I think I screwed up !
Posted 04 February 2008 - 03:57 PM
Posted 04 February 2008 - 04:10 PM
when ever I disassemble I mark with a magic marker for reference.
Posted 04 February 2008 - 05:31 PM
Posted 04 February 2008 - 07:20 PM
glad ot hear that Celestron was helpul!
Posted 04 February 2008 - 07:36 PM
Yes they told me to try it a certain way around. So I cleaned it and put it back together. No chance of testing, as this is the UK and it is raining again. I don't really know how I would know if I tested it ? I have nothing to compare to ? Or is it easy ?
Posted 04 February 2008 - 07:38 PM
It sounds a really drastic step to have to ship your 'scope back to the US but from the limited search I made on the subject tonight, it looks very much as if somewhere along the line the corrector plate does need to be professionally realigned.
The only thing I would make sure of before taking this step, is to ask whether you've looked in detail (even perhaps under a magnifying glass), for any original marks made by Celestron technicians during the 'scope's assembly.
I did manage to locate an old 5" - 8" Celestron manual from the early seventies which describes the disassembly of the "C" plate (a feature which Celestron apparently removed from future manuals but which probably cross references at least in principle to your 6SE) but I don't think it will be of much help. Nevertheless you never know till you look.
Failing that and rather than having to send it back to the US, couldn't David Hinds reseat it for you or alternatively, maybe Seeview Observatory in Cambridgeshire which also deals in Celestrons ?
Hope it all works out to the good as soon as possible,
Posted 04 February 2008 - 08:02 PM
Further to the above, I've just found that our member Bob T. seemed to have run into the same problem and posted under the title "Correction Plate Alignment" requesting help, (1st, Feb. 08) on the "Cats and Casses" forum (see his posting now on page 2).
He did receive some advice which you may find useful. If so, perhaps try a personal post to him to see how he's getting on with the solution to the problem ?
Hope this helps,
Posted 04 February 2008 - 08:07 PM
I rather pay Â£50 to ship it to the US.
Posted 04 February 2008 - 08:18 PM
Well that does seem to be the best option in light of what you've just said.
Good luck and best regards,
Posted 04 February 2008 - 08:39 PM
Posted 04 February 2008 - 10:27 PM
Posted 05 February 2008 - 04:35 AM
Posted 05 February 2008 - 06:29 AM
1) How can I tell if the corrector plate is on the right way around.
2) I spent a long time trying to clean smudges out of the corrector plate, how can I tell if I damaged it's optical coatings.
This is really worrying me now, your help would be hugely appreciated.
Thanks in advance.
Posted 05 February 2008 - 11:22 AM
Another place to visit might be Robert Pudlo's site where he walks you through the break down and and rebuild of a N5 OTA. Very easy to follow instructions with lots of photos of the pieces and parts ... Pudlo ... Clink on projects in the top menu and then NexStar5 tuneup, left menu, next page.
I hope this helps some ...
Posted 05 February 2008 - 02:14 PM
To me, it looks very much from what I've now read within this thread plus all the links, that your choices are limited to either getting the plate reset professionally, at cost, (whether in the more expensive UK or paying an equivalent sum in just shipping to the USA) or resetting it yourself.
Should you choose the latter option, it then seems to me that from the literature searches so far conducted and displayed here, all mentioned procedures unfortunately lead back to the necessity to have marked the corrector before disassembly: the one and critical aspect you do not have.
Assuming further, that if the job were to be undertaken professionally, I suppose that would entail the use of special optical alignment equipment which would not be available to the amateur telescope constructor.
Thus if you do opt to carry out the work yourself, you will have to evaluate its quality by trial and error and in fact this was the advice given to Bob.T by Jeff (NeoDinian) on that "Cats and Cassies" forum. However, this is not to say that the necessary alignment can't be done.
That's as far my logic takes me, so I personally would try to reset it myself using perhaps an artificial star and then just rotate and test the plate until I gained its best position possible on this basis. If, however, I got no satisfactory result after trying this, I would then seek professional help but at least my vain attempts to reset the plate would have, up till that point, cost me nothing and who knows, I might strike lucky!
Purely my own view as to what I would do under the circumstances. You of course must decide your best next move.
BTW, I would also have to assume that the secondary mirror had been in alignment prior to the removal of the plate because to rotate the plate AND try to adjust the secondary would really compound the problem.
Therefore, I would say, get the plate set as best you can and then and only then, tweak the secondary if, and only if, necessary.
Posted 05 February 2008 - 03:15 PM
Makes complete sense. Unfortunately, the secondary has also been adjusted already. I collimated the scope after the first removal of the plate. I don't think there is anywhere in the UK to align my plate. I don't believe D Hinds have the equipment for this either.
So my only choice is to try to do it myself.
What do you think to the cleaning and possible damaged caused ? Do you think its likely ?
Posted 05 February 2008 - 03:47 PM
Well of course I don't know how you cleaned the plate and with what material(s) but I guess you have to assume its OK unless you have any real doubt yourself. With what, for instance did you clean it ? I take it the point you are making is that if damaged, you'd be wasting your time aligning it ?
Assuming however that there is no damage, there's nothing you can do about the fact you've also adjusted the secondary. I think if you do attempt the work yourself, and as I said, that costs nothing more than your time and effort, you will have to live with fact that the plate or the secondary or both will be out of alignment when you start the work.
In this case, I personally would start by adjusting (rotating) the plate to a point where I could not improve on the image and then lock it in that position. I would then work on the secondary to see if I could attain something approaching the ideal.
As to whether "David Hinds" could do the job, I'd send them an email to find out and if so, at what cost and under what time scale. After all that costs nothing.
Meantime I'll take another look around and see if there's anything or anyone else out there in the UK who might help.
Posted 05 February 2008 - 05:37 PM
As far is damage is concerned, visually the only thing I noticed are 1 or 2 tiny little scratches and the rest are just very faint smudges. Am I correct in assuming that the effects of this should be fairly minimal ? I mostly used distilled water, lens cleaner and warm water to clean the plate. I used cotton wool buts, a very soft cloth, not sure what it is called but I had ordered it for the Plasma TV and some Kleenex tissues. Obviously somewhere along the way, during my rubbing and cleaning I managed to put those two scratches on. I hope they don't render the scope useless.
Posted 05 February 2008 - 06:21 PM
I am now told that certainly the Nexstar 6SE (I am not sure which others) is made in China and it is made in such a way that orientation does not matter !
I've been told by multiple sources (including Celestron) that all the C6S OTAs with the exception of test or pre production models were/are made in China.
The orientation issue is very interesting. Perhaps the manufacturing process used in China is different enough to allow for this flexibility? If this does apply to all C6s it would certainly indicate lower cost manufacturing (less handling, less time to manufacture).
As far is damage is concerned, visually the only thing I noticed are 1 or 2 tiny little scratches and the rest are just very faint smudges. Am I correct in assuming that the effects of this should be fairly minimal ? ... Obviously somewhere along the way, during my rubbing and cleaning I managed to put those two scratches on. I hope they don't render the scope useless.
No, slight scratches and smudges won't affect the view. You need to have really really obvious debris to affect anything. There are even scopes around with visible chunks taken out of the primary mirror that serve up fantastic views.
Before you consider cleaning it again you might want to read up on the process a little, some additional suggestions are discussed here: CN Thread on cleaning SCT correctors
Put all this behind you and just enjoy that great scope.
Posted 05 February 2008 - 06:30 PM
Posted 05 February 2008 - 06:36 PM
I must admit that I find that one hard to believe that the plate requires no orientation (no pun intended !) - just because Celestron 'scopes (and they are) now built in China !
Nevertheless,-- I say "Go for it and assemble". After all you've nothing to lose. If as they say, it doesn't matter how the plate's positioned, then you've only got the misalignment of the secondary mirror to concern you which in turn, should only require a normal collimation.
As to the scratches, if they are minor ones they should make no difference to your 'scope's overall performance.
Next time around though, (and cleaning should be as infrequent as you can tolerate), I think this link explains it all :-
and as cleaning fluid, use "Optical Wonder" from Baader.
Super Stuff ! IMHO Second to none !
Good luck and best regards,
Posted 05 February 2008 - 06:38 PM
Thank you very much for your help with this one ! I don't really know enough about the workings of an SCT so can't comment on the feasibility of not requiring orientation. Who knows.
Posted 05 February 2008 - 06:48 PM
Any chance you took a photo of your new scope before disassembly? specifically of the corrector? If so, you can blow that pic up and print it out. Use a straight edge and pencil on the photo to align various points on the secondary dust cap or collimation screws, corrector retainer, retainer screws and the edge of the tube.
Use those points and the straight edge, the more the better, to align the corrector. It may not be exact, but should be very, very close.
If you do not have such a photo, perhaps the previous owner?
LOL, Tel beat me to the "China" thing.