The instructions for drift alignment in the Questar manual felt awkward and confusing to me, so I put off making this a part of my standard setup. I concentrated on doing a careful polar alignment when doing longer exposure images and found that a compass and level alignment worked well for lunar and planetary imaging with a large sensor camera.
Two changes prompted me to revisit drift alignment:
These gave me an incentive for accurate alignment and a tool to make it easy.
I started with the excellent Starizona Telescope Basics web site, which gives excellent drift alignment instructions all from the eyepiece point of reference. Applying these to the Questar, I also realized that there is no need for a reticle eyepiece as described in the Questar instructions. You can just use your camera.
If you are not using a camera, you can do a fine alignment for visual observing with just a level and a compass. If you are using a camera it is almost certainly a digital camera with built in magnification and reticle features. Your camera’s electronic focus preview mode will work better than a reticle eyepiece.
These instructions are for a camera at the Questar axial port. If you use a camera or a reticle eyepiece at the eyepiece port, then you must reverse left and right.
Once you’ve been through the process a couple of times, all that you need to remember is:
If star drifts UP, and the star is high above, move it to the RIGHT or when the star is down in the east, move it DOWN on your screen. Reverse adjustments, if the drift is downward. A shorter version that I manage to remember is: if start drift UP -> move star RIGHT if above -> move star DOWN if east.
This process will work for any telescope adjusted as needed for left right reversal. The image below shows the altitude and azimuth adjustment locations on the SkyWatcher wedge that I use. The controls are similar on the Astrotrac and many others.
Content created: 2017-04-11
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