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Imaging Newtonian Mods

Guest Kheldar

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Guest Kheldar

Rather than leave this ramble in the equipment gallery, I thought I'd move it into a mod thread as there will be plenty more to come :)

Mod time!

I stripped it down and assessed the cell. The clips (in my humble opinion) were a little over tight, but even like this the mirror could move a good 2mm or so.

Out came the mirror!


Now some have used too much silicone causing problems later with collimation and the mirror not being able to flex enough during cool down. I have gone for the "less is more" approach.


Mirror back on and into it's overnight storage (child and dust proof!)


Edited by Kheldar
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Guest Kheldar

So I checked the results of the silicone, and it looks like less wasn't quite more this time round. There's still movement!

I guess it's a fine line, but I'm not doing it again so I decided to shim two of the three lateral cork supports with cardboard.

Solid now! However I'm not overly enamoured with those springs ... I think I will change it to the same setup as my 200P : strong springs and no locking bolts :ph34r:


The flocking arrived from FLO today, great stuff this is. My pictures don't do it justice!

With everything stripped down, I measured (twice) and cut out four sections leaving enough for a small overlap at each join.

Here's one in place.


and the completed OTA with the front baffles back in.


It's going to be a week or so before my springs arrive so rather than strip it all down again I'm just parking it till then.

In the meanwhile I need to work out a concrete way of assessing the placement of the centre donut.

I'm not convinced it's in the middle ..... by a fair few mm!

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  • 2 weeks later...
Guest Kheldar

A couple more tweaks tonight!

First up, secondary collimation. The screws on this scope are MUCH better than the hex key grub ones on SW scopes, however I am a fully signed up member of the cult of Bob :)





I did have to put a little lithium grease on them as unlike previous sets they are extremely tight! However they now adjust silky smooth :)

Next up was squaring the focuser. Not really a mod, but a useful exercise.

Step 1) Trace the focuser aperture and two of the six top cell screw holes


Step 2) Flip this over and place inside the OTA, lining up the cell screw holes marked earlier


Step 3) By simple maths, the centre of the marked out focuser hole is directly under the centre of the actual focuser hole! Put a nice blacked out doughnut here


Step 4) Finally, using a well collimated laser ensure that the beam (there is no secondary in) hits the doughnut in the centre. A credit here to the engineering as I have to do no shimming at all, it was perfectly centred :)


The front end is all back together again, fingers crossed for a delivery tomorrow : still waiting for my centre spots and template!

First light closes in ..... :D

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Guest Kheldar

Last of the mods were tied up last week. Couple more ideas, but the desire to get first light (which I'm still processing .... badly ....) was too strong!

First up new centre spot, the stock one was MILES out. I used a Catseye spot and their template to fit this (angle in picture makes it look off but I assure you it's perfect!)


More loveliness from Messer Bob! These springs are advertised for a Lightbridge I think, but fit perfectly.


The rear assembled (with no lockers as they aren't needed!)


and a finishing touch to prevent any stray light coming in at the primary end


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  • 10 months later...

A very interesting and informative thread - nicely photographed, well ordered, and laid out - a lot of newbies will benefit enormously just seeing what's inside their scopes, never mind the modifications. Good one matey :)

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