Beginner help

[tetris (Travis)]

Hi Guys,
I just bought a 10 inch Saxon Dobsonian telescope. I have inserted the 25mm lense, and can focus on relatively close landscape items.. but when I try on anything that is 500m or further away I am unable to get the telescope to focus- any ideas?? The focuser tube is sliding in and out without problems, and close items come into focus no problem.. but not the distant ones - which makes stars hard to see )

Would this mean I didn't do the collimation correctly??

[scagman (John)]

Hi Travis,

Welcome to IIS. Congrates on your new toy. You will be very happy with the views thru a 10"

Do you need to move the focuser in or out to get focus. If you slowly pull the eye piece out of the focuser while looking thru the eye peice, does it get closer to focus. IE the star gets smaller. If this is the case you will need to get an extension tube for the focuser. Something like one of there http://www.bintel.com.au/Accessories...7/catmenu.aspx

If you have a diagonal you could try with that in place as this should give you a bit more back focus.

Hope this helps.

I'm sure some of the experts here will give more advice re collimation.

Cheers

[tetris (Travis)]

Thanks,
I just realised I had both the 2inch adapter and the reducer connnected which was making the focuser too long.

Guess I'll wait till dark and see how it goes