Polar aligning the HEQ5

Your almost there....the mount is now calibrated and now we are ready to set up and align on Polaris and thus the North Celestial Pole or NCP.

If you have carried out the previous steps this next section tells you how to set up the scope to align on Polaris ready for observing.

If you want to go back to the previous pages click HERE for aligning the reticule and HERE for setting up the polar scope setting circles.

simple polar alignment tools
The latitude scale on the HEQ5
Setting the polar circles
Setting up the mount
Ideally for this stage you will have a bubble level or spirit level and for the complete novice a compass is useful. A typical bubble level and compass of the type I use are shown in Fig 10.

OK from the previous steps you have all of the data calibrated into the setting circles and can align to Polaris accurately using the Polar scope and the polar scopes setting circles.

Before you do that you need to make sure your mount is level ( that's what the bubble level is for ) and that you are pointed North ( that's what the compass is for ) don't worry - you don't have to be too accurate on this step.

Once the mount is level and facing north you need to set your Latitude on the Latitude scale. This is shown in Fig 11. I am located at Latitude 51 degrees. You will need to locate your own latitude for your location. This is easily available from Google Earth or almost any on-line streetmap. Elevate your mount using the altitude adjustment bolts until the correct Latitude for your location is showing. Again this doesn't have to be too accurate.

NOTE: When you adjust the altitude or azimuth bolts you must remember to screw the opposing bolts in the opposite direction until alignment is complete and then lock them up against one another to maintain the alignment.

Aligning to Polaris
We are almost ready now. Make sure both your RA Index Scale and the Date Circle are set against their respective Zero marks ( e.g. RA Index Scale is set to 0 against the RA Index Mark and Date Circle is set to 0 against the Date/Longitude Index Mark. ). Make sure the RA scale is locked using the RA Index Scale Lock screw. Now rotate the RA axis of the scope until the date on the Date Circle and time on the RA Index Scale align for the time you are observing. As you rotate around the RA axis only the date circle will move. the RA scale will be locked.

For example - assume you are out and wish to align to Polaris. The date is the 15th of June and the time is 22:00 GMT ( or whichever time-zone you set your mounts transit time for ). Make sure the RA scale and Time Date scale are at their respective zeros ( see previous page ), lock the RA scale and rotate the RA axis ( NOT THE SCALE ) until 15th June is level with 22:00 - see Fig 12 for how the scales will look. Now lock the RA Axis.

Don't worry about the scope ( if its attached and now pointing in an odd direction - this is only to align the mount ).

Now with the scales set at your correct date/time and the latitude set correctly and the polar scope pointing north you should be able to locate Polaris.
Look through your polar scope and centre Polaris in the small circle marked 'Polaris' using your altitude and azimuth bolts.

Your done. You have successfully set up the mount, located Polaris and fixed it and thus the NCP.

You can monitor how close the tracking is by looking at Polaris and watching it move. If everything has been set correctly you will see Polaris move slowly around the edge of the larger circle that surrounds the NCP.

Questions and Answers on this guide - the following are common questions I have been asked

Q How often do I need to set-up the polarscope setting circles ? It depends on what level of accuracy you want. The polar setting circles if done accurately should get you within 5-6 arc minutes of the NCP. Thats plenty accurate enough for observing and short exposure photography. The polarscope circles are not perfect instruments and consequently some error will creep in. Normally I would check a transit time for the time and date when I want to set-up so its as accurate as possible.

Q Do I need all of this just to observe ? No, and in fact before I upgraded I would just set my latitude for 51 ( the latitude where I live ), Set the mounts Declination at 90 degrees and point the mount North. Get Polaris into the centre of the view by adjusting the alt-azimuth and go with that. Its good enough for most observing I found.

Q What are the star patterns for in the reticule ? Apart from Octans which is used for alignment to the South Celestial Pole

( SCP ) the other two constellations are there for rough alignment. You can match the view you are seeing to the constellations shown in the polarscopes reticule as a rough guide. You don't actually see the constellations IN the polarscope - you have to look at the polarscope and the sky and compare the two. Personally I find it easier to do the precision type set-up explained in this guide.

Can I use this guide to set up mounts other than the HEQ5 ? I can't say for sure. The HEQ5 and EQ6 mounts are very similar, the Orion equivalents are identical. I know from reading the manual the EQ3-2 is also very similar to the HEQ5 in basic operation. The main difference is a simplified reticule and the fact that the EQ3-2 has no reticule adjustment screws but relies on the polarscope being adjusted by larger external screws rather like a finderscope. The basic principles are the same but obviously there are differences in the way the mounts are assembled and the location of their various controls.

Return to Astro-Baby Home Page

Reference Sources:

HEQ5 and EQ6 Manual from Sky-Watcher located at http://www.opticalvision.co.uk/manuals.asp

Special Thanks to Steppenwolf at the Chanctonbury Observatory for his help in compiling this.