10mm Delos or 9mm Nagler

[Ricochet]

Also, as an answer to the initial question, 10mm Delos, unless it is for use in a binoviewer in which case you will need a pair of Naglers. 

[Stardaze]

20 minutes ago, John said:

We would all benefit from more reviews that are as comprehesive as that

What translator are you using there John? Google can't translate all of that text for me? 

5 minutes ago, Ricochet said:

It's the square root of two (ish). Using that spacing between eyepiece focal lengths results in a doubling or halving of image brightness (for extended objects), which is equivalent to one step in brightness as far as the human eye is concerned. For DSOs I think it is the ideal spacing. At high powers you may need tighter spacing so that you can match your magnification to that supported on a particular session (e.g. for planetary observation). 

Ah ha - thanks!  I think you've gone the clever route from memory, of a 14 and 10 with the x2 Barlow option to get you to the higher mags? I like the idea of getting the core EP's right. 

[Stardaze]

1 minute ago, Ricochet said:

Also, as an answer to the initial question, 10mm Delos, unless it is for use in a binoviewer in which case you will need a pair of Naglers. 

I am still leaning towards the Delos after all of this I think..

[Ricochet]

Just now, Stardaze said:

What translator are you using there John? Google can't translate all of that text for me? 

Ah ha - thanks!  I think you've gone the clever route from memory, of a 14 and 10 with the x2 Barlow option to get you to the higher mags? I like the idea of getting the core EP's right. 

Yes. 28, 14, 10, 2x TeleXtender. There's a gap at 20mm that almost had an HDC in it but I wasn't sure it was needed and so I've not bought one (yet). 

[Stardaze]

8 minutes ago, Ricochet said:

Yes. 28, 14, 10, 2x TeleXtender. There's a gap at 20mm that almost had an HDC in it but I wasn't sure it was needed and so I've not bought one (yet). 

You've managed for a fair few years, so I'm sure you don't absolutely need it. The 14 and 10 make a lot of sense for doubling up. How's the 28? 

[Highburymark]

47 minutes ago, John said:

We would all benefit from more reviews that are as comprehesive as that

Hear hear John.  The French astronomy press appears to be a little more courageous than some others....

[Ricochet]

22 minutes ago, Stardaze said:

How's the 28

For the money, extremely good. It isn't perfect, there is a slight distortion of star shapes towards the edge, but I suspect the majority of people wouldn't even notice. It's slight enough that I can't remember off the top of my head which, possibly astigmatism. The face cup means you have to turn your head a bit to look through it but that really doesn't matter. The 31N is probably the only similar eyepiece that is (slightly) better.

[Solar B]

1 hour ago, John said:

We would all benefit from more reviews that are as comprehesive as that

I love this review ... must delve into it more   deeply ... I’m surprised at the Tak , Nikon & Pentax results and wondering what EP would merit a 18/20 or higher result 🤔 the only EP I own from the test is the lowly Luminos but I really like it in my PSTs it’s just great fun , however when switching to SM60s I require superior optics to achieve the desired sharpness & contrast , so yes perhaps an EPs fun factor should be rated ... Luminos 4/5 😅

Brian.

[jetstream]

10mm Delos.

[Geoff Barnes]

Blimey, they only rate the XW at 12 and the Ethos and Delos at 15/16 out of 20! 

Certainly leaves a lot of room for improvement in performance but one has to ask how on earth that could be achieved. 🤔

[John]

6 hours ago, Geoff Barnes said:

Blimey, they only rate the XW at 12 and the Ethos and Delos at 15/16 out of 20! 

Certainly leaves a lot of room for improvement in performance but one has to ask how on earth that could be achieved. 🤔

A number of factors go into that overall rating - ff the Delos / Ethos were 30% less expensive as the XW maybe they would have got 18/19 out of 20 ?

I'll have to have another read and see if I can understand exactly how those scores are derived. Any fluent French speakers around ?

It would be interesting to tot up just the optical performance ratings and see what the result is.

The surprise for many might be the Tak and Nikon scores. Both those eyepieces get great reviews from those who own them.

[Geoff Barnes]

@John, I used Google Translate, but it couldn't cope with the whole page, so I copy and pasted each individual EP section into Translate and it coped with that.  

[Stardaze]

30 minutes ago, Geoff Barnes said:

@John, I used Google Translate, but it couldn't cope with the whole page, so I copy and pasted each individual EP section into Translate and it coped with that.  

It was a little odd in that the web page for translate couldn't translate the whole document, but loading up the PDF separately worked. 

[Don Pensack]

21 hours ago, Stardaze said:

Thanks Don. Apologies up front, but what’s the of 1.4 decipher?

The idea is to yield the same increase with each change of focal length.  Dividing by 1.4 = a 40% increase in magnification.

That is where Pentax came up with the 20--14--10--7--5--3.5mm focal lengths for their XW eyepieces, as one example.

There is nothing sacred about a 40% increase--some people like more, or less.

But since you posted you had a 16mm and 6.7mm, I was trying to find an in between focal length that would yield a fairly even change in perception.

Ricochet explained it quite well.

[Stardaze]

After all of this, I’ve managed to find an 8mm Ethos secondhand for the same as the Delos new. Can’t wait to give it a whirl but the forecasts still don’t look good for the week.

Realised that I could do with a Baader 28mm extension too so something else to sort. I’ll have to keep an eye out for a 6mm to match at some point, but really happy with my core 100 degree EP’s (20/12/8) for now.

[John]

Well done on finding a good deal on the 8mm.

I use 28mm Baader Fine Tuning Rings as 2 inch barrel extensions on my Ethos 13, 8 and 6. Mostly because I can then use 2 inch filters with them.

 

[Stardaze]

13 minutes ago, John said:

Well done on finding a good deal on the 8mm.

I use 28mm Baader Fine Tuning Rings as 2 inch barrel extensions on my Ethos 13, 8 and 6. Mostly because I can then use 2 inch filters with them.

 

I hadn’t read much around the Ethos beforehand John, so I’ve realised this morning the need for one. I’ll get one ordered up as adding the O-III is handy for some planetary nebulas. Also covers the protruding 1.25 central piece which is always a good thing in my book. Looking forward to seeing what some of the current globula’s render with it.

[Dantooine]

On 22/08/2020 at 17:49, John said:

Well done on finding a good deal on the 8mm.

I use 28mm Baader Fine Tuning Rings as 2 inch barrel extensions on my Ethos 13, 8 and 6. Mostly because I can then use 2 inch filters with them.

 

Would the 13, 8 & 6 still fit in a diagonal with the baader skirts fitted? I have the 2” click lock and this would finish off the eyepieces really well. 

[John]

1 minute ago, Dantooine said:

Would the 13, 8 & 6 still fit in a diagonal with the baader skirts fitted? I have the 2” click lock and this would finish off the eyepieces really well. 

Yes they do. It does affect their focal position though because the full length of the barrel plus the extension is a bit longer than a normal length 2 inch barrel and it won't fully insert into most 2 inch diagonals.

The Ethos focal positions are all over the place though so a small adjustment does not make a lot of difference in practice.

 

[Dantooine]

2 minutes ago, John said:

Yes they do. It does affect their focal position though because the full length of the barrel plus the extension is a bit longer than a normal length 2 inch barrel and it won't fully insert into most 2 inch diagonals.

The Ethos focal positions are all over the place though so a small adjustment does not make a lot of difference in practice.

 

It must be close to the prism. With a filter on the skirt I would imagine my Zeiss prism wouldn’t be very happy. 😡

[John]

50 minutes ago, Dantooine said:

It must be close to the prism. With a filter on the skirt I would imagine my Zeiss prism wouldn’t be very happy. 😡

There is usually a ring down inside the barrel to prevent anything coming into contact with the optics of diagonals. Well there is on mine anyway.

 

[Dantooine]

39 minutes ago, John said:

There is usually a ring down inside the barrel to prevent anything coming into contact with the optics of diagonals. Well there is on mine anyway.

 

You have tv diagonal, I think that has. My baader doesn’t, it’s a straight edge all the way to the glass. Best I “rough it” for now with the dual barrel  just in case. 

[John]

2 minutes ago, Dantooine said:

You have tv diagonal, I think that has. My baader doesn’t, it’s a straight edge all the way to the glass. Best I “rough it” for now with the dual barrel  just in case. 

I have an AP and a couple of TV's. Both brands have that stop. I used to use a 2 inch barrel on my Zeiss T2 prism diagonal but with that arrangement the body of the diagonal makes sure that the 2 inch barrel does not get to the prism.

If you are using the 2 inch skirt you have to watch for that 1.25 inch barrel. More than one person here has dinged their prism !

I mostly use the Ethos in my 12 inch dob so no problem with that of course. My fracs tend to get my 1.25 inch eyepieces.

 

 

 

[Stardaze]

Just given my new Ethos it’s first light and am very impressed. Only issue Is that it tops out the focuser, but with the click lock I can clamp it a few mm out to gain focus. Guess an extension / spacer rings are a necessity.

The field seems much flatter than my APM 13 but didn’t compare, got lost in some globs.

[Dantooine]

31 minutes ago, Stardaze said:

Just given my new Ethos it’s first light and am very impressed. Only issue Is that it tops out the focuser, but with the click lock I can clamp it a few mm out to gain focus. Guess an extension / spacer rings are a necessity.

The field seems much flatter than my APM 13 but didn’t compare, got lost in some globs.

Which focal length is it? Too much mystery.