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Can't afford a 4" APO?

Posted by Gary Poliquin   12/17/2007 00:00:AM

Sure I'd love to have a 4" Apo, a nice short portable tube with excellent color free images but I don't have a spare $1000+ bucks lying around.

A couple of years back I fabricated a nice 4" f15 scope using an Antares 'Vixen Spec' lens. It was supurb but required a substantial mounting and was barely portable.

I wondered if the F15 Antares lens was this good just how well the f6.5(660mm) lens would perform. I decided to order one (with fully adjustable cell).

I didn't order the complete tube assembly even though Hands on Optics is selling them for less than $400 because I have heard not so endearing things about the supplied 10-1 Crayford focuser.

I mounted mine up in some 4" PVC. I know this sounds cheesy but it actually works out very well only requiring a 13 and 1/2" piece. I placed one 3" baffle in the tube and am temporarily using a Synta 2" focusor.


Well I am very pleased and somewhat surprised. Stars are pinpoint with nice in and out of focus ring paterns. Color? Yes there is some but you really have to look for it. Looking at the 1st quarter moon the craters were sharply defined and I had to remind myself to look for the color on the lunar edge. It was very minimal. Next; Vega, not too bad at all. The orion nebula with a low power 2" wide field eyepiece was wonderful as was the double cluster.

My intention was to use this scope mostly as an RFT but it holds power quite well. I have a Wyrock focuser on order because this scope deserves more than a Synta.

I thought I would have to use a minus violet filter with this scope but I really don;t tink it needs it. I highly recommend this 'Vixen Spec' achro and please don't confuse it with some of the cheap 100mm F6's that are around.