202 replies to this topic

[Rustler46]

It has been 35 years since I had a slide-off roof observatory. Now I’m looking at construction of another simple, relatively inexpensive observatory to facilitate observing from home. It will still utilize the same permanent pier used in the original installation. Here are some photos of Klamath Observatory at my former Bortle 1-2 site in far Northern California in 1985.

 

 

 

My limited construction skills are evident in this design:

• Dirt floor
• Corner posts set in concrete pods
• 4-inch steel water pipe set in concrete pod for pier
• Light weight slide-off roof
• Corrugated fiberglass roof & siding

This observatory was principally used for when I was involved in photoelectric photometry of variable stars, as described in the following link.

 

https://www.cloudyni...d-present-r3269

 

My Celestron C-8 was used to capture magnitude measurements highly valued by scientists. This resulted in my being considered a co-author in around 10 papers in scientific journals. Nowadays I am no longer involved in that activity. But I do recognize the value of a permanent structure to house my telescope. I’m open to any suggestions from forum members about design features in the new observatory.

 

My plan is to make something similar to the previous version. I will be employing a skilled friend to build this one that I call Ocean Observatory. The steel pier with ~800 lbs. of concrete attached has been my garden observing site at my new home for a few years. Now it is time for it to be covered so that the telescope is ready to use at a moment’s notice. That time saving will allow for much more observing even in my light-polluted environment. The pier has AC mains power with a GFI outlet at its base.
 

While I have been involved in astrophotography in the past, nowadays I’ve transitioned to mostly visual observing. But with my C11 on the Losmandy G-11/G1 mount, lunar/planetary photography is an option. Here’s an example of that from the last time Mars was close.

 

 

So I’m investigating what it would cost (materials & labor) to get another observatory structure. I’m optimistic my wife will agree to this project. It has its benefits:

• I will less likely to injury myself during telescope setup & breakdown in the dark.
• Less of my time will be needed for each observing session.
• It will provide my friend with some income for his services.

If we decide against the observatory, likely I’ll sell the C11 or trade for a C-9.25. The 11 is just too heavy for this old man to keep hefting up onto the mount. I would appreciate any words of wisdom regarding the proposed new structure.

 

All the Best,

Russ

Edited by Rustler46, 05 January 2024 - 10:26 PM.

[palaback]

Sounds like a good idea. Only thing I am wondering if it’s a good idea to have a dirt floor. I have had mice get into my observatory making havoc with my mount. With a plywood floor you might be able to seal it better from dust and mice.

[Rustler46]

Sounds like a good idea. Only thing I am wondering if it’s a good idea to have a dirt floor. I have had mice get into my observatory making havoc with my mount. With a plywood floor you might be able to seal it better from dust and mice.

Thanks for the suggestion. I’ll discuss that with my carpenter friend. The former observatory was at a much different climate than now on the Oregon coast. I haven’t had problems with mice at either location. Perhaps spiders and hornets would be more of a problem. Excess heat isn’t the problem it was formerly. I always left the door open on hot days before. Now ventilation for moisture control is a bigger issue. 
 

As for mice, they will have much better accommodations in my woodshed than trying to scale up the steel pier. Snow isn’t a problem here. So a very gentle roof slope is OK. The roof will be pushed open by muscle power. The new design will include a support track at roof level to hold the roof suspended in the open position. Formerly I just leaned it against the S wall or laid it on the ground. In the closed position it was secured to the walls with 4 trunk latches. 
 

It will continue to be simple, inexpensive and functional. If I can pour the 6 concrete foundation pods with metal hardware to attach wooden uprights, total time to build should keep labor costs within reason. The foundation pods will be perhaps 10-inch by 24 inches - 4 for building corners & 2 for the open roof supports. The building site is level, currently covered with landscaping weed barrier cloth.

 

I believe that I won’t need a building permit for what will be a “tool shed” and kept lower than 8 feet in height. But this simple design worked quite well for me in the former situation. It seems like like construction shouldn’t take more than 3 days, likely less. Material cost will be what it is. Structural members will be treated wood. I’m hoping the entire cost will be less that $2K. And I trust my friend to do good work. I’m quite excited about the prospect of a proper structure for Ocean Observatory.

 

Clear Skies,

Russ

Edited by Rustler46, 06 January 2024 - 01:45 AM.

[JimTheEngineer]

It’s great to have friends to help! I don’t think you would get a contractor to do the works for any less than $10,000. The actual structure is just one thing of many requirements (ie: power, data, etc, etc).

[gordtulloch]

Sounds like a good idea. Only thing I am wondering if it’s a good idea to have a dirt floor. I have had mice get into my observatory making havoc with my mount. With a plywood floor you might be able to seal it better from dust and mice.

I agree I put both my 10x10 and now 5x5 micro-observatory (see thread below) on 2x6 joists elevated over the ground to allow airflow under the building and keep critters as much at bay as possible - the hole for the pier is stuffed with stainless steel wool, which discourages incursions.

 

Edited by gordtulloch, 11 January 2024 - 05:27 PM.

[Rustler46]

The replies to this thread are much appreciated and will help as I develop plans for the new observatory. Progress is being made in several areas:

• My wife is on board in helping make the decision to build the observatory, taking into consideration the impacts (positive and negative) it would have on our situation. 
• As with the original observatory, the new one will have pressure-treated wood in areas that will be subject to liquid water.
• Even if initially the floor is native soil, the option to add wood flooring will be incorporated in the design.
  Native soil will continue to be covered with synthetic landscaping cloth.
  • Joists for such flooring can to be treated 2X4s, since these will be laying on soil for support. Provision for ventilation under flooring will be necessary. If plywood is used for the floor, it would of necessity be marine grade. It might be cheaper to use plastic material (i.e. outdoor decking). 
• I believe that a building permit for my "garden tool shed" observatory will be unnecessary, if kept under a certain overall height. I'll verify the requirements for that with the city planning department.
• Absolute water tightness against blowing rain will not be needed, since the optical tube and mount will be covered with a waterproof Telegizmo 365 cover when in storage under the closed roof. As a result the roof pitch will not need to be much to shed water under most circumstances. This worked fine with the old observatory shown in the OP. Infrequent snow accumulation can easily be removed using a push broom or other tool operated from ground level.
• Longevity of this structure will not be of great importance for me, since I'm approaching 80 years of age. So if it lasts 20 years while keeping costs down, I'll be satisfied. With that in mind some best construction practices could be compromised. For this I will rely on my carpenter friend to make sound decisions.

So that's where I'm at with planning the observatory. Next I'll be sketching some plans and getting a materials list. This will allow getting cost estimate for the completed project. A lot of the labor can be done by myself, as personal time and energy levels permit:

• A post hole auger will be used to excavate for concrete footings. These can be poured one at a time.
• Once the building frame and roof is completed by my friend, I can finish up with applying the siding material.

Here's what will be housed in the new observatory - Celestron-11 and AT115EDT APO refractor.

 

Here is a view of the entire pier and surroundings.

 

I know that others are using piers that are much larger in diameter. But after nearly 40 years of use, I've never been less than fully satisfied with the 4-inch diameter water pipe as a pier. It is very rigid , and is not subject to vibrations under observing conditions. It helps being set in a large amount of concrete in the ground. The interior of the pipe is filled with vibration damping gravel.

 

Note:

There is a weatherproof 120VAC GFI-protected mains outlet on the back side of the pier.

 

Comments and suggestions are appreciated.

 

Best Regards,

Russ

 

Edited by Rustler46, 20 January 2024 - 10:56 PM.

[Rustler46]

Another thought - when I started as an amateur astronomer over 60 years ago, I was just 16. A kindly older man in our local astronomy club took me under his wing as a father figure. My own had died when I was just 12 years old. But Bill taught me how to make my own telescope from scratch. And he had the ugliest 8-inch reflector I have ever seen, even to this day. Yet his telescope performed quite well. But his words of wisdom have stuck with me:

• "A telescope is made to look through, not to look at!"

Now for sure others will not be swayed by such a utilitarian viewpoint, particularly on a cloudy night. In such a case how the telescopes looks is way more important than what can be seen looking through it. In any case my utilitarian pier and rudimentary building skills have served the purpose well all these years. No doubt my finished observatory will leave some others feeling they would not permit such a contrivance to be attributed to themselves. Any embarrassment in that regard felt by myself will not be visible to others when it's dark. That is as long as it serves my purposes.

 

Anyway, I would appreciate any helpful hints as to how to make the new observatory a success, even if the result isn't unduly ugly.

 

All the Best,

Russ

Edited by Rustler46, 20 January 2024 - 11:34 PM.

[mmalik]

Thinking of Another Simple Observatory

 

Simpler observatory would be NO observatory; just a TG365 would do. Read here.... If needed, build a warming/cooling shed nearby. Regards

 

 

.

Edited by mmalik, 21 January 2024 - 08:12 AM.

[Rustler46]

Simpler observatory would be NO observatory; just a TG365 would do. Read here.... If needed, build a warming/cooling shed nearby. Regards

 

 

.

Thanks for your comment and suggestion. For some that might be the solution. For myself the mount already resides under a TG365. But I don't feel comfortable leaving the telescope and Gemini electronics outside under the cover between times of use. For that it takes 20 minutes to set up before observing and another 20 minutes when I'm done. Also if I was to build a warming/cooling shed nearby, it makes more sense to just enclose the already set up telescope inside an observatory. Then it would be around a minute to slide the roof off and be ready for observing. That's what is best for my circumstances.

 

Best Regards,

Russ

[mmalik]

Also if I was to build a warming/cooling shed nearby, it makes more sense to just enclose the already set up telescope inside an observatory. Then it would be around a minute to slide the roof off and be ready for observing. That's what is best for my circumstances.

 

Common misconception is that equipment will be exposed to lesser elements in an observatory than TG365. My experience has been quite the contrary and I provide the actual environmental specs.... I DO get the point observatory would be more secure from theft or physical damage perspective than a TG365. Since your question was 'minimal', that's where TG365 comes in.

 

 

Warming/cooling shed is just for the proximity and convenience. Build minimal observatory by all means if you need to but of course it will not be comfortable to be out there throughout the night, hence the cooling/warming shed recommendation. It is just whole another experience. Regards

 

 

.

[Rustler46]

Common misconception is that equipment will be exposed to lesser elements in an observatory than TG365. My experience has been quite the contrary and I provide the actual environmental specs.... I DO get the point observatory would be more secure from theft or physical damage perspective than a TG365. Since your question was 'minimal', that's where TG365 comes in.

 

 

Warming/cooling shed is just for the proximity and convenience. Build minimal observatory by all means if you need to but of course it will not be comfortable to be out there throughout the night, hence the cooling/warming shed recommendation. It is just whole another experience. Regards

I may have misunderstood what a warming or cooling shed would be used for. If it is for the telescope itself, mine are mostly stored nearby in a garage, which has minimal temperature variation. The largest temperature variation is around a 10 degree F increase over ambient on a warm day. On cold nights the garage is almost always above freezing.

 

My mild maritime environment is not subject to large temperature extremes. In the summer it rarely gets above 75 degrees F, though that could change if global warming continues to be a factor. Nighttime lows are usually less than 10-15 degrees below ambient sunset temperature. As a result observing conditions are not uncomfortable. On the rare occasions when it is below freezing, I just employ periodic blasts of an electric hair-dryer down the inside of my clothing  to take the chill off. Usually just dressing for expected temperature is enough for multi-hour observing sessions. Under the conditions described, a warming/cooling shed for observer body or telescope is unnecessary.

 

The main reason for the observatory (simple or not) is to reduce set-up and take-down time. This will increase the number of nights I feel like observing, even if only for a short clearing of the coastal clouds. My Losmandy G-11 mount has resided outside under the TG365 for years without much fear of theft. If someone went to the trouble to take off the cover, most would not know what was there or be willing to go to the trouble of disconnecting it from the pier. Of course anything could happen. In any case the observatory would make theft less likely.

 

Best Regards,

Russ

[mmalik]

I may have misunderstood what a warming or cooling shed would be used for.

 

Warming/cooling shed would be for your own self, your living quarters..., NOT for the mount/telescope. Regards

 

 

.

Edited by mmalik, 23 January 2024 - 05:00 AM.

[Rustler46]

One of the problems encountered with the original observatory was that the corrugated fiberglass roof and wall panels were heating up in direct sun. The first photo in the OP shows how sunlight penetrated the translucent panels, heating up the interior.

 

I attempted to alleviate that effect by applying an aluminum reflective fabric to the interior wall. The material was what had been used as a "fire shelter" for wildland fire fighters. In essence this was a quick tent of heat resistant material that would provide protection for the fire-fighter if overrun by a wild fire. When these fire tents had been used during practice deployments, they developed small pinhole defects that rendered them unsafe for use under wildfire conditions. Since I was working for the US Forest Service at the time, I was able to obtain a supply of these rejects for use in my observatory.

 

Now some 40 years later my new observatory will be dealing with the same problem. So I'm looking for roof and siding material that might be less prone to overheating. This material has caught my eye:

• Suntop Corrugated Foam Polycarbonate Roof Panel

It would likely still heat up. But with 100% sunlight blocking it might do the job, particularly if available in a light color. Provision for ventilation will be a plus as well. That would also help with moisture buildup in my moist climate. 

 

Comments?

 

Russ

Edited by Rustler46, 23 January 2024 - 04:18 PM.

[KI5CAW]

I have a simple roll off cover for my open tube 12 inch. It's made with a  2X2 frame and standard metal roofing. It protects the scope in all kinds of weather.

I'm not so sure it would be enough out there. I have lived on the coast and near Cave Junction, and when it rains out there, it really rains, sometimes for days at a time. In New Mexico, 70 mph wind gusts are the more common problem.

The 12 inch is the exception to my Oregon rule, which is to use a solid tube of weatherproof materials. Aluminum is the best, but outdoor plywood coated with several coats of oil based enamel works well too.

The whole point is to minimize setup time. Near the coast, you might get a one hour window between cloudy storm systems, and you want to be ready. And it commonly happens that it's clear all during the observing session, but rains hard after you've gone to bed.

[Rustler46]

It has been 35 years since I had a slide-off roof observatory. Now I’m looking at construction of another simple, relatively inexpensive observatory to facilitate observing from home. It will still utilize the same permanent pier used in the original installation. Here are some photos of Klamath Observatory at my former Bortle 1-2 site in far Northern California in 1985.

 

B6E55EE2-7475-442D-A9E6-8ADC663B41C9.jpeg

 

08BB5A7B-8B11-44C1-8542-C3FC54D27230.jpeg

 

My limited construction skills are evident in this design:

• Dirt floor
• Corner posts set in concrete pods
• 4-inch steel water pipe set in concrete pod for pier
• Light weight slide-off roof
• Corrugated fiberglass roof & siding

The slide off roof on the original observatory was secured in the closed position with trunk latches similar to this:

 

[Rustler46]

It has been 35 years since I had a slide-off roof observatory. Now I’m looking at construction of another simple, relatively inexpensive observatory to facilitate observing from home. It will still utilize the same permanent pier used in the original installation. Here are some photos of Klamath Observatory at my former Bortle 1-2 site in far Northern California in 1985.

 

B6E55EE2-7475-442D-A9E6-8ADC663B41C9.jpeg

 

08BB5A7B-8B11-44C1-8542-C3FC54D27230.jpeg

 

My limited construction skills are evident in this design:

• Dirt floor
• Corner posts set in concrete pods
• 4-inch steel water pipe set in concrete pod for pier
• Light weight slide-off roof
• Corrugated fiberglass roof & siding

Looking at the photos in the OP, and having a better understanding of proper construction practices, I can see right away some changes that need to be made to ensure a longer life for my "simple observatory. These will no doubt add a bit to the cost, but should be worth it in the short and long term. 

1. Unsupported 2X4s spanning 8 feet between supports will eventually sag. 
2. The lightweight roof structural elements (2X2 rafters) spanning 8 feet will need some help to avoid sagging as well.
3. Other problems? Comments?

What to do about these problems? For each of the above potential problem areas, here's what I'll do:

1. To reduce sagging, mid way in each span I'll run a vertical 2X4 between top and bottom 2X4s. From the midpoint of each span I'll run a set of diagonal braces to stiffen up the entire span via triangular structures. Sure there will still be potential for sagging in each of the resulting 4 foot spans. But the effect will be much less detrimental.
2. To maintain overall light weight of the moveable roof, I'll continue to use 2X2s. To allow for added stiffness against sagging I can add a 1-2 inch stand-off block mid span under each rafter. Then I will run a light duty metal cable from each end of the span (under the standoff) that can be tightened via turnbuckle to lift the center of the rafter up. Of course I'll need to provide clearance for this apparatus to clear the end wall frame when sliding the roof open.

I've decided to do all the labor myself for the following reasons. 

• As far as the structure goes, this isn't a particularly complex endeavor. I'll just follow directions for the roofing material and advice from my carpenter friends.
• I can do the work in stages, buying just the materials needed for that stage, which will spread out material cost over a longer period of time. This also fits in well with my limited stamina as I near 80 years of age. After about two hours of work, I'm ready for an afternoon nap. 
• I can still ask my carpenter friends for advice as I develop the design. As additional potential problems become apparent, I can modify design as needed. This is compared to having the whole design and materials in place for hired labor to proceed without undue delay or added labor cost.

Base on the suggestion of Vladimir (forum member vsteblina), I'll be using Palram Suntop polycarbonate foam roofing material. Thanks, Vladimir! This material is not inexpensive, but has important characteristics for my observatory.

• 100% blocking of solar light
• UV resistant (10 years)
• Light weight
• Some insulating properties

That's where I'm at in planning for my new observatory. As always comments and suggestions are appreciated.

 

Best Regards,

Russ

Edited by Rustler46, 25 January 2024 - 04:35 AM.

[Rustler46]

There was a brief discussion in the Binoculars Forum about an observing shelter to block wind and local light pollution. It is best continued on this forum. Here is one solution for a shelter. First the frame:

 

Frame of small diameter EMT metal conduit at what I call Ocean Observatory. Also shown is the 4-inch water pipe pier used to carry optics from an AT115EDT refractor to a Celestron-11. A Celestron equatorial wedge for C-8 fork mount is shown. Attached to the north of the pier is a waterproof 120 volts AC GFI-protected outlet. Also seen is a small aluminum shelf constructed from the remnants of a log truck bumper.

 

Clear Skies,

Russ

Edited by Rustler46, 26 January 2024 - 05:53 PM.

[Rustler46]

Here is the fully assembled shelter using synthetic light-blocking fabric and Velcro attachments.

 

 

Perhaps something like this would be of use for telescope or binocular users.

 

Clear Skies

[Rustler46]

I've been working on the plans for a "new & improved" Ocean Observatory. Here's what I've come up with to give some focus on how to proceed. The main shelter will be 8 feet square with the roof having a 1-1/2 inch rise per foot as recommended by the manufacturer of the roofing (Palram Suntop). The corner posts and track support posts will be treated 4 X 4s. Most of the rest of the structure will be treated 2 X 4s. The posts will be supported by 12 inch diameter, 18 inch deep concrete pods. Initially the floor will be native soil with provision to add a wooden floor later. To deal with moisture buildup, there will be plenty of ventilation via gaps under the siding and the top of the siding. Perhaps a fan may be needed to make this effective. The door opening will be 2-1/2 X 7 feet.

 

 

The roof will continue to as light as possible, while being as strong as can be. The 2 X 2 inch rafters will be reinforced with a tensioned steel cable. Trunk latch hardware will secure the roof to its track in both open and closed position. I still need to verify that 7-1/2 feet will be enough height to clear my Celestron-11 when parked in its home position. This will be with counterweight shaft horizontal and telescope pointing south.

 

For reference here's another photo of the original Klamath Observatory.

 

 

Checking cost of materials obtained locally, it seems like $1500 would cover that. Labor might add another $500-1000. So 2K seems like a reasonable figure for a simple, functional observatory.

 

Any comments or suggestions?

 

Best Regards,

Russ

 

Edited by Rustler46, 27 January 2024 - 03:43 PM.

[Rustler46]

Anyone thinking of building a small simple observatory would greatly benefit from watching the following video.

• ​Your First Observatory: Keep It Simple! from AAVSO, featuring Richard Berry

Richard is a well known, experience amateur astronomer, who has found what works best, though experience in building multiple small observatories. The video consists of an hour photo lecture followed by another hour of questions and answers. My notes from that were replete with useful tips and design hints, that I will be incorporating in my own structure. Some highlights:

1. A small observatory makes extended observing sessions possible and fun.
2. Keep it simple in keeping what could be considered a "temporary structure"
3. Don't use a concrete slab for a floor. It heats up and will release that heat over the evening, causing problems with local seeing
4. He recommends a wood floor at least 12 inches off the ground. The floor stays dry, cool with airflow underneath. Also varmints are less likely to take up residence.
5. Provide for lots of air flow to prevent problems with condensation of moisture
6. Peaked roofs are prone to leakage the peak. Recommends a sloped roof.
7. Roof panels should not be dark, opaque. SunTuf, white will allow light to enter, deterring insect nests. Ninety percent of incident light will not penetrate, much is reflected or absorbed leaving about 5% reaching the inside. The light roofing makes the inside well illuminated during the daytime.
8. Walls should be thin and lightweight, so they will cool rapidly.
9. Richard had recommendations for metal track and rollers for the slide-off roof. Aleko is the manufacturer for these.
10. Use lots of roof overhang to prevent excessive rain on the walls
11. "Nothing is forever - repair, adapt and change!" See what works in your environment. Make changes as necessary.
12. Again, build light with lots of air flow.
13. With proper ventilation, inside temperatures will get 5-10 degrees above ambient daytime temps.
14. Temperature is less important than ventilation.

Undoubtedly many will find in that video much useful information for building a simple observatory that works in the local environment. That's one point that Richard emphasized is that there are different environments to consider. What works in one situation may not be the best in others.

 

Clear Skies,

Russ

Edited by Rustler46, 31 January 2024 - 03:49 PM.

[Rustler46]

Anyone thinking of building a small simple observatory would greatly benefit from watching the following video.

• ​Your First Observatory: Keep It Simple! from AAVSO, featuring Richard Berry

Richard is a well known, experience amateur astronomer, who has found what works best, though experience in building multiple small observatories. The video consists of an hour photo lecture followed by another hour of questions and answers. My notes from that were replete with useful tips and design hints, that I will be incorporating in my own structure. Some highlights:

1. A small observatory makes extended observing sessions possible and fun.
2. Keep it simple in keeping what could be considered a "temporary structure"
3. Don't use a concrete slab for a floor. It heats up and will release that heat over the evening, causing problems with local seeing
4. He recommends a wood floor at least 12 inches off the ground. The floor stays dry, cool with airflow underneath. Also varmints are less likely to take up residence.
5. Provide for lots of air flow to prevent problems with condensation of moisture
6. Peaked roofs are prone to leakage the peak. Recommends a sloped roof.
7. Roof panels should not be dark, opaque. SunTuf, white will allow light to enter, deterring insect nests. Ninety percent of incident light will not penetrate, much is reflected or absorbed leaving about 5% reaching the inside. The light roofing makes the inside well illuminated during the daytime.
8. Walls should be thin and lightweight, so they will cool rapidly.
9. Richard had recommendations for metal track and rollers for the slide-off roof. Aleko is the manufacturer for these.
10. Use lots of roof overhang to prevent excessive rain on the walls
11. "Nothing is forever - repair, adapt and change!" See what works in your environment. Make changes as necessary.
12. Again, build light with lots of air flow.
13. With proper ventilation, inside temperatures will get 5-10 degrees above ambient daytime temps.
14. Temperature is less important than ventilation.

Undoubtedly many will find in that video much useful information for building a simple observatory that works in the local environment. That's one point that Richard emphasized is that there are different environments to consider. What works in one situation may not be the best in others.

Based on the advice given in the video, here are some design modifications I'll be incorporating in my observatory. Regarding the numbered points above:

• Items 3 & 4 - Initially my floor will be native soil covered with synthetic landscaping cloth. That is what presently surrounds the metal pier. There will be provision in the design for adding a wood floor if needed.
  
  Why not a wooden floor? My earlier observatory worked fine with native floor. The environment was similar to my present one, except previously it got much hotter in the summer. Over the past 30+ years rainfall in my PNW environment has varied from 25 inches to over 100 inches per year. Where I live now we have two seasons - cool-wet and warmer-dryer. It seldom strays outside of 32-75 degrees F in my Oregon coast location.
  
  I may add an impermeable moisture barrier under the cloth or wooden floor to reduce the amount of water entering the structure from below. If wooden floor is used, I'll lay 2X4 treated joists on the ground over the vapor barrier. The soil will support these joists. Varmints will be kept out with metal screens at the ends. This will allow for some air flow.
• Items 5 & 8 - roof will be white SunTuf polycarbonate corrugated sheets. Walls will be colored Suntop polycarbonate, which is similar to the recommended SunTuf product, but a bit less expensive. Walls will not extend all the way to ground level, with 4-6 inches exposed for ventilation. This will be covered with metal screen for ventilation and varmint exclusion. I may add additional ventilation openings on the walls, perhaps with thermostat controlled fan. While the roof will be white polycarbonate, the walls will likely be an opaque color that will look more pleasing in our vegetable garden setting.
• Item 9 - The lightweight, sloping roof will slide off, wood on waxed wood, rather than metal track and roller. Why? That is what worked well in my former observatory. It is in keeping with light, simple and inexpensive. The roof will be secured to the underlying structure using trunk-latch hardware in both open and closed positions.

So that's where I'm at now in the design process. Lots of time on cloudy days and nights for do the planning. Since October 1st, we've had almost 50 inches of precipitation, with more on the way. 

 

Edit:

One positive is that my wife is supportive of my new observatory. It will likely cost up to $2000 from our savings. But she sees its positives, particularly regarding her elderly astronomer husband. Some days when I'm feeling especially tired from the day's activities I ask myself "do I really want to take on this extra project?" At other times I remind myself that this can be accomplished in stages, many of which I can do myself as energy levels allow. The concrete footings for the structure (numbering 7 in all) can be done easily with my post-hole auger, a couple of sacks of Quickcrete and a couple of hours labor. Each of these footings will be around 8-inch diameter and 18-inches deep. Leftover concrete can be used to make some stepping stones for our flower garden. The soil at the observatory site is easy to drill into, being loam, clay and sand with very few stones. The auger will make quick holes. And I have places where the excavated soil can be put to good use. Some people use Sonotube for forming their footings. I'll just pour concrete into the native soil hole. This will make a good connection with the undisturbed surrounding soil. This keeps cost down and no concern about the Sonotube disintegrating over the years.

 

If my carpenter friend is willing, it would be best that he is involved in building the structure's main framework. This would seem to be a one day project, costing around $300. The rest of the work I can easily do in stages by myself. I'll have my friend take a look at the plans beforehand.

 

I'm getting excited about having a real observatory again! The prospect of having my old C-11 back in action would be a thrill. Getting its 30+ lb. weight up on the G-11 mount is getting harder for this old man. Thus it hasn't been used for a couple of years. Last time it had the AT115EDT riding piggyback. That provided a nice comparison of the views with each optic.

 

All the Best,

Russ

 

Ocean Observatory with Celestron-11 and AT115EDT Refractor

Edited by Rustler46, 31 January 2024 - 10:59 PM.

[Rustler46]

My carpenter friend now has my tentative plans and immediately had a good suggestion. For the slide-off roof he suggested replacing the 2X2 wooden rafters with galvanized metal studs. These would be lighter, stronger and likely less expensive than wooden members. The wood is subject to sagging over time, while the metal would not. Here's one possibility for metal roof rafters from Lowes:

 

 

For sure this product will present some challenges in attaching the wooden purlins that the roofing will be attached to. But I can envision how to put it all together. It should be lighter and still strong enough for a slide-off roof.

 

Also for the concrete footings, I've determine that 8-inch diameter by 15 inches deep would be the quantity supplied by one 60 lb. bag of quick concrete mix - 0.45 cubic foot. 

 

So the project is progressing. I keep y'all posted.

 

Russ

 

 

[Rustler46]

Well, I had a further change in plans, and an improvement as best as I can tell. At a local hardware store I looked for galvanized steel studs, and none were available. But I did notice 2-1/4 X 1-1/2 inch X 10 foot galvanized rain downspout. This product looks even better than the galvanized stud material for roof rafters. Here the reasons the reasons:

• Heavier gauge steel with more robust galvanizing would be more resistant to degradation in a moist environment.
• The rectangular cross section cylinder versus open on one side C-channel is much more resistant to deformation under load.
• Thicker metal will provide better purchase for the screws holding the wood purlins.

For the roof structure I've come up with a plan for diagonal bracing, which will preserve the square shape of the roofing support structure. When using wood, the braces resist deformation both in tension and compression. I plan to use very small diameter, multi-strand steel cable, which would resist deformation of the structure in tension only. This steel cable would go from corner to corner. Each of the two cables would have a small adjustable turnbuckle that would adjust tension. The structure composed of metal pipe rafters and wooden purlins would resist the cables pulling in tension. The two bracing cable's tension is balanced to produce a square frame.

 

Construction tip:

• Having worked in the logging industry, I learned a simple, inexpensive method to fashion loops at the end of a stranded steel cable. Usually one just buys some hardware that secures the loop at the cable end. But the less expensive method involves just unwinding some of the twisted wire bundles into two smaller groups of strands. These are then be separately looped over each other in opposite directions forming a loop. And here is what is real neat. These separate groups of cable strands just fit back into each other forming a nice loop without any extra hardware. It is hard to describe in words. But when I get to that stage, I'll post some photos on how it is done.
• This method works, but is not allowed in the logging industry for safety reasons. The problem is that the finished loop ends up with two "tails" of wire cable poking out of the sides just below the finished loop. So this method isn't allowed in industrial situations. But these tails can be captured by wrapping some solid steel wire around to make the tails lay flat against the finished loop.

Using this method I'll make two cables which will form the diagonal tension bracing for the roof structure. Each diagonal will require a small turnbuckle and some attachment loops at each corner of the frame structure. Thing are coming along!

 

Russ

Edited by Rustler46, 07 February 2024 - 12:50 AM.

[Rustler46]

Also another sign of progress is that I went to the local city planning department to see if my new "tool shed" would be permitted under current planning laws. I was a bit surprised when they said it would need a permit for "accessory structure". Some years ago when I built a small greenhouse, no permit was required, if it was dirt floor and under a certain height. 

 

This time I was told that the rules are being enforced differently. After describing my project and looking at my property on the city records, there was some question if my new structure would violate the 65% maximum coverage of structures on my property. But after some discussions between the clerk and the city planning staff, it was decided that an 8X8 foot dirt floor structure could be permitted if I submitted an "Accessory Structure Use Review" along with $60 application fee. I was so pleased with that, and so grateful the clerk took the time doing the research and discussing the matter with the city planner. So I'll get the paperwork filled out tomorrow and get it submitted. The clerk said it usually took about a week for the process. Then I can proceed, knowing that it will comply with current land use rules. My garden observatory will indeed be used to store tools of various kinds - some for the garden and others for astronomy.

 

Russ

Edited by Rustler46, 07 February 2024 - 01:12 AM.

[peculiar_polar_ring]

Not too derail this thread, but how did you get involved in the magnitude measurement science?