Best way to collimate a GSO-RC10

[cventer]

What current view on best and easiest way to collimate something like a GSO-RC10 or C925 ?

Prefer a method I can do during day. ie with artifical star or software.

I know there are several methods like software, laser collimators , Tak Collimator etc...

Whats the easisest for someone who never realy learned to do this right to learn ?

Any suggestions and pointers to equipment would be great.

[Paul Haese]

Sorry, I have tried them all. Only one works best. A star with steady skies. Don't touch the rear screws on the RC, unless you have a Takahashi scope and you know what you are doing. The SCT just needs the collimation screws adjusting at the front.

[casstony]

I like to collimate my SCT's in the day with an artificial star.

The C9.25 would probably need to be done outside on an overcast day, unless you have access to a hall where the light source can be positioned far enough away from the scope. You can take your time, use high power and get the first in-focus diffraction ring even. Then check the collimation on a star to see if mirror movement has changed it - tweak if necessary.

The light source only has to be far enough away to form an image, unlike testing for optical quality where you need to be concerned about introducing spherical aberration.

[g__day (Matthew)]

My preferred method was always to centre a bright star - use a camera and defocus the star until you get a sizeable doughnut. Check that the hole of the doughnut is in its exact centre. Adjust the collimination until the hole is dead centre (re-centering the star's entire doughnut every time you adjust the mirror).

From memory this is the method CCD Inspector used - as they found it more sensitive and successful than competing methods.

CCD Inspector is available from CCD Ware as a free 30 day trial - maybe give it a go and see if you like it?

Oh and Bob's Knobs (Teflon replacement screws for the 3 front screws that Celestron use on the corrector plate for the secondary mirror) are much easier to adjust than poking around with a screwdriver in the dark on your SCT! Bintel sell them for under $30 from memory.

[allan gould]

Don't forget AlsCollimation aid as it really helps to determine if you have nailed that star!!!