Top notch eyepiece choices

[AstralTraveller (David)]

A mate has asked me to help him chose a top-notch set of eps to go with his Obsession 18" f/4.2 (ultra compact) with servocat. Not having much experience with large scopes I'm looking for a bit of advice.

I think I have the low-power end of the DSO eps covered. I'm suggesting a 31 nagler and 21 and 13 ethos, though I notice that some people would leave out the 21. The 13 gives 147x and 41' fov which I'm sure will get a lot of use but I'm wondering whether a higher power would get much use for DSOs? The 10E (191x and 31') is probably a bit close to the 13 so it might be the 8E (238x and 25') but how much use would it get? How often will the seeing allow this sort of power?

The other consideration is planetary eps. I love my orthos and my 10mm Zeiss Jena ortho is better on-axis than my 9mm T6. I assume the orthos would also be better than the ethos on-axis but I like to hear from anyone who has made the comparison. I'd also like to know what is the highest power it is likely to be practical to use. The rule-of-thumb of 50x per inch gives 900x but of course the seeing will never support that. What would be a reasonable upper limit?

Of course the orthos biggest drawback is the short eye relief. Both my mate and I are old-school (for a good reason) but even I find my 5mm ortho difficult to use. If eye relief becomes an issue what would be a good alternative to the ortho, a TMB perhaps?

Thanks for any comments!

[barx1963 (Malcolm)]

I am far from an expert in optics, but I have invested moderately heavily in Ethos EPs for my 20" f5 so I have some knowledge.
My kit consists currently of the 10E, 13E, 17E, 21E and 41 Panoptic. My most used EP is the 17E which gives 150x in my scope and a nice 30' field. The 21 is very nice but I just find the sky just a smidgen less black than in the 17, and as I am mainly a galaxy observer, the 121x power of the 21 is not really enough.
In comparing Ethos and Naglers, in my opinion there is no comparison. The 13E compared to my old 13mm T6 Nagler gives not just a much wider field but the stars are sharper, focus is easier to achieve and although the eye relief is only 3mm more in the Ethos, 15mm as against 12mm, for a glasses wearer that is significant. The 10E in my scope makes a very nice planetary EP giving 254x. In an 18" UC it will give 192x. I found the best views ever I have seen of Saturn with this EP (PM Paddy for his opinion if you want!) at Snake Valley last month, the Cassini Div was like a pencil line, band of colour, the polar storm and even the Encke Div was visible. Of course seeing was exceptional that night and I would not expect to see it like that many times in a year. The one thing I have learnt is that a bigger scope definitely enables more power, no way would I even think of using 254x in the old 12". So good high power EPs are a worthwhile investment.
One thing to consider with the Ethos is that the 6 100deg versions are designed so that a group of 3 will give a 3x increase of actual field size per increase of focal length. So a set of 6mm/10mm/17mm or 8mm/13mm/21mm will work well together.

Malcolm

[Steffen]

For planetary use the Tak LE 5mm and 7.5mm would very be high on my list. I find them very comfortable to use. They have a 52˚ AFOV and 10mm eye relief, and the rubber eye cup puts the eye right where it needs to be.

I've never warmed to the TMBs, and I don't find 100˚ AFOV eyepieces very attractive, esp for the price.

Cheers
Steffen.

[BPO]

Originally Posted by Steffen

For planetary use the Tak LE 5mm and 7.5mm would very be high on my list. I find them very comfortable to use. They have a 52˚ AFOV and 10mm eye relief, and the rubber eye cup puts the eye right where it needs to be.

Seconded without reservation. The TAK LEs seem to be much underrated.

[Profiler (Profiler)]

Another grossly under rated EP is the Nagler Zoom. It is also one of the few TV Eps that are still made in Japan - This is a review in comparison to the Tak LE.

http://www.cloudynights.com/item.php?item_id=336

[ausastronomer (John Bambury)]

Originally Posted by barx1963

although the eye relief is only 3mm more in the Ethos, 15mm as against 12mm, for a glasses wearer that is significant.

Malcolm

Hi Malcolm,

I can't quite agree with this comment. While the ETHOS have 3mm more eye relief than the Nagler T6's, it is still inadequate for use with eyeglasses IMO. It would be less than 1 eyeglass wearer in 50, who can use the TV ETHOS with eyeglasses; and take in the full FOV. So for eyeglass wearers, it isn't significant, it's a very moot point in fact. However, the extra 3mm of eye relief does provide more comfort for non eyeglass wearers.

The useable eye relief of all Televue eyepieces is in my experience less than what is stated by Televue. I believe Televue measure the eye relief from the top of the eye lens. Practically however you can never get your eye this close to the eye lens.

Cheers,
John B

[barx1963 (Malcolm)]

John
I am basing my comments on my experience. I had no significant issues using my 13mm T6 Nag with glasses, it was close but with a bit of practice doable. In the 12" I also tested if the image improved with glasses removed and it was very minor improvement so I usually observed with glasses on.
Since upgrading to the 20" f5, I am using Ethoi just about exclusively, though I did paly with some Naglers. I have fond no significant difficulty using the Ethoi with glasses on. Of interest is that the image is significantly better now without glasses, so that is the way I tend to observe now.
With regard to seeing the full FOV, I find I have to move my head regardless of whether I have glasses on or not to see the edge, but as a rule I am not really interested in the edge, only in the quality of the image near the centre, and the Ethoi win hands down against other EPs I have tried.
Maybe I am the 1 in 50 but I can only relate my experience. I guess that observing is often a personal experience and what one person finds comfortable may not work for someone else.

Malcolm

[ausastronomer (John Bambury)]

Originally Posted by AstralTraveller

A mate has asked me to help him chose a top-notch set of eps to go with his Obsession 18" f/4.2 (ultra compact) with servocat. Not having much experience with large scopes I'm looking for a bit of advice.

I think I have the low-power end of the DSO eps covered. I'm suggesting a 31 nagler and 21 and 13 ethos, though I notice that some people would leave out the 21. The 13 gives 147x and 41' fov which I'm sure will get a lot of use but I'm wondering whether a higher power would get much use for DSOs? The 10E (191x and 31') is probably a bit close to the 13 so it might be the 8E (238x and 25') but how much use would it get? How often will the seeing allow this sort of power?

The other consideration is planetary eps. I love my orthos and my 10mm Zeiss Jena ortho is better on-axis than my 9mm T6. I assume the orthos would also be better than the ethos on-axis but I like to hear from anyone who has made the comparison. I'd also like to know what is the highest power it is likely to be practical to use. The rule-of-thumb of 50x per inch gives 900x but of course the seeing will never support that. What would be a reasonable upper limit?

Of course the orthos biggest drawback is the short eye relief. Both my mate and I are old-school (for a good reason) but even I find my 5mm ortho difficult to use. If eye relief becomes an issue what would be a good alternative to the ortho, a TMB perhaps?

Thanks for any comments!

Hi David,

I have an 18"/F4.5 Classic Obsession and regularly use an 18"/F4.2 Obsession Ultra Compact as part of our 3RF scope arsenal.

Does your friend have a budget in mind? If he is not budget constrained there are better options than ETHOS, which are superior optically with longer eye relief.

In terms of planetary eyepieces, I find that in the shorter focal lengths (ie <10mm) while the long eye relief eyepieces are fractionally behind the simple eyepieces optically, over long periods I see more because of the greater comfort and reduced eye fatigue / strain. eg comparing the 5mm Pentax XO, which is about as good as it gets, to my 5mm Pentax XW; I find the XW gives about 95% to 98 % of the performance of the XO. However, I always choose the XW because of the comfort, ease of use and reduced eye strain.

Personally I find the Pentax XW's and Televue DELOS to be outstanding planetary and deep sky eyepieces because of the exceptional optical quality and long eye relief/comfort factor.

I am at Kiama. I would be happy to meet up with you and your friend so he can try some of my Nagler's, DELOS and Pentax XW's before he shells out his hard earned cash.

Cheers,
John B

[Profiler (Profiler)]

I would have to concur with John. For optimal viewing I find the Pentax XW ultimately the best. However, as a smaller EP for quick set-ups and less concern about weight/portability I reach for Naglers. I find it hard to optically discern much in the way of differences between them as both are excellent. Instead, I mostly differentiate them by other criteria such as ER (eg XWs) or weight/portability (Naglers)

[ausastronomer (John Bambury)]

Originally Posted by barx1963

John
I had no significant issues using my 13mm T6 Nag with glasses, it was close but with a bit of practice doable.
Malcolm

Hi Malcolm,

You are the first person I have heard of who can use a T6 Nagler with glasses on. They really only have about 10mm of useable eye relief.

IMO that is a really good way to scratch the sh_t out of either an expensive pair of glasses, or an expensive eyepiece. It's something I will not be trying, having ruined a $1,000 pair of Zeiss eyeglasses many years ago, trying to use them with an 11mm Nagler T1, which has more eye relief than the T6 Naglers. Although it didn't have a rubber eye guard like the newer eyepieces.

Cheers,
John B

[AstralTraveller (David)]

Thanks for all the useful replies. It's begining to look like the low power end is sorted, down to a 13Ethos, and a Pentax 5XW looks like it's a good idea, but what to put in between is still up in the air. I'm concerned that the seeing won't allow 380x to be used regularly and perhaps a 7mm or even 10mm XW is also needed. Or should that be a 8E?

John, thanks for the very kind offer, I'll PM you soon.

[wavelandscott (Scott)]

I think you would be hard pressed to seperate the Pentax XW and Delos eyepieces...good eye relief and ergonomics...

The question is the Ethos v Pentax/Delos...i like my wide field of view but for planetary the Pentax/Delos would be hard to beat.

I would sure take John up on the test drive if at all possible. While you could not be far wrong with any of the elite pieces of glass it sure would be nice to try them before buying them...

[AstralTraveller (David)]

I've had one brief look through a Delos. The seeing was terrible so there was no chance to test its quality. What I did find was that it 'kidney beaned' very easily. I've coped with this in other eps but this seemed exceptionally bad. The ep position wasn't ergonomically good for me but I was still disappointed. I have used other eps with the same issue but not this bad. Was I just having a bad night or is this an issue with the Delos - and how do XWs compare?

[wavelandscott (Scott)]

Originally Posted by AstralTraveller

I've had one brief look through a Delos. The seeing was terrible so there was no chance to test its quality. What I did find was that it 'kidney beaned' very easily. I've coped with this in other eps but this seemed exceptionally bad. The ep position wasn't ergonomically good for me but I was still disappointed. I have used other eps with the same issue but not this bad. Was I just having a bad night or is this an issue with the Delos - and how do XWs compare?

The 20 mm eye relief takes some getting used to in both and you really need to take the time to adjust the eyepiece so that you get your eye placed in the right spot. But both have pretty good systems to adjust their eyeguards to the right place.

The first few times I used my Pentax eyepieces it was hard for me to get used to them especially when going from the TV 16 mm T5 Nagler (which I love) where you need to mash your eye in all the way in...contrasted to the 20 mm eye relief of the Pentax XWs. However, once I got the eyeguard set to the right place using the Pentax became a snap and very comfortable to use. I've come to appreciate the comfort of longer and relaxed looks afforded by the Pentax.

I still love my Ethos and Nagler eyepieces but there is something "right" about the Pentax XW (at least the 10 and 7 that I own). especially when trying to eke out detail on planets. I personally prefer to look at planets with the XW over some of the heralded "planetary eyepeices"...the extra glass hasn't bothered me and the wider FOV is appreciated.

I have used the Pentax XW 10 mm and 7 mm a lot and only had a few chances to look thorugh the Delos line and never in a direct side by side situation so take that into account with my comments...I do not feel there is much between them.

In my opinion TV using their "newer" design with updted coatings made a similar eyepiece to the XW range with their Delos eyepieces...all the things I liked with the Pentax I liked in the Delos and I feel they are pretty interchangeable (where focal lengths match)...

If I had to choose between them I'd pick on price...or some reason of vanity not necessaruly linked to the eyepiece themselves. I believe I could enjoy either of them equally.

But by all means do try them out if you can before you buy them...but do give them time to work their magic.

Oh and I should note for those not familiar with my eyepiece case, I am not a "fanboy" (well maybe a "fanboy of gear in general"), I have plossls (TV and not TV) and Panoptics and Naglers and Ethos and Pentax XW and Denkmeir (really likeable) and some TMBs...they all have their uses and depending on the scope and situation they all get the occassional call for use.

[GrahamL]

If the cost benefit considerations are enough of a concern ,consider an 8.5 xf, its not going to give you indegestion if its sits away a few months,and its a cracker of a little eyepiece.

[ausastronomer (John Bambury)]

Originally Posted by nightstalker

If the cost benefit considerations are enough of a concern ,consider an 8.5 xf, its not going to give you indegestion if its sits away a few months,and its a cracker of a little eyepiece.

Yes it is. I have one of those too and its one of my favourite medium/high power eyepieces in all of my scopes. Enough eye relief (16mm useable) to use with glasses on and very sharp with good contrast and light throughput. At a bit over $200; it's one of the great bargains out there for a high quality Japanese made eyepiece.

Cheers,
John B

[AG Hybrid (Adrian)]

Originally Posted by ausastronomer

Personally I find the Pentax XW's and Televue DELOS to be outstanding planetary and deep sky eyepieces because of the exceptional optical quality and long eye relief/comfort factor.

Cheers,
John B

Couldn't agree with you more. Brilliant eyepieces.

[Allan]

Great thread considering the week I've just had. Picked up my new Orion XT12g from Bintel in Sydney on Monday. I have spent all year researching eyepieces and bought a 13 Ethos with the scope.

In an ideal world you would line up all the eyepieces you were interested in, and look at them through your telescope. Then you would buy the ones you liked. Obviously it doesn't work like that, so you have to go by the info you find on sites like this and talking to people at star parties for example.

So, having forked out top dollar, what is my initial conclusion? Best described by my first view of Eta Carinae. WOW!!! The detail in the dust lanes, the contrast, the pin point stars to the edge of the field. This eyepiece has it all.

Now the negatives. The only other eyepiece I have at the moment to compare it with is the cheapo Orion Deep View that the telescope came with. Now while this eyepiece has almost none of the above virtues, it has very good eye relief and a less than extreme field of view. What this eyepiece has taught me is that there is no way the Ethos has 15mm eye relief. I have to spend the night with my eye jambed into the Ethos eyeguard to see the full FOV. After a while this starts to get quite tiring. And I like the way the Orion eyepiece frames objects in the smaller FOV as compared to the Ethos.

I would really like to hear from someone who has Ethos and Delos eyepieces, because I think I would be better suited with the slightly smaller FOV and better eye relief that the Delos offers.

I want to keep expanding the eyepiece collection, but this experience is confusing me at the moment. Any suggestions as to my next move would be greatly appreciated. Cheers

[Kunama]

Allan I too love the extra eye relief and really hate having to jamb my eye against the EP. I know nothing about the Delos but love my lineup of Vixen LVWs with their genuine 20mm ER.

Good luck finding the right ones for you.

[Allan]

Thank you for the PM I have received. Technical problems have prevented me replying.