Focussing problems

[cyborg421]

Hi all,

I was just outside tonight with my telescope and was just about to start observing when I found I couldn't focus on the moon with my 10mm eyepiece. I switched it for a 32mm and could just about get it in focus with the screw thread at its furthest point back. The scope was collimated with a Hotech laser and everything has been fine before tonight.

I've got a Skywatcher 250p.

Anyone know what's going on? Am I being dense?

Thanks

Simon

[Bizibilder]

Sounds like you have moved the focal point further out of the tube when collimating. Did you move the secondary towards the primary mirror at all? Or move the primary "up" the tube (towards the secondary)? You could re-collimate but make sure that the primary is as far "back" in the tube as it will reasonably go.

Another solution would be to buy a short extension tube or unscrew the lens from a Skywatcher Barlow, if you have one, and use the "empty" tube to place the eyepiece further "out"!.

[cyborg421]

Thanks Bizibilder,

I don't think I've done anything different to normal although I may have done. Everything worked fine up to now.

The only thing I could think of was that the "stop" in the focusser had been moved although I didn't know.

I thought I'd ask the advice of experts before I did anything.

Thanks for your help.

Simon