Trouble focusing

[Sirius Starwatcher]

Can any one explain why I can't get focus and also advise on remedy please.

I have fitted a 2 inch  Baader Clicklock to the focuser tube on my SW Startravel 120mm. My least powerful eye piece is a vixen SLV 20mm. With the focuser tube all the way home with no travel left I am unable to get focus. I have no problem with my other EP's.

[Moonshane]

I presume you are using the 2" diagonal in your list? This might be the issue as they take up a lot of in travel (2" diagonals that is probably 100mm). Weird that it's just the 20mm. Are you getting close but not quite or a long way off?

Baader clicklocks also take up some travel (about 35-40mm) so maybe it's the combo?

 

 

[Sirius Starwatcher]

Thanks Shane. That would explain the problem. Yes the 2 inch Diaganol is used and I am very close to focus but not quit there. So without getting too technical, am I right in assuming that because I am using the clicklock and 2 inch Diaganol I have extended the focal point of the scope which is causing the problem?.

Is this going to give me the same problem when I get my 120 ed (FL 900) if so is there a fix?

[Sirius Starwatcher]

I will revert to the SW supplied Diaganol and see what happens.

[Moonshane]

the focal point has remained the same but you are eating up in focus with additional 'extensions'. I doubt you'll need the clicklock on the 120ED as it has compression fittings. I think there should be adequate room on the drawtube with the 120ED. I'll check mine later although I seem to remember being told someone had removed about 7mm from the tube to allow use of the clicklock so maybe I am wrong. That said, I have a Moonlite on it now so it won't be the same distances anyhow.

[Sirius Starwatcher]

I have replaced the 2inch Diaganol for the supplied Skywatcher 1.25 erecting prism but kept the clicklock on the scope. I have had a quick check albeit on a terrestrial target. When in focus with the 20 mm eye piece I still have about 20 - 25 cm of travel left on the focuser tube. So it would appear that the 2 inch Diaganol was causing the problem. Weather report for the next few days is not good here so may have to wait awhile to check it out of Astro targets.