Stellarvue sv110ed focusing problem

[aleetk]

Hi! I have a Stellarvue sv110ed telescope. It's focal length is 770mm and focal ratio f7. I noticed that when I use a 20mm eyepiece without a diagonal, I can't seem to achieve a sharp focus on the moon or a star no matter how far out I extend the focuser. I tried the 20mm eyepiece with a diagonal and I somehow could get a better focus but still not a sharp focus even with the focuser fully extended. Anyone have similar experience or know what is wrong?

[bornfree]

Hey Alex, i asked and checked around the refractors will need a diagonal. without it, the image cannot be focused. saw this setup similar to yours and it had a extender to extend the focuser. maybe you can have a look.

http://www.cloudynights.com/ubbthreads/ ... in/4872245

[Davegn]

Hey Alex, i asked and checked around the refractors will need a diagonal. without it, the image cannot be focused. saw this setup similar to yours and it had a extender to extend the focuser. maybe you can have a look.

http://www.cloudynights.com/ubbthreads/ ... in/4872245

Yes. You need a star diagonal or an 80mm extension tube.

[cloud_cover]

Hello!
Most refractors are designed to come to focus with most eyepieces and a diagonal.
To know if insufficient outfocus is the issue, try racking in and out completely. If its a case of insufficient travel, the image should get gradually better but not quite reach focus. On the other hand, if its an optical problem, then the image will get better but as you continue racking out it will get blurrer again
If you think its insufficient focus travel, then try pulling out your diagonal and eyepiece a bit and see if it comes to sharp focus.
Finally, is you version the SV110-BV? The BV version is designed to work with Binoviewers and has a particularly short focuser/OTA tube and will need extenders to reach focus with normal diagonals/EP. This should have been provided to you if its the BV version.

[orly_andico]

My AT90EDT is not BV ready but it also needs an extension tube to reach focus without a diagonal. Actually short eyepieces don't quite reach focus with a 1.25" diagonal, but they do with a 2" diagonal with its longer optical path.

[aleetk]

Thank you guys for all your input. I will give it a try again with a 2" diagonal or extension tube once the skies are clear. My telescope is also not the BV model but it's stated in the manual that it can be used with a binoviewer.

[rlow]

TS, your scope should come with a 121mm threaded extension tube. It was designed that way so that it can be more compact for travel portability.

[antares2063]

nice...stellarvue 110.. is yours the Carbon Fiber version? ;)

Off topic: the scope that bornfree posted looks good, cant help but be drawn to the dual Nikon eyepiece in the binoviewer..

regards,
Junwei

[aleetk]

antares2063: Nope, mine is not carbon fiber. The carbon fiber one is another model. My model is the Stellarvue SV110-25SV.