My scope has to suffer a bit of a dusty environment thanks to my 2 dogs mainly I guess, and though my 10" is only a couple of months old I've cleaned my primary twice, and I have even had to clean my secondary once now as well.
(Yes, I am going to make some shower cap style dust covers for both ends).
A quick tip for other newbies like me: rather than unscrew my secondary totally from the spider assembly and risk it dropping or sliding down the tube (potential mirror on mirror collision - nasty!) I thought I'd try to remove the entire spider/mirror assembly as a whole and put it back in place the same way, in theory saving myself from having to re-collimate my secondary all over again. I had hoped that at worst I may be in for a quick adjustment.
I used calipers (or dividers if you have some) to check the secondary's position in the tube beforehand (and yes it was precisely centred, as it should be in an already collimated newt). When I secured the spider again I made sure that the centre "hole" of the centre screw of the secondary was again positioned dead centre.
Happily the result was that in my case the secondary mirror had not moved at all relative to the rest of the scope, and so my secondary apparently required that no adjustment at all. A
very quick and minor 2 screw adjust of the primary and I was back in business - as good as it was before.
A quick note on collimation for beginners: I had been using the "film cannister" method of collimating initially but wasn't satisfied with the results. Again remember that I am a newbie to all of this, my newt is only about 12 weeks old. People with much greater knowledge than I seem quite able to collimate very well using a simple cannister or other home made tool and their experience.
Sadly I needed to get it collimated NOW as I was not seeing the optical clarity that I knew this scope was capable of, and to be honest it was peeing me off somewhat. So about 5-6 weeks ago I invested $69 in a combination sighting / Cheshire tube, made a world of difference to the speed and accuracy of my collimation. Worth it's weight in gold!! I have found that a couple of friends from this forum are very happy to let me loan them this tool too for use on their own scopes.
Steve
PS: Last Sunday morning Graham Long (for anyone who knows this gentleman) generously offered to check my collimation with his laser collimation tool (the return target type) and gave it a little tweak. While it was close, and as good as I have had it since owning the scope, it was not perfect. After his gentle adjustment it was certainly as close as humanly possible.
I still think the combo sighting/Cheshire tube is fantastic and shows you quickly and easily what is out of line and where it has to be, however the laser tool (make sure you get the type with the return target - you'll see why) gives you that last tiny bit of perfection. I can see myself buying one of those soon too - currently around $60 at Andrew's I believe. I think for me both tools have a definite place in my essentials case, and for any other newbie who isn't really sure what to adjust when and in which direction.
