Newtonian Focuser Question

[DeejayP999]

Newtonian Focus Question

Well, my new Explorer 150PL turned up this week (thanks FLO!) and of course it’s been cloudy ever since.

As such, I’ve only tried the scope on terrestrial objects and I’ve hit something of a snag.

Basically, it doesn’t seem to have enough “Out focus” i.e. I begin to focus on, say, a tree but just before it comes to focus, the focuser runs out of outward travel.

This happens with all eyepieces, including the ones supplied with the scope.

Now, if I carefully take the eyepiece out and hold it about 1cm from the focuser then I can bring objects to focus (currently I’m using an old Barlow with the lens removed to extend the focuser).

Now, is it a case of “Houston we have a problem” or am I simply trying to focus on objects that are too close (the furthest terrestrial object I can see is only about 60 yards away)?

Incidentally, I didn’t have this problem with any of the refractors that I’ve owned.

[Mr Spock]

Reflectors aren't really designed to focus that close. The focusser probably has 2" or less travel. A refractor will have considerably more travel to it's focusser and so will focus closer.

[Barry]

DeejayP999

I wouldn't worry. I have the 150P and it will not focus on objects close by. It is fine however for visual and DSLR use on celestial objects. I think the manual says how close it will focus.

Barry

[DeejayP999]

Cheers folks,

That's Ok then.

I only intend looking at celestial objects - I just wanted to make sure that the lack of near focus is a feature of the scope and not a fault of some sort.