Quote:
Originally Posted by mental4astro
Mick, what was the eyepiece you were using? Or was this problem present with all your eyepieces?
Were you able to adjust the focus while Venus was in the centre of the FOV and get a good image?
Without knowing the eyepiece design, it is impossible to offer any help. There are some eyepiece designs that are a very poor optical match with Newtonians. Nothing wrong with the eyepiece or scope, just that the eyepiece would most likely be designed to be an optical match with refractors, SCT's and Maks. There is a big difference between these three and Newtonians. Use the wrong EP in the wrong scope design, and the image quality can be terrible. Put the same EP in the appropriate scope design, and the image is brilliant.
Barlow lenses will also typically exacerbate an optical mismatch. Barlow lenses (by what ever name you want to give them, the term is used generically here), are not optically neutral. They are an active member of the optical train, so by definition WILL influence the way light is transmitted and redirected, and will have an affect on the way light is dealt with by the eyepiece.
Alex.
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Hi Alex,
I was using either my 40mm GSO Super Plossl or my 32mm Celestron Omni Plossl. I will take a better note this evening and report back.
When in the centre I could still adjust focus but it was never good.
Thanks
Mick