Posts Made By: Darren Drake

Which configuration between the 2 gives better off axis images given that the f ratios are the same after the newtonian's f ratio has been multiplied by 1.15X?

I'm wondering if sa can be mimicked by a bad secondary or would astigmatism be the only/most likely effect of a bad secondary?

I've never heard of such a thing which I guess is no real surprise. A high quality optic at each end of a sonotube I guess isn't something anyone really wants to try but my question is why not? It would certainly reduce costs and thermal problems would be minimized.

OK this may sound strange at first but when dealing with the public's questions about how powerfull the scope is and having to deal with Q's like "how far can it see?" or "how much does it magnify?" it's sometimes difficult to convey just what the scope can really do.
I recently conducted an experiment with a 60mm refractor stopped down to 10mm to see just how far away it could under a high X/inch mag read the print on a newspaper. It came out so that at a distance of 46 feet I could only with difficulty read newspaper print with a perfect 10mm telescope. YMMV a little of course but the idea is that if you scale up the aperture you can determine a fairly accurate answer to the question posed in the heading and have another way of telling the public how powerfull your scope is.
So if your scope is well collimated with 1/4 wave or better optics without a huge obstruction you can easily figure out how far your scope could hypothetically in perfect seeing and lighting read a newspaper by multiplying the aperture in mm by 4.6 or the aperture in inches by 117. So my 18 inch goes a little over 2000 feet and the HST to 2.1 miles!

I've always wanted to see an eyepiece forum and saw one while logged out but after logging in it dissapeared. Why?

I just returned from Niagfest where 20/20 had many of the new 5000's for sale. I noticed a few things about the enormous 30mm UW I thought I'd mention. First the eyelens is difficult to get your eye up to because there is no nose room. You have to view at an angle. Somewhat annoying. There is a little less eye relief than the 31 Nagler and is more difficult to use for eyeglass wearers. It is about 30% larger and heavier than the 31 Nagler as well. There is probably no more glass, just more casing.
While looking though a 6 inch Celestron refractor in daylight, I noticed the orange ring also seen in the 31 Nagler. It also has a very fuzzy field stop which is somewhat surprising for a premo eyepiece. It does get an A for looks and wow factor. The big question, how does it do near the edge with a fast newt still has yet to be determined.

According to Starry Night Pro on May 22nd Pluto will pass within 1.3 arcseconds of a 10.4 mag star. It should be interesting watching over several successive nights to see as it appoaches and receeds from the much brighter star.

So many here have commented that if a mirror is commercial it simply cannot compare to something the likes of a CZ or Swayze. Yet in my experiences I have seen several examples of commercial mirrors that are quite superb. My 8 inch f/6 Meade starhopper that would pull in no more than $350 here on the mart is such an example. It shows a nearly perfect star test with well defined diffraction rings and shows a perfect null on the null test. Of course it has thermal issues and a plasic fosuser and other issues but the optical quality is first rate in that scope. Maybe there is some element of luck involved but I think it is a mistake for someone who has a commercial scope to believe there is no chance it can compare to a premium mirror if they see no initial problems with image qualty and see a good star test.

Now there's a scope.
Or is it
http://paragrama.net/manalokos/view_photo.php?set_albumName=album05&id=merakkkk

I recently got the 15mm and 28mm Edmund Plossls with a new astroscan. These are not the RKEs. I really haven't compared them to the older RKEs but am wondering if anyone has. I haven't really put these through the full baterry of tests yet but may soon out of curiosity. Are the RKEs out of production?