collimate on a planet

Not long ago someone posted a thread about using a planet to collimate a scope. could that someone please repeat the process....
Thanks

Here ya go...


Easier way to collimate an SC accurately
Posted by Brett Wylie on 1/11/2003 12:35:14 AM

The "experts", writing in articles and on the net, and the telescope manufacturers themselves, tell us to collimate using a slightly defocused star..the two diffraction rings scenario. This is difficult and thus in my opinion, absolute crap! Even so, most people hardly bother to go this far, collimating instead while looking at the 'big donut'at low power and are happy with "just about or good enough" collimation. With miserable results.
Don't collimate on a star at all! Why not? Well at 500-600x what do you see?..even with relative steady air the defocused highly magnified star will still be wobbling and the diffraction rings will be wiggling all over hell and back...how accurate a measurement can you do with this scenario??
Instead, try this...thread on a straight thru visual back adapter..don't use the diagonal..center Jupiter in the field of view..now you have a rock solid steady object to look at!..big difference..it's also bright and easy to see, large in the field of view...start at about 300x..look at the limb of Jupiter, usually one side will have a halo. That halo is a secondary image of the planet caused by miscollimation, & if your seeing that, your NOT getting NEAR the view your instrument is capable of, your not getting the most out of your SC telescope...go to the front of the scope and tweak the screws until that halo disappears..completely..now kick it, the magnification up, to 600x..say 4.6 mm eyepiece 2xbarlow combo...very very fine movements/changes now..1/15th turn..when your finished there should be no evidence whatsoever of limb halo, you should be looking at a solid planetary edge!..and I will guarantee you your eyes aren't going to believe the difference..when it's right on...WOW..POP..all those fine details you thought were impossible to get, with an SC, are going to suddenly be there.