Obsevatory and polar alignment

[dan_adi]

Hey guys, in the last few days I noticed my polar alignment keeps changing. I’ve build a small observatry ontop of my house. The pier is made of brick and cement. Do you have any iddeas as to why I am losing my polar alignment in 2-3 days. A couple of days ago I had an error reported by phd asistant below 1 arc minute and last night 5 arc minutes. Could it be the pier? Everything is bolted down, I have double and triple checked. It’s getting frustrating

[michael8554]

5arcmin error is such a tiny measurement that it is well within the possible accuracy range  of the measuring software IMO. 

So don't expect to see the same reading every time. 

5arcmins is as close as you need to get, don't agonise over not having perfect PA, most software will easily guide that. 

Also on top of a house you will get some movement unless your pier is like a freeway overpass support. 

Michael 

[Dr_Ju_ju]

How well is your house built ??  e.g. can you feel any vibrations from passing traffic etc. ??  if so then I'd expect things to move....

[dan_adi]

The house is built ok, no vibrations with traffic. Also it’s in a rural zone, no heavy trafic. So I don’t have to panic over a couple of arc minutes variation in aligment. Thanks for clearing things up