Ethos Upgrade???

[Paul73]

Firstly. I was entirely(ish) happy with my eyepiece collection until I made the mistake of starting a thread entitled "Perfect Number of Eyepieces". Then along came Steve's (BomberBaz) "How Do You Justify Your EP Colection".......

I am now toying with exchanging my Mid & Low Mag eyepieces into 2 Ethos offerings:

Out - ES 82° 24 & 30mm's

In - Ethos 21mm

Out - Delos 12 & 17mm's

In - Ethos 13mm

My scooes are a SW 10" f4.7 Dob and a f7.5 SW ED80 on a modified AZ3 Mount. There will be a bigger dob along at some stage in the future, but I am more concerned about the here and now.

I'm worried that I'll loose the flexibility to fine tune the contrast that multiple eyepieces allows.

Thoughts?

[jetstream]

If you obs the North American neb with an OIII often, keeping the 30mm ES might be a good idea. I own this EP just for that neb area... I would want to keep the 17.3mm Delos too... My best  alround galaxy eyepiece is the 10E...(f4.8 dob).

[alan potts]

Paul,

I am not sure you will do it just with 2 eyepieces but that is a start. You would find I feel that the extra FOV with the Dob is very useful but I am not sure what F4.7 will do with regards to coma on these larger views. You may well be the best judge of that as you already have 82 degree EP's and the big one for me would be a keeper.

Personally I am glade I off loaded many of my Delos, in any case I could see no difference in quality over many hours testing, I find now I can enjoy my astronomy more. Before I think I spent too much time changing eyepieces. Both EP's you selected apart from the cost are superb but I feel you may need something a little shorter too.

Dont worry about fine tuning, you just end up with a larger range of Ethoi like a few of us and hey presto.

Alan.

[Paul73]

Thanks Guys.

Alan - don't worry. I have the Delos 8mm and a few shorter offerings for the higher mag work.

Gerry - Interesting point re the 30mm. I usually find myself using the 24mm or my little scope for that area as the contrast is far better. Re the 17.3 Delos. This is a concern as I often have to drop from the 24mm to the 17mm to get the faintest of Fuzzies. Will I get enough contrast with the drop from 24 to 21mm.

Paul

[SimonfromSussex]

Hi Paul,

I have 21 & the 13 ethos and love them.

Obviously we are all different so one person's eyepiece range might not suit another but I tried and tested quite a lot of eyepieces and differing ranges of power before settling on these numbers. 

I use the 21 ethos as my main go to eyepiece for lots of the deep sky stuff and then crank up the power occasionally when needed.

However my focal length is longer than yours (1880) so the 21mm gives me x89.

For my widest view I have a 31mm nag which give x60.

With your new set up I think you would be similar to my spread though.

The 21mm in your scope would be x56 (similar to my 31mm)

The 13mm in your scope would be x90 (similar to my 21mm)

The 8mm delos in your scope would be x145 (similar to my 13mm)

Perhaps get the 13mm first and try it. As I say the 21mm for me (equivalent to 13mm to you) is by far my most used eyepiece.

I then drop to the 13mm (and sometimes a 10mm) on globs and galaxies when conditions allow. 

Hope that helps a bit?

[Scooot]

I have both the 13mm ethos and 17.3 Delos. After buying the ethos I thought I might sell the Delos but I've decided to keep it. They both give more or less the same tfov but sometimes I prefer the mag of the Delos.

[Mike73]

Paul exit pupil is something which is very important when it comes to galaxies and by having a choice of EP's you'll be able to find the best exit pupil the the galaxy your observing.

Just as an example, if you were viewing say the Markarians Chain with a 13mm Ethos you'd obviously see lots of galaxies but by being able to fine tune your exit pupil by using two Delos you may be able to see a little deeper and see galaxies that the exit pupil of the Ethos wouldn't show.

Its simply a case of matching the exit pupil to the surface brightness of the galaxy your observing.

I like to have x2 EP's for galaxy season, one with a exit pupil around 1.8mm and the other around 2.1mm.

My advice would be to get a 13mm Ethos and also keep a Delos.....So er....get your wallet out! 

[John]

My 12" dob is F/5.3 and the eyepieces that I use most with it are the 21, 13, 8 and 6 Ethos. I have the 31 Nagler for a slightly wider view than the E21 but I also have some light pollution to contend with so more often than not the latter gives a darker background sky with it's 4mm exit pupil v's the 5.8mm of the big Nagler. I'm 55 years old so my dilated pupil won't be as large as some of the "youngsters" on here

I actually find my 8mm Ethos used very frequently on deep sky objects and often it's the next step up from the 21E. Despite the 199x magnification the true field is half a degree which is enough to fit many DSO's in and really study them. The 8E gives an exit pupil of 1.5mm.

You current set is hardly shabby though and, as Alan says, maybe coma will become more of an issue at 100 degrees so a coma corrector might need to be factored into your planning ?.

[Paul73]

My advice would be to get a 13mm Ethos and also keep a Delos.....So er....get your wallet out! 

I knew that I would regret asking the question. ££££

I do have a 18mm BCO which sits nicely in the 17.3 Delos mag bracket which is fine for single galaxies. But, in my limited experience, nothing goes as deep as a Delos. The other option is to use my Mk1 Parracor which brings the 21mm Ethos pretty much exactly into line with the Delos 17.3mm in terms of magnification and Exit Pupil.

Paul

[Paul73]

John

I have a Mk1 Parracor.

I am happy with the levels of Coma in the ES 24mm but find it intrusive at times in the 30mm and not having all of the stars in the FOV in focus is beginning to get on my wick (not coma seagulls). Putting the Parracor in basically turns it into a Really Heavy vesion of the 24mm!

I'm not doing this very fine eyepiece down. These are minor points, but.....

Would an Ethos control coma to similar levels to the ES 24mm 82°?

Paul

[bomberbaz]

consider following a similar path to me and get a 21E, 17E and powermate although I would still like something at 14mm there if it were me tbh

steve

[bomberbaz]

Should have mentioned, I do not have a paracorr, instead I have the baader MPCC which I find works very well for me to date. Have not tried the new EP in it yet but see no reason why that should be any different.

[ollypenrice]

I use a 13 Ethos and 26 Nagler in a 20 inch F4.1 and find the stars are better at the edges than they are in lesser EPs even with much narrower fields. I don't have a Paracor and the visual buffs who use this scope declare themselves happy withut it as well.

Olly

[Moonshane]

I had a 13mm Ethos and sold it. Now have a 17.3 Delos and am going to get a 12mm (swapping out a 12mm Nagler T2), 10mm and possibly 8mm Delos in the future. If I had a 12mm and 17.3 Delos I'd keep them and not bother with the Ethos. I actually prefer the still large but smaller field of the Delos by some margin.

[Lorne]

How about the ES20 100 and the ES14 100 instead of the 21 and 13  ethos's ethoi  Televue EP's as your low to mid range, possibly keeping the ES30 82.

PS..... cost wise, 21 Ethos = ES20 100 PLUS ES14 100 leaving you enough for a few pints, a fish supper AND the bus fare home!!!

[YKSE]

Would an Ethos control coma to similar levels to the ES 24mm 82°?

Paul

Coma comes with parabolic mirrors, it increases squarely with FOV, 100-degree eyepieces show 30% more sky (linearly) than 82-degree, all these extra 30% FOV will show more coma than 82 degree in theory, tolerable or neglegible is something YMMV.

To my knowliedge, there were Pretoria eyepices correcting coma,  no present in-production eyepiece does that.

[Mike73]

I knew that I would regret asking the question. ££££

Yeah unfortunately I think the only way to find the 'best' eyepiece is to actually try different eyepieces and decide for yourself.

[alan potts]

Yeah unfortunately I think the only way to find the 'best' eyepiece is to actually try different eyepieces and decide for yourself.

Now I know why I bought almost all the TV eyepieces .

Alan

[Paul73]

Thanks guys

I was hoping for a more or less universal "go fo it". This would have sent me to next week's Astro show with a short but pricey shopping list! As it is, opinion seems to be split.

I'll be heading to one of the October Star Parties. Hopefully I can find someone to let me give them a try in my scope. I've only ever observed with Ethos(s) in much bigger Dobs, so am unsure if the view was scope or eyepiece. If that is favourable, I'll buy new. If this test is not possible, I'll go second hand so that I can move them on with limited loss if they don't fit the bill.

Paul

[estwing]

the mob are at SWSP Paul....but you don't want me walking up with that 21E in my hand!...ask simon,steve, etc.......by the way 21E and 13E...but let me say this the 8E has edged the 13 into 3rd place and that takes some doing...go for it.

[Paul73]

the mob are at SWSP Paul....but you don't want me walking up with that 21E in my hand!...ask simon,steve, etc.......by the way 21E and 13E...but let me say this the 8E has edged the 13 into 3rd place and that takes some doing...go for it.

Ha ha. I remember the thread about the colourful language!

I may well be there on the Thurs & Friday nights.

I'll bring the beer.

Paul

[alan potts]

Paul,

I will ehhco Calvins "go for it" as I just don't see how you can better these eyepieces especially if we are talking Dob of any type, if you buy larger later then they still will be the front runners no matter how big it is.

My only reservation was the amount and I like Calvin feel it would need to be 21mm, 13mm and 8mm in the end though as you say you have the 8mm Delos, which lets face it is not a stock eyepiece.

The trouble is they are just not really hitting the streets secondhand so for me it would be dig deep and soak up those views.

I do like spending others money .

Alan.

[swamp thing]

I may well be there on the Thurs & Friday nights.

I'll bring the beer.

Paul

Now your talking, Hmmm! beer.