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#21
October 13th 03, 05:25 PM
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$3000 and which scope???
In any case you don't need wide field for that either. A finder scope and
detailed charts are also advantageous. A wide field certainly helps when star hopping. A 10 inch scope at 40X with a near 2 degree FOV will pickup those faint fuzzies a whole lot better than a finder scope. I think that one needs two scopes atleast, a widefield moderate aperture scope and a larger scope that could be an Nextstar 11. jon Hey, that sounds like a plan! Yeah, its one plan, not my plan even though I suggested it. My plan is to have a nice sized DOB or two for Star hopping and some smaller scopes for Starhopping. But certainly IMHO a NextStar 11 is a viable option, especially for someone who wants to have a large SCT that is reasonably easy to setup. jon 
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#22
October 13th 03, 05:51 PM
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$3000 and which scope???
the largest Zambuto Starmaster that it would buy.. scrounge up eyepieces
and DSCs later. On 12 Oct 2003 07:31:51 -0700, (david) wrote: If you had a limit of $3000, what scope setup would you buy and why? No, I haven't won the lottery... David Herm Astropics http://home.att.net/~hermperez
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#24
October 13th 03, 07:12 PM
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$3000 and which scope???
(Rod Mollise) wrote in message . com...
(david) wrote in message om... Rod, How 'bout the NexStar 9.25? That big 11 incher is heavy : ) David Hi David: The 11 _is_ heavier than the 9, but not by much. And the excellent design of the handles (surprisingly ignored by scope makers up to this point) means that it is incredibly easy to set the 11 up on its tripod in alt-az fashion. I mean, this broken-down old hillbilly can have the NS11 out the door and setup in the backyard in 10 minutes or less. If I can do it, ANYONE can. It really is NOT more of a problem or strain than my Ultima 8. It's actually easier to get out the door and into the car, as I have a wheeled JMI case for the NS11. And the bottom line is that nearly 2 inches _does_ make a difference, nice as the 9.25 is. Peace, Rod Mollise Author of _Choosing and Using a Schmidt Cassegrain Telescope_ Like SCTs and MCTs? Check-out sct-user, the mailing list for CAT fanciers! Goto http://members.aol.com/RMOLLISE/index.html Ok so its just a few pounds heavier (I checked the Celestron site!), so how much longer do you need to allow for cool down as compared to an 8" sct? I like the idea of the wheelie bars, got to watch out for the back!! Thanks, David
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#25
October 13th 03, 07:29 PM
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$3000 and which scope???
In article ,
Tony Flanders wrote: (david) wrote in message . com... If you had a limit of $3000, what scope setup would you buy and why? What scope would *I* buy or what scope should *you* buy? Two different questions. He only asked the first question though.... :-) ...he probably realizes he must make up his own mind about what scope *he* should buy.... -- ---------------------------------------------------------------- Paul Schlyter, Grev Turegatan 40, SE-114 38 Stockholm, SWEDEN e-mail: pausch at stockholm dot bostream dot se WWW: http://www.stjarnhimlen.se/ http://home.tiscali.se/pausch/
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#26
October 13th 03, 08:40 PM
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$3000 and which scope???
But it's best not to introduce those extra elements into the optical train,
especially when one considers that the Schmidt-Cassegrain design is optically inferior to that of a classical Newtonian, This is open to discussion, especially when one considers things like coma and flatness of field. Certainly the Schmitt Camera make possible widefield photos that are impossible with a Newtonian. ---- Since we are talking F5 Newtonians, maybe it would be good to remember that F5 Newtonians suffer from coma and to obtain top notch widefield images, a Paracorr is required, or at least one needs expensive highly corrected eyepieces. On the SCT side of things, the F6.3 reducer/correctors not only reduce the focal length but flatten the field, both good things. Sometimes when I am using my 12.5 inch F4.1 Newt at high powers I amuse myself by considering the optical train, two mirrors, a paracorr with a few elements, a barlow with 3 elements, and an eyepiece with anywhere from 3 to 8 elements. So I wonder, is this a reflecting telescope, a Catadioptic Telescope or is just mostly a refractor with a couple of mirrors added? And then think, all this to achieve what a long focal length scope might do with a simple 4 element eyepiece. Yeah, I like Newtonians, thats why I have 4 of em, they are simple and easy to understand. But that simplicity comes with a price and part of that price is coma. Tell me, sir, would you say that I made a mistake in opting for an 8" f/5 Newtonian over an 8" f/10 catadioptric, and for general observing, optically- speaking, that is, without portability or other convenience issues. These are decisions based on personal choice. Certainly an 8 inch F5 Newtonian can provide some nice images, but then so can an 8 inch F10 SCT. One problem with F5 scopes is that those widefield views people such as myself enjoy occur at large exit pupils. Once one exceeds a 35mm eyepiece (and maybe even a 25mm eyepiece), aperture is being wasted. Certainly often this is a wise choice because the FOV is often more desireable than aperture. But a 42mm eyepiece in an F6 scope provides the same exit pupil and FOV with less inharent coma so one has to decide..... My choice is for DOB mounted Newtonians because I like simplicity and elegence. But I know there are trade offs and part of the compromise is accepting the optical aberations of the fast newt. jon
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#27
October 13th 03, 08:42 PM
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$3000 and which scope???
For $3k, I'd spend a winter in the workshop and come out with a big
dob. You can get a wonderful 16" mirror for under $2k, and use the rest for spider, secondary, focuser, and building materials. You could have a top-notch Dob for that money. Why? -I want to hunt galaxies. At 16" you're getting enough light that this is practical and fun. -There's no beating aperture. -There's no better value for aperture than a Dob. -I like building stuff (woodworker), and would like to try a scope -Mike (david) wrote in message . com... If you had a limit of $3000, what scope setup would you buy and why? No, I haven't won the lottery... David
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#28
October 14th 03, 01:36 AM
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$3000 and which scope???
I agree, that's why I plan to piggyback a nice rich field apo on my N11
(maybe the Orion 80 ED ..) best of both worlds "Jon Isaacs" wrote in message ... Wide field is sorta over rated. It's really cool and all that. But the vast majority of deep sky objects are actually rather small. john What seems to be true is that the vast majority of DSOs with names that fit in a done degree FOV relatively small. But there is much to see that is on a large scale like the structure in the nebulosity of the Milky Way. In a 5 inch scope with a 3+ degree FOV this is impressive as are the star fields and large clusters of stars. A geologist once told me that if you took 100 geologists and showed them a wall of rock with a small red spot in the middle every one of them would run right to the red rock and ignore the rest of it. I sometimes think amateur astronomers are like this, zoom in on a small cluster or nebula and ignore the big picture. Lots to se that won't fit into a 1 degree FOV. And of course for those who like Starhopping a wide FOV is a big advantage. I think that one needs two scopes atleast, a widefield moderate aperture scope and a larger scope that could be an Nextstar 11. jon
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#29
October 14th 03, 03:17 AM
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$3000 and which scope???
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#30
October 14th 03, 03:59 AM
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$3000 and which scope???
The only thing I use my dew shield in Colorado for has been to cut down on
stray light and counter balance my 35mm Pan. Of course we don't have the same quality of seeing on the here on the front range ... "Alan W. Craft" wrote in message ... On 13 Oct 2003 19:40:24 GMT, (Jon Isaacs) ...reflected: But it's best not to introduce those extra elements into the optical train, especially when one considers that the Schmidt-Cassegrain design is optically inferior to that of a classical Newtonian, This is open to discussion, especially when one considers things like coma and flatness of field. Certainly the Schmitt Camera make possible widefield photos that are impossible with a Newtonian. ---- Since we are talking F5 Newtonians, maybe it would be good to remember that F5 Newtonians suffer from coma... Someone who owns a Synta 8" f/5 posted within and stated that he detected only a negligible amount of coma, to which I replied that that was good to hear, so I'm not scared, mister. Though... Once mine, the Parks, arrives, I'll give a full unbiased report on both the coma, and the o.t.a.'s compatibility with the Vixen GP-DX on which it's to be placed as previously promised. ...and to obtain top notch widefield images, a Paracorr is required, or at least one needs expensive highly corrected eyepieces. On the SCT side of things, the F6.3 reducer/correctors not only reduce the focal length but flatten the field, both good things. Sometimes when I am using my 12.5 inch F4.1 Newt at high powers I amuse myself by considering the optical train, two mirrors, a paracorr with a few elements, a barlow with 3 elements, and an eyepiece with anywhere from 3 to 8 elements. Yes, an... ...f/4.1... So I wonder, is this a reflecting telescope, a Catadioptic Telescope or is just mostly a refractor with a couple of mirrors added? And then think, all this to achieve what a long focal length scope might do with a simple 4 element eyepiece. Yeah, I like Newtonians, thats why I have 4 of em, they are simple and easy to understand. But that simplicity comes with a price and part of that price is coma. Tell me, sir, would you say that I made a mistake in opting for an 8" f/5 Newtonian over an 8" f/10 catadioptric, and for general observing, optically- speaking, that is, without portability or other convenience issues. These are decisions based on personal choice. Certainly an 8 inch F5 Newtonian can provide some nice images, but then so can an 8 inch F10 SCT. Which of the two, and without Paracorrs or focal reducers, or even barlows, would be best for general observing, from wide-field vistas to the serious long-term study of Galilean transits? That's all I'm asking. One problem with F5 scopes is that those widefield views people such as myself enjoy occur at large exit pupils. Once one exceeds a 35mm eyepiece (and maybe even a 25mm eyepiece), aperture is being wasted. Certainly often this is a wise choice because the FOV is often more desireable than aperture. But a 42mm eyepiece in an F6 scope provides the same exit pupil and FOV with less inharent coma so one has to decide..... O! I would've vastly preferred an 8" f/6, but the tube was just too long; and it's not like I haven't considered the exit pupil issue, as I had already resigned myself to perhaps not being able to go much above a 32mm ocular in conjunction with even my 4" f/8 refractor, let alone the 8" f/5. Still, by just how much would the effective aperture be reduced with, say, even a 50mm ocular, and for someone in their advancing years with a maximum 5mm dark-adapted pupil? Alas, I'm only 39, but creeping on up there to be sure... ...Dad. My choice is for DOB mounted Newtonians because I like simplicity and elegence. That's STILL a classical Newtonian, as I wasn't necessarily entering mounts into the equation. That's a whole other ballgame. But I know there are trade offs and part of the compromise is accepting the optical aberations of the fast newt. Yours, at f/4.1, is on a freeway... ...mine, at f/5, will simply be meandering down an old country road. Oh, and then there's another little tiresome aspect of catadioptrics... ...dew... ...with its consequent wires and strips and shields and such. Alan
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