Quote:
Originally Posted by Screwdriverone
OK I have officially had it with this piece of crap.
I cannot for the life of me get the secondary mirror lined up under the focuser properly.
I adjust its position in the tube so that I can see a ROUND circle in the image, then tilt the secondary to get all three clips of the primary visible in the secondary mirror and the image then becomes OVAL shaped.
I back off the secondary allen key screws, adjust the position of the mirror to make it close to centre of the focuser and then when I try to tilt it again, it goes OVAL again.
I have tried Darryl's suggestion of snagging the secondary mirror and holding it in place while I adjust it up, but this doesnt work either.
For the life of me I cannot resolve it and am becoming extremely p'd off with this. Is anyone close to me available for me to bring it over and see if they can kick the tires and cast a more experienced eye over it?
Please?
Anyone?
Chris  |
Screwie - I hope what I'm thinking here is correct and that your ***** scope is redeemable!?! I have placed in bold, part of your quote (above) and need to ask you what you mean by this?
What do you mean by "I can see a round circle
in the image" ? - you are not meant to be concerning yourself with any "images" (and by that I'm presuming you mean reflections) at this stage!
Rotating the secondary (mirror and holder) thus is to make the
actual appearance of the
actual mirror seem circular as you peer down the chesire/sight tube or film canister or with the naked eye etc! You are not meant to be looking at any reflected imagery, but at the
real, actual edges of the sec mirror and how it is
aligned within/inside the real bottom edges of the focusser tube. Do not get distracted or mesmerized into looking into, or at, any reflections for this procedure! The piece of white paper fixed inside the scope tube opposite and behind the sec mirror and holder helps some people here.
When this is achieved, the sec mirror will not only appear circular, it will also appear concentric within the actual bottom edge of the focusser tube (which is of course circular.)
A number of instructions also include a bit about trying to get some of the primary mirror visible in the secondary mirror's surface when doing the above: but as this complicates the procedure by having to worry about this when in fact it occurs automatically I do not suggest you concern yourself with it! (I'll make a comment about it further down in my post)
Suffice to say that when you achieve the above (and keep remembering as you do the above Screwie, do not look at the shiny surface of that sec, just the very real, touchable edges......do not look into any mirrors or reflections..... do not look into....!)
you pinch up those 3 outer sec mirror screws to hold it in this position.
Then you adjust these 3 screws, going from to another until slowly and carefully you bring the circular image of the primary (and its three clips) into concenticity with the sec's surface. (for this part you are now looking into/onto that sec mirror surface!)
At this point the spider and sec (which is an actual reflection of this unit in the primary, reflected back off the secondary into your eye) will hopefully be somewhere on the circular image of the primary with clips mentioned in the preceding paragraph!
This is when you now turn to your primary and using its' adjustment screws centre that spider (mentioned in the paragraph above) within the whole darn lot! You will more than likely find that you'll have to go back to the sec mirror's 3 screws and fiddle with them again and then back to the primary's screws, a couple of iterations brings it all together: BUT MAKE SURE YOU FOLLOW THE ABOVE PROCESS AND DON'T TRY AND SHORT-CIRCUIT ANYTHING IN THE SEQUENCES DESCRIBED!
In my 5th paragraph I mentioned about not worrying too much about getting the primary mirror reflection
on the sec mirror surface when rotating the sec and holder to get the sec concentric within the bottom of the focusser tube. If none of the primary is visible on the sec mirror surface after you've rotated the sec, and adjusting the sec's 3 screws doesn't bring the primary into view, then you've most probably thrown everything right out of whack Screwie: possibly when (as I think you said) you removed the spider and sec mirror assembly.
This will call for using a rule to adjust the nuts on the spider arms to get the centre point of the spider (and sec mirror) smack dab in the centre of the scope tube. Then, of course, winding the sec's central bolt/screw to get it centralized under the focusser and thence into the above procedures.....Lastly I presume that the primary mirror's adjusting screws are in an "equilibrium" mode and that one or two of them have not been jacked up and the other one slackened right off during your desperado attempts....!
Hope this helps, I've just about got keyboard RSI now Chris - but if none of what I've said makes sense or doesn't apply then hopefully you'll find someone: there must be an AA mob around your area!
Best of luck, Darryl.