Ethos eps

[PCH]

Hi All,

can anyone offer an opinion on the use of Ethos eps. Firstly, I'm wondering if these are best suited to any particular type or quality of scope.

For example, I have an ETX125 with perfect optics, and a 12" LB with a fairly badly pitted/spotted/spoiled primary. With the LB, the pitting doesn't seem to affect the views using my current TV and Hyperion eps imo to any great degree. But I'd be reluctant to spend ethos type money if I won't get the best possible results. Of course they'd still be there to use with any future (better) scopes.

Finally, can anybody say which ethos might be best with a 12" LB, which is 1500mm f/l?

All suggestions appreciated :thumbsup:

[Rodstar]

Hi Paul,

I am very happy with my 13E. In fact, it is my favourite EP. It is very easy in terms of eye placement, has comfortable eye relief (I do not wear glasses when observing), and does not really need a Paracorr - its correction is excellent.

At a focal length of 2513mm, I get a magnification of 193x which is fantastic for galaxy hunting and fine galaxies on steady nights. However, at such a relatively high power, there are some nights when I cannot use it because the seeing cannot sustain that power.

At your focal length, a 13E would give you 115x magnification, which would make it for you a nice low-mid power EP with roughly 52 arc minutes FOV. This would be wonderful for open cluster and nebulae.

A 10E would be better if you want to hunt down galaxies and fine globulars at 150x. An 8E would be pushing things a bit, at about 187x, and you may not get quite as much use out of it.

Some like me love the immersive FOV of the ethos, others feel a little overwhelmed by it. The best advice would be to go to an observing night and try in your lightbridge to see how the various iterations suit your set-up.

The degradation to your mirror may not be as bad in terms of actual use, even if it looks bad in the light of day. The human eye has trouble detecting anything less than a 10 per cent difference in brightness, so let's say you have lost about 8 percent of the light through the damage, what you are looking at is probably almost identical to what it would look like with a pristine mirror.

[PCH]

Hi Rod,

thanks for that in-depth review. The detail is much appreciated. Do you think the ethos would suit my ETX125 which has a f/l of 1900mm from memory?

Cheers :thumbsup:

[Blue Skies]

I've not had extensive experience with them but I would say no. They are not designed to be used with a long focal length SCT and it shows from what I've seen. The first time I looked through an ethos it was in a 8" SCT and it seemed pretty ho-hum. But put it in my short focal length dob and WOW! You're probably better off looking at the Radians or Plossls (gotta admit those TV plossls are sharp in constrast).

[marki]

The 17mm is good on a SCT @F10 but the seeing has to be pretty good to use the 10mm (I do not own the 13mm). I would say they will not work well on an F15 scope (ETX 125). The 6,8,10 and 13 have 1.25" barrels and these will not be suitable at that focal length unless you are living on top of a mountain in Chile (13 mm being the unknown). The 17mm have 2" barrels and these wont fit into the ETX unless you have the SCT adaptor and a 2" diagonal. Try some of the Pentex XW series, these work well in all my scopes ETX included.


Mark

[coldspace]

I use a 17mm in my 12 inch Lx scope on steady nights and it fantastic. I use naglers and a panoptic for different focal lengths and these are just as good just different AFOV and magnifications,
You can not go wrong with any of the Televue eyepiece range, its night and day for clarity compared to th cheaper eyepieces.
Bang for buck, I would look at Naglers for your scopes while Aus dollar is high, the ethos 17mm is very heavy so it won't fit you ETX as its 2inch and may over balance your LB.
Then again in dark skies with an ethos on a well balanced LB would make for a nice very wide views. I love mine with the LX scope.

Regards Matt.

[CoombellKid]

I think I'll be adding a 13mm to my kit in the future. But would love to
see one first.

Cheers,CS

[Rodstar]

Paul, like others have said, the Ethos may be overkill for the ETX125. I have never used an Ethos in that size scope, so I defer to others as far as that is concerned. The Ethos are ALL large eyepieces, even the 6mm is big, so weight may be an issue???

[PCH]

Jacqui, Mark, Rob, Rod and Matt

many thanks for those replies guys. I appreciate your time and opinions.

OK, sounds like the ETX is not going to benefit much. I'd like to try a 10 or 13 on my 12"LB before spending that sort of money though. However, I think the opportunity to try one first is going to be challenging to say the least over here in Perth.

Thanks again for your replies guys :thumbsup:

[marki]

Paul, I am in Perth and have both the 10 and 17mm Ethos EP's. Send me a PM, might be able to work something out.

Mark

[tnott]

Not quite sure what people are talking about in saying that the 13mm Ethos is not suitable for an ETX 125, other than weight, which may put the GOTOs out a bit.

I use a 13mm T6 Nagler in mine regularly and it gives fantastic views at 146X, great for globs and the moon for example. It is exactly half the weight of the Ethos though. Also use the 9mm T6 Nagler for 211X power

Because it is F15 you could get away with using a cheaper wide field instead as the the light entering the eyepiece is very flat.

In the F5 12" dob the 13mm Nagler or Ethos would be much better corrected to the steeper cone of light, meaning that the stars would be much sharper at the edges of the field of view.

Cheap widefields in short focus dob are yuck!