11 replies to this topic

[Sreesha]

Hi have a Dobson 12.5"  f/4.5

 

Would it make a worthy difference between owing a Tele vue 10mm ethos vs 10mm delos for visual observation?

Assume money is not a constraint, but my question is on the "value for money".  Will I be able to see a value of difference by opting to go for ethos?

.

 

Pls advise.

[C0rs4ir_]

Of course you will. 100° vs 73° field of view is a big difference. But you will need a Para corr.

[TayM57]

Yup. This one is fairly obvious. If you don't wear glasses, than the 10E. If you wear glasses, than the 10D.

 

Either way, at f/4.5, a Paracorr II is a good investment. I would start there first.

[SeattleScott]

Divide the cost of the Ethos by 100 and the cost of the Delos by 72. That is your value for the money.

Of course if you wear glasses, you want long ER like Delos. Or if you don’t want to mess with a coma corrector, then keeping the AFOV narrower makes sense.

What isn’t being said is that some prefer long ER superwides over hyperwides, regardless of needing the ER for glasses, and regardless of coma. Others would take hyperwides in a heartbeat assuming they don’t wear glasses and have a coma corrector. So personal preference is an issue, and you won’t know where you stand unless you try them yourself. Dozens of us can tell you what we prefer. And assuming a coma corrector and no glasses, most votes will probably be for the Ethos. But that doesn’t guarantee you will prefer the Ethos.

[TayM57]

What isn’t being said....

is the quality of the optics. Assuming an excellent figure, OK, expensive eyepieces are a consideration. But if the star test looks bad or looks suspect, I would not be considering premium eyepieces at all.

[havasman]

These questions of yours are more complex than you probably realize. There's more going on than just cost, eye relief and FOV. The guy I know with the largest Dob and 35 years of experience can afford anything he wants and uses Ethos in the high focal length range and Delos at 10mm and down because he clearly sees better optical fidelity in the Delos. He observed with Al Nagler using prototype Delos ep's just before their release and Nagler suggested the Delos optics were the best TV had ever made. This was well before that one-off 11mm Apollo they made.

 

Neither my scope nor my observing capability can appreciate the optical diff that may exist and I love the 100/110^o AFOV's so I use Ethos all the way down through 3.7mm.

[SeattleScott]

is the quality of the optics. Assuming an excellent figure, OK, expensive eyepieces are a consideration. But if the star test looks bad or looks suspect, I would not be considering premium eyepieces at all.

That too.

[turtle86]

These questions of yours are more complex than you probably realize. There's more going on than just cost, eye relief and FOV. The guy I know with the largest Dob and 35 years of experience can afford anything he wants and uses Ethos in the high focal length range and Delos at 10mm and down because he clearly sees better optical fidelity in the Delos. He observed with Al Nagler using prototype Delos ep's just before their release and Nagler suggested the Delos optics were the best TV had ever made. This was well before that one-off 11mm Apollo they made.

 

Neither my scope nor my observing capability can appreciate the optical diff that may exist and I love the 100/110^o AFOV's so I use Ethos all the way down through 3.7mm.

 

I've heard similar things about Delos vs. Ethos, but suspect that the difference is very hard for most people to discern unless we're talking about a very large (22" or bigger) premium mirror *and* excellent seeing.  For my purposes, the Ethos is plenty good enough.  I've found that two of the higher mag Ethos, the 10mm and 6mm, are particularly outstanding, and think others have commented that the 6mm has the sharpness of a high quality ortho.

 

Another option for the OP might be the new 9mm Nagler Type 7, which will be coming out later this year.

[Neanderthal]

"Value for money"? A good look at the Morpheus 9mm should be in this race as well.

[Inkie]

...as well as the Pentax XW 10 mm (with a narrower field of view of 70 deg).

[Sreesha]

Thank you all for the inputs.  Let me explore further.

[CrazyPanda]

Hi have a Dobson 12.5"  f/4.5

 

Would it make a worthy difference between owing a Tele vue 10mm ethos vs 10mm delos for visual observation?

Assume money is not a constraint, but my question is on the "value for money".  Will I be able to see a value of difference by opting to go for ethos?

.

 

Pls advise.

The 10mm Delos is one of the sharpest eyepieces I've looked through. I would say it's a very slight hair sharper than the 10 Ethos but requires a good objective to pick out the differences.

 

For critical planetary observing, I would pick the Delos over the Ethos.

For general purpose deep sky observing, I would pick the Ethos over the Delos just for the expansive field of view, but only if you have or plan to get a Paracorr. Coma at F/4.5 in a 100 degree eyepiece is distractingly annoying, and it makes no sense to spend several hundred dollars on the field correction you get from Tele Vue only to use it in an uncorrected telescope.

 

The 10 Ethos is the most comfortable of the line for me - was my favorite when I owned it. I only sold it because I replaced it with a Nikon NAV-HW converted to 10mm mode. Not everyone likes 100 degree eyepieces, but the 10 Ethos is one of the most comfortable 100 degree eyepieces you can get.

 

Optical differences between the two are splitting hairs. Ergonomic differences between the two are significant. It's hard to say which one would be best for you - you sort of just have to try them for a while and see which you really prefer.