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Mak-cass v Mak-newt: best planetary scope?

Started by lthaxton, 07/30/2005 06:58AM
Posted 07/30/2005 06:58AM Opening Post
This is an off-shoot of the longer thread re: newtonians v APOs. Many folks mentioned Mak-newt or Mak-cass scopes as good planetary performers and that got me started thinking about trying one or the other in a large size. I have owned a couple of Mak-newts (MN56 and MN76) and found they provided excellent performance as visual planetary scopes. My experience with Mak-cass scopes is almost nil- one 6" F/12, Intes as I recall. I am wondering what folks have experienced with 8" and larger mak-cass scopes (TEC 8" F/15) versus something like an MN86. The MN has a much smaller secondary obstruction while the Mak-cass enjoys a longer focal length and use of more relaxed eyepieces to reach equal powers. Is there a consensus (bad word I know!) on which format makes a better visual planetary instrument? Seems like an 8" to 10" MN would be a great choice though something like Roland's 10" Mak-cass may be even better. Your thoughts and experiences?
Posted 07/31/2005 01:09PM #1
The problem with a typical mak-cass (meaning not made by AP) is the large secondary obstruction. If you live in an area with good to great seeing, they are great scopes. If you live in CT, like me, the seeing can be terrible. Then the large first diffraction ring merges with the airy disk to form the "airy blob". I had a Intes-micro 7" Mak-cass with certified 1/8 wavefront optics. Wonderful scope. Except 90% of the nights the seeing was so bad you couldn't even form an airy disk. On nights like that, deep sky observing is the thing to do, but the mak-cass has such a narrow field it is not suitable for that. In short, a great scope that for 90% of the time, like the vice-presidency, wasn't worth a pitcher of warm spit.