Quote:

---

Under average seeing conditions, a useful rule of thumb in astronomy is that a good 3" to 4" refractor will usually outperform an average 6" to 8" reflector or Schmidt-Cassegrain for seeing details on the Moon and planets, splitting binary stars, and resolving globular clusters."

---

Post Extras:

Quote:

---

Quote:

---

Under average seeing conditions, a useful rule of thumb in astronomy is that a good 3" to 4" refractor will usually outperform an average 6" to 8" reflector or Schmidt-Cassegrain for seeing details on the Moon and planets, splitting binary stars, and resolving globular clusters."

---

Well, you can't always believe what your read. I have several 3 and 4 inch refractors including one of each that I consider excellent. They are no match for my pedestrian 8 inch F/5 Synta reflector on the planets, globulars etc..

If your average seeing conditions are so poor that a 4 inch outperforms an 8 inch, you have my sympathies and I am glad that rarely is the seeing that bad around here.

Jon

---

I agree with Jon. I have had a 3 inch and now have a 4 inch ED refractor with excellent star tests and the are not a match on planets or the moon to my 8 inch SCT. They beat my sct for ease of use and wide fields but the 8 inch scope has more resolving power that can not be matched by the smaller scopes even when the seeing is below average.

When the seeing is that poor, i usually stay indoors

Post Extras:

Quote:

---

My only refractor I have ever owned was a 50mm toy. So this should be quite a learning and enjoyable experience.
Also, what really made me want to get a refractor aside from refractors being awesome, was the book starlight nights. One of the best books I have ever read.

---

Post Extras:

Quote:

---

"And if you are not using a Paracorr and the good eyepieces in your Dob, you might be in for another treat."

I'd bypass extras for the old scope and focus on the new toy, the refractor instead, like a pier to clear the tripod which will allow for more comfortable, direct, straight-through observing, if so inclined, in addition to extra two-inch oculars, if lacking.

Refractors do not require coma-corrective devices.

Cheers,

Alan

---

Alan:

I know you don't seem to appreciate the capabilities of a large Newtonian but the refractor is a companion to that Newtonian and both can benefit from high quality eyepieces. The combination of high quality eyepieces plus a Paracorr in a 15 inch Newtonian can provide those nice pinpoint stars all the way across the field of view, the difference being that they can be about 3 magnitudes dimmer and still be seen.

And it is true, faster refractors do not require coma correctors but they do require correctors for field curvature if sharp to the edge views are to be obtained...



Jon

Post Extras:

Quote:

---

The integrated dew shield will delay dew formation for only a short time. There used to be foam-lined dew shield extensions offered, I've forgotten the brand, but AstroZap currently offers a felt-lined shield which slips over the end of the scope's shield and would help extend observing time. I've been looking at the electric dew controllers, and they're the best, particularly if you observe for several hours, with heating straps for the objective, eyepiece, etc. I haven't decided which method to choose myself...probably the electric system.

Cheers,

Alan

---

There are a number of options. What I find works best is to live in a dry climate...

Jon

Post Extras: