The main benefit of the Maksutov-Cassegrain is that it puts a long focal length in a short package. Unless compact size is very important to you, go with the 4.5". The larger aperture will give you brighter, sharper views.
Pay no attention to the maximum magnification. You can get any magnification you want from any telescope with the appropriate eyepieces. 325x is unreasonably high for either telescope. Magnifications beyond about 2x/mm (50x/inch) won't show you any more detail, and most observing is done at lower powers anyhow.
2007-04-16 05:06:53
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answer #1
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answered by injanier 7
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Lets forget that 325x magnification bit to start with, for that is really just a marketting rouse.
The important things are resolution (obviously the 4.5" wins), diffraction (obviously the Maksutov wins since it does not have that rotten spider), and finally, in spurious air currents within the tube, (and again the Maksutov wins being a sealed tube). Over all the smaller telescope has the advantage, but...
I am currently replacing the spider in an el-cheapo very old Tasco 4.5" telescope with a Maksutov corrector, made from an old grinding tool. Why waste a perfectly good bit of glass?
It's a simple matter of determining the refractive index of the tool and then doing the simple equation to predict the concave surface, before spending a weekend grinding and hogging, and figuring the surface.
With the new miniscus lens and cell, (adding extra mass and moving the balance point) with the secondary mounted through that lens, without a spider, it should out-perform the basic 4.5" Newtonian reflector having all the Maksutov advantages, especially in terms of clarity, air currents and resolution.
I would then be swapping the 494 with the 497 as the 497 should be on the better instrument, if not running the 494 as a slave on the smaller telescope. However, if the choice is to purchase an instrument, I believe the 497 is a better system but it seems wasted on such a small telescope. It would be an advantage to buy that scope just for the 497.
The field of view depends on the system's focal length, and obviously, the longer that is the higher the magnification and the smaller the field of view, so depending on the object or one's interest, one adjusts things such as the magnification with the choice of eyepieces, such as to view Jupiter (higher magnification 100x or more) or to view the great Orion nebula (low magnification about 30x or less).
Then again, some eyepieces are not designed for the users choice of telescope especially when viewing the heavenly object. This is a worry as some eyepieces give dull views (a poor optical marriage) and others work well. For instance, of my 5 different 12mm eyepieces, some work effectively in the 4.5", the others in the 3" , but then, only one of those that work in the 3" works really well in the 8" F-6 telescope. Oddly, none of those that work in the 4.5" work to my satisfaction in the 8" F-6, but they all seem to perform equally in the 8" F-11 (and I suspect badly:-).
Some Messier objects and ring nebula require larger diameter telescopes to appreciate, such as a 10" or 12", and then focal length before magnification really counts. Sure, they are visible, for Messier said when he compiled the list, "don't look here for these are not comets". In some cases it took the 72" Ross telescope in Ireland to resolve some of them.
If the purpose of the telescope is to view the appartments next door, the lowest magnification possible is the only recourse, as the general field of view of most telescopes is just too small. At 40x, a small balcony pot plant can easily fill one's view. It depends on one's definition of VIEW and really what one wants to observe. At 100 x, if using a terrestrial inverter, one can read the neighbour's newspaper. :-)
As the magnification increases, so do the problems with diffraction and stability, so the last part depends on the quality of the final image, as small seismic vibrations and other factors shake the mounting and the telescope. Sirius is a classic example on which to test magnification and image quality, as most Newtonian telescopes produce so much diffraction glare, the companion star remains hidden even in a 12". The companion becomes barely discernable in a maksutov, but then become quite clear when the 12" mirror needs to be re-aluminised.
Is that a suitable answer?
regards
Robert
2007-04-19 12:56:49
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answer #2
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answered by Robert L 1
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I have a very large Dobsonian and on good nights I have not been able to get a decen view at 325x so don't think you will either.
The Earth's atmosphere prevents most telescopes from achieving their full potential.
Maksutov Cassegrains are corrected for off axis aberrations. As a result, stars at the edge of the field in a Maksutov Cassegrain should have less coma than the stars in a newtonian reflector.
The Maksutov Cassegrain should offer nice planetary and lunar views. It's difficult to say whether or not it will offer nicer views than the reflector though, and the reflector will be more versitile. Personally, I'd just get the reflector.
P.S. Reflectors don't have color aberration. Refractors do.
2007-04-16 11:34:20
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answer #3
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answered by minuteblue 6
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The more light you gather, the brighter the image. And, the brighter the image, the easier it is to see and distinguish details. It's that simple. Take a look out your front window at noon then at midnight and you can see for yourself how much of a differece is made by the light amplitude.
A reflector is larger, bulkier, and differently balanced than a refractor. Take that into consideration also. The base/tripod will be different as well as the weights and balances when moving them.
2007-04-16 04:23:08
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answer #4
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answered by Richard M 7
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A 90mm aperture Maksutov-Cassegrain telescope gathers enough light for views of brighter deep space objects like globular clusters, nebulas, and bright galaxies. It only weighs approximately 6.5 lbs. It also is portable and can be mounted on a desktop or tripod. In my opinion it is an excellent novice or well experienced stargazers tool.
2016-05-21 03:08:38
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answer #5
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answered by ? 3
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Maks are very nice 'scopes, but at those sizes the only real difference is the light grasp. Assuming they're equaly well made I'd go for the 4.5". I'd rather spend the money on a bigger dobsonian and maybe get an equatorial mount for it later, but it's down to personal preferences.
2007-04-16 04:39:33
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answer #6
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answered by Iridflare 7
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The Mak should have less color aberrations than the reflector if it's built well and 325X is way too much for either scope. The image will be way too dim and the scopes aren't big enough to support it without serious diffraction limited problems..
2007-04-16 04:26:52
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answer #7
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answered by Gene 7
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we cant answer that only u can which one do u think is better
2007-04-16 04:14:37
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answer #8
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answered by ozkanjr 3
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