Installation and Operational Notes
I love to shoot mosaics—and there are a lot of mosaic opportunities in the southern hemisphere. But mosaics require an extreme amount of exposure time—usually hundreds of hours. So I had the idea to build a dual wide-field rig. I actually wanted to use two Takahashi FSQ106s like the one I have at Deep Sky West outside Santa Fe. But Takahashi discontinued that telescope so it became extremely hard to get. I wanted to place this at Obstech’s Observatorio El Sauce in the Atacama desert in Chile (one of the premier astronomical observing locations in the world).
After evaluating offerings from Askar, Astro-Physics, Teleskop Service, and others, I settled on the William Optics UltraCat 108. Though not really considered an observatory-class telescope, I’ve used William Optics scopes at home and on the road for years and have been very happy with them. Although it has a longer focal length at 518mm than the Takahashi FSQ106, which means a narrower field of view, it makes up for it by supporting a medium-format sensor. That essentially gives it an almost identical field of view, and with the longer focal length, it should (in theory) produce more detail.
Beyond choosing the telescope and the camera, I expressed preferences for other gear, but I wasn’t sure how that stuff might work in this situation. I also had no idea how to mount two telescopes on one rig and get them to work together. The folks at SeaWest worked through all that. They came up with solutions at every step—including fabricating a custom dovetail system that would allow both scopes to ride on a Planewave L-350 mount and be able to target the same spot in the sky with pinpoint accuracy.
SeaWest field tested the rig in California and then shipped it down to Obstech’s Observatorio El Sauce.
Like the TOA130, Sea West completed installation and commissioning on July 13, 2026 and handed it off to me.
I got about six hours of data that night and then the storm of the century blew into the west coast of South America, washed out the roads to the observatory, and took down power, water, and internet access. The observatory didn’t come back online until September 4, 2026.
I got about a month of good use out of it and then on October 5, 2026, Obstech decided to switch the locations of this telescope with the larger TOA130 that was nearby in the same building. This had to do with their provisioning needs. Both used Planewave L-350 mounts, so it was not a huge change for this telescope—except that would put it on a mount that was malfunctioning. Planewave is sending the parts to fix that mount, so I hope to have it back up and running soon.