On Jul 20, 2022, at 16:48, ernie.mastroianni@... wrote:

In regards to the USB data throughput port on the Mach2, would a USB-C to USB-A cord have an advantage over the older-style USB cords? I have a newer Lenovo PC with a USB-C port. I'd like to connect my camera to my laptop through the Mach2 mount, but using the older style USB cords in this way has been touch-and-go at times.
Ernie Mastroianni

Wade - are you saying you are imaging in 30mph winds, and then only throwing out 10%?

you are far more courageous than I 

On Wed, Jul 20, 2022 at 9:18 AM W Hilmo <y.groups@...> wrote:

I live in an area of high wind.  I will eventually have a permanent observatory, but life keeps getting in the way of that project.

My original setup at this site was an AP1600-AE on an AP portable field pier.  I set 6" plywood squares on the ground, and set the feet of the pier on top of them.  That setup has worked for me in remote (low wind) environments for a long time, so I thought it would be fine here.  It was not - not even close.  Imaging either guided or unguided was awful.  I rarely got round stars.

I tried setting up a wind block, and that helped a whole lot, but eventually the wind block succumbed to the wind when a significant gust ripped the anchors out and the wind block blew across the field, shedding parts (and tipping the mount over on it's departure).  It was a really serious wind gust.  I know of two local observatories that lost their roofs on that day.

So I gave up on a temporary wind block and tried to stabilize the pier by filling it with sand bags.  That actually helped, but I was still throwing out about half of my subs.

I few weeks ago, I picked up a used AP1100-AEL with an ATS pier.  I'd heard good things about the stability of ATS piers, so I plopped down some more plywood squares and set it up.  The results were awful, just as bad as I'd originally seen when I first moved here.  Based on reports I've heard on the ATS piers (including Roland's results in the wind with his 17" scope), I decided that the common variable was the plywood squares.

So my latest attempt was to eliminate the plywood squares under the AP1600.  I had a different number of squares under each pier foot, to bring the pier close to level.  So I picked up some 12" x 12" by 2" pavers.  I dug holes in the appropriate spots that were deep enough that I could make the pavers level with each other, plus some extra depth.  I then filled the holes with packed sand and set the pavers into that, so that they are level with each other.

The combination of pavers, plus sand bags in the pier, with the pier directly on the pavers is getting very close to acceptable.  We've had winds for most of the last week that were 30ish mph with gusts, and I probably have to toss about 10% of the subs or so, which is the best results I've had so far.

I may experiment with vibration absorbing material under the pier feet, but I no longer think that vibration is my problem.  I am guessing that the 10% of subs that are problematic are happening during extra strong gusts.

I am heading off to a star party next week with the AP1100-AEL and the ATS pier.  When I get back, I'll probably make a spot for it with the same paver arrangement that's working well for the 1600.  I have a couple of different options for attachments to the feet on the ATS pier, so that will be my platform for experimenting with anti vibration materials.

The moral to the story, at least to me, is that a stable platform starts at (actually, under) the ground and goes up.  Oh, and I am done with using wood, anywhere, in supporting the rig.

-Wade

On 7/20/22 8:44 AM, Roland Christen via groups.io wrote:

The second is more interesting - I love the wood's deadness to vibration, but I do go from 50% humidity to 95% each night, and it sits there as the humidity rises further. It seems possible, despite being well sealed, that wood is expanding, moving, stretching or something.  Not sure hot to test that either other than buying a different tripod/pier.  I am curious if others using a Berlebach Planet, especially in nightly setup situations, have noticed this when shooting unguided.

I stopped using wood tripods when testing mounts here at the observatory. Wood does move with temperature and humidity. It also twists and flexes and changes the polar alignment thruout the night. When I put my Mach2 on the Eagle tripod, that all went away.

Roland

-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io
Sent: Wed, Jul 20, 2022 9:47 am
Subject: Re: [ap-gto] DEC Arc Model drift question

On Wed, Jul 20, 2022 at 12:30 AM, Ray Gralak wrote:

Yes, the mount could settle and you probably could not tell that it had. It doesn't take very much to throw off alignment by an arc-minute. Even cement piers can move when the ground swells or contracts from moisture or heat.

I'm in an area not prone to sinkholes, though there are many other hazards - usually involving naked crackers and meth, sometimes with alligators.   But so far they haven't intruded at night.   (Anyone not familiar just google "Florida Man Story"). 

So I spent some time staring at the setup this morning when I brought it in, and it seems to me there are three likely possibilities: 

1) The ground moves
2) The wooden tripod is moving
3) The only thing I left a bit loose is the four altitude locks, they are finger snug not tight

The first is possible but I really doubt it because the indicated errors on the polar alignment are not consistent over time, if it was shrinking or expanding as the night went on, I would think it would have a more consistent direction.  But possible, just don't know how to test it.  The ground around here is all the same (even under driveway pavers, still sand/soil). 

The second is more interesting - I love the wood's deadness to vibration, but I do go from 50% humidity to 95% each night, and it sits there as the humidity rises further. It seems possible, despite being well sealed, that wood is expanding, moving, stretching or something.  Not sure hot to test that either other than buying a different tripod/pier.  I am curious if others using a Berlebach Planet, especially in nightly setup situations, have noticed this when shooting unguided.

The latter -- well, not sure.  I leave them snug, then as I adjust I lower it and try to achieve alignment on an upward motion, but I do not crank down on the knobs, it (I thought) seems to hold OK since it has the adjustment built lifting it.  I guess it is POSSIBLE that I am introducing some overall slop, even side to side, by leaving them less than tight.  I can certainly change that next time out, but I am not hopeful - the fit between is very uniform, and there's a fair amount of weight (even with the light OTA) sitting on those bolts.  And I do have the azimuth very tight, working against each other to achieve PA. 

I'd welcome any other things to explore, but at the moment my best guess is the tripod. 

Though -- to a question I asked a while back -- this is a good example of why guiding is not ready to die.  This setup guides with excellent results, well under the C11's image scale even with a 3.7um sensor.  So I do not have a PROBLEM.  But I do have a mystery. 

Linwood

--
Roland Christen
Astro-Physics

--

Brian 

Brian Valente

astro portfolio https://www.brianvalentephotography.com/astrophotography/

portfolio brianvalentephotography.com 

astrobin https://www.astrobin.com/users/bvalente/

The second is more interesting - I love the wood's deadness to vibration, but I do go from 50% humidity to 95% each night, and it sits there as the humidity rises further. It seems possible, despite being well sealed, that wood is expanding, moving, stretching or something.  Not sure hot to test that either other than buying a different tripod/pier.  I am curious if others using a Berlebach Planet, especially in nightly setup situations, have noticed this when shooting unguided.

I stopped using wood tripods when testing mounts here at the observatory. Wood does move with temperature and humidity. It also twists and flexes and changes the polar alignment thruout the night. When I put my Mach2 on the Eagle tripod, that all went away.

Roland

-----Original Message-----
From: ap@... <ap@...>
To: main@ap-gto.groups.io
Sent: Wed, Jul 20, 2022 9:47 am
Subject: Re: [ap-gto] DEC Arc Model drift question

On Wed, Jul 20, 2022 at 12:30 AM, Ray Gralak wrote:

Yes, the mount could settle and you probably could not tell that it had. It doesn't take very much to throw off alignment by an arc-minute. Even cement piers can move when the ground swells or contracts from moisture or heat.

I'm in an area not prone to sinkholes, though there are many other hazards - usually involving naked crackers and meth, sometimes with alligators.   But so far they haven't intruded at night.   (Anyone not familiar just google "Florida Man Story"). 

So I spent some time staring at the setup this morning when I brought it in, and it seems to me there are three likely possibilities: 

1) The ground moves
2) The wooden tripod is moving
3) The only thing I left a bit loose is the four altitude locks, they are finger snug not tight

The first is possible but I really doubt it because the indicated errors on the polar alignment are not consistent over time, if it was shrinking or expanding as the night went on, I would think it would have a more consistent direction.  But possible, just don't know how to test it.  The ground around here is all the same (even under driveway pavers, still sand/soil). 

The second is more interesting - I love the wood's deadness to vibration, but I do go from 50% humidity to 95% each night, and it sits there as the humidity rises further. It seems possible, despite being well sealed, that wood is expanding, moving, stretching or something.  Not sure hot to test that either other than buying a different tripod/pier.  I am curious if others using a Berlebach Planet, especially in nightly setup situations, have noticed this when shooting unguided.

The latter -- well, not sure.  I leave them snug, then as I adjust I lower it and try to achieve alignment on an upward motion, but I do not crank down on the knobs, it (I thought) seems to hold OK since it has the adjustment built lifting it.  I guess it is POSSIBLE that I am introducing some overall slop, even side to side, by leaving them less than tight.  I can certainly change that next time out, but I am not hopeful - the fit between is very uniform, and there's a fair amount of weight (even with the light OTA) sitting on those bolts.  And I do have the azimuth very tight, working against each other to achieve PA. 

I'd welcome any other things to explore, but at the moment my best guess is the tripod. 

Though -- to a question I asked a while back -- this is a good example of why guiding is not ready to die.  This setup guides with excellent results, well under the C11's image scale even with a 3.7um sensor.  So I do not have a PROBLEM.  But I do have a mystery. 

Linwood

--
Roland Christen
Astro-Physics