TUNING STEP 1: Disassembling the telescope
The following describes the complete disassembly of a Skywatcher Quattro 150.
A) Disassembly of the tube clamps
NOTE!!! If the tube clamps are loosened or disassembled, it can be helpful to remember the position of the telescope in the clamps. Especially the angle of rotation has an influence on how, among other things, spikes on stars are aligned. So if you want to stack older images (before disassembly) with images (after disassembly), you should pay attention to the alignment!
The disassembly of the tube clamps is very simple! Loosen the clamping screws and then open the clamps so that you can remove the telescope. Please note - there are different clamp systems, one-sided with joint and clamping screw as well as screwed on both sides. In the second case, both screws have to be removed, so that you can take off one part of the tube clamp. It is not absolutely necessary to remove a mounted prism rail for this. It is only important that the telescope lies on a table for this....please do not do this on the mount, if the telescope drops down the damage is usually huge!
NOTE!!! If you only want to mount an mirror mask or a new secondary spider, the disassembly of the tube clamps is of course not necessary! Instead, you can fix the telescope on the mount, align it horizontally and safely perform the modification work.
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B) Disassembly of the main mirror cell
The main mirror cell of all Skywatchers is fixed with four or six M4x5 screws. The disassembly is quite easy! You should be careful not to touch or accidentally scratch the main mirror while pulling out the mirror cell and during installation. Since the mirrors are quite heavy (most underestimate this if you never had a mirror in your hands) it often happens that the main mirror cell slightly slides down when the guidance of the tube is lost!
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1) Removing the four M4x6 screws (cross recess).
Please note that the mirror cell is no longer secured after removing the last screw and can fall out in principle! If the telescope has to be positioned differently for the removal, you should keep this in mind and secure the mirror cell!
2) Pull the mirror cell straight out towards the end of the tube.
If the mirror cell cannot be moved, you can loosen it carefully with a flat screwdriver between the tube and the mirror cell.
3) After removing the mirror cell, it can be equipped with a primary mirror mask, for example, or put aside for further modifications to the telescope.
We recommend covering the main mirror with a cloth and making sure that nothing can fall onto the mirror.
The installation of the mirror cell works in reverse order. Please pay attention to the tube fold, because the mirror cell has a cutout and fits only in one position into the tube ;-)
NOTE!!! Since the tolerances are quite tight, it may take a moment for the cell to fit neatly in the tube. Please do not use force! It usually helps if you use your thumbs to press the sheet metal tube into shape when inserting the main mirror cell. Especially when the tube is lined with velours, it can get tight! In this case, it is recommended to remove the Velours in the area of the mirror cell if necessary.
C) Disassembly of the secondary mirror
The disassembly of the secondary mirror can be done on most telescopes before removing the secondary spider. However, with the <6" telescopes it will be quite tight (depends a bit on the size of your hands, of course) and you should remove the secondary mirror from the secondary spider after disassembling it. Alternatively, you can remove the main mirror cell and disassemble the secondary mirror from behind.
Important note: If you remove the secondary mirror without removing the primary mirror, you should lay down the telescope for this or align it horizontally on the mount so that nothing can accidentally fall onto the primary mirror!
1) In the first step, loosen the adjustment screws on the secondary mirror so that the adjustment screw in the center of the secondary spider can be removed without force. It is sufficient to unscrew the adjustment screws one or two turns, so that the secondary mirror becomes loose and the tension on the mounting screw is released.
2) In the next step, hold the secondary mirror with one hand and remove the screw in the central hole that fixes the secondary mirror holder. Please note that there is a compression spring between the secondary spider and the secondary mirror holder, so slowly remove it backwards.
Now you can remove the secondary together with the holder from the tube and place it on a clean surface. I always use a cotton cloth for this.
D) Disassembling the front end ring and the secondary spider
In order to disassemble the secondary spider, the white end ring should be removed first. The original sheet metal spider can also be removed without removing the end ring, but there is a risk of bending the thin sheet metal struts of the spider too much, which makes straightening necessary later. However, if you want to install a CNC machined spider, for example, the disassembly is absolutely necessary.
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1) Remove the four M4 screws and pull off the end ring.
2) To remove the spider, the four knurled nuts must be completely removed. These nuts provide the fixation in the tube and the pretension of the sheet metal struts.
3) Now the spider can be removed first from the mounting holes and then forward out of the tube.
E) Disassembly of the Focuser and the Findershoe
In order to line the tube with velor, for example, it is advisable to also disassemble the focuser. This is not difficult and can be done within a few minutes.
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The focuser is fixed with four Phillips screws (M4), which are fastened with a nut inside the tube.
It is therefore helpful to fix the nuts in the tube for disassembly. For this you can use a pair of pliers or a suitable 7 mm open-end wrench.
After removing all four screws, the focuser can be removed and put aside or prepared for further tuning steps.
The findershoe is attached in the same way as the focuser. The two Phillips screws are secured in the tube with two M4 nuts. In addition, there is a thin plate as a reinforcement in the tube, which is also fixed with the two screws. This plate additionally reinforces the tube in the area of the findershoe.
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Done !!!
If you have been able to hold out until this point, it should look similar to this on your workstation, a perfect starting point to modify the Newton from scratch and equip it with some useful upgrades.
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