Televue Ethos 10mm and BigBarlow 2x

[pvaz]

First of all, my previous experience with high end EPs is none, so this is a review based on my 1st impressions of the Ethos 10mm and the way it behaves against my Baader Orthos with and without the barlow.

The 1st thing you notice when looking through the Ethos is it's massive FOV. I could just fit the entire moon in the FOV at 120x which is really overwhelming.

With Mars at opposition it was the natural target for the test. I started with the 9mm ortho and ND filter and could see a lot of detail, the polar cap was well defined with a large dark feature close to it, a few darker features in the south hemisphere ware very well defined too. I switched to the Ethos and the view was the same to over 80% of it's massive FOV. Towards the edges it was still very sharp but it seamed the planet stretched a little, but nothing much really, it was barely noticeable. So the 10mm Ethos seams on par with the 9mm ortho.

Then I went for the 5mm ortho, the planet became bigger but it lost a bit of sharpness and I could see 4 faint rays of light extending from it, which I think are caused by diffraction on the spider. I slided the 10mm Ethos along with the big barlow and the image looked as sharp as without the barlow, the 4 dim rays of light seen with the 5mm ware no longer there. This combination showed the best views as the planet doubled in size and retained sharpness and detail. I removed the ND filter with the same combination and, at this mag, it was dim enough to still see the detail. Just for laughs I used a trick I read where a 50mm extension tube is put in between the barlow and the EP, making the barlow work as a 2.5x. The planet increased in size but lost a little bit of sharpness, still it was almost as good as the previous view.

So 1st impressions are excellent, if I confirm this over my next observations I'll be selling the orthos, although they are excellent, the Ethos seams as good in terms of contrast/sharpness, it takes the barlow better and is much more comfortable to use on all accounts.

Considering the main purpose of the Ethos was to observe small DSOs as it produces an FOV equivalent to most 13mm EPs, I'm very pleased to find it may actually replace a few more EPs.

I'll update with conclusions taken from other sessions.

[John]

Very interesting report Paulo. I've been thinking of getting a decent 2" barlow to use with my Ethos 13mm for a while and your report might just prompt me to take action !.

The favourable comparison between the ortho's and the barlowed Ethos is pretty impressive when you consider the amount of glass in the latter combination.

Thanks for the report.

[pvaz]

Very interesting report Paulo. I've been thinking of getting a decent 2" barlow to use with my Ethos 13mm for a while and your report might just prompt me to take action !.

The favourable comparison between the ortho's and the barlowed Ethos is pretty impressive when you consider the amount of glass in the latter combination.

Thanks for the report.

Yes it did impress me the most, so I focused the review on that. I wasn't expecting this result at all.

I searched around to see if it was just a coincidence and found a thread on CN where some said they couldn't tell the difference between an ortho and an Ethos while some said it was obvious although the Ethos behaved very well regarding contrast/sharpness but lacked a bit of light transmission.

I need a few more observations to come to a conclusion. Maybe the fact that Mars was so bright last night and the seeing was steady had something to do with my observations.

[arad85]

I have a 6mm TS planetary HR eyepiece. I'm hard pushed to tell the difference between that and the 13mm Ethos ontop of the Ultima 2x... They are darned good eyepieces - the 13mm is the first eyepiece I just think is fab at every time I look through it... Expensive - yes, but worth every penny!

[pvaz]

Went out again today and observed Mars for about 2 hours which allowed for better conclusions:

Ethos 10mm vs Baader Ortho 9mm: I struggled to notice any difference. On sharpness and detail they looked the same. On Light transmission the image looked slightly more bright on the Ortho, but it toke careful observation to see it. Overall I can't really say I prefer any of these in terms of quality. On comfort the Ethos wins without any margin of doubt due to the extra FOV that allows longer periods between scope nudges.

Ethos 10mm + BigBarlow 2x vs Baader Ortho 5mm: I have to revise my previous observation, last time I had the sensation the ortho was slightly worsth then the ethos+barlow combination, today the ortho looked as good or even slightly sharper at times. On sharpness and detail they looked the same at first. After a longer period the ortho seams to show pockets of good seeing more often then the Ethos. This may be subjective, either it was luck that made the atmosphere more stable at times when I was using the ortho or the ortho seams to tolerate the turbulence slightly better. On light transmission the ortho was a bit more bright and this time it was easier to see a slight difference. Still the views with the Ethos ware nothing short from great, near excellent, and the difference in comfort was even more noticeable. I also noticed it was harder to reach perfect focus on the ortho, I suspect yesterday the focus might have been just a bit off which made it look worst.

To further test the barlow I tryed the Ortho 5mm vs Ortho 9mm + Barlow: With this combination the differences ware a bit more noticeable, the 5mm had more detail and more brightness then the 9mm+barlow. Despite it, the quality was still great with the 9mm+barlow and the difference may be in part due to the extra magnification combined with the average seeing conditions. Still the barlow perfomed very well.

[michael.h.f.wilkinson]

Nice review!

I know the feeling of seeing the whole moon at more than 100x magnification (using my 14mm UWA) it is absolutely great. For planetary work I do not really need a 100 deg AFOV because I have a good equatorial mount. For a dob it is great of course.