Celestron excel 12mm

[barry f]

I have one of the above on my nexstar 6se but find that its not as clear as i was hoping when iuse the   25 mm plossl altho the images are smaller it seems a lot clearer is this because the excel isnt up to the job and should invest in something better  or maybe something else ?

thanks guys 

 

[John]

Do you mean the X-Cel LX or the older X-Cel ?

Actually, in an F/10 scope like yours both should work fine and give good, sharp views at 125x. Things to check are that your scope is properly cooled down (can take 30-60 minutes if taken from a warm environment), that the optics of the scope are not misted. 

 

 

[barry f]

I dont think they are misted as i take extreme care with it 

its the newer excell i wondered if it was a  quality thing as i know they are not the most expensive of ep's

but my plossl is so much sharper not really sure what to do  ????

[John]

The newer X-Cel LX eyepieces are pretty good. It should certainly be as sharp as an ordinary plossl.

What targets appear sharper when you view them with a 25mm plossl over the 12mm X-Cel LX ?

When I said misted I meant dew - the schmidt-cassegrain type scopes attract dew like a magnet sometimes on the exposed top surface of the front corrector lens. It's sometimes not possible to spot that it's happened in the dark, apart from the views going fuzzy but that would affect the 25mm plossl as well of course.

Making sure that the scope is properly cooled, not viewing from inside and through a window, and those sorts of things would have negative effects on image quality which would show up more at the higher power that the 12mm eyepiece gives.

 

 

[bomberbaz]

A 25mm plossl in your scope gives you x60 magnification whereas the 12 will be around x125. 

I would have thought that the views through either eyepiece at these levels would be sharp although there may be a slight fuzziness when looking at brighter objects such as the moon or jupiter with the 12mm, is this (fuzziness) what you are refering to?

Steve

[barry f]

yeh looking at jupiter the other night i thought  it was  a tad fuzzy afer looking at it thro the 12 mm maybe it could have been where it had not cooled enough now you mention it i will try again when the skys  permit and take a judgment from that

[bomberbaz]

Good idea. It could be either the scope not cooled properly, however the effects of atmospheric currents are also exaggerated the higher the magnification you go especially on brighter objects although it could be a combination of them both.