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Where to erect tripod - grass or concrete?

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#1 Tulloch

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Posted 23 May 2020 - 09:12 PM

Hi there, in the realm of those questions that I really should know the answer to but haven't yet asked, I was wondering if anyone had any wisdom they could share as to what surface I should set up my tripod on in the back yard.

 

I have a small area out the back that is half concrete slab and half grass. As I naively see it, the concrete base has the advantage of being solid and away from the wet grass, but can transfer vibrations as I walk about on it (something I've noticed so I don't move while imaging) and hold its heat for longer (although imaging at 5:00am reduces this prospect). The grass can absorb some vibrations but since it is winter over here and generally below 10 degrees Celsius, the grass is wet and I'm concerned that it might be increasing the likelihood of dew forming on the optics if I set up on it.

 

Right now I'm kind of straddling the boundary as this gives me the best view looking east and west, with two of the tripod legs on the concrete and one on the grass (so the best/worst of both worlds). 

 

Any tips appreciated.

 

Thanks, Andrew



#2 BQ Octantis

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Posted 23 May 2020 - 09:22 PM

I have a slab on the sunset side of my house and a big grassy backyard with a wide view that's shaded at sunset. So the grass is the obvious choice for AP. Except for when I'm doing planetary imaging in the gusty outback winds—the shifty grass is no match for the concrete at dissipating buffeting while keeping the planet on the sensor. I first noted this major difference while imaging Jupiter last year. I got a huge difference in image quality, too. But then again, the Canon only captures at 30 fps…

 

Cheers,

 

BQ


Edited by BQ Octantis, 23 May 2020 - 09:34 PM.

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#3 MikiSJ

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Posted 23 May 2020 - 09:22 PM

The only problem I see putting a tripod on grass or bare dirt is the weight of the rig possibly sinking disproportionally into the ground. One item your might want to use on tripod on the ground would be to slip a large washer over each leg of the tripod so the sinking would be limited.


Edited by MikiSJ, 23 May 2020 - 09:23 PM.

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#4 vtornado

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Posted 23 May 2020 - 09:34 PM

This does not apply to your situation, but I have a black top driveway that makes it very easy to roll a scope out the garage and start viewing.

I was watching Jupiter and had crummy views 3 hours after sundown.   Then I had to tree dodge which involved me picking up the scope and moving it to the lawn.

There was an instant increase improvement in the view.  So I put the scope back on the driveway, and once again the image degraded. 

 

One of my friends suggested I hose the driveway down to cool it.  I haven't tried this.


Edited by vtornado, 23 May 2020 - 09:35 PM.

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#5 xiando

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Posted 23 May 2020 - 09:37 PM

grass, on patio tiles (IMO). Unless the ground is really mushy anyway Polar alignment is crucial, at least for equatorial mounts

 

but setting up on concrete asphalt is often very convenient, so... (As I recall, one trick with "stone" is to cover the area with a reflective tarp during the day prior and remove it shortly before dusk to reduce the surface temp a bit)


Edited by xiando, 23 May 2020 - 09:38 PM.

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#6 Kokatha man

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Posted 23 May 2020 - 10:23 PM

...as you said, you've answered your own question Andrew - or at least outlined the major differences of each surface.

 

At home I opt for the grass as it does cushion clod-footing around wink.gif & is generally the more stable surface for vibrations etc, although I guess you could use pads under the tripod...my EQ8 tripod, which is the permanent "at-home" structure (we use the ally pier when away) has levelling pads with rubber cushioning underneath but they sit on pavers I sunk flush with the lawn - this was initially for the EQ6 & are aligned for a N-S situation so that either tripod could be sat on them. (they have a couple of markers for each tripod)

 

My suspicion is that the grass probably attracts more corrector fogging but on a night when it is a major concern I'm not sure how much benefit the concrete position might offer... but it might.

 

Heat dissipation is a factor to consider with concrete holding it much more than grassy earth...but when you do need to rapidly cool a scope for imaging shortly after Sunset we have not really had any issues at Sedan where we do a lot of imaging & the pier arrangement sits on a bitumen road, although probably only a couple of inches thick.

 

Mount#9.jpg

 

NewPierInActionSmall.jpg


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#7 Sunspot

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Posted 23 May 2020 - 10:24 PM

I recently added a deck to my backyard for my telescope. I was concerned about heating (I live in near Phoenix, AZ where 110+ degree temps are not unusual). The deck is on the east side of my house meaning that after about 4pm the deck is in total shade. Turns out the heating has not been a problem in any way that I have experienced. Also, it is great not to have to wade through mud after rain to get to the scope. I wish I had done this 20 years ago! That's my experience. Here is a picture of my setup.

 

Paul M.

Attached Thumbnails

  • Building a Deck-028.JPG

Edited by Sunspot, 23 May 2020 - 10:24 PM.

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#8 Tom Glenn

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Posted 24 May 2020 - 01:33 AM

In theory, grass would be better for thermals, although in practice I agree with those above that have said it surprisingly doesn't seem to matter that much.  I suspect this is largely due to the fact that, in my case at least, I'm also imaging across roads and neighbors houses, and even if you had your thermals perfect in the vicinity of your scope, imaging something above a rooftop is going to override that.  This is one of the major reasons why elevation matters, such as the kind you are currently enjoying down South.  The heat rising from roads and houses is very significant.  


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#9 Tulloch

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Posted 24 May 2020 - 02:19 AM

Thanks all for the helpful comments, I guess I knew the answer already, I guess I was just looking for confirmation.

 

My only real issue for setting up on the grass would have a possible increased chance of dew formation but since it's so close to everything else (houses etc) I guess it makes no difference.

 

Looking forward to a clear morning tomorrow, if the sky cooperates it could be good fingerscrossed.gif

 

Andrew



#10 BQ Octantis

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Posted 24 May 2020 - 03:14 AM

Thanks all for the helpful comments, I guess I knew the answer already, I guess I was just looking for confirmation.

 

My only real issue for setting up on the grass would have a possible increased chance of dew formation but since it's so close to everything else (houses etc) I guess it makes no difference.

 

Looking forward to a clear morning tomorrow, if the sky cooperates it could be good fingerscrossed.gif

 

Andrew

Yep…concrete on grass is the answer! I've thought about putting pavers out in the grass. But then my ideal setup location changes according to my target for the evening. So I guess ideally, I'd have the backyard peppered with little concrete circles, all perfectly separated.

 

On a temporary basis, I've wondered about using my Celestron vibration damping pucks on the grass. But I suspect they'd give me the best results on terra firma. After all, they're made for the kind of concrete vibration you describe.

 

BQ


Edited by BQ Octantis, 24 May 2020 - 03:15 AM.


#11 kevinbreen

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Posted 24 May 2020 - 04:08 AM

My shed is down at the bottom of the garden, on a concrete base which extends about 2 feet beyond the door, but away from any other concrete expanses. For planetary I positioned the shed so I just have to roll the C11 tripod half out the door, lock the wheels and I'm all set.
For deep sky I just carry the rig out onto the grass where I have 3 wooden pegs hammered into the ground, angled at 45 degrees. The tripod feet fit snugly so I sometimes have very little tweaking to do to obtain polar alignment. As for vibration, I find there's more on grass, especially if it's damp, but that's where the delay functionality of my intervalometer comes in handy - I'm well away from the scope in the 5 seconds I set it to.

#12 xiando

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Posted 24 May 2020 - 06:41 AM

Yep…concrete on grass is the answer! I've thought about putting pavers out in the grass. But then my ideal setup location changes according to my target for the evening. So I guess ideally, I'd have the backyard peppered with little concrete circles, all perfectly separated.

 

On a temporary basis, I've wondered about using my Celestron vibration damping pucks on the grass. But I suspect they'd give me the best results on terra firma. After all, they're made for the kind of concrete vibration you describe.

 

BQ

you could just buy three 1x1 ft pavers and carry them out to where you setup. That way at least you have a relatively stable foundation, and you haul them back to the garage or wherever at the end of your session or the next day so the grass doesn't get killed...then you can move them elsewhere when you setup elsewhere. 



#13 BQ Octantis

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Posted 24 May 2020 - 09:26 AM

you could just buy three 1x1 ft pavers and carry them out to where you setup. That way at least you have a relatively stable foundation, and you haul them back to the garage or wherever at the end of your session or the next day so the grass doesn't get killed...then you can move them elsewhere when you setup elsewhere. 

I'll see what Bunnings has tomorrow…

 

BQ


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#14 schu

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Posted 25 May 2020 - 07:42 PM

My home setup is similar to a couple mentioned above - 3 pavers that were placed in the yard.  Has worked very well for me.




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