ATM Another poor man collimating

[rjb <rjb@lynden.com>]

Hi again folks

Thanks to all who responded to my queries re recoating, and the use of
chemicals cleaners.

On the subject of collimation, i currently use a Cheshire tube (cheapy
from Orion). After reassembling my 10-inch Starfinder the parts seem to
end up more or less in the right place, so it doesnt take long to get it
all basically lined up. However i have some questions re using the
Cheshire

1) I can easily get the two cross-hairs to more or less line up, but HOW
CLOSE is reasonable? Problem is that the tube itself moves slightly
within the focusser, throwing the crosses out of alignment. Furthermore
i cant focus on both crosses at the same time, so am never totally sure
how close the alignment is. Is it a case of "if it looks close it IS
close" ?

2) I assume the Cheshire test does not ensure that the main mirror is
centred in the field of view. Should I mark the center with a dot, then
line this up with the center of the Cheshire?

3) Does a laser collimator do a better job than the Cheshire, or is it
just another way of blowing money on astronomy :=}
If laser collimation is the best way, is there a big difference in
quality between the difft laser products? (there is a fair range in
price - Orion has em for $60+, while others are well into the 3 figures)

thanks for any help

Bob