Collimation issue?

[george7378]

Hi everyone,

I was looking at some stars this evening (I also saw ISS and Progress - I could see the shaping of the Progress ) and I noticed that there was a spike of light pointing in the same direction every time on the brighter stars. I assume it's a collimation issue?

Thanks.

[stafford_stargazer]

sounds like diffraction spikes from the spider to me,maybe wrong

Cheers G

[yeti monster]

If not a diffraction spike, then possibly a smudge on a mirror or EP?

[stafford_stargazer]

I have also noticed that cheap prism diagonal give a spike too.

G

[Ogri]

I've been getting this 'spiking' down here since about mid March (with my ST120 refractor).Viewing hasn't been too good at all since.

It wouldn't be high altitude ash would it? There's been all sorts of volcanic activity, not just in Iceland, and the upper atmosphere seems to be a bit hazy at the best of times.

When it started I couldn't get any sort of focus without big spikes, and I was starting to wonder if the focuser had a nervous breakdown and fallen apart or something.

[Astro_Baby]

If its a single spike on bright objects with the reflector it might be thermal issues.

I have seen my newt suffer from this at times usually when the scope hasnt cooled enough. It creates like a single bright line away from an object.

[george7378]

Yes - it is a reflector. I noticed the effect with some stars and not others. I also checked the optics and there are no defeccts. I'll put it down to temperature.

Thanks!

[Astro_Baby]

Give the scope a long time to cool - my 8" can show that kind of thing for up to an hour or so (a few times longer than that).

[Plantins]

Also if stars have concentric ring patterns in and out of focus you can rule out collimation.