APO Telescope - Page 6

h0ughy (David) · #**101** 09-05-2008, 08:11 PM

Quote:

Originally Posted by acropolite

Sounds like there's a severe bout of spendthrift fever happening here, I await the results with keen interest.

yes, saving $$$$ is the main aim

netwolf · #**102** 09-05-2008, 08:19 PM

Hmm as i had suspected, i would say this is being made in the same factory where they make gear for Celestron and Meade. I linked to some photos in a thread i started sometime back. Good detective work there Houghy. The question still remains on the Quality control levels.

Regards
Fahim

h0ughy (David) · #**103** 19-05-2008, 12:30 PM

http://osdv.de.dd17216.kasserver.com...38&language=en

http://www.meade.uk.com/meadeedapochroma.html

marketed as Meade in Europe…………..

JohnH · #**104** 23-05-2008, 11:52 AM

Quote:

Originally Posted by Astrod00d

There is a field flattener designed specifically for the FLT110, no field flattener for the 127ED as far as I can determine. Gotta check the field flatness of the 127ED!

Any progress with your investigations re field flatness?

Astrod00d · #**105** 23-05-2008, 12:36 PM

Quote:

Originally Posted by JohnH

Any progress with your investigations re field flatness?

Haven't tried it myself yet, gotta get my 'scope first!

Allan Gould's posts indicate the field of his 127ED is somewhat flatter than the field of my Orion ED80. The WO P-flatII is supposed to work well with the ED80, although I haven't tested a P-flatII myself. I did try a P-flatIII with the ED80 and it over-corrected the field. Once we get a few 127ED's in this group I'm sure well be able to pool our resources and find the best solution.

casstony · #**106** 23-05-2008, 01:45 PM

In case you guys are interested, there's an interferometer test of a sample of this lens at the site below; go to "Tests of Optics" then "APO prototype test".

Edit - something funky with the link - click on Astro-foren at the top of the page to get to the site.

http://translate.google.com/translat...%3Den%26sa%3DG

wavelandscott (Scott) · #**107** 23-05-2008, 05:24 PM

Quote:

Originally Posted by casstony

In case you guys are interested, there's an interferometer test of a sample of this lens at the site below; go to "Tests of Optics" then "APO prototype test".

Edit - something funky with the link - click on Astro-foren at the top of the page to get to the site.

http://translate.google.com/translat...%3Den%26sa%3DG

The link worked but I don't know enough about refractors to make heads or tails of the results...

In a few sentences, in plain English...were the optics okay or not?

h0ughy (David) · #**108** 23-05-2008, 06:02 PM

Quote:

Originally Posted by wavelandscott

The link worked but I don't know enough about refractors to make heads or tails of the results...

In a few sentences, in plain English...were the optics okay or not?

yes I agree - I have no idea - anyone read technical.........?

Satchmo · #**109** 23-05-2008, 06:14 PM

This was a prototype lens. A bit zony looking wavefront and a Strehl ratio of 0.83 in Green light ( ie 83% of possible available light into the Airy Disc ) . Not particularly brilliant for high power , but the color correction is good and should make a great deep sky imaging scope which doesn't particularly push the optical quality. The error is mostly consisted of Spherical Aberration

This was only a sample of one of course. I'va attached a screen from Wolfgang's test report .

netwolf · #**110** 23-05-2008, 07:10 PM

So Mark when are you getting one to test it out for the rest of us.

Or are you strictly a Reflector man?

casstony · #**111** 24-05-2008, 12:46 AM

Quote:

Originally Posted by wavelandscott

The link worked but I don't know enough about refractors to make heads or tails of the results...

In a few sentences, in plain English...were the optics okay or not?

Fortunately Mark has provided a clear interpretation since half of the info is gobbledegook to me too. However, if you look at the strehl ratio and the distances that the colors focus from one another, then compare those figures to other scopes, I think you get a reasonable idea of how it might perform.

For example, I have an ed100, one of which tested at a similar level of optical quality as a TV102. They both had strehl .95 while the TV had better red correction and the ed100 had better blue correction (from memory). This only compares one sample of each but it's still interesting info.

bluescope · #**112** 24-05-2008, 01:48 AM

Well after having followed this thread with much interest I guess now everyone waits a week or so to see what happens when Houghy gets his scope. I for one will be ready to cough up some dollars if it is what it seems to be .... I like the idea of adding a 127mm refractor to my collection.

Good luck Houghy .... I hope it works out for all members with a spare bit of cash .... bargain !

Satchmo · #**113** 24-05-2008, 06:24 PM

Quote:

Originally Posted by netwolf

So Mark when are you getting one to test it out for the rest of us.

Or are you strictly a Reflector man?

I usually test at 632nm Helium Neon , which is fine as reflectors are perfectly achromatic. Refractors at the minimum need to be tested in Green wavelength which is the peak visual sensitivity.

These OTA's seem to be getting great reviews: just don't expect a Televue at Guang Sheng prices..

I love refractors: they make great finderscopes

h0ughy (David) · #**114** 29-05-2008, 09:23 AM

so who has had an email stating delivery date?

ijontichy · #**115** 29-07-2009, 11:54 AM

So how did this story end?

seeker372011 (Narayan) · #**116** 29-07-2009, 12:00 PM

lots of us wound up with the scope

and then spent a little bit extra on replacing the focuser