by jgabany » Tue Dec 27, 2005 6:37 pm
Hi:
Schmidt and Maksutov Cassegrain telescopes take the approach you mention- the secondary mirror is attached to the underside of a clear lens that is placed at the opening of the scope.
These kind of telescope designs are some some of the most popular in the world- Meade and Celestron have sold hundreds of thousands over the past 30 or more years.
While this removes the twinkle artifacts (also known as diffraction spikes, by the way) it introduces other issues caused by forcing the light to pass through a piece of glass before stiking the primary mirror.
Unless the large lens at the front of the scope is carefully made, subtle color smearing, a slight loss of light and loss of details can be introduced to the image.
I have owned several telescopes by both these fine manufacturers but, through experience, concluded that I would rather have the twinkles. :>)
Hi:
Schmidt and Maksutov Cassegrain telescopes take the approach you mention- the secondary mirror is attached to the underside of a clear lens that is placed at the opening of the scope.
These kind of telescope designs are some some of the most popular in the world- Meade and Celestron have sold hundreds of thousands over the past 30 or more years.
While this removes the twinkle artifacts (also known as diffraction spikes, by the way) it introduces other issues caused by forcing the light to pass through a piece of glass before stiking the primary mirror.
Unless the large lens at the front of the scope is carefully made, subtle color smearing, a slight loss of light and loss of details can be introduced to the image.
I have owned several telescopes by both these fine manufacturers but, through experience, concluded that I would rather have the twinkles. :>)