Sky-Watcher 130MP Mod

[Alienfox]

I have a S-W 130P that I have added a motor drive to and really wanted to use my DSLR and a Webcam to capture images of Planets & DSO's, having bought the S-W 130P I find that it's absolutely useless for astrophotography, I have looked at various posts about mods, the common one seems to be moving the primary mirror 4cm up the tube? Has anyone done this and if so, 1. does it work, 2 how do yoou do it?

I have seen posts about springs and extra length bolts etc, but noe real guidence how how you do it.

Can anyone help?  I have only had the scope for a few months and at the moment cant afford to buy a 200PDS which I am saving for (should have enough buy next Christmas) so am seriously thinking about trying a mod so I can use my cameras.

Thanks  Den.

[beamer3.6m]

I modded my 130pm last night by moving the mirror up the scope.

To do this I used 70mm m5 screws, m5 nuts and wing nuts. I did not bother with springs.

I started by removing the back plate which is just 3 simple screws.

I removed the mirror from the bottom of the tube. You undo the 4(?) Screws which circle the tube sides at the mirror end. This allows you to pull out the entire back end.

I then removed the mirror clips which allows the mirror to lift out of the mirror cell. I put the mirror in a sandwich bag to keep it clean.

I then removed the screws from the bottom of the cell. 3x normal screw and 3x hex rods (very short).

Where the normal screw were I replaced them with a 700mm m5 screw. I added a nut which butted up against the BOTTOM of the cell so that the cell did not fall down the screw. You will see that these holes are not threaded but instead the screw screws into the inner cell.

The other hex rods were also replaced with 70mm m5 screws but this time I added a wing nut to but up again at the bottom.

I just screwed it all back together and then slowly moved the nuts further back up the 70mm screws until I was about 40mm further up the tube that before. I then ran the other screw up to meet the bottom of the mirror cell and used the wing nut to tighten.

Collimation was a pain in the proverbial as you cannot see the mirror clips anymore and getting the mirror central was not a quick tasks. But I managed it.

I had rubber o rings in the original and I kept this by just putting the 70mm screws through them. No point really.

It seems to work. My 400d focuses on the stars and I could even still get visual use if I racked all the way out and then pulled the eyepiece out a little also.

I have about 5mm on onward focus left with the 400d focused.

[Alienfox]

Hi Beamer, thanks for your help, I'm not entirely sure I have grasped everthing you have said, but will read it a few more times to see if I understand it better.  I have always been a visual learner so I think i need to find a technical sheet with pictures to help me.

I will have a go at this once i get it, LOL.

Thanks again.

[Alienfox]

OK, so I have been digging around on the internet and have found a few mods that may or may not work, Beamers mod, it would appear is quiet a common one, I found a website with instructions and pictures, useful, but I cant help wondering that if I drill holes further up the scope and remount the primary mirror then that should work? or am I missing something?

Watch this space.

[happy-kat]

You have to retain the ability to be able to adjust and collimate the mirror and it sounds like drilling holes further up is a ridged move of the mirror which will not work.

[beamer3.6m]

Drilling more holes will not work as the mirror cell is wider than the tube. You can see this from the black ring which encircles the tube. That is part of the mirror cell.

If you want to drill more holes then you have to shorten the tube also.

My whole mod cost me about £6.00 in screws and bolts and about 2 hours of my time with collimation.

Simples.

[Alienfox]

Ok guys, thanks very much, so no hole drilling, just a thought, I think I will go with beamers mod at some point, I have seen kits on the internet to do this, but like the idea of £6.00, as the kits are over £30 for 3 screws and springs.

Thanks again guys for your help.

[booth_robert]

this is the same problem i am having i am thinking of removing the primary cutting 40mm re dill rixing holes one question ? is 40mm to much or to little to cut off

[beamer3.6m]

It is difficult to know how much further in focus will be needed as it depends on the camera, filters etc etc.

I think the screws are very easy to do and is completely reversible as well which makes it a no brainer for me.

I personally cannot see the advantage of cutting the tube as you can never go back.

[booth_robert]

Thank is there a link for the site with pics and instructions

[Jesterowl]

I can connect a 1100D to a SW130P and get focus but only if i use the 2x barlow. 

[beamer3.6m]

I can connect a 1100D to a SW130P and get focus but only if i use the 2x barlow.

The Barlow trick will always work but it will reduce the field of view... A lot.

For real prime focus you need to move the mirror... or buy the 130pds.

[Alienfox]

I found the following somewhere?

See attached file.

Moving the mirror on the SkyWatcher 130M.docx

[beamer3.6m]

I think that link is for the 130m. Not the 130p.

I understand that these have different fixings on the mirror cell but I could be wrong.

[Alienfox]

Thank you Beamer.