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Beginner question on Nexdome #1

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#1 ssa2294

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Posted 25 July 2021 - 01:16 PM

I am getting closer and closer to where I will (hope to) be ordering a Nexdome for my backyard. I have a number of pre-ordering questions to ask so I know what I am getting myself into.

 

1.) I had intended to build a basic deck. Is this advisable, necessary, other options? Would large paver stones be an option, then bolt the Nexdome to a few of the pavers? I can get a 16"x16" paver stone for $4.

 

2.) I do not anticipate I will be able to have an underground power line run by this winter. Advise on running power extension cords 20-30' in the winter? Should I try to protect it somewhat, or just plan on rolling it out on the nights I would image? 

 

3.) I fully intended to just use my mount's tripod, I did not see where the added expense of a pier + installation + frustration would buy me that much more. BUT if I did decide to through in a pier at some point, are the quick setting cement mixes used most often for fence posts an option or would I need a true to form real cement mix. This would just be holding a telescope mount, not supporting my deck after all. 

 

4.) A question for the non-DYI/non-techno gadget build it yourself types. How difficult/complicated was it to fully setup and automate your dome? Both shudder and rotation, aligning these to your scope, etc.? Kind of making the whacky assumption that the dome should be positioned same as mount and coordinate rotation and such.

 

5.) I live in Minnesota, which in January/February can be quite miserably cold. I know Losmandy promotes their mounts being able to operate in cold temperatures. But I would have to think the cold has to have some negative effects; ZWO camera, mini-PC, telescope, Pegasus powerbox, etc. So it begs the question, should I also look at have some sort of minimal heating within the dome, something to just warm it some? So if it is -10F, maybe bring it to 5F. Better question, is their a temperature limit I should look to avoid?

 



#2 Omeganon

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Posted 26 July 2021 - 12:05 AM

I just received my nexdome and am in the process of building the pier/foundation for it. I have done quit a bit of reading over the months I’ve waited for it and can offer my best opinions inline below. 
 

I am getting closer and closer to where I will (hope to) be ordering a Nexdome for my backyard. I have a number of pre-ordering questions to ask so I know what I am getting myself into.

 

1.) I had intended to build a basic deck. Is this advisable, necessary, other options? Would large paver stones be an option, then bolt the Nexdome to a few of the pavers? I can get a 16"x16" paver stone for $4.

 

It’s not strictly necessary. I’d personally add a couple inches of gravel below the pavers to get further from the ground/possible rainwater seeping in. 
 

2.) I do not anticipate I will be able to have an underground power line run by this winter. Advise on running power extension cords 20-30' in the winter? Should I try to protect it somewhat, or just plan on rolling it out on the nights I would image? 

A heavy duty construction extension cord would be fine. I use one to run my greenhouse heater and lights all winter long. 

 

3.) I fully intended to just use my mount's tripod, I did not see where the added expense of a pier + installation + frustration would buy me that much more. BUT if I did decide to through in a pier at some point, are the quick setting cement mixes used most often for fence posts an option or would I need a true to form real cement mix. This would just be holding a telescope mount, not supporting my deck after all. 
 

Yep. I just built my pier base out of 9 bags of Sakrete. It’s commonly used. 

 

4.) A question for the non-DYI/non-techno gadget build it yourself types. How difficult/complicated was it to fully setup and automate your dome? Both shudder and rotation, aligning these to your scope, etc.? Kind of making the whacky assumption that the dome should be positioned same as mount and coordinate rotation and such.

 

Largely depends on the software you use. The nexdome shutter and rotator have suitable indi and ascom drivers. I use NINA and fully expect I’ll be able to control both mount and dome, in sync with each other. 

 

5.) I live in Minnesota, which in January/February can be quite miserably cold. I know Losmandy promotes their mounts being able to operate in cold temperatures. But I would have to think the cold has to have some negative effects; ZWO camera, mini-PC, telescope, Pegasus powerbox, etc. So it begs the question, should I also look at have some sort of minimal heating within the dome, something to just warm it some? So if it is -10F, maybe bring it to 5F. Better question, is their a temperature limit I should look to avoid?

 

Colder is generally better for the electronics. You’ll want a dew strap/heater for your telescope though to keep frost off the objective. 
 

Chilly imaging rig

 



#3 ghilios

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Posted 26 July 2021 - 08:03 AM

Are you going to automate it, or manually rotate the dome through the nights? If you are automating it, I highly recommend putting a pier. The dome calculations are sensitive to offset measurements, and with a pier you know it is not going to change. It also simplifies polar alignment since you can really dial it in and leave it alone for several months.

 

I have a Nexdome, and also implemented the Dome support (including scope synchronization) in NINA.



#4 kathyastro

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Posted 26 July 2021 - 09:10 AM

4.) A question for the non-DYI/non-techno gadget build it yourself types. How difficult/complicated was it to fully setup and automate your dome? Both shudder and rotation, aligning these to your scope, etc.? Kind of making the whacky assumption that the dome should be positioned same as mount and coordinate rotation and such.

I am sure that there is an automation kit for the Nexdome.  If you don't consider yourself a DIY-er, that would be your best bet.

 

If you plan to do your own automation, there are several things to plan for:

 

- Getting power to the shutter motor which is on a rotating platform.  Some kits use a battery and radio (bluetooth) control.  Others use power contacts on the dome, and limit shutter use to the home position.

 

- Knowing the azimuth of the dome with accuracy.  An AC or DC motor is simple to wire up, but it can't stop the dome accurately in a known position.  Options are an encoder system, or a big stepper motor.

 

- Synchronizing the dome slot to the mount.  The azimuth almost never matches that of the scope, so you need software to calculate the proper position from the mount position.  Fortunately, most session-control software includes dome control that does the calculation for you.  For software to do it, though, you need an ASCOM driver, which is a complication for a DIY project.

 

If you go for a DIY rotation solution, I can help you with the synchronization.  I wrote my own rotation controller, ASCOM driver, and synchronization software.


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#5 GUNER

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Posted 26 July 2021 - 10:23 PM

  I can give you my feedback on question 1

I am also putting my NexDome on pavers.  I bought 24x24 pavers from HomeDepot.  During my research about how to build a patio most of the recommendations I read to prevent it from settling wrong is 3-6 inches of gravel then one inch of sand.  Lowes had a good write up here but they recommend 6" of gravel 3" first then compacted then 3" more & compacted then the sand:

 

https://www.lowes.co...d-a-paver-patio

 

  I wish I could give you more advice.  I should be done with it but screwed up my back so I haven't started yet.  Hopefully I will be starting in a couple of weeks.



#6 ghilios

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Posted 27 July 2021 - 01:13 PM

Ugh. Unnecessary comment. Well done Kathy, I wish I had your hardware DIY skills. I stick to software!

#7 ssa2294

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Posted 27 July 2021 - 07:06 PM

Are you going to automate it, or manually rotate the dome through the nights? If you are automating it, I highly recommend putting a pier. The dome calculations are sensitive to offset measurements, and with a pier you know it is not going to change. It also simplifies polar alignment since you can really dial it in and leave it alone for several months.

 

I have a Nexdome, and also implemented the Dome support (including scope synchronization) in NINA.

I wouldn't think of getting the Nexdome unless I included the shudder and rotation. I think my concern had to do with comments I had seen while back when I first found out about Nexdome. Comments regarding issues getting the dome to rotate correctly with the mount. 

 

Thinking this over I probably will go with building a deck, actually seems easier to pick up  deck pieces and screw them together. I am hesitant about making this too permeant (i.e. if I decide to sell and move in couple years). Even a deck could be disassembled. My mount would be using the Losmandy heavy duty tripod, and if I did not move it, disassembled, etc. and marked the positions and just left it as is, shouldn't I be then able to rely on the automated dome rotation & polar alignment?  



#8 kathyastro

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Posted 27 July 2021 - 07:20 PM

if I did not move it, disassembled, etc. and marked the positions and just left it as is, shouldn't I be then able to rely on the automated dome rotation & polar alignment?  

Yes.  If you accidentally moved the tripod, you would not only have to re-do your polar alignment, you would also have to re-measure your dome sync parameters.



#9 GUNER

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Posted 27 July 2021 - 09:26 PM

A deck would be better but for some reason my town calls my dome mounted to a deck a "permanent structure" but the same dome on a patio is a "non-permanent structure" go figure?shrug.gif



#10 ghilios

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Posted 27 July 2021 - 09:30 PM

I wouldn't think of getting the Nexdome unless I included the shudder and rotation. I think my concern had to do with comments I had seen while back when I first found out about Nexdome. Comments regarding issues getting the dome to rotate correctly with the mount. 

What issues are you referring to? I've spent quite a bit of time in this area while working on dome synchronization, including discussion with Tim Long (developer of the Nexdome software and firmware) and NINA users trying out the dome support. Perhaps I can answer or clear something up.



#11 ssa2294

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Posted 29 July 2021 - 02:11 PM

A deck would be better but for some reason my town calls my dome mounted to a deck a "permanent structure" but the same dome on a patio is a "non-permanent structure" go figure?shrug.gif

Ugh, I did not even think about that. Thankfully I won't have an HOA, but will need to check at very least if I need a permit. I bet with combined decking & dome it would be a "permanent structure".

 

What issues are you referring to? I've spent quite a bit of time in this area while working on dome synchronization, including discussion with Tim Long (developer of the Nexdome software and firmware) and NINA users trying out the dome support. Perhaps I can answer or clear something up.

It was over a year ago I was searching, and it was probably much older posts of issues people were having. I just wanted to primarily know if the setup was intuitive, user-friendly, or sensible. Or if it requires me to go back to school, get a doctorate, get a few years of field experience and then try to tackle it lol.gif.

 

I think my worry is getting this dome is going to be a significant task, and the automated shudder does not worry me as much as the dome rotation. More specifically being able to have the confidence the dome will rotate with the mount with no hiccups. 



#12 ghilios

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Posted 29 July 2021 - 02:35 PM

With a nexdome, and likely any other budget dome, you will likely run into the following challenges:

  1. Ensuring the rotator motor meshes tightly enough around the entire dome as it rotates around. Math is *not* your friend here - if you bolt in your walls to be a perfect circle and then put a slightly oblong dome on top (nothing is perfect!) you'll likely find that the gear jumps in some spots. Avoid bolting in your wall posts until you've confirmed the motor can rotate the dome successfully on a cold night.
  2. Meshing the shutter reliably is tricky. There's a screw behind the assembly that's supposed to tighten the motor gear against the chain rail, but I found that it doesn't get tight enough. There were a few discussions on the Facebook group about ways to make this better
  3. Dome measurements. To get scope synchronization working you will have to tweak various offset measurements until it works. I made sure NINA hot loads measurement changes to simplify this process. If you change a measurement in the options when "Dome Follows Scope" is on, then then it'll take effect immediately. Fortunately you only need to measure this once if you have a pier.
  4. With Nexdome particularly, the door is bad. Like, truly awful. I'm considering building my own door in a few months because you can't really lock it, and it doesn't provide good protection from the elements.

 

If you go into this expecting it'll take you several weeks of tweaking and periodic maintenance (like spraying teflon to keep the shutter moving smoothly), then I think most people can handle the setup. If you expect it to be turn key, you will be extremely disappointed. It's a labor of love! If you want turn key, expect to pay 30-40k+ (and I'm sure those systems have their own problems too).



#13 ssa2294

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Posted 03 August 2021 - 10:20 PM

 

 

If you go into this expecting it'll take you several weeks of tweaking and periodic maintenance (like spraying teflon to keep the shutter moving smoothly), then I think most people can handle the setup. 

Right now my only option is to (best case scenario) drive 25 miles on Friday or Saturdays only, and only when skies are clear. If new moon is on Tuesday, or if it is cloudy on Friday, well it sucks to be me. Just being able to setup my mount in a backyard is infinitely a step up from where I have been the past few years. 

 

A couple more questions have popped up for me:

 

  • I was looking at the "Sample Observatory Deck Design" where they use 6x concrete footings connected to 4x4x8 pressure treated/ground contact boards. Question I have is should the concrete footings be placed on top of ground or buried some? What about doing smaller paver blocks on top of gravel, then placing concrete footing on pavers?
  • I had thought to maybe not cut the 4x4x8's down but to actually had some boards across for siding, and then add a simple hinged door in front of the Nexdome's door as an added layer of security. 
  • Does the side skirts require ground contact boards, or can those be above ground treated?

 

Right now I am more inclined to have something that I need to replace/upgrade/improve upon in a year or so and not have something too permanent I need to tear down in a couple of years should I move. Idea of deeply buried concrete pier & footings is not ideal at this time. 



#14 GUNER

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Posted 04 August 2021 - 02:58 PM

I believe if you are going to build your deck on concrete footings their depth depends on your region.  They have to be deeper then the frost line for your area.  It prevents upheaval.  At least that is what I read when I was going to put in a deck.  Depending on your area it could be 12" or it could be 48"+.  You should be able to find out from your town what the depth has to be.  They do make deck footings that don't require digging deep.  They usually have some sort of long pipe that gets jack hammered in but you'd have to see if your town's code allows something like that. 

  This is one of the one's I was going to use so I didn't have to dig footings.  My soil is very rocky.  But those long pipes in the ad need to be driven into the ground.

 

https://www.homedepo...P1200/306232936



#15 ssa2294

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Posted 04 August 2021 - 06:47 PM

Is a base less than 100 square feet at the weight of the Nexdome  necessarily going to require frost line foundation for the short term. I can understand several years of winters would affect the the decking over time. 

 

One thing I did think of, if I used 4x4s dug in 4' with concrete base, then if I did need to tear down for a move, I would just need to cut the 4x4s down some and could bury them. 



#16 Luke Skywalker

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Posted 04 August 2021 - 07:46 PM

I ordered a NexDome at the end of June beginning of July and was told there is an 18 to 20 weeks lead time because of delays on supplies from pandemic. I will be building my observatory on an elevated deck roughly 8 feet up, 10x10 structure with 4 foot walls. I am going with 4 helical piles 8 feet down. The floor will be framed with 2x10. I don't plan on automating it. 


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#17 GUNER

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Posted 04 August 2021 - 10:00 PM

Is a base less than 100 square feet at the weight of the Nexdome  necessarily going to require frost line foundation for the short term. I can understand several years of winters would affect the the decking over time. 

 

One thing I did think of, if I used 4x4s dug in 4' with concrete base, then if I did need to tear down for a move, I would just need to cut the 4x4s down some and could bury them. 

I wouldn't know about short term.  I was planning my deck to last for years.  I don't know how quickly there would be a problem with movement with footings above the frost line.  Someone with a better understanding will have to answer that for you.  I would hazard a guess that it would depend on how bad your winters are & the type of soil you have.




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