Building an 8" pier for smaller telescopes
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Frequently Asked Questions
How durable is the cover?
Why don't you make a fiberglass cover?
The cover is remarkably strong for such a light structure. The fact that we use aluminum foil faced foam board and pure aluminum tape brings into play the advantages of a metal finish. Aluminum isn't affected by UV radiation like other materials, particularly plastics.
Unpainted, the cover is more susceptible to dings or punctures, but can easily be repaired using a strip of the aluminum foil tape. The polyisocyanurate foam board wasn't intended to be left exposed forever but we left ours outdoors for 4 years and it kept our scope safe and dry.
Painting the foam board will add a durable finish. If paint alone is intended, the cover should be cleaned and primed with an aluminum primer and then painted with an exterior enamel paint like Rustoleum.
If you are unsure of the harshness of your environment, leave the scope outdoors while the weather is good and bring it indoors while the weather is bad until you have confidence in your installation.
The nice thing about the Motel o'Scope cover is that you can always rebuild it or build a new one if you're unhappy with the results or just want to change to a different finish.
The Dacron covering process adds a whole new level to the durability. Aircraft covering systems are very well understood as aircraft have to endure very harsh environments while lasting for many years.
It would make the cover much heavier and more expensive.
Motel o'Scope Questions
Can you describe the installation of the Dacron covering?
Dacron is a trade name for polyester fabric. There are several well know processes for covering aircraft (or telescope enclosures) with this fabric including Ceconite, Stits Poly-Fiber and others. They are all good methods but dated in regards to environmental impact. Many are based on the use of nitrate and butyrate dopes which are very flammable. We chose to use the Stewart Systems method which uses a water soluble latex base.
Panels of dacron fabric are cut to size to cover one panel of the enclosure cover and glued around the edges using a latex-based contact cement. Once a panel is in place, it can be heat shrunk using a household iron (at least an old one!). The temperature of the iron has to be established with a meat thermometer at about 250f.
Once all of the sides of the enclosure have been covered and heat shrunk, 3" reinforcing tape is glued along every seam or edge and later smoothed with the iron.
The fabric is sealed, primed and protected against UV with 8 coats (1 quart) of Stewart Systems EkoFill. The first two coats are brushed on with a foam brush at 90 degrees to each other (called a cross-coat). The remaining 6 coats can be rolled on using a foam roller and brushed using cross-coats as well. See our Links page for suppliers.
Finally, the cover can be painted with an exterior latex enamel house paint, applied by spray or a roller.
To make the process a little easier, Dan's Pier Top Plates will offer a pre-sewn Dacron envelope kit with reinforcing tape that can be slid over the entire finished cover. The envelope wraps around the bottom and is glued and then shrunk all at once.
Can I use other materials to build the cover?
Yes. Motel o'Scope is a diy project and you can try whatever you'd like! However, don't use Duct tape or any other kind of plastic tape. It doesn't resist UV and it's too flexible. Don't use styrofoam since it isn't very rigid. If you can't get foil-faced rigid foam board, you might consider a dense rigid commercial foam board and glue aluminum foil to it using contact cement.
Changes to Motel o'Scope
In 2015 we made changes to how we sell Motel o'Scope.
We made a change wherein we only sell the custom plate kit and the Dacron cover. The custom plate kit is made up of 16 joining plates that make up the core of the Motel o'Scope base. The rest of the parts for the enclosure are mostly off-the-shelf items from US sources such as McMaster Carr, Essentra Components etc. We have decided to make the kit instructions and parts list available and let customers source the parts themselves. There is an updated parts list with sources as well as the installation manual available to download on the Motel o'Scope product page.
We love the enclosure but we haven't really made any margin on it because we only get discounts on a few items or the parts we make ourselves. It will be more work for our customers but they won't have to pay any markup.
How does the telescope stand up to high heat and humidity within Motel o'Scope?
It stands up just like it would in any observatory except that in the Motel o'Scope we're not letting the air change. Once the cover is latched down there is very little air infiltration if properly built. In a typical small observatory there is much more air infiltration and that is what adds humidity from dew and condensation. Humid air is much harder on the telescope than dry air.
We recommend that a Motel o'Scope owner keep some desiccant inside the enclosure. We keep a couple of 1oz packets of silica gel beads in ours at all times and recharge them in the microwave a couple of times a year. We do live in a very dry climate however and one could certainly add more depending on the environment. A 1lb bag of silica gel desiccant can be purchased for $10-15.
We've also measured the temperature of our installation using a remote sensor for several years and have been very impressed with the ability of the foil faced foam board and the dacron cover (if painted mostly white) to keep the temperature down within reason. On a 100f day we would never see a temperature above 110f inside the enclosure. That kind of a temperature doesn't do any damage to a telescope at all. Any type of rubber, plastic, fiberglass etc. would need temps well above 150f to soften them.
We did some testing early on using fans and a thermostat to move air through the enclosure when it became very hot but we found out that we couldn't control the moisture inside the enclosure at all. Our equipment does much better using our current method of completely sealing the enclosure when the cover is on.