French test for 10mm f.l. eps

[Piero]

I guess many in here are already aware about this French Test. If not, here you are: 

http://www.cieletespace.fr/files/InstrumentTest/201306__6_oculaires_10mm.pdf 

It's an interesting technical comparison between the 10mm f. l. of TV Delos, TV Ethos, Pentax XW, Nikon NAV10-SW, Takahashi Tak10-UW, Celestron Luminos . 

[Ruud]

Hi Piero,

Indeed, some of us have found this review. Ciel et espace also have this one: Neuf oculaires à grand champ and a few dozen other bench tests, mostly on telescopes.

They seem to have stopped with their bench tests. That's a pity. They make for very factual reviews.

[John]

Very detailed reviews. UK and USA magazine reviews can seem a little superficial by comparison. Maybe they are serving a different market though ?

Having owned both the Delos 10mm and the Pentax XW 10mm I didn't see anything other than the slightest differences between them and those ergonomic preferences rather than anything more quantifiable performance wise. My rating for them would be equal and I'd offer the prospective buyer a Euro coin so that he / she could flip it to decide !

Thats probably why I don't write articles for a French magazine - too indecisive

 

[Highburymark]

A fascinating article, and something that the uk and us mags should be offering. 

[YKSE]

I've read this test too. From my simple engineering (none-optical) way of thinking, I would  like to see more detailed information about evaluation and scoring system used there.

For example, there's only 16 rows of different tests, where does the number 20 comes from? If we simply add the scores for all the 6 EPs, we get 78/6(Delos), 71/6(Ethos), 58/6(XW), 52(NAV), 51(UW), 40(Luminos), how do these numbers converted to 16/20;16/20 ...etc?

There're 8 tests (50% of the tests), using wave front error for evaluating, If we look closer at Delos and XW in these tests, Delos score 38/6, and XW 24/6. The worst XW wave front error is 1/19. Does it have any practical meaning? most telescopes are closer to 1/4 wave front error, that's 5 time more.

The first two test are about chromatical aberations, I'd have expect some measured values than descriptive words.

I'm sure the author has answers to all these questions, still, translating many technical measurements to ONE simple number is not very easily done, IMHO.

[Piero]

9 hours ago, YKSE said:

For example, there's only 16 rows of different tests, where does the number 20 comes from? If we simply add the scores for all the 6 EPs, we get 78/6(Delos), 71/6(Ethos), 58/6(XW), 52(NAV), 51(UW), 40(Luminos), how do these numbers converted to 16/20;16/20 ...etc?

That wis my concern too. Maybe that document is just a summary of a more extended one where the details for each experiment are provided. I'll look it up on the Internet and see whether I find something.

[Highburymark]

Agree not all the marks stand up to rigorous analysis. Giving the Ethos 1/6 for price/value is a bit meaningless considering its . But still it provokes some interesting debate.