|If like me you opened up your
bright new shiny HEQ5 mount and found yourself stumped by the instructions then
this page is for you !!
than use technical jargon I have kept this simple and its a basic step by step
guide to setting up the polar scope on the popular HEQ5 Mount.This seems to be a common problem judging by how many times it
appears as a question on astronomy chat and help boards so here you are - if
you have made it to this page then your problems are ( hopefully over ) - at
least if you live in the Northern Hemisphere - this guide only works for
setting up in the Northern Hemisphere.
this guide is written specifically for the Sky-Watcher HEQ5 mount the unit is
very similar to other EQ5 and the EQ6 mounts so it should be applicable to
Orion EQ mounts and many other types as far as I know. To
check the HEQ5 out and to see if it is the mounting you have or to see where
some of the parts referred to in the PolarScope set-up guide are
check the diagram
NOTE: Its easier to do this procedure
without the telescope or weights on the mount. This puts less stress on the
altitude and azimuth bolts both of which are quite soft and prone to shearing
if placed under too much stress it also makes it less likely you will hit your
head on the telescope tube and hit the telescope tube against the mount during
the alignment procedure.
|GETTING THE POLAR SCOPE READY
|Before starting you will need to remove the covers for the polar
scope. The front cover simply clips off, the rear cover has a screw thread. You
must also lower the weight bar and rotate the mount through its declination
axis until the polar scope is clear. You can check just by looking down the
hole underneath the front cover.
|NAMING OF PARTS
|The first thing you need to do is get familiar with the parts of the
mount around the polar scope set-up. I haven't detailed
the altitude and azimuth set up because that's simple enough even for idiots
like me but if your really stuck
check the diagram here. The polarscope is also simple BUT not well
explained on most web pages or the HEQ5
|The diagram to the left shows all of the major
components of the polar scope APART FROM THE DATE/LONGITUDE INDEX SET
SCREW. If you rotate your mount through its RA access and look at the ring
that carries the DATE/LONGITUDE INDEX MARK you will see a small grub screw on
the ring that carries the index mark. You will need to loosen this
Note also the RA INDEX LOCK SCREW will ONLY
lock the RA index in its Zero position. You'll see as you go through the
procedure that this is perfectly correct as it is only used in the polar
Also on the diagram on the left
you can only see one of the reticule adjustment screws - there are three of
these around the eyepiece of the polar scope. The focus ring can be very stiff
when new - turn counter-clockwise to focus the polar
Before starting the alignment
procedure you will need an Allen key that fits the reticule adjusters AND a
small jewellers screwdriver to release the Date/Longitude Mark
OK we are now
ready to set up the scope for alignment.
First you need to
adjust the reticule to make sure that its lined up with the mount correctly.
You can skip this step if you wish and are planning
only to use the scope for observation use rather than photography.
Skipping this step will introduce some errors into the alignment but that wont
matter very much if you are just observing as you will be able to correct any
error via the hand controller.
Skip aligning the reticule and take
me to page 2
||Possibly the toughest and scariest job for a newbie on the HEQ5 is
getting the reticule aligned correctly to the mount.
Trust me its not as hard as you might
think and if you take your time and don't rush quite a simple
This is an easier job if done indoors
with decent lighting and your adjustment tools by your side. You will need one
Allen key to adjust the reticule using the reticule adjustment screws shown
above. There are three of these around the eyepiece and you will need to
slacken one and tighten the others to take up the slack slowly and bit at a
time to get alignment. DO NOT TURN ANY OF
THESE SCREWS MORE THAN 1/8 OF A TURN AT TIME or else the
reticule may fall out. These screws are quite coarse and are adjusting the
reticule by fractions of a millimeter - a small amount of turn make the
reticule move quite a bit as you will see.
I would also advise to do this with the mount set for
zero elevation and with the polar scope almost horizontal. That way if you do
end up having the reticule fall out it wont go too far.
The manual assumes you will have the mount pointed at
Polaris but its far easier to do this task with the scope aligned to a distant
object. I use a light on top of a distant radio tower but you can also use a
small dot on a white card pinned to a wall. The further away the target object
polar scope at the target, using the altitude and azimuth screws on the mount
to fine tune. When you look through the polarscope the central area has a
cross-hair. Align this over your target as in Fig 1.
Now rotate the mount through the RA axis
by releasing the RA lock and turning the mount slowly through 180 degrees and
then lock the RA axis . Observe the target against the cross-hairs. Chances are
it drifts off as in Fig 2. This indicates the polarscope is out of alignment
with the mount and will need correcting.
To correct this drift of the target from the cross-hairs use an Allen
key to slightly loosen the reticule adjustment screw most nearly opposite the
cross-hair in the direction by which the the target is 'off' i.e. in Fig 2 you
would slightly release the screw nearest the 2 'o' clock position. Now tighten
the screw that's nearest to the object you are targeting on. You will find the
screws are quite tight and will tend to 'click' a little as they are loosened.
I use these clicks as a guide in any event - remember never to release any of
the screws more than 1/8th of a turn.
You need to adjust for HALF the distance that the target has drifted.
As an example in Figure 3 adjust the target to be halfway along the red
Now release the RA lock and rotate the
mount back to its original position and re-lock the RA. Realign the target on
the cross-hairs and now release the RA and rotate the scope
If the target still drifts you will need
to keep repeating this until the target stays on the cross-hairs as the mount
rotates. With a little experience and taking things slowly you will achieve a
good accuracy in quite a short time.
In these examples I have shown the target as drifting by a huge
amount to illustrate the point. In reality you will find the drift is very
small and quite easy to correct.
Once done I
usually put a small amount of tightening to each Allen bolt and recheck.
DO NOT OVERTIGHTEN as you will damage the
The reticule is now aligned - take
me to page 2