Why my polar alignment kept drifting

2026-04-09 · ~3 min read

For weeks my stars trailed after about twenty minutes of tracking, no matter how carefully I drift-aligned. I blamed the mount, the worm gear, even the firmware. The actual cause was embarrassingly physical.

1. the tripod was sinking

I set up on the back lawn. After dew settled, the tripod legs slowly pressed into the soft ground — unevenly — which quietly rotated my polar axis over the session. On a concrete patio the same gear held alignment for hours.

2. testing it properly

Drift alignment still works, but you have to give each axis enough time. I rushed the declination check and kept re-introducing error. The routine that finally worked:

1. star near meridian, equator -> adjust azimuth
2. star low in the east       -> adjust altitude
3. wait 5+ min per check, don't rush
4. re-check the first star at the end

3. what I changed

Three flat paving slabs under the tripod feet fixed the sinking. I also stopped extending the legs fully; a lower, wider stance is far more stable and I rarely need the eyepiece that high anyway.

misc.

A polar scope gets you close, but for imaging you still want a drift or software-assisted refinement.
Wind is underrated as a source of "tracking" error. A small dew shield acts like a sail.