Steve,

I've just come to believe collimation checks need to be done every set up.
I had collimated the scope a few months ago... I'm fairly sure I did a good
job, but I might have only done the center-the-obstruction thing. Still, I
haven't really moved the scope much... no car trips, no accidental hits on
anything... but apparently just carrying it around and taking it on/off the
wedge was enough to misalign it again.

Mars really looked almost featureless before the collimation (just one
slightly darker smudge), and after much more like the average of what Gene
Horr linked to earlier at
http://elvis.rowan.edu/marswatch/images/2001-06.html. Really amazing.

Thierry Legault's great site at http://perso.club-internet.fr/legault/ has a
great section on collimation... I find the last one of a focused star with
the airy pattern easiest to deal with. The center-the-obstruction unfocused
thing isn't very accurate, and I never have seen the off-center rings
clearly enough to easily tell what needed to be done. I just stick in a 2x
barlow and a 6.4mm eyepiece for around 400x and try to get the airy pattern
centered. To me, unless I blink very rapidly, all I really see there is a
bit of a flare going off to one side when it's out of collimation... not
really the nice neat simulated pattern on Thierry's page. I just take the
screw opposite the flare and twist it a bit then turn the other two the same
amount in reverse to match... real easy.


Darron Black

>
>Date: Sat, 30 Jun 2001 23:56:35 -0400
>Subject: Re: [M]: FWHM values, backlash correction, and the 201 autoguider
>
>Hi Darron,
>
>You might have answered a question that has been puzzling me. I don't
>seem to see much detail in my 8" lx50. Perhaps I need to collimate.
>Though I don't seem to see the off centered rings when unfocused. I
>really haven't observed this at anything over 24mm. Maybe it's time to
>buy Bob's nobs. I find that when I do something to the best of my
>ability everything in life it works better. Too bad Meade didn't do this
>with their documentation. You might not have fried a fuse or potentially
>worse.
>
>Steve Brown

View index by [date] [author] [subject]
Previous message: [M]: Re: H alpha Filters, mnewton1
Next message: [M]: unsubscribe, Ilija Kovacevic
Next message in thread: Re: [M]: FWHM values, backlash correction, and the 201 autoguider, Darron Black
Previous message in thread: Re: [M]: FWHM values, backlash correction, and the 201 autoguider, Steve Brown