Primary mirror

[Ju Piter]

hi again.so i have done quite a few mods to my heritage 130p (flocking,light shield,9x50 raci finder,ptfe on the focuser)now what is bugging me is 2 things firstly it seems i have to collimate everytime before i start viewing so would better primary mirror collimation screw springs help as the ones i see are quite thin so would have travel from compression and decompression which would answer why i need to collimate everytime(not alot but always slightly out).secondly my primary mirror sits on 3 thin cork rectangular pieces connected to a flimsy piece of plastic.is this even needed does is serve a purpose.my thought is it just stops the mirror from direct contact with the base plate.just from my novice conclusion can i just get rid of it as it would help the primary mirror cool quicker.sorry if this sounds stupid.

Neil

[Peter Drew]

You need to support the mirror in a minimum of 3 equidistant places to allow it to sit comfortably with no wobble. For small mirrors, 3 pieces of cork are ideal.  If you lay the mirror on a "flat" surface it will distort non-uniformly.   

[Ju Piter]

You need to support the mirror in a minimum of 3 equidistant places to allow it to sit comfortably with no wobble. For small mirrors, 3 pieces of cork are ideal.  If you lay the mirror on a "flat" surface it will distort non-uniformly. 

ok ty for clearing that up

[happy-kat]

What about the screws I too would be interested to know if collimation would hold better as mine needs a twiddle every time.

[ed_turco]

What about the screws I too would be interested to know if collimation would hold better as mine needs a twiddle every time.

I'd invest in some heavier springs in your cell.  Not so heavy that you cannot turned the screws, but stiff enough not to collapse under the weight of the mirror and the tension from the screws.  It sounds as if in moving your telescope, the mirror does a jiggle or two, and doesn't come back to its original position.

What will it cost, a a pound or so?

[Ju Piter]

i found out it is actually the focuser slop.looking through the collimation cap and turning the focuser changes the position of the centre spot quite a bit so always seems out of collimation.i have ptfe round the focuser which has stopped alot of the slop but still whe turning always goes off center so i have marked the ptfe tape with black marker at the focus points for my eps then when i need to change eps i line up the mark collimate(takes about 10 seconds)and off i go.

[laser_jock99]

Have you checked the centre spot is actually in the centre? They are often several mm out.

[Ju Piter]

Have you checked the centre spot is actually in the centre? They are often several mm out.

thank you for the info i will check that out did not know they could be out