IS it coma, badly collimation?

[Astro-Nova]

I just had a look at a star through my 8" refrector....

Only thing I could see is a disc and am able to see spider legs, secondary mirror(black dot in the middle) and something lil square on the right hand side.

Is this just a sign it needs collimating??

[Peter Drew]

Sounds to me that it needs focusing, do you have another extension to the focuser?

[Tinker1947]

It could be the EP, what Scope and EP are you using....

[Astro-Nova]

I do have something that I can place on the focuser, big black thing, i think its to fit a 2" eyepiece on

[Astro-Nova]

Im using both 25mm and 10mm. Moon is no problem but stars it is, I will try saturn when it pops above the houses in an hour, see how that looks like

[Astro-Nova]

I just tried on mars, my theory so far is that I focus is way to far with my eye pieces, mars got quite decent look (no details ofcourse cause its way to far for these eyepieces) and when I go slightly zoom in more it gets the spider legs again.

So what Ill do is to wait for saturn and should be picking it up as its closer so hopefully its just me knowing nothing about focusing lol

[John]

When you say zoom I think you mean focus - ie: to turn the focus knobs one way or the other which moves the eyepiece in or out. When you see the black shadow of the spider and the secondary mirror you know you have moved out of focus - the point of correct focus is very precise - you only need to move the focus knobs a tiny bit and the object will go out of focus.

Saturn is much further away than Mars of course but it's a much larger planet so it looks larger in the eyepiece than Mars does. You should notice the rings clearly even at low power if you are looking at the right object.

I don't think you have either a coma or a collimation problem - it's just getting used to how precisely you need to focus. You will need to adjust the focus a bit when you change eyepieces and when you use the barlow lens as well.

[Caelus]

I might be barking up the wrong tree, but you haven't attached both the 2" and the 1.25" adapters, have you? I have seen someone else on here report focussing issues and that's what they'd done. If you have, just to clarify you only need the 1.25" tube (sorry, it's correct name evades me) attached to use the supplied eyepieces.

[Astro-Nova]

thank you all for the kind helpful replies!!!

No, I knew it was for 2" eyepieces so there is no use for it as I dont have 2" EP......yet! But it would have been a silly mistake that I could have made, knowing myself lol

Anyway at the end, I managed to find saturn and got my WOW factor, whole neighbourhood must have heard me calling my wife to hurry up and come and look, as the clouds were coming in!! Took a lil snap shot with my phone with decent quality, here I did realise I really need to start saving up for higher magn. EP's and/or barlows!

again thank you very much for your replies, they have really helped

[Caelus]

Glad to hear you got it sorted out - Saturn is a fine sight through a 200!