drift polar alignment goto

[Gfischer]

robin,
I have been using goto tool to manually move my dob on an eq platform to both the points used for drift polar alignment. Dec is always 00 00 00 and Ra is current sidereal time. For the east or west coordinate i add or subtract time. To see drift I watch the dec seconds in the goto window showing current position. This is much quicker than using a reticle.
a tool using this method would be a great addition to the current pa tools. Great for people without a view of the polar area.

[admin]

Hi,

that sounds familiar - using a rotation in RA to avoid the wait for drift to happen is a good technique. You have to be careful though to only allow the mount to move in RA - using GOTO to move can be an issue, since some mounts will move the DEC axis even if the new target DEC is the same as the current DEC (for you on the platform it's obviously az moving equivalent to RA and alt equivalent to DEC).

What I don't quite follow is reading off the declination seconds - normally I would expect plate solving to be used to find out true declination against the expected declination.

cheers,

Robin

[Gfischer]

Robin,
I’m sorry I didn’t make myself clear on previous post. I use the goto to get to points then let mount track the same as normal drift alignment. I then watch the drift by watching the change in dec seconds for each new solve. I tried the method of moving mount through arc of platform but that created to much random movement of base plate on ground.
The way I align works great because of the accurate measurement of the drift from plate solves. The reason I mentioned this idea is the process could be made user friendly by auto selecting drift start points, showing drift trend after mount moves, tell operator which way to move mount.
A less involved solution would be to add three buttons in the goto tool. One to load coordinates for the intersection of the equator and meridian. two buttons to load east or west 20deg above horizon and on the equator. Then operator could start goto platesolve and observe drift. With the excellent pa tool included in sc this would only be of value to people with no polar area visible or like me using a platform.

[admin]

Hi,

ah, I see, basically a drift align made easy using plate solving, and you are using the PushTo tool because it automatically plate solves regularly. Sneaky!

I think that AstroTortilla has some sort of similar plate solving based drift polar align routine, but it's a long time since I used it... I can see that in theory you should be able to work out and guide the adjustment of the polar axis - unfortunately having made a drift measurement you need to rotate 90 degrees in RA before the adjustment can be made I think.

cheers,

Robin

[Gfischer]

I guess I can get sneaky
The direction to move mount would come from which direction the dec measurement is going up or down moving east or west when on the meridian point. Then the up or down movement direction of mount axis would be determined by change in dec when on east or west area. After moving mount dec change is monitored again to see if enough movement of mount axis was made. This is just standard drift alignment.
Just having a couple of buttons to load coordinates of points in sky to track would be awesome.

I attached file giving you an idea of what im doing

George