In Search of Dark Skies - My Search Is Over - GifNet.US Observatory

[chris_g]

Hello all,

I can speak with 99.9% confidence that I will be closing on my new home in northeastern rural Louisiana in about a month. I'm trading a Bortle 5 sky, SQM 19.96, artificial brightness of 945 for a Bortle 4 sky, SQM 21.63, artificial brightness of 69.8. It is a good compromise with my wife. She didn't want to move to Rachel Nevada where the sky is Bortle 1 and live with That was a consideration at one point. The property is 2 acres with about 1.75 acres cleared. The future home of the GifNet.us observatory has been secured as well as my own so I can finish my journey riding off into the sunset while staring at the stars to the end of my days. My semi-permanent tent will now become the tent of choice when out camping in truly dark skies that can only be obtained by no real civilization within 30 miles! I'll be asking a lot of questions and will document the progress here.

I'm looking for designs for a roll off roof observatory, it needs to house at least three telescopes. The roof needs to be able to be automated. I am not a construction type of DIYer, so I am hoping to find either a company that comes to me or a company that has designs specs that I can provide to a local company. Anyone have any personal experience with something or someone along those lines?

The next question. What would be the benefit of a permanent pier vs a pier tripod that would never be moved once placed on a concrete pad?

Hope for lots of feedback and suggestions.

Clear Skies,
Chris

[SkyHiker]

I can speak with 99.9% confidence that I will be closing on my new home in northeastern rural Louisiana in about a month. I'm trading a Bortle 5 sky, SQM 19.96, artificial brightness of 945 for a Bortle 4 sky, SQM 21.63, artificial brightness of 69.8. It is a good compromise with my wife. She didn't want to move to Rachel Nevada where the sky is Bortle 1 and live with That was a consideration at one point. The property is 2 acres with about 1.75 acres cleared.

Sounds fantastic, I wish I could afford a 2 acre property where I live. Congratulations.

I'm looking for designs for a roll off roof observatory, it needs to house at least three telescopes. The roof needs to be able to be automated. I am not a construction type of DIYer, so I am hoping to find either a company that comes to me or a company that has designs specs that I can provide to a local company. Anyone have any personal experience with something or someone along those lines?

I have some experience, here are my thoughts.

First off, why 3 telescopes? Operating more than 2 at once seems hard and rare to me. Think about what is practical because the more scopes, the more room you need, the harder it will be to build, the larger an open space you have through which the wind has free play. I would just shoot for one scope, or one main scope and a small one, and keep things as small as possible.

About full automation: Keep in mind that the roof needs to be latched at 4 places to keep it from flying into the neighbor's yard. You may also need latches to hold the roof while it is rolled off. These latches can be automated but most likely you will have to do it manually. So, full automation will likely not happen.

If you decide on a standard garden shed as the base, find a design that has low enough walls to look out over, so you don't have to cut straight through the doors. Also, resin sheds are much heavier than metal sheds and harder to work with from what I've seen here. A lean-to shed has only one roof section, which makes it possible to some up with a slide-off alternative instead of having to add ugly rails. If you place the tall wall on the North side, I think there is enough coverage of the entire sky. If you decide on roll-off, consider that you can put the rails in the ground instead of in the air to avoid an eyesore. Using a standard garden shed as a base has the advantage that the doors and vents are taken care of. A resin shed may need an extravagant amount of framing from what I can tell, so you might as well build one from boards, unless you use a metal shed. Resin and metal avoid maintenance of rotting wood.

The next question. What would be the benefit of a permanent pier vs a pier tripod that would never be moved once placed on a concrete pad?

My G11 HD tripod is super solid, I would recommend considering it. My plan is to drill 2 holes around the feet and put a bolt in there to lock the feet in place. I did that on my driveway too and it feels rock solid. IMHO a pier is not needed. If you walk around a lot during imaging, you will need one though because I've read reports that concrete transfers vibrations really well.

[chris_g]

I have some experience, here are my thoughts.

I thought you might and am looking forward to them. Thank you for the link to the post...

First off, why 3 telescopes? Operating more than 2 at once seems hard and rare to me. Think about what is practical because the more scopes, the more room you need, the harder it will be to build, the larger an open space you have through which the wind has free play. I would just shoot for one scope, or one main scope and a small one, and keep things as small as possible.

Currently I run two imaging rigs, the C8 on the EQ6 and the Z73 on the EQ5. I'm thinking about adding an EQ8-R to replace the EQ6 and move the EQ6 to where the EQ5 is and use the EQ5 as an EAA/observation rig since it's also AZ, so I can have something to do on those nights I didn't or couldn't setup a scope outside once imaging plans started. However, I would think that an outside pad would suffice for the EQ5 setup, doesn't take long and would keep me in practice for setup when I grab and go. So, the observation room would need to be big enough able to run an EQ6-R and an EQ8-R or equivalent with an outside observation pad and a warm room. The sections of the pad will be separated from the observation room to help dampen vibrations. How tall do the walls need to be to get a view starting at 30 degrees? This will be a metal build and not by me personally! When you say tall wall to the north, why? Why not make all the walls the same size and roll the roof back? So if that's the case, how much space do I need and how tall do the walls need to be for the two mounts to get 360 degree unobstructed access to the sky starting at 30 degrees?

Thank you for the advice about latches and full automation, not going to happen so, a hand crank will suffice! Things just got simpler.

[SkyHiker]

When you say tall wall to the north, why?

This was just in reference to the idea of a lean-to shed like the one I have. It has a single roof and avoids the hassle of making rails for a roll-off roof. If my observatory works as expected I am considering moving it to the driveway where I have a full view. My backyard is out because of a huge oak tree. To minimize visual pollution, I could camouflage it with arbors or trellises with vines growing on them in planters. In that case I would put the tall wall to the North side because there is not much to look at near the celestial pole, and the way a telescope rotates, it would still cover quite a bit of area there including M101, M51 and the Markarian chain if I am estimating it right.

Your project sounds much bigger than what I have in mind, and you are going to have it custom made. A concrete pad and a metal build sounds like a good plan, good luck and keep us posted.

[chris_g]

I think you really just made this part of it easy, 8' diameter base, 6.5' perimeter opening, 5.5' attitude. is big enough to run the EQ5 on it's tripod. The EQ6 with scope stands about 6.5' tall in the home position. The EQ8-R 6.5 with no OTA, I would imagine closer to 7. So, breeze dampening, 7' walls, two tripods each with it's own 8' perimeter base,

Observation Room - Physical dimensions minimum width 16', minimum depth 8', minimum height, = 7'

What is the actual width and depth needed to achieve a 30 degree horizon at a 7' altitude. My brain tells me that this would work, however I would really like the math to prove it. @JayTee , I checked out your thread again and looked at the final wall height, how tall is your northern wall? I remember that being an issue with the initial building. You mentioned doing trig, one course I didn't take in high school! Did you have any design software to help determine the dimensions? I promise, no Harry Potter comments! Help!

[Graeme1858]

Hello Chris

I'm sure if you post a sketch showing the dimensions of your floor plan and the height of your RA axis on your mount, someone will be glad to do the trigonometry and work out your wall height!

Graeme

[SkyHiker]

Do you need to extend the legs of the EQR-8 Pro at all? What is the largest scope that you will put on it? What kind of roof design, a lean-to like Jaytee's or mine, or a normal roof? A normal roof would have extra space to park the scope at the center, and the calculations and tolerances would be easier. Even when you know all that, you need to figure out the scope's distance to the ground in different RA positions, which is not trivial. The simplest and most reliable way is to buy your EQ8-R Pro and largest scope first, move it around and start measuring.

Did you consider a Pier-Tech 2 or 3? The price is not unreasonable, I can imagine how nice it is to raise and lower the scope while maintaining polar alignment.

Personally I use Scilab to design stuff, for instance here. To program it you need to know trig though.

[AstroBee]

If you are looking for a turnkey project, not cheap though, check out these guys. https://backyardobservatories.com/products/

Henk, As far as keeping the roof in place on a remote rolloff roof, if you use garage door track that will keep the wheels captive inside the track and prevent lift. If you ahve a gate motor or garage door opener attached to t facilitate opening, that keeps the roof in place side to side. People have been doing it this way for quite a while.

[JayTee]

I promise, no Harry Potter comments! Help!

Hey -- I love Harry Potter!

Yes, my northern wall is 7 feet tall. My southern wall is 4 feet tall. My building dimensions are 15 feet long and 10 feet wide (10' by 10' for the observation room and 5' by 10' for the warm room. Subtract 4 inches all around to come up with inside dimensions. My cement pad is 16" long and 16" wide. The unused part of the pad is for guest telescope mount set up should there be guests who bring their own scopes.

I wanted the cement pad to be 20' by 20' but that put the construction cost way outside my budget.

I'm here to answer your questions.

[SkyHiker]

Henk, As far as keeping the roof in place on a remote rolloff roof, if you use garage door track that will keep the wheels captive inside the track and prevent liRiverside Telescope Makers Conferenceft. If you ahve a gate motor or garage door opener attached to t facilitate opening, that keeps the roof in place side to side. People have been doing it this way for quite a while.

Well we must be stupid then, I was browsing Mike and Kerry's threads, they used V tracks. Good information though, I think garage tracks are the way to go.

[AstroBee]

[AstroBee]

Well we must be stupid then, I was browsing Mike and Kerry's threads, they used V tracks. Good information though, I think garage tracks are the way to go.

V tracks are fine for a home observatory if you are going to be around to secure it or plan to operate it manually. Or if you live in an area where you do not get extreme winds.
Most remote observatories that I've seen use the garage door track for security from wind. Here in Vegas, we get some crazy winds so even though my observatory will be in the backyard, I plan to use the garage door track method too.

[Graeme1858]

I used angle iron and fixed castors. It works well although there is no wind uplift protection when the roof is open. But I won't be opening the roof if it's windy. When it's closed there are two toggle clamps to lock the roof and hold it down. (Well, there will be when I put them in! )

Graeme

[chris_g]

I'm sure if you post a sketch showing the dimensions of your floor plan and the height of your RA axis on your mount, someone will be glad to do the trigonometry and work out your wall height!

Thank you all, I've gleaned enough information to get a basic design going, I'm going to cost out several different options, starting with a 20x20 pad, 16x10x7 observation room roll back roof, w 16 ' northern and southern walls, 5x16 warm room off of southern wall observation room, building positioned as such to allow for outside observation setup on pad. Observation room pad requirements are each station on a separate inner pad for vibration dampening. Mount placement is by pier on tripod on pad poured to exceed max width of tripod at base, allowing for a more of a permanent pier installation and for flexibility of tripod height adjustment. The EQ6-R at minimum height with C8 is 6'2". The EQ8 is most likely over kill for the biggest scope I'll use. Keeping it simple, I'll probably end up going with a strain wave mount and height on that would be about the same as the EQ6. The OTA I'm looking at is either a 120mm or 150mm refractor so wall height 7 feet to help with wind mitigating, automated roof to be discussed with builder.

Determination needed for placement of two mounts, in 16x10x7 room to support 360-degree FOV 30 horizon, minimum height of OTA determined by tallest mount currently in use, 6'. Once positioning is determined, individual pads will be poured to size of maximum width of tripod which will then have final dimensions pad poured to surround the two stations.

Ok, now I'm looking for some decent design software; once I've got a good sketch out of it, I'll come back with it.

If you are looking for a turnkey project, not cheap though, check out these guys. https://backyardobservatories.com/products/

Thank you for that, while those are pricey, it does give a good budget idea of what I need done. Once I have figure what size pad works within my budget, I also found a metal building construction that lets you design custom metal buildings and gives their price for it. https://alansfactoryoutlet.com/product/ ... al-garage/

I've got designs in the head, need to find some decent software that will let me lay something out.

[SkyHiker]

FWIW, I added an estimator of the minimum Altitude for 100% clearance to my observatory simulator. Given the geometry of the observatory, the mount and the scope, it will sweep the scope over RA=-90 to 90 degrees in this example, and DEC from -180 to 180 degrees. It plots the minimum clearance Altitude in the same XY geometry as the observatory just with a different Z axis, which is now degrees not the wall height. The parameters are all easily configurable if you know Scilab and don't mind editing the parameters in a script. Probably best to take this offline for the details if you are interested. It is fresh off the press; I want to use it for my own observatory to find out the best place to put the G11. The attached figures are for the G11 but it should work for any EQ mount with the right parameters.

[chris_g]

This will be my last post in this thread unless you all have questions.

The observatory is functionally complete except for a few minor finishing touches. It's been a heck of a ride and quite a journey provided by this project. Here are some pics to show you what the final configuration looks like and how lucky and blessed I am to have such a building at my disposal.

Let's start with the floor, I covered it with closed-cell foam anti-fatigue mats, cut to size, and taped together.

Hey @JayTee

I think you can make this simple for me. Your pier, how far away is it from the Northen wall and what is its horizon, doesn't matter what OTA, just a rough will help. And in your one shot showing both mounts in use, the C11 and CEM70, how far apart are they? The CEM70 is one I am considering.

Thanks,
Chris

[chris_g]

Had a little bit of time to do some research on this while understanding one of the math disciplines that will provide the answer I need, Geometry. Now, while I didn't take trigonometry in high school, I did take Geometry. I need the hypotenuse angle for a right triangle. Knowing the length of A and B, the angle of the hypotenuse can be calculated. And that is what I am needing. Phewwy to Trig!

https://www.omnicalculator.com/math/triangle-height

7' wall, distance from wall 10' = hypotenuse Angle = 34.99. If you want a horizon at about 30 degrees, the distance from a 7 wall would be about 12 feet. Now this is measured from farthest point from the wall, so you have the added flexibility of being able to move the mount closer to the wall as you increase its height. The height of mounts in the example below is estimated at the halfway point of the ground leg of the right triangle.

35-degree horizon at 5 feet from any wall, minimum height of mount = 42"
30-degree horizon at 6 feet from any wall, height of mount = 42"

Minimum height of EQ6-R on pier tripod = 49"

20x20 pad, 20x15 building. Northern, wall 20'

obsy room 15x15, warm room 5x15, outdoor pad, 5x20
Mount #1 = 5' from eastern wall, 6' from Northern wall
Mount #2 = 5' from western wall, 6' from Northern wall
Distance separating mounts = 5'
Mount 1 and 2 = 9' from Southern wall, (Plenty of room to set up chairs in the obsy room.)

Looking at this, I see the roof sliding off to the East.

Comments, suggestions welcome, please!

Clear Skies,
Chris

[chris_g]

Quick FYI, with 8' walls, the back distance needed is 12 feet to achieve 33.7 Degree horizon, obsy room can stay the same area, the tripod points would need to move to the south 1.5' and inwards 1'. Now things are getting a little tight, putting the mounts only three feet apart instead of 5'. However, since the mount is at least 49" in height, that most likely wouldn't be necessary. Taller walls, more wind resistance. Hmmm...

[chris_g]

I wanted the cement pad to be 20' by 20' but that put the construction cost way outside my budget.

LOL! I just ran basic estimates on pad and building, budgetary constraints have kicked in since the automation part of the roof, I have no estimate yet. design paring is needed!

[JayTee]

I think you can make this simple for me.

Sorry Chris, I meant to answer this question but it got set aside and then I forgot. I'll try to get to it tonight or tomorrow.