Russell, with the 'Cheshire', it takes 2 people to collimate 'easily'. If you try it yourself, you'll be up & down all night. Reason = image shift/earth rotation etc etc.
The laser collimators are useable by 1 person. The beam is reflected back to a 45deg surface that you can see from the base/bottom of the t'scope. So you can see which way to adjust the primary mirror without having to go to the E/Pc. Then do a star test to finalise. (may need 2 people here).
One thing tho., make sure the laser collimator itself is collimated. ie; the beam is coming out 'on axis'.
See attached......
HTH a bit ....... L.
OK, if anyone can give me a quick answer, as I'll probably be ordering today, if you could get just 1 collimating tool, a $29 Cheshire eyepiece, or a $79 laser collimator, which would you get?
Oh well, too late now. I faxed my order through - bare bones for now - you wouldn't believe the number of unexpected bills that have suddenly arrived. 8" GSO and Cheshire eyepiece. I'll have to save up for everything else.
Oh well, too late now. I faxed my order through - bare bones for now - you wouldn't believe the number of unexpected bills that have suddenly arrived. 8" GSO and Cheshire eyepiece. I'll have to save up for everything else.
Hopefully it'll arrive before the weekend.
That's all you will need for quite a while. I only ever use a cheshire eyepiece to collimate, the first time its a bit of a bore but after that its just a tweek each session.
Russell, The 'Cheshire' will be all that you require. Just takes 2 to do it reasonably 'hassle free'. Like Rob, I only use the 'Cheshire', when nec.
Rob, if I may ask, why is it nec. to 'tweak each session'?
I do star test when set up, but collimation is not required. Haven't touched it for over a year. Still in perfect coll. ??????????
What moves? Main/2ndary?? Just curious. L.
Quick comment on DSC vs GoTo. At Star Camp, I had a chance to see the Argo PushTo in action on a 10" Dob as well as the motorised Goto on an EQ mounted 8" Celestron. The PushTo was far easier and quicker to use, doesn't make that annoying whining noise, does not bump your OTA (optical tube) against the mount and does not run out of batteries. So the only advantage I see to the Goto setup is tracking.
The great thing about the 8" Dob you're getting that you can have either. You could put the OTA on an EQ with Goto, or fit DSC's and a controller to the Dob base.
Geoff (Starkler) has done his PushTo on a budget using a 2nd hand Palm Pilot in place of the Argo control unit.
Rob, if I may ask, why is it nec. to 'tweak each session'?
I do star test when set up, but collimation is not required. Haven't touched it for over a year. Still in perfect coll. ??????????
What moves? Main/2ndary?? Just curious. L.
Its just a check each session. Very rarely do I actually have to do anything and I don't actually use the locking screws as I find they tend to push the primary out of alignment and add another, unnecessary level of complexity to the whole process.
i check each session too... it rarely needs doin tho.
and i collimate with a cheshire alone yeah its a hassle going up and downthe tube but with my monkey arms i can actually rech 2 or the 3 col screws while looking in the EP
Geoff (Starkler) has done his PushTo on a budget using a 2nd hand Palm Pilot in place of the Argo control unit.
I actually have an old IPAQ (not sure why it died,maybe battery, but I never looked into it). So that might actually be a good idea, if I can get the thing fixed.
The scope turned up today - unfortunately he arrived just after the wife went to pick the kids up from school, so he left again Hopefully his timing will be better tomorrow
OK got the scope, got it almost together (with a lot of 'help' from the kids) and have run into a problem with the springs.
The instructions do not show putting the bracket thing on the base, and it is tapered with a large sectiona nd small section sort of like this
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So I put the narrow part to the inside, so, the spring doesn't slip off, but the spring doesn't fit over the large part.
Trying to unscrew it and turn it around, the bracket int he shipboard base that you screw into, came out of the chipboard, instead of the bolt coming out of the bracket - both sides, and they're jammed together.
I'ms till not sure that evehn if I do get to turn it around, that the spring will fit over the bolt head. I'll try and post some pics tomorrow night if I can, and see if anyone has any advice.
Dragge dit out though for the kids to have a look at mars, and it was so low in the sky, the scope kept falling forwards :| But we did get a quick look before they went to bed, and I need a breal for the night now.
Sorry, I don't understand what the problem with the base is exactly. Pics will help. If you're having trouble putting it together (i.e., with the "instructions"), try the Orion XT8 user guide:
Heh, excuse my last post, I was tired, cranky and rather incoherent.
After I'd calmed down a bit, found my multigrips, and tackled the problem again, I managed to get the spring supports un-jammed (with only minor mangelation of the chipboard screws) and the spring does, just, fit over the bolt ends. So all is OK for now, although the tension from the springs seems pretty strong, and the bolts were straining up a little - hope they don't break out.
Something that might be a little easier to follow. When testing how easy the based turned, it's a little inconsistent, with half the rotation being relatively free and easy, but at a point it gets stiffer and harder to turn, and if you keep going, it frees itself up again. I've put in the milk-bottle washer mods to free up the rotation, and it did help, but there's still this half-losse/half-tight rotation. if I add 1 more washer, the base wobbles up and down, although I didn't try more washers while the scope was mounted, but this loose/tight action happened even without the scope on.
Try backing off the centre bolt half a turn. Sounds like the base is not perfect in its alignment and by loosening the bolt it will free it up that bit to allow for the variation.
bout $30 or sumpin i think
L.
yeah its a hassle going up and downthe tube but with my monkey arms i can actually rech 2 or the 3 col screws while looking in the EP 
