Nightmare Collimating SW Skyliner 200p Dob

[TheThing]

Google Andy's Shot Glass for a much easier guide to collimating. Very clear and perfect for those just starting out in collimating.

It's not a dark art and nothing to worry about. Some guides are just over complicated and confusing when you're starting out - too much extra information that you don't need at all.

Whereabouts in the country are you (can't see on Tapatalk)? Maybe someone local from SGL can have a look for you?

TheThing

[John]

2. Once in sight it would not come into focus, no matter how careful I was with the focusing wheels. It was just blurred really. I tried the 10mm and couldn't see the moon at all.

You have had some good advice above on the collimation and finder scope alignment issues. Do check that the rubber "O" ring is in place around the body of the finder and is firmly holding the finder in place in the front end of the finder scope mount. Without this the finder will flop around and not hold any adjustment you make to it.

On the "blurred" focus issue, a scope that is out of collimation will still come to focus reasonably sharply. Getting the collimation right will make the focused images sharper still and will give you more contrast, ie: subtle features will be easier to see and will stand out more clearly.

If you can't bring the scope to any sort of sharp focus then it's quite possible that you are using both the 1.25" and 2" eyepiece adapters at the same time. They need to be used separately, depending on the size of eyepiece you wish to use. Using them together means that an eyepiece in the 1.25" adapter can't reach the position needed to focus on an astronomical object.

The instructions are not clear on this one so it's a common mistake !.

[umadog]

Yes, but be careful of using the Andy's Shotglass video. It incorrectly tells you that everything should be concentric through the focuser and it doesn't warn about the pitfalls of using a laser collimator.

[aurochs]

auspom I will definitely follow your guidelines for aligning the finder.

I did a collimation again today, this time I had Astro Baby's guide in hand and followed it step by step. I tried and tried and still had a slight deformation at the top of the secondary mirror, I rotated it by hand and everything. It was visible this time even without the Cheshire in. I'll try again. This time I also tinkered with the primary (wasn't so bad after all.) and now the ring actually goes over the circle in the middle. I also re-fit the finder scope and I took it outside this afternoon and lined it up with both some trees and clouds, it seemed to be accurate, certainly more so than last night. But I only checked it with the 25mm EP.

I am sure I was not using the 1.25" and 2" focuser/adapters simultaneously. It's quite possible I did leave the focuser in a locked position.

Thanks for the help everyone. I think I'll post again once I have some success.

[TheThing]

I disagree. I've always used this method successfully. It works for Mr Shot Glass and many others and is a good place to start.

Other guides are much too complicated and contain unnecessary details. Some are entirely erroneous in suggesting that you need to see all the mirror clips when this is not always possible (necessary or desirable) in a fast scope.

I'd always recommend Andy's Shot Glass to everyone starting out in collimating.

Still, we can agree to disagree. It makes the world a more interesting place!

TheThing

[Aenima]

Hi auroch,

I very much understand your troubles collimating a fast scope, though the 'fast' bit isn't the real problem, and sometimes too much worry and not enough confidence can really spanner up your works. Mine was only a 130p when my collimating crisis started, and the people on here were very helpful but I didnt have it clear in my head and was lacking confidence.

Firstly to this day I have not managed to get ALL three clips visible in the focuser/cheshire after a year of collimating, it just needs to be central - I have to put slight pressure - evenly each way -on the secondary to get the clips in sight and as long as this is a TINY amount each direction and the SAME distance from the edge - its as if your mirror needs to be 1mm bigger all round - then you can assume its okay, coz if two are visible and one is not, then your scope could be off.......Sounds strange but your clips need to be all visible or all EQUALLY invisible......sorry it does sound strange but thats how mine is.

And then the secondary, its scarier but not too difficult, just adjust the screws in tandem with each other and use your cheshire/cap to fine tune. I found this to be less covered in tutorials as the primary, you'll need to dive in and learn it soon as your able, it'll get easier.

Both astro baby and andys shot glass are good to focus your head and give you a helping hand as well as all the above advice - take it in then find your own way from there.

Good luck and clearskies

Regards

Aenima

ps one more thing - a lot of secondary mirror's edges are rough and ground a bit weird - only the surface needs to be smooth - this probably isnt your problem but it worries some people occasionally including me.