|
Andrew,
Drift alignment will allow you to get spot-on with your polar alignment, and with practice you can get reasonably close reasonably quick.
I suggest you can use your imaging setup to drift align. If you orient your camera so that RA is in one plane,eg horizontal, then your dec will be in vertical. For drift alignment you will only be interested in the dec shift.
I use my veiwing pogram to zoom in as much as I can when aligning, as this will produce the most change for the shortest time.
There are plenty of sites describing how to do it.
I suggest you start a note-book and write down which way you have to turn your knobs to produce what change. This will help you the next time(s), since when you notice a drift one way, you will know which knob to turn which way.
Also while doing this, you can keep an eye on your RA tracking rate over time. While sidereal is sidereal, you may be experiencing Periodic Error, which is a problem produced by small inaccuracies in manufacture of the worm gear that in short-term causes the RA to get ahead, and then drop back over the worm gear cycle time. This shows up as elongated stars stretched in the RA plane.
Many mounts have a Periodic Error Correction (PEC) capability which allows you to program in a negative PEC bias which cancels out the physical errors.
If this doesn't work, then there's guiding as an option, if the mount supports it, which is a whole other realm.
HTH,
BC
|