How do I wedge align my scope using All-Star polar alignment?
October 11, 2011
Whether you are using the HD Pro Wedge and Heavy-Duty Tripod or another wedge-tripod combination, once you have a wedge for your scope, the All-Star polar alignment consists of 4 parts: Rough Alignment, EQ North Align, Polar Align and repeating EQ North Align. (In the Southern Hemisphere, substitute EQ South Align for EQ North Align.)
Note: If you are used to older methods of aligning your wedged scope, you may want refer to the CPC menu tree in the new CPC manual.
Rough Alignment (this can be done before the scope is atop the wedge):
1. Set up the wedge you on your tripod and adjust its mechanical features to the approximate latitude of your observing site.
2. Incline the wedge to your latitude using its latitude scale.
3. Align the wedge so its axis is running north-south. The hinge or pivot will be towards the north (south in the Southern Hemisphere).
4. Once the scope’s on the wedge and the tripod is level, move the tube and scope until the tube is parallel to the fork arms, the fork is pointing north, tube handle is down, star diagonal upright.
5. Lock the scope’s clamps and move the entire tripod-wedge-scope assembly so the tube points close to Polaris. Get it close enough so that it’s within the limit of subsequent adjustments that can be made using the altitude-azimuth adjustment screws on your wedge (if it has them).
6. Turn your wedge’s altitude adjustment screw(s) to fine-tune the altitude. Likewise, use the azimuth adjustment screw(s) to fine-tune azimuth to properly position the mount for polar alignment. This finishes the rough alignment.
EQ North Align:
1. Turn on the mount. (If it has a GPS, allow the GPS to successfully link.) Initialize the mount and choose EQ North Align when prompted.
2. Choose either EQ AutoAlign or EQ Two-Star Align for the most accurate polar alignment.
EQ AutoAlign: Requires alignment of the scope’s altitude to the altitude index marks and also alignment of the scope’s east-west orientation until the optical tube is pointing at the meridian. Use the hand control direction buttons to move the scope when prompted to do so. Once both movements are done, the tube should be pointing at the highest elevation of the celestial equator in the south (north in the Southern Hemisphere). AutoAlign then chooses two alignment stars for you and will slew to them.
EQ Two-Star Align: Does not require the altitude and meridian alignments, but you do have to locate two stars for the alignment procedure.
Once the EQ North Align is finished successfully, choose a bright star in the south around or below the celestial equator that you will use for the All-Star polar alignment routine. This makes the fine adjustment controls relatively easy to reach while at the eyepiece. (Those observing in the southern hemisphere would choose a star in the north around or above the equator.)
Slew close to such a star and use the Identify function in the main hand control menu. The star should be the top one on the list. Press Enter and your scope will start to slew to it. Press Undo immediately to get to the top of the menu and press Align. Choose Polar Align and choose Align Mount. Your scope then completes (re-slews) to the star that you just identified and goes through the All-Star polar alignment. Follow the prompts and adjust the mount manually using the wedge’s adjustment screws. Do Not Use the Hand Control Keys. Once you are done, press Enter and the message “Polar Align Complete” will be displayed. This completes the Polar Align.
Your scope is now polar aligned. However, since you have shifted the whole scope slightly to do this, you must re-align to the sky for best results.
Turn off then turn on the mount and conduct another EQ North alignment. (You will repeat the EQ AutoAlign or EQ Two-Star Align, so your scope is again aligned to the sky.) Check Align > Polar Align > Display Align to see the accuracy of your polar alignment. An alignment within a quarter degree of the North Celestial Pole is good enough for most purposes.