Skywatcher 130 collimation

[watchoutforthatduck]

Hi friends! I've just started trying to use my sons telescope that I got him for christmas, after being beaten by the frost bitten fingers, I've spent longer trying to learn all the bits and pieces.

We saw Pollux but it appears to not be circular, which I thought was quite odd.. There was a black semi circle taken out of the bottom of it, so today I tried to align it and I got to step 1 of adjust the "3 screws"

there weren't any screws inside of it.. I found 3 screws and put those in but dont really see any difference with them being finger tight as opposed to lose, same effect.

When I look through the aline eye piece at the day time sky without the spider, the crosshair is centered.. With a strange little black square at the side..

So I took out the secondary mirror to clean it and noticed its a clip that holds the mirror, guessing that isnt an issue at night time with a correctly aligned scope? (Just noticed it gets bigger/smaller when I focus the eye piece)

Sorry, I digress.. I'm not sure if something was in front of pollux in space, that was stopping it from being an actual circle or if its because of the poor alignment.

It's very difficult for my camera to pick up the sight with the spider on but this is the best I could get after 20 picture attempts

I have no idea and I am just getting extremey overwhelmed! I'm happy with my progress but I can't do it on intuition alone, please help!

Thank you for your patience.

Edited May 21, 2023 by watchoutforthatduck

[Cosmic Geoff]

There is lots of information online about collimation. You just have to do a search for it.

Pollux should look like a dot, not a circle, notched or otherwise.

Edited May 21, 2023 by Cosmic Geoff

[watchoutforthatduck]

Thanks, yes, I have searched about it, read the manual, watched videos and I got stuck upon the "3 screws" for the secondary mirror which part has subsequently led to me asking here for help.

Edited May 21, 2023 by watchoutforthatduck

[Peter Drew]

To be able to make adjustments to the secondary mirror you will first have to slightly loosen the central screw.  The collimation does look to be considerably out, make adjustments gradually and carefully and you will soon have it better.        🙂 

[watchoutforthatduck]

34 minutes ago, Peter Drew said:

To be able to make adjustments to the secondary mirror you will first have to slightly loosen the central screw.  The collimation does look to be considerably out, make adjustments gradually and carefully and you will soon have it better.        🙂 

Thanks, the target is in the center until I add the spider then its way off center, I loosen and readjust the center screw and align the secondary mirror to be facing the primary mirror and got it as centered as I could by checking through the eye piece.

Then I add the spider, relook through the eyepiece and its like the spider is impeding the view, I am still trying to research alongside posting here, but its a slow learning curve for me.

Thank you for taking the time.

[Spile]

My guide shows how the outer and inner bolts work with one another. https://astro.catshill.com/collimation-guide/ Basically push pull. If you can take a photo through a cap (put a piece of paper behind the focuser), I’ll be able to check the alignment. However, I’d first check that the three outer and single centre bolts are working correctly.

[bosun21]

Here we go then. Tilt the scope to the horizontal position to stop anything dropping on the main(primary) mirror. As the collimation is already way out loosen or remove the three screws on the small mirror (secondary). Looking through the focuser tube tighten or loosen the centre screw until the small mirror is directly below the centre of the focuser draw tube ( ignore the tilt of it whilst doing this). Once centered place a sheet of paper directly opposite the focuser, this will outline the shape of the mirror easier. Replace the three screws and screw them in until they are almost touching the mirror holder. Next turn them a little bit each in succession until they lightly touch and hold the mirror in position. Looking through the focuser or collimation cap adjust the screws one at a time until the mirror appears perfectly round and centered in the focuser tube. Once this is attained gently nip up the three screws. Double check the mirror didn’t move whilst tightening the three screws. If you do this and reach this point I will then take you through what to do with the large mirror (primary). I will follow this thread to keep an eye on your progress. Good luck.

[Jim L]

Those three screws you put into the secondary mirror holder - I think you’ll need to remove them.  I believe those screws you installed are now covering the metric grub screws which you will need to adjust with the help of a properly sized Allen wrench, like so:

The actual collimation is a bit more involved than is easily put to writing, but these gentlemen do a very good job of explaining and demonstrating the principles:

You’ll notice they’re using a laser collimator, which needn’t be expensive. Anyway, this is a good approach to get you on the right path. Good luck!

 

[watchoutforthatduck]

Wow what a cornucopia of information, I've just woken up and need a coffee but I'm re energised today, the 2mm Allen key slides into the 3 holes and recessed deeply are the 3 "missing screws" that alluded me.

That combined with the links images and how to, I should have no problem now.

15 hours ago, bosun21 said:

Tilt the scope to the horizontal position to stop anything dropping on the main(primary) mirror.

It sounds so obvious, I had already dropped a screwdriver down it and my heart sank, luckily it was a small one.. But yeah, horizontal from now on!

 

11 hours ago, Jim L said:

Those three screws you put into the secondary mirror holder - I think you’ll need to remove them.  I believe those screws you installed are now covering the metric grub screws which you will need to adjust with the help of a properly sized Allen wrench, like so:

The actual collimation is a bit more involved than is easily put to writing, but these gentlemen do a very good job of explaining and demonstrating the principles:

 

Yeah, completely correct with the allen key, if I wasn't so overwhelmed at the time, I should have just shined a torch down the recessed holes. I watched that video around Christmas time but was like a fish out of water, now a lot more phrases and terms make sense to me so should be less like decoding the hieroglyphs.. I hoped it just arrived collimated and used it anyway.. ☺️

Thank you all for taking the time, I'm hoping to update you all later with the results of the astounding success.

Really appreciate all the support, thank you!!

 

Update 1: Just realised I've been calling the dust cap cover "the spider". 🤓

Update 2: I think ive collimated the secondary mirror sufficiently, now I'm just trying to align the primary so that the dot appears in the center, I've got it close but needs more tweaking. 👌😁

Edited May 22, 2023 by watchoutforthatduck

[Carpy]

Jason from the Small Optics Youtube channel made some good videos on collimation