Building a Telescope Pier
Once again this is a retro-active blog post: the telescope pier build took place in July 2022.
In an effort to streamline my astrophotography setup, I decided to take on the project of building a concrete pier onto which my mount and telescope could sit, instead of using the portable tripod. The primary benefits of the pier would be:
Having a permanent pier saves me the need to carry out ~60 lbs worth of tripod and telescope mount each night,
Having the mount in a semi-permanent setup means no need to polar align each night; and I can instead jump right into imaging, and
Theoretically, the concrete pier will be more stable than the tripod, and allow for slightly longer exposure times (although I don’t think the tripod is necessarily the weak link in my setup, anyways).
The most important part of the pier’s function is that the mount (Celestron Advanced VX) can attach securely to the pier. Normally, it is made to fit perfectly to the top of its accompanying tripod, so in order to attach it to the pier, I need to make my own mounting plate.
The design starts with a lot of measuring, and then a cardboard mock-up to make sure my design seems practical. The plate design passes the cardboard test, so I get an exact model drawn up in CAD, and send the files off to SendCutSend to have them mill some aluminum for me.
Now that it will be possible to actually attach the mount to the pier, I can work on details of site selection and planning the pour while I wait for the plates to be shipped. There are three important factors that weighed into selecting the site: 1) my back yard isn’t very large, 2) a lot if it is under the canopy of a few large trees, and 3) southern Maine’s ground is fraught with ledge, and I do not want to rent a jackhammer to deal with that. A bit of digging around the parts of the yard with exposed sky reveals one particular location is free of ledge until just about the frost line, which will have to suffice.
With the site selected and the hole dug, I get to learn how to mix and pour concrete! After a lot of reading and learning, I feel ready to attempt the pour. At this point, the plates have arrived, and I’ve built the mounting bracket with feet that should it securely in the concrete (although I never took a picture of them, unfortunately). To facilitate the pour, especially since I’m working alone, I also build a wooden bracket to hold the Sonotube plum and in place.
On top of a few inches of gravel I pour enough concrete to fill about six feet of 8” Sonotube, place the mounting brackets into the top aligned to north, agitate sides of the tube to minimize air bubbles, and screed the top flat beneath the plates, which are just shimmed in place until the concrete sets. Getting these plates perfectly level isn’t strictly necessary yet, since I built a lot of room for adjustment in, but getting it very close makes everything easier.
A few days later, the concrete is set, so I remove the Sonotube and fill back in the sides with some of the excavated dirt, and the pier is ready for use!
Overall, the pier turned out to be incredibly sturdy, and made for a very fun project combining some engineering and hands-on construction, and I am quite happy with how it turned out. Unfortunately I cannot speak much to the actual function, since shortly after completing the build, weather took a turn for the cloudier the rest of the summer, and then life simply got in the way of being back home until we moved again recently. While this pier had to be taken down during the move, this project left me confident in my abilities to build another one once the time is right.