe 30 to 50 points. 
  • Use that model for the evening.

  • Next night, enable the previous 30-50 point model's pointing and tracking corrections and recal at the zenith or maybe at the intersection of the celestial equator and meridian.
  • Create and run a new "tiny model" of 9 points (Zenith and 4 East and West).
  • Do not install the new 9 point model.
  • Check the APPM reported errors for each point in the new model.
  • If they are all less than about 1-2 arc-minutes (or other criteria), discard the 9 point model and use the previous recal'ed 30-50 point model.
  • If there are larger errors in the "check (9) point model", go ahead and run a new full model.
   The intent for me is to run a new model while the previous one is active. (This assumes the old model is activated / enabled and a recal has been done.) Hopefully, the recal'ed old model should have accounted for orthogonality errors and differences in polar alignment. The new 9 point run is a way of checking how much difference there is between the old and new models.

   Does anyone do anything like this? Will it work? I do plan to try it out and see for myself. I expect the downsides to be differences in temperature and air pressure from night to night but I assume those differences are also present if you have a permanent set-up.

John


Re: APCC Pro Error FindFreeQacindex: no free entries!

John Upton
 

David,

   I had that happen to me last night for the first time. After seeing it happen a few times, I found that it appears to be caused by the mouse hovering over that emergency stop window when the slew completes. The windows turns yellow(ish) when the mouse hovers over it. If the mouse is not over the window, it closes and goes away but when the mouse is hovering over the window, it remains on screen and doesn't automatically close until you manually dismiss it. At least that is what I was observing last night...

John


Re: APPM Model sanity check (suggestion)

ap@CaptivePhotons.com
 

Brian Valente wrote:

 

 

  • Based on my experience, i think you can safely reuse the model from nigh to night, you just need to solve and recal your pointing position

 

I do.  Thanks.

 

  • There is a built-in sort of check in APPM where you can skip model building and just assess the results. I am not in front of my computer so I can't tell you the details there

 

What I found checks each point, so it takes the same time to process as it would to rebuild.  Hence the thinking of a sanity check instead of a complete verification.

 


Re: APPM Model sanity check (suggestion)

 

Hi Linwood

Based on my experience, i think you can safely reuse the model from nigh to night, you just need to solve and recal your pointing position

There is a built-in sort of check in APPM where you can skip model building and just assess the results. I am not in front of my computer so I can't tell you the details there




On Sat, Nov 6, 2021 at 8:33 AM ap@... <ap@...> wrote:
The discussion on refreshing reminds me to ask this.

I set up and tear down nightly, but fairly precisely in the same setup (example: I usually land within 5' of polar aligned after I put things together). 

I have built a nice model of the sky, but for just time constraints (and I guide) I do not build a new model each night, and because I worry the model is no longer good, I generally do not use one at all. 

I know that APPM has a verify process, that will check each model point for consistency (presumably to flush out equipment variability that may be invalidating it from run to run). 

Would it be possible to have a similar process, perhaps a "model sanity check", which would take 10% (or some specified number of model points), and check just those.  The idea is to see if your model is still good but in far less time than a complete verify run (which basically takes the same time it would to build a model). 

I am not sure how to interpret it, but some kind of correlation calculation could tell you if it looks good or bad, and is worth using.  The idea is spending 10 minutes to validate a fairly large model rather than 60-90 minutes to build a new one.

Or... am I just crazy to consider reusing a model after a tear down and reassembly? 

Linwood



--
Brian 



Brian Valente


APPM Model sanity check (suggestion)

ap@CaptivePhotons.com
 

The discussion on refreshing reminds me to ask this.

I set up and tear down nightly, but fairly precisely in the same setup (example: I usually land within 5' of polar aligned after I put things together). 

I have built a nice model of the sky, but for just time constraints (and I guide) I do not build a new model each night, and because I worry the model is no longer good, I generally do not use one at all. 

I know that APPM has a verify process, that will check each model point for consistency (presumably to flush out equipment variability that may be invalidating it from run to run). 

Would it be possible to have a similar process, perhaps a "model sanity check", which would take 10% (or some specified number of model points), and check just those.  The idea is to see if your model is still good but in far less time than a complete verify run (which basically takes the same time it would to build a model). 

I am not sure how to interpret it, but some kind of correlation calculation could tell you if it looks good or bad, and is worth using.  The idea is spending 10 minutes to validate a fairly large model rather than 60-90 minutes to build a new one.

Or... am I just crazy to consider reusing a model after a tear down and reassembly? 

Linwood


Re: Concrete pier

Peter Bresler
 
Edited

I have done two concrete piers now... had them done by hand. 10" sonna tube 2 ft deep on one, and a square pier for an L-350 on the second. Used 10 to 25 sacks of Qukcrete. Make a template for all thread bots to set in the concrete for the base plate.


Re: Concrete pier

Glenn Wallace
 

Here’s my pier design, with lots of help from Ajai Sehgal.
It was designed for an AP1200. Ground doesn’t freeze (Seattle).

We dug a square hole 4’x4’ and gave up at about 3.5' deep. We laid a short layer of small gravel, maybe 1”.

I used a 12” Sonotube, with enough height to come up to my desired height in observatory.
I made an Excel model of observatory roll off roof height and overall parked scope height and determined a “pier plate height above grade”.
My observatory is on threaded pier blocks too I also have some height adjustment there too.

I created a form/frame to hold the sonotube off the ground at the desired height holding the cut to length sonotube.
I created a dummy pier plate from marine ply with 4 1/2” J bolts mounted in it. This later became a template to drill my metal pier plate.
It is stood off the cement pier using two nuts and two flat washers per J bolt, so height and level can be adjusted.

We poured the concrete in one session, used one of those vibrating noodles to get the air out.
We filled the 4’ square almost to grade, to the bottom of the tube, and then filled the tube and inserted the J bolt and pier plate form.

I made a 12” circular pier plate (I think 3/8” thick) and drilled J bolt holes from form and drilled and threaded holes to take one of the AP flat surface adapters, aligned with North of course.

The observatory floor has an oversized pier hole to disconnect floor from pier and a flexible foam rubber floating collar to keep most critters out.

There’s no movement of the pier.

The biggest issue in the whole project was breaking a tap in the pier plate and having to eat it out with special acid.
(yes I used cutting oil and carefully tapped forward and back, stuff happens)


Re: Concrete pier

Astrobob
 

 

 

Sent from Mail for Windows

Hi Howard,

 

Back in my day it was wise to rope the sonotube. The bigger commercial construction sonotubes are much sturdier today and some are made to become part of the structure. I looked in my notes of 20 years ago it took me 3days, a lot of digging and it cost me less than $100 to build my pier. Probably not much different today if you consider inflation.

 

Good luck with your project,

 

Bob


Re: How often do people refresh their All-Sky Pointing Model? (Observatory)

Chris White
 

Bumping this topic to see if I can get more feedback.  Thanks in advance!


Re: Concrete pier

vk3cjk
 

Howard, I dug a 2 cubic metre hole by hand, constructed a reo-bar cage in it, and also attached 8 upright reo-bars to form the pier.  After the cube base was poured an 18" Formtube was placed over the uprights and readymix concrete was poured.  The 2.2 metre high concrete pier is as solid as a rock and supports 100 kg of scope and AP 1200 mount (which are actually on top of a 1.2 m steel pier bolted to the top of the concrete pier).  It was straightforward to do myself but I wouldn't want to mix the concrete by hand.   
Cheers, Chris

On Sat, 6 Nov. 2021, 02:42 Howard Ritter via groups.io, <howard.ritter=mac.com@groups.io> wrote:
I want to put my upcoming AP 1600GTO on a concrete pier. My plan is to dig a 24” circular pit a foot deep, auger a 12” hole 3-4’ deep in the middle of this, put a 7-8’ Sonotube down to the bottom, pound some rebars into the ground at the bottom to fix them in place, fill the pit with concrete as a stabilizing collar, and then fill the Sonotube with concrete for a pier about 42” high.

So, a small pit, a hole, an 8'Sonotube and 30’ of rebar, a few cubic ft. of concrete. Do it myself? Sounds like a fair amount of work, plus renting an auger and an electric mixer. Contract it out? How expensive can that be? Sounds like a better deal to me!

Well. The estimate from the neighborhood landscape contractor – if I dig the 2’ x 1’ pit - was $4450! He didn’t itemize the estimate, but I just cannot conceive of how such a figure was attained. I looked at it twice, and it’s not $445.00 with a zero missing.

This is now a DIY project after all. Advice?

—howard







Re: Concrete pier

weems@...
 

It depends on the type of tube. Some are rated for above ground fill up to a fair height. Others, especially the cheap ones that big box stores sell, may only be rated for 24” free standing. When I did mine, there was a shortage, so I got two of the cheap tubes that fit snugly together and reinforced them with ratchet straps, to get up to the height I needed. Probably not necessary, but having had concrete forms burst in the past, I didn’t want to take any chances.

If you can pour a wider base below the frost line, it will reduce heaving even more. Steel piers are nice, but if you know the height you need, concrete is much less expensive, and even more stable. Literally rock solid. I can kick it hard and not see any vibration, even at high powers.

Chip


Re: Concrete pier

Howard Ritter
 

Thanks, Bob. More appealing ideas to think about. For one, I hadn’t considered the effects of the hydraulic pressure exerted by hundreds of pounds of wet concrete on freestanding Sonotube. I wonder if a big hose clamp every 6” or so would hold the pressure. But aren’t all those cylindrical pillars you see in outdoor applications everywhere all poured with Sonotube, and not roped? 

Maybe I’ll go with an aluminum pier after all! 

After reading all the suggestions and reports I’ve gotten, I’m thinking that maybe all I need is a 2’ hole 3’ deep filled with concrete, no rebar or Sonotube, and the metal pier bolted onto that. Anyway, that would give us flexibility compared to a concrete pillar if we ever move again.

I just looked at the Sonotube website. Supplemental banding is NOT needed.

—howard

On Nov 5, 2021, at 7:31 PM, Astrobob <imager1940@...> wrote:

This is what I did 20 years ago and it’s still working perfectly. I dug an 18" round hole 5' deep with a post hole digger and   put a 10' sonotube (or whatever height you want) In the center. Then I placed four 10' rebar equally spaced inside the sonotube. Then I filled the 18" hole and sonotube equally 3 1/2 feet with concrete. The sonotube was then heavily roped around the outside perimeter to avoid bursting from the concrete filling. Over the next few days I filled the tube 2' more each day until I got the height I wanted. Then I was able to remove the rope. The reason I filled the 18" hole only 3 1/2 feet with concrete was to fill it the rest of the way with dirt. This avoids stepping directly on any concrete that might shake your telescope with your feet. 
I used 60lb bags of Redimix concrete in a wheelbarrow and shoveled in in where and when necessary. The whole job took me 3 1/2 days and even with todays costs, it shouldn’t cost more than 2-3 hundred dollars. Readmix is not expensive.
 
Good luck, 
Bob
 
Sent from Mail for Windows
 


Re: Concrete pier

Astrobob
 

This is what I did 20 years ago and it’s still working perfectly. I dug an 18" round hole 5' deep with a post hole digger and   put a 10' sonotube (or whatever height you want) In the center. Then I placed four 10' rebar equally spaced inside the sonotube. Then I filled the 18" hole and sonotube equally 3 1/2 feet with concrete. The sonotube was then heavily roped around the outside perimeter to avoid bursting from the concrete filling. Over the next few days I filled the tube 2' more each day until I got the height I wanted. Then I was able to remove the rope. The reason I filled the 18" hole only 3 1/2 feet with concrete was to fill it the rest of the way with dirt. This avoids stepping directly on any concrete that might shake your telescope with your feet.

I used 60lb bags of Redimix concrete in a wheelbarrow and shoveled in in where and when necessary. The whole job took me 3 1/2 days and even with todays costs, it shouldn’t cost more than 2-3 hundred dollars. Readmix is not expensive.

 

Good luck,

Bob

 

Sent from Mail for Windows

 


Re: Concrete pier

dan kowall
 

Hello Howard,
You haven't told us some pertinent information such as your soil type and the frost line in your area.  Plans will be different if your digging in sand vs. clay for instance and you definitely want the base of your pier below the frost line.
Your collar is a definite no-no.  If the base of the collar is above the frost line any frost heave will lift your whole pier.
The bottom of your pier should be on undisturbed soil and the wider the better.
I know a lot of people do it differently but you can skip the rebar.  Concrete is immensely strong in compression, not so much in tension.  Rebar is added when tensile forces are strong but the tensile forces in an amateur's pier just aren't that great.  Pounding the rebar into the ground at the bottom of the hole is also not called for.  Standard rebar needs to be completely enclosed by concrete.  If left exposed it will rust, expand, and crack the concrete.
If you use a sonotube remove the tube after the concrete has set.  It just unwinds.  When you backfill do it in stages and compact the fill as you go.  Watering the fill will help it compact.
Stainless steel threaded rods can be used as your anchors but trap a large washer between two nuts at the bottom to resist any pulling force on the anchor.
Follow good concrete procedures such as 'working' the mix when it's still fluid to remove entrained air and keeping the mix damp while it cures.  Also, a stiff mix is stronger than a watery one.

dan kowall


Re: Concrete pier

Brian McFarland
 

I have that same AP blue refractor! I love that thing.

Brian

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