Cleaning the primary a far more difficult job than cleaning the Corrector Plate of the Meade, so the best solution as for most things is prevention, here especially so.
The preventive methods are to -
Always run the cooling fans and to -
Always fit the dew shield for every visual and photographic session.
The fans' power comes from the main 12v battery that runs the mount, and that is permanently being charged from the mains.
However, should it need cleaning, perhaps many, many years from now (see the photograph and note on the Meade 14" cleaning page as to when it may need cleaning), I have an agreement from Barry Pemberton, Founder of the company, Orion Optics, and father of their MD, that if we contact them for a date, we can take the telescope to their factory in Newcastle Under Lyme, where they will clean the primary free of charge. To do so they will remove it from the telescope and clean it, then re-assemble it, re-set the mirror to mirror distance and provisionally collimate the secondary. It has to be removed from the tube to clean it, as it cannot be cleaned in situ without endangering seals etc. inside, so it is better done by them than by us.
Collimation from new is a 2 step process.
Step 1
Collimation is more easily done by two people one making the adjustments and the other checking the results. but it can be done easily enough by one if the chosen star is not too high up in the sky.
Fit the Ronchi tube into the 1.25" adapter and the 26mm eyepiece into the end of the Ronchi tube, then screw the adapter to the telescope, a large thread. Point the telescope at a bright star, Mag 3 to Mag 1 and with the drive running, centre the star in the middle of the eyepiece field. Adjust the focuser so as to put the star out of focus, inside focus, not outside focus. Make sure the now doughnut shaped star is in the middle of the eyepiece field, this is important. To do it you'll have to have your eye close to the eyepiece so you can see all the outside of the field. The white disc of the doughnut is the star and the black centre in it is the secondary mirror. The aim in collimation is to get both discs concentric with each other. If the black disc looks to be central or very close to it you have successfully completed Step 1.
However, if the image we see in the eyepiece is more like the one on the left of this image, we'll have to make adjustments.
The picture above is of the secondary holder, showing the 3 collimation Allen screws, 3mm, and the larger central Allen screw, 5mm, which secures the secondary holder to the spider, don't touch the central one at this stage. The central screw holds the secondary holder to the spider, the 3 adjusting screws work in a push/pull fashion. If you slacken one you can tighten the other two to get them all to a similar tension, and if you tighten one you should slacken the other two, but when making small adjustments it is not easy to do this.
Adjust one of the 3 collimation screws by about a 1/4 turn. Note - If you have got Step 1 done well this 1/4 turn is almost too much to move it. This is where you gain experience in collimation, knowing which screw moves the image in which direction. After 2 or 3 attempts it will become clear. Note in which direction the image in the eyepiece moved. Reposition the telescope to get the doughnut into the centre of the field again (note that you cannot judge accurately till you have the star in the centre of the eyepiece field). If it went in the right direction, continue to make adjustments in a similar manner. If it went in the wrong direction make opposite adjustments. A little time spent here, on the preliminary collimation will bear dividends later when we come to the final collimation with higher magnifications.
An easy method to remember which screw to move is to remember 'Bulge -- In'. This means turn the screw that matches the bulge of the doughnut, the thickest part, inwards. ie. clockwise.
Assuming we now have the black disc in the centre of the doughnut we have successfully completed the Preliminary Collimation and can move to Step 2, Final Collimation.
Step 1
Collimation is more easily done by two people one making the adjustments and the other checking the results. but it can be done easily enough by one if the chosen star is not too high up in the sky.
Fit the Ronchi tube into the 1.25" adapter and the 26mm eyepiece into the end of the Ronchi tube, then screw the adapter to the telescope, a large thread. Point the telescope at a bright star, Mag 3 to Mag 1 and with the drive running, centre the star in the middle of the eyepiece field. Adjust the focuser so as to put the star out of focus, inside focus, not outside focus. Make sure the now doughnut shaped star is in the middle of the eyepiece field, this is important. To do it you'll have to have your eye close to the eyepiece so you can see all the outside of the field. The white disc of the doughnut is the star and the black centre in it is the secondary mirror. The aim in collimation is to get both discs concentric with each other. If the black disc looks to be central or very close to it you have successfully completed Step 1.
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The picture above is of the secondary holder, showing the 3 collimation Allen screws, 3mm, and the larger central Allen screw, 5mm, which secures the secondary holder to the spider, don't touch the central one at this stage. The central screw holds the secondary holder to the spider, the 3 adjusting screws work in a push/pull fashion. If you slacken one you can tighten the other two to get them all to a similar tension, and if you tighten one you should slacken the other two, but when making small adjustments it is not easy to do this.
Adjust one of the 3 collimation screws by about a 1/4 turn. Note - If you have got Step 1 done well this 1/4 turn is almost too much to move it. This is where you gain experience in collimation, knowing which screw moves the image in which direction. After 2 or 3 attempts it will become clear. Note in which direction the image in the eyepiece moved. Reposition the telescope to get the doughnut into the centre of the field again (note that you cannot judge accurately till you have the star in the centre of the eyepiece field). If it went in the right direction, continue to make adjustments in a similar manner. If it went in the wrong direction make opposite adjustments. A little time spent here, on the preliminary collimation will bear dividends later when we come to the final collimation with higher magnifications.
An easy method to remember which screw to move is to remember 'Bulge -- In'. This means turn the screw that matches the bulge of the doughnut, the thickest part, inwards. ie. clockwise.
Assuming we now have the black disc in the centre of the doughnut we have successfully completed the Preliminary Collimation and can move to Step 2, Final Collimation.
Step 2, Final Collimation.
Replace the 26mm EP with a higher one, 12 or 15mm and go through the collimation process with this eyepiece to obtain centrally located perfectly concentric white and black discs. This will be more difficult than with the 26mm eyepiece, but persevere. To improve still more, for photography, add a Barlow or a shorter EP, perhaps 4mm, or add a Barlow to the 15mm one, making the process even more difficult, and requiring very small adjustments to the adjusting screws, in the region of 1/16th of a turn of the Allen screws and corresponding care in getting the tension equal on the screws.
Using a high magnification eyepiece requires that we use eyes without any sign of astigmatism too.
Now ensure the central screw is secure, and the job is done. An occasional recheck with a short FL eyepiece should be all that is necessary.
BJ-6.2.16/19.9.16/30.9.16
Replace the 26mm EP with a higher one, 12 or 15mm and go through the collimation process with this eyepiece to obtain centrally located perfectly concentric white and black discs. This will be more difficult than with the 26mm eyepiece, but persevere. To improve still more, for photography, add a Barlow or a shorter EP, perhaps 4mm, or add a Barlow to the 15mm one, making the process even more difficult, and requiring very small adjustments to the adjusting screws, in the region of 1/16th of a turn of the Allen screws and corresponding care in getting the tension equal on the screws.
Using a high magnification eyepiece requires that we use eyes without any sign of astigmatism too.
Now ensure the central screw is secure, and the job is done. An occasional recheck with a short FL eyepiece should be all that is necessary.
BJ-6.2.16/19.9.16/30.9.16