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How to assemble SW 70mm Guide scope system on to 150 PDS EQ-

PostPosted: Wed Aug 31, 2011 8:30 am
by PARTY MARTY
Hi all members of Astronomy Shed! :D

Here is simple step by step Haynes style tutorial, which you show you how to assemble the Sky watcher 70 Guide scope on the 150 PDS on a EQ-5 Mount. Obviously this tutorial can used as a guide line for other telescopes and mounts, but this mainly aimed for the Sky watcher models. So read on and enjoy.....

ITEMS NEEDED

70mm Guide scope (Including 100mm rings, guide bolts)
2x 6mm x 25mm Allen Bolts
Sky watcher Medium (21cm) Dovetail plate

TOOLS REQUIRED

6mm Allen key wrench
6mm Thread cutting tool or Drill with 6mm Drill bit
Philips or Cross point screwdriver


1. Firstly take off the Dew shield of the Guide scope.

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2. Now take off the 3 screws supporting the Lens cell and tube, using a Philips screw driver. The screws are quite small so be careful not to lose them!!

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3. The Lens cell can now be taken off the tube.

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4. Then screw by hand the 6 x Guide Bolts onto the 2 Guide rings loosely enough so that you can slide the guide rings through the tube.

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5. As you can see wrong in this picture the M6 x 25mm mounting bolts can not be mounted from the inside of the 100mm Guide ring preventing the Guide scope tube from sliding through, However depending which size guide scope rings you have determines whether you can slide the tube or not.However I had mount the bolts the other way round, but luckily the rings had M6 thread to enable for me to do this way round.

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6. Then take off the Main Scope mounting rings, so that you don't mark or damage the main scope tube, Then you can do 2 things:
You use the 6mm thread cutting tool (Tab) carefully re-cut the 1/4 thread on the the main tubes or alternatively you can drill them out
using a Drill fittted with a 6mm drill bit, Just bear in mind when you do this you will not be able to use the camera adaptor thread
which usually comes with the scope main rings if you do this way!!! I prefer the the thread tapping method myself!!!

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7. Now when you ready to mount the guide rings, you need the Sky watcher medium (21cm) Dovetail plate, And you'll need to take off
the 4 little Allen bolts mounted on the plate it self, Then as you can see on the picture below indicates where you need to place the
M6x25 bolts through when mounting the guide rings and the main scope rings.

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8. You can fit the Guide rings without the Dovetail plate, However you won't be able to the Guide scope on to main tube properly, so
a Sky watcher Dovetail plate is necessary to provide a small gap as shown in this picture below. that's the main reason why a plate is
required and I prefer the Dovetail because the the Guide rings are held and much more. You can Alternatively make a Dovetail yourself
as well, but I recomend the Sky watcher Dovetail to be honest with you!

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9. Now use the Allen Key wrench and screw the M6x25 Bolts at each end of the Main telescope rings, SW dovetail plate and the Guide
rings together, Don't tighten them just yet!!

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10. Now feed the SW 70mm Guide scope tube through the guide rings, And screw the guide bolts in-ward onto the tube, What is does is
enable the guide rings to be centralize along the Guide scope tube and Dovetail plate.Once fitted tighten up the 2x M6x25 Bolts up,
carefully Do not over-tigthen which you may damage the threads and strip them on the Guide rings itself, So it's only
finger tight to 5 to 10 Nm that is all!!! Use a Torque Wrench if necessary.

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11. Now re-place the lens cell back on the Guide scope, and tighten the 3 screws with the Philips Screwdriver.You might need to loosen
the Guide ring bolts to enable you to rotate the Guide scope to tighten the last screw!! After tightening all lens cell screws replace the
Dew Shield and Lens cap.

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12. Now carefully mount the Guide scope assembly and Main scope rings back on the telescope and mount altogether. And you'll need to
Re-balance the scope set-up, by adjusting the main tube and counter- weights. If you unsure how to do it, refer to Dion's tutorial on
Telescope Re-balancing and set-up clip.

13. Now after adjustment your scope should look like this and ready for capturing great images HAVE FUN!!! :D :D :D ......

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Re: How to assemble SW 70mm Guide scope system on to 150 PDS

PostPosted: Wed Aug 31, 2011 8:45 am
by PARTY MARTY
Also I forgot mention, That the Guide scope can be adjusted the same way as you do for Finder scope alignment. Simply use a low power eyepiece, Get the image into view and central in the field of view of the main Scope and then adjust Guide scope accordingly with the image viewed from main scope, by adjusting the Guide bolts. It's that easy!!!!! :D :D :D :D

Tip: If you have a Recticle Eyepiece, mount it on the main scope first and get the object viewed and central to the cross hair and then adjust the Guide scope with the Recticle Eyepiece at the same object, Providing much more accurate alignment!!! :D :D :D