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Forgive me if this is posted somewhere, but I did a search and I couldn’t find exactly this.
I am at a fork in the road on building my observatory. Either a very small outhouse type covering just my G11G on a pier or a bigger observatory where I can put my scope on the G11G that on the heavy duty tripod. The first is super cheap. The second is super convenient.

If I go the first route, I will take my scope off after every imaging session and then put it on to start the next one. I only get two image sessions at most a week for a couple hours a night, and as usual for most of us, there are long sessions of weather, full moon, etc. where I cannot image for weeks at a time. ?The scope will be kept fully assembled and wired up in a warm room about 10’ from the pier when not used.

My scope is a Stellarvue SVX 140 and loaded up it pushes 35 pounds.

If I very accurately PA the G11G on a pier and then set my scope on it for the next session will the PA stay accurate for doing this many times? Avoiding PA most of the time is the main point.

This is the last question on which route to go. A permanent pier with a removable scope and a very small outhouse type of rolloff building (or even lift off) or the much bigger affair where I just turn the power on after rolling off the roof.

Many thanks

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How well your scope stays well polar aligned depends on the quality of your mounting hardware and how much you bang on the mount while loading the saddle. For visual this is not a big deal but for imaging you won't know how well you are PA'd without checking and if you have to do this every time you use the scope why not just stay setup all the time??

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My advice is to just bite the bullet and build the ROR and leave the scope in the saddle year round. Be sure to have a low watt heater in there to keep moisture at bay. It helps to cover the scope tune and put a low Watt heating element like a Golden Rod below the cover to push moisture.?

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I'm sure others will have an opinion on this.?

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I can verify that the PA is unchanging over months of taking the scope on and off of my gm811g. In fact I store both the scope along with the mount inside, and am able to reposition everything very precisely every night. The key is to make a durable base for the tripod to be placed using pipe and pipe flanges. I've been doing this for years and it works great with about 3 minutes of setup time per night. Details here:

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On Tue, Nov 19, 2024 at 10:33 AM, <sctom1@...> wrote:

If I very accurately PA the G11G on a pier and then set my scope on it for the next session will the PA stay accurate for doing this many times? Avoiding PA most of the time is the main point.

This is the last question on which route to go. A permanent pier with a removable scope and a very small outhouse type of rolloff building (or even lift off) or the much bigger affair where I just turn the power on after rolling off the roof.

Many thanks

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Reply

How long your mount holds PA really depends on how much you jar it with any one action. Just putting a scope on may or may not nudge it of place. I think for larger heavy scopes this would be more common than small lightweight gear. You can see in your guiding whether PA is off. All your Dec corrections going in one direction up or down is a PA issue. Also check how well your target stays centered over the course of a few hours. If it is constantly drifting toward one side of the sensor that is PA. Other incidents like walking into the scope in the dark, or hitting your head on it (happens to most of us at some time) can knock out PA. My G11 on a pier in my shed can stay aligned for months if I never take the scope off. Then one night I'll see drifting and I know something has finally worked loose. So, the answer is how fastidious do you wish to be. Do a PA every time and be sure, or just watch for drift issues to get so bad you need to take action.

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Regards,

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John

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Losmandy G11G2 on pier; refurbed Losmandy G11 with OnStep controller; SkyShed design roll-off observatory; ZWO ASI2600MM-P; ZWO ASI071MC; Sky-Watcher Esprit 100 ED with field flattener; Celestron C925 Edge HD with 0.7XFR, William Optics Zenithstar 61 APO; PHD2, NINA, Sequence Generator Pro and PixInsight user

Thanks all. ?Good advice.

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Thanks all. ?Good advice.