In the lower sketch the left side screw’sisthreadthreadedcut iintto the mirrbottormsupportplate andplatewouldandliftwillthepullmirrorthat side down, the right hand screw has it
up.
The spring loaded mirror support is easier to manufacture and to work with. On the other hand the resilience of the springs can change with temperature and age, resulting in frequent loss of colli- mation of the main mirror. Therefore springs are used only in smaller Newtonian telescopes. Ad-
justment by push/pull screws are a little more costly to produce’sanadjustmentsmore elaboratedue totoknockswork withand but they guarantee practically no movement of the main mirror
vibrations (transport). They are therefore mainly used in larger telescope systems with the larger weight of the main mirror.
Adjustment of the main mirror is done best by two persons. While you are turning the main mirror’s adjustment screws your friend would be reporting about the movement of the reflected laser light beam.
Case 1:
The main mirror of your Newtonian may be out of adjustment’tquitsee thea bitreflected. laser beam on the This may result in no success in step 1 above, i.e. you don
reference plane at all. In this case cautiously glance through the grid towards the secondary mirror.
With a little bit of luck you will see somewhere at the inner walls of the eyepiece holder the grazing’s light reflection of the laser– continuebeam. Iftheyouadjustingsee it, adjustoperationthe mainuntilmirrorthe beamfirst isto centeredbring the onlaserthebeamgrid, sho
point onto the gridw- ing full collimation.
Case 2: ’t see any reflection of the laser beam at all – well, your system is a long way out of a
You dond-
justment. Laser-Colli™
Again yourcan help.
First look into the tube front down to the pri- mary.
On the main mirror you see the reflection of the secondary mirror and the reference grid. In the grid plane itself you see many reflected images of the laser dot.
If these reflected images are not orientated in a straight line but spread, as in the picture left, you have to adjust the main mirror in such a way to line them up in a straight line (see pic- ture below).
Picture above again shows the view from the tube’s front to the reflected images of the secon- dary mirror and the grid plane.
If the red reflections are exactly orientated in a line the main mirror is well adjusted already (white line shown in the picture serves only for clarification).
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