[DIYman (Doug)]

In my case I am trying to align an equatorial platform and I have really racked my brains on this one and cannot identify a solution. Alignment in the azimuth is no problem as it is a matter of drift alignment near the meridian and celestial equator – but getting the right angle in respect to the CP (altitude) is another ball game without the benefit of an EAST or WEST horizon. In my case trees block up to 60 degrees in both directions. (It’s not like a GEM where just pointing the scope at the CP with the tube positioned directly above the RA axis and then adjusting the height of the axis until the CP is in the middle of the field.)

I have wasted too much viewing time trying to resolve this issue. Tried using spirit levels to level the platform for my latitude but none are sufficiently accurate. My goal is to get at least half a minute accuracy to make it less work for the auto guider when imaging.

Would this solution work?

Place the reticule of a guiding eyepiece on a star (near the celestial equator) which is say 30 minutes from transit Let the scope track for 30 minutes and at the time of transit note the position of the star in the eyepiece. Let the scope track for another 30 minutes and then again note the position of the star. My reasoning is that if the altitude of the platform is too high in relation to the SCP, then the star will appear to move north at transit but then move back to the starting position (centre of the field) after 30 minutes. The opposite will occur if the altitude is too low in respect to the SCP. (One would have to be careful that any drift is not caused by poor azimuth alignment which needs to be very close for the proposed solution to work.)

Sorry for the length of this post but it has been good therapy for me.

Regards
Doug