Quote:
Originally Posted by adman
have a look at this link - will get you started. very simple and fast to do polar alignment using PHD. Love it.
Adam |
there are a number of processes where you can use PhD to drift align. I would like to just highlight a couple of errors in the method described in the link.'
1. you never drift align using RA drift. It has nothing to do with it. The author says "To check the RA alignment chose a star at 0° elevation close to the meridian." This just doesn't make sense. For a start you can not see a star at 0 deg elevation. He is in fact talking about checking the Azimuth adjustment and you choose a start at 0 deg declination but close to the meridian.
2. The author then says for the Dec to select a star as close to the horizon as possible. Once you get below 15 deg elevation to the horizon refraction plays a big part in the apparent position of a star. Preferably select a start at 0 deg (+/- 5 deg) dec again and between 15 and 20 deg elevation. This star is used to adjust your mount elevation.
3. in step 2 ignore what he says and replace with my comment in 1. above.
4. Step 9. No you do not have to recalibrate. My suggestion is setup your initial calibration, stop guiding, go into the brain box and tick disable guide output. This way the graph will still work but no pulses will be sent and only drift (and PE) will show on the graph.
I've not used the Dx/Dy. I can't see the benefit. If you watch the graph the dec line of the graph will start to drift almost immediately if polar alignment is out.
To make all this process much simpler I would recommend that when you put your guide camera in and get it started, turn on the bulls eye reticule and press your up and down buttons (dec) on your hand controller (prior to callibrating). Rotate the camera so that when you press the up button the star moves up parallel to the reticule and the same down. If you are using a star diagonal then it must be orientated vertically along the centerline of the scope. (or at 90 deg pointing left or 90 deg pointing right. I suggest straight up and down.)
I'll reiterate something that I seem to say over and over when showing people how to drift align using PhD or K3.......... IGNORE RA!!!!! It has absolutely NOTHING!!!!! to do with drift alignment. You are adjusting Elevation and Altitude to remove drift in DEC ONLY.