Seletek Armadillo: My Automated Focus Upgrade!

Automating My Observatory: Achieving Perfect Focus with the Seletek Armadillo

Automatic focusing was one of the last puzzle pieces I needed to put in place to fully automate my observatory. For true, reliable autofocus, an absolute positioning system, typically driven by a stepper motor, is almost essential. While several absolute positioning solutions are out there – Robofocus is probably the most famous – I found it quite pricey, and its connectivity seemed a bit dated to me. So, I decided to go with a different, more affordable option from Lunatico: the Seletek Armadillo.

Compared to other brands in a similar price bracket, the Seletek Armadillo really stands out. It boasts the ability to drive two focus motors simultaneously, offers temperature compensation, and is designed to be expandable – pretty neat!

The control box itself is super lightweight, so I decided to mount it directly onto my filter wheel using some heavy-duty, residue-free double-sided tape. It’s a clean and secure solution!

Connecting the unit is straightforward: it hooks up to the computer with a USB 2.0 cable and requires a 12V power supply. The motors themselves connect via standard DB9 serial cables. For now, I’m only running one motor, but I’ll be adding the second one soon.

The stepper motors themselves are really well-built, and their resolution seems on par with what you’d get from Robofocus. My initial tests using MaximDL have been incredibly promising! For the first time ever, this system allowed me to break the 1.4 FWHM barrier. With my previous setup (an Orion Accufocus and Shoestring Astronomy interface), I could never get below 1.8 – so this is a significant improvement!

Unfortunately, the crummy weather we’ve had lately hasn’t allowed me to dive deeper into testing. But as soon as the skies clear up, I’ll be sure to write a full, in-depth article about my experiences with it!