His next scope is one of those 2-inch refractors available in toy stores. Sent from my iPhone
On Jun 27, 2015, at 9:51 AM, Siegfried Jachmann <siegfried@jachmann.org> wrote:
This was not an inch for inch replacement. Patrick came with 4.5" reflector. The 4.5" dob from Orion. He has regressed.
On Sat, Jun 27, 2015 at 9:21 AM, Brent Watson via Utah-Astronomy < utah-astronomy@mailman.xmission.com> wrote:
Good work, Patrick. I don't want to start an argument here, but a good newtonian on any mount inch for inch will provide higher resolution than a catadioptric telescope. Light gathering also goes to the newtonian because of the smaller diagonal. Portability is in the eye of the beholder with a weight advantage for the newt, but size is the strong point of the cat. My experience has been that a good six inch newt will provide about the same view as an eight inch cat, although the cat would be a bit brighter in this instance. The reason for the better resolution is the simpler optical system, ease of manufacture and smaller diagonal size. Resolution can be very well approximated by using the equation for Dawe's limit, and using the equivalent aperture of the telescope. The equivalent aperture is equal to the real aperture minus the minor axis of the diagonal.
On Saturday, June 27, 2015 5:55 AM, Wiggins Patrick <paw@digis.net> wrote:
Hi Joel,
On 26 Jun 2015, at 19:15, Joel Stucki <joel.stucki@gmail.com> wrote:
Ok I am going to display my ignorance. I thought a C-8 was more compact than a similar aperture Dob. What I was reading was that they had superior resolution and a smaller optical tube thus the higher price tag. Is it the tripod that is a pain or do I just have it all wrong? I am very interested as I am trying to decide if I want to invest in a more serious scope (currently using a 5" reflector on EQ mount Orion SpaceProbe 130 ST). Also yes Orion seems to be an awesome company for service and quality.
When it come to light gathering power, resolution and quality the C-8 is always better than my new little Dob.
But the C-8 does take up more room and is much heavier.
What I was looking for was a small, lightweight scope that provided acceptable views of things like the Moon and planets and that could be used by kids without their having to use a step ladder.
So for more serious viewing the C-8 rules. But for in-city star parties with lots of kids the little Dob works well.
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-- Siegfried _______________________________________________ Utah-Astronomy mailing list http://mailman.xmission.com/cgi-bin/mailman/listinfo/utah-astronomy
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