Good collimation tricks

[Ashen (Caleb)]

Anyone know any good collimation tricks for a newt? Ive tried a bunch of methods but always seem to be out.
Thanks.

[TimHarbour (Tim)]

Here are a couple of good links if you haven't as already seen them.
https://youtu.be/KkX_MHpqozE?si=ibQIGniVXWMybjwV

https://youtu.be/hvlVzz-a_s0?si=hXfD6ex6KiNFRUSi

https://youtu.be/vM5bqIhq1V0?si=F0pDSj91PQNsjiCO

https://www.astro-baby.com/astrobaby...ian-reflector/

[Matthieu (Matt)]

Hey Caleb,

The first one I have is that you always want to collimate your secondary first. As it doesn’t move much over time it’s worth getting it as well collimated as you can.

The second one is to collimate the primary with the scope at an angle closer to how you’ll observe if your newt experiences mirror shift.

Also, your mileage may vary with different collimation tools. What are you using and at what f ratio?

[doug mc]

One trick I picked up, was to move the out of focus star with central shadow visible to a place in the field of view, where it looked collimated. Then adjust it back to central position with collimation screws.

[Matthieu (Matt)]

Hey Doug,

That’s something I haven’t heard of before so quite keen to understand and try it out. So if I understand correctly, you would:

• Position the star in the center of the fov
• Out focus the star until the central obstruction just appears
• Move the scope in the direction where the star focuses properly
• Use collimation screws to move it back to center

Is that right?

I assume that requires a tracking mount, is that right? If so, I might try it out next time I collimate my C5.

[rmuhlack (Richard)]

My goto for achieving accurate collimation with my imaging newtonians is to use a laser (to get in the ballpark), followed by a cheshire eyepiece, followed by a Catseye auto-collimator (with the additional offset viewing port). Note this method requires a catseye collimation sticker to have been placed (correctly centred) on the primary mirror.

[gb44 (Glenn)]

http://www.astrophoto.fr/collim.html

This explains it well. Collimation by Thierry.
After all the equipment is used, the final thing is you must use high power on a defocussed star and tweak the primary to remove the final bit of flare adjusting the star back to the centre of the FOV after every tweak.

GlennB