Quote:
Originally Posted by ZeroID
Only problem is the aperture is restricted by central obstruction and a longish focal length which would limit it's performance somewhat. But one of the better options IMHO.
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Maks typically have a smaller central obstruction than SCTs - about 33% of diameter / 10% of area compared to about 40% of diameter / 15% of area for an SCT. So yes, all things considered, a 90 mm Mak may have a bit less brightness and contrast than a 90 mm refractor (perhaps comparable to an 80 mm refractor), but it is a LOT more compact, which makes it an ideal travel-scope in my opinion - which is what this thread is about.
Plus, the very good optical quality that you can get in an affordable small Mak can easily compete with an affordable achromatic refractor, and can rival a much more expensive Apo / ED refractor. Affordability is another important factor for me in choosing a travel-scope, as it's likely to get a few bumps and knocks, and even be susceptible to theft. (I'd certainly think twice before I packed a $1,000+ Apo refractor into a suitcase, and handed it over to the baboons who work in some airport baggage handling departments!)
Yes, the long focal length of a Mak may limit its usefulness for nebulae and galaxies, but it can be an excellent scope for lunar and planetary work - as always, there are trade-offs and compromises. A 32 mm Plossl in a 90 mm / 1200 mm FL Mak will give you about 1.5 degrees Field of View at 37.5x magnification, and that is an acceptable compromise for me for a travel-scope.
