AAVSO Observer Code CMJA / Minor Planet Centre Observatory Code H61 / Global Telescope Network Partner GTN-33 / Center for Backyard Astrophysics
Dome Weather Stripping
Problem Description
Some Home Dome users (myself included) have experienced snow blowing into their domes. This is especially true when weather conditions are such that the snow is the fine powdery stuff and the winds are high. This causes the snow to sift into the dome around the shutter lip and up, around and over the gap between the dome and dome base. While you can place a tarp over your equipment to protect it from the blown-in snow, that is not always practical because you might forget to tarp it, or you have a remote set-up that would require someone at the remote location to remove the tarp prior to use. Also, I found sweeping, and yes, shoveling, the snow out of the observatory to be a real bother. So I came up with some innovative weatherstripping that seals the gap between the dome lip and shutter, as well as between the dome and dome base.
USE AT OWN RISK. The weatherstripping described herein are not OEM parts, and may interfere and/or damage your dome and/or your dome mechanical systems.
Weatherstripping the Shutter
This was an easy solution. I noticed that some sliding patio door manufacturers attach a "fury" weatherstrip to the back side of the screen door. These weatherstrips are typically seven (7) feet or so in length, although you might find a supplier that kind provide custom lengths, and attach in a snap-on fashion. I found a supplier that carried white and brown weatherstripping. I opted for the white shown below left. You can see how it easily snaps on to a "simulated" dome lip which is approximately 5 mm thick, as shown below right. The weatherstripping has 20 mm long "fur" made from moisture-proof polypropylene, and which is of sufficient length to seal the gap yet not interfere with the moving shutter.
The figure below shows the placement of the weatherstrip. The spine of the weatherstrip snaps on to the top of the dome shutter lip which wedges the "fur" between the outside of the shutter lip and the inside of the shutter. The shutter rides on the weatherstrip spine, which is sufficiently smooth to allow the shutter to move.
IMPORTANT: Be sure to secure this weatherstripping to the dome lip or risk having a moving shutter pull it off once in place. I used stainless steel wire through the weatherstripping and through small holes drilled in the shutter lip to secure the weatherstripping several places along the length of the dome lip.
Weatherstripping the Dome/Base
The solution to this problem required a more innovative approach. It consists of two layers moisture-proof landscape fabric cut in a curved fashion that define the dome or base radii. One layer is attached the dome, and the other is attached to the base. The layers move relative to each other as the dome rotates. The figure below shows where the layers are with respect to the dome base interface around the reverse flange. I used Velcro to attach these fabric layers. In the event of a snag during dome rotation, the Velcro will "let go", without damaging anything else.
The strips are 80 mm wide. If laid out on the floor, these 80 mm wide rings would have a diameter of about 3 meters. Each ring has Velcro "loop" material sewn to their outside edge their entire length.
At the inside bottom of the dome (along the outside edge of the dome equatorial flange), Velcro hook material was attached using construction adhesive. The first fabric ring is then installed loop-to-hook around the inside bottom of the dome, and the fabric was tucked under the reverse flange.
Before installing the second fabric ring, I cut out thin, curved plywood strips that are secured to the top of the reverse flange with "clamps" made from short sections of split-open PVC tubing. Velcro "hook" material was fastened to the plywood strips using 6 mm staples.
The second fabric ring is installed loop-to-hook around the top of the reverse flange with the outside edge of the fabric touching the dome wall as shown below. Note the first fabric ring is in place and tucked under the reverse flange.
In the Winter, both fabric rings are left in place and act as an effective baffle against snow blowing in around the Dome support ring, base ring upper flange and reverse flange. In the Spring, Summer and Fall, the second ring is removed.
As an added bonus, there is much less dust and insects in the dome, especially with the dome/base baffle in place.