Despite a forecast for rain, it was dry enough to open the shutter last night after having just fitted the new wedge and bolted on the telescope. I was keen to check the new aluminium wedge's "raw" alignment, especially since I have not slotted the mounted holes yet, and am hoping not to have to file too much out....
Anyway, I centred the eyepiece on Spica (not too much else visible), and with a mag of about x270, it drifted only quite slowly, such that after 20 minutes, it was about halfway across the FoV. Then the sky clouded in.
Compared with the trial wooden wedge, I have beefed up the all-thread that connects the new aluminium one to the steel pier to 3/4". The final result is quite rigid, such that if belt it with my hand, there is only what I would call high frequency vibration, and it dampens down in less than one second. (Total pier height above-ground (concrete + steel) is a little over 3 metres.) The red steel pipe is 275 mm diameter with a 6 mm wall thickness. It is not sand-filled, as I wanted to minimise mass towards the top of the tall pier. The steel pier is fixed on top of a 457 mm dia RC pier.
looks an awesome setup, but i have a few questions, the top plate is fixed at the angled welded - how are you able to assure yourself you have polar alignement when you cant keep the base is level and not being able to adjust or correct?
David,
My objective was to make a solid wedge then mount it as accurately as I could, so that only very small adjustments would be necessary to properly align it. At local noon, I scribed a line parallel to the shadow cast by a vertical object, and have mounted the wedge according to this line, so I am hoping that the required azimuth adjustment will be just a small fraction of a degree. Having said all that though, I am a complete novice at polar alignment - not having ever done one before!
So, having four mounting bolts (and not three) and no independent altitude adjustment may complicate my task, but I figure that ultimately, I just need to get the telescope base axis pointing at the pole.... I expect that I may not be Robinson Crusoe with this endeavour, and would be happy to hear from others who have taken on the same challenge.
Using the drift method, I anticipate needing to perform iterations of alt/az adjustments (because they're not independent of each other). I also wonder whether an accurately aligned (with the telescope) laser could be put to use, but realise that there is no object to view exactly on the SCP.
