After collimation

[wookie1965]

I collimated my skywatcher 150p did a star test i didnt see the concentric rings just the focus tube e.g although when i turned the scope round to Saturn i got some great views but the ring nebula wasnt good at all i can usually resolve the ring very clearly i cant now can someone point me in the right direction please.This picture is just a reference its not exactly what i see i can see two rings then it just goes like the picture.

[Daniel-K]

wookie it may have been down to conditions dont blame your scope straight away. is there any way you can get a picture down the drawtube to let us see? the 150p are usually quite forgiving if its just for visual

[Moonshane]

to do a star test you are much too far out of focus. it looks like your secondary might need turning as the image is not round. I agree a shot down the scope might help.

dim objects are not as dramatically affected as bright/contrasty objects when it comes to collimation and the effect with the ring nebula is likely to be light nights or seeing, not the scope. give it another month and a clear dark sky and you'll see a big difference with or without accurate collimation.

[Stargazer_00]

I have a 150p and can tell you that the ring is quite variable in how well it shows up. I can never see it with direct view (damn central retina cone sensistivity, bad design nature!) but can mostly see the smoke ring with averted vision looking just near it.

I can just about see it directly in the 250px and can see it directly just fine in the 350p, so aperture helps on this one. A UHC is supposed to make it much easier to see as well but to be honest it doesn't from my location. It looks the same with or without the UHC and I prefer the non green version.

[wookie1965]

I will take a picture down the draw tube when i get back from the hospital and ive always been able to resolve the ring nebula even told my friend its like a smoke ring in the sky he wanted to look at it, i can normally go straight to it took a while find it then it was just a blur thats why i think scopes maybe just a bit out. I will try getting a photo through my cheshire.

[Stargazer_00]

The 150p is remarkably resilient to bangs and knocks and holds collimations amazingly well. I'd be surprised if it's far out unless you've dropped it recently or given it a real bang (walked into it or something).

I go through all my scopes once a week if I haven't been out just to check their collimation (although the 350p gets collimated when it's set up everytime anyway so this is a bit pointless). The 250px is rarely out and the 150p never needs doing. It's good to check them though and occasionally I'll just randomly put them out of alignment so I have something to do putting them back. It keeps you practiced and keeps your eye in.

[wookie1965]

These are the pictures one down draw tube and one down Cheshire. I have not banged the scope it is treated with kid gloves everytime.

[Stargazer_00]

looks alright to me, close enough is good enough

[wookie1965]

Thank you very much i really appreciate you taking the time to look and advise me looks like it was just the seeing conditions then, I will try again at M57 leave it until later in the night and when its really good seeing conditions perhaps its the heat im not used to it as i have never used my scope when its been this hot.

[Moonshane]

looks like your secondary drawtuve and rotational position is Ok but your tilt is slightly off. the cross hairs (fuzzy) should intersect on the central donut which they currently don't. in relation to you photo (second one) the donut needs to go up a bit and possibly right a bit.

do that and then centre your primary and you won't be far off.

that said, this small error on the secondary will not affect things greatly - the current sky conditions, however, will.

[wookie1965]

In relation to the donut going up and right a bit will that be accomplished with the tilting thank you.

[Moonshane]

should be, but bear in mind that sometimes the next adjustment messes up the last adjustment slightly and you sometimes need to repeat the previous step. eventually the differences get so small as to be negligible. at this point you rarely have to adjust all but the primary again.

[wookie1965]

Great thanks for that i didn't think i was too far out, it only takes practice and i just need that bit more.

[Moonshane]

the difference would be minimal but you may as well get it right as the more regular maintenance is much easier.

[wookie1965]

Yes i want to get the best out of the scope as i can, as when i change scopes that may need collimating more often i need to be able to do it competently.

[Moonshane]

often even the largest scopes need only the primary doing.

[Moonshane]

I should say after the initial major collimation is accurate.

[wookie1965]

This was the first time ive ever touched my secondary as i wanted to to check if the three bolts had points on them they do, going grind them down in near future so they dont leave dents and im sure ive read i can get a better spring.