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  #21  
Old 19-02-2021, 02:52 PM
SkyWatch (Dean)
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Hi all, I think it is important to try before you buy if you can with the 100° eyepieces: they are not for everyone!
I know this may be heresy to some, but personally I prefer a smaller apparent field; I am not that keen on having to turn my head to see the edge of the fov, which I find I have to do in most 100° eyepieces. In fact I once had a 13mm Ethos, which is a great eyepiece; but I sold it because I preferred my 13mmT6 Nagler, both in terms of the ease of the view and the size of the beast!
I have the ES 20mm, and again it is a great eyepiece, but I find that I rarely use it. It is massive, and I find I prefer the view through my 18mm Radian (which actually has an identical tfov to the 13mm Nagler!).
Others may disagree, but when I ran the 20mm ES against a 21mm Ethos in a variety of scopes (f5 dob, f4.5 dob with flattener, f8 and f6.3 refractor and f10 SCT) I could see very little difference. The Ethos was just a fraction sharper at the very edge of the field, but I couldn't see that without turning my head anyway... Both seemed equally bright and the contrast was similar.
I only paid 1/3 of the price of the Ethos for the ES (it was on a special some time back), so I see it as great value for money if you want to get into ultra wide-field viewing.

- Dean
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  #22  
Old 22-02-2021, 05:13 AM
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Originally Posted by gregbradley View Post
Hey Don,

What's your view on native short focal length eyepieces versus Barlowing a longer focal length with a good Barlow/Powermate?

Do the look the same or do they lose a bit? I mean in general as I am sure there are lots of possible scenarios, and not all eyepieces would behave the same, but in general what would you expect?

I am thinking most likely there would be a gain going native as there would be less glass but then some eyepieces gain better correction by using a Barlow/Powermate.

Greg.
If it's a high-end Barlow, like a Baader VIP or TeleVue powerMate, there is no difference in performance between the higher power eyepiece and the Barlowed lower power eyepiece in general.
Except:
--the higher power eyepiece without a Barlow will be a lot lighter and put less stress on the focuser.
--the lower power eyepiece with a Barlow may, in some circumstances, show more light scatter or internal reflection. That depends a lot on the Barlow.
--the combination of Barlow and Eyepiece might be difficult for users of coma correctors. That stack can get very long and heavy.
--a lower power eyepiece that has induced astigmatism from fielding a short fat light cone might have less astigmatism when used in a Barlow.

I would also comment that my lifetime-best view of Jupiter was with a PowerMate (4 elements) + Paracorr (5 elements) + 8mm Ethos (9 elements). It looked like a Christopher Go or Damian Peach image, only sharper. Full technicolor, too. No more light scatter than I saw in the eyepiece by itself. Different colors on each moon, and albedo features on Ganymede. The keys: great optics and stunningly perfect seeing. Lens count? Not very important, it seems, at least with optics of that quality.
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  #23  
Old 22-02-2021, 08:25 AM
astro744
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Originally Posted by Don Pensack View Post
...

I would also comment that my lifetime-best view of Jupiter was with a PowerMate (4 elements) + Paracorr (5 elements) + 8mm Ethos (9 elements). It looked like a Christopher Go or Damian Peach image, only sharper. Full technicolor, too. No more light scatter than I saw in the eyepiece by itself. Different colors on each moon, and albedo features on Ganymede. The keys: great optics and stunningly perfect seeing. Lens count? Not very important, it seems, at least with optics of that quality.
I had a similar experience with a Tele Vue 35mm Panoptic with 4x Powermate giving me one of the finest views of Jupiter and Saturn I had ever seen. Telescope was 10.1" f6.4 Newtonian with (Suchting) refigured primary. What I liked about the view was the huge eye lens the Panoptic provides and at the higher power the Powermate offers.

What was the telescope you used your combination on, Don? I'm curious what magnification you had.

Note the Powermates are essentially invisible unless you're chasing 15th magnitude Quasars in which case a design with less but highly polished lens elements would be advantageous, (contrast is the key). I like the way the Powermates retain eye relief exactly as the original eyepiece design was intended to have.
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  #24  
Old 22-02-2021, 08:38 AM
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Originally Posted by astro744 View Post
I had a similar experience with a Tele Vue 35mm Panoptic with 4x Powermate giving me one of the finest views of Jupiter and Saturn I had ever seen. Telescope was 10.1" f6.4 Newtonian with (Suchting) refigured primary. What I liked about the view was the huge eye lens the Panoptic provides and at the higher power the Powermate offers.

What was the telescope you used your combination on, Don? I'm curious what magnification you had.

Note the Powermates are essentially invisible unless you're chasing 15th magnitude Quasars in which case a design with less but highly polished lens elements would be advantageous, (contrast is the key). I like the way the Powermates retain eye relief exactly as the original eyepiece design was intended to have.
456x in a 12.5" newtonian with Zambuto primary mirror and Antares Optics 1/30 lambda secondary in a contrast-optimized structure. Cooled with 2 large boundary layer fans and one rear fan, collimated with Glatter laser,
Farpoint Cheshire, Catseye autocollimator. PowerMate was 2X 2".
Since then, I've obtained 6mm, 4.7mm, and 3.7mm Ethos eyepieces, so I sold the PowerMate because I no longer needed it to get close to 500x.

Your experience with the 4X PowerMate doesn't surprise me.
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  #25  
Old 22-02-2021, 11:12 AM
astro744
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Originally Posted by Don Pensack View Post
456x in a 12.5" newtonian with Zambuto primary mirror and Antares Optics 1/30 lambda secondary in a contrast-optimized structure. Cooled with 2 large boundary layer fans and one rear fan, collimated with Glatter laser,
Farpoint Cheshire, Catseye autocollimator. PowerMate was 2X 2".
Since then, I've obtained 6mm, 4.7mm, and 3.7mm Ethos eyepieces, so I sold the PowerMate because I no longer needed it to get close to 500x.

Your experience with the 4X PowerMate doesn't surprise me.
Nice! I too have shorter Tele Vue f.l. eyepieces to choose from now. The 4x Powermate/35 Pan combination was heavy and is OK for high altitude viewing but anything low and I need to counterbalance. Still got the PM in case I need for photo or want to recreate the visual experience.
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  #26  
Old 23-02-2021, 08:59 PM
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Originally Posted by Don Pensack View Post
If it's a high-end Barlow, like a Baader VIP or TeleVue powerMate, there is no difference in performance between the higher power eyepiece and the Barlowed lower power eyepiece in general.
Except:
--the higher power eyepiece without a Barlow will be a lot lighter and put less stress on the focuser.
--the lower power eyepiece with a Barlow may, in some circumstances, show more light scatter or internal reflection. That depends a lot on the Barlow.
--the combination of Barlow and Eyepiece might be difficult for users of coma correctors. That stack can get very long and heavy.
--a lower power eyepiece that has induced astigmatism from fielding a short fat light cone might have less astigmatism when used in a Barlow.

I would also comment that my lifetime-best view of Jupiter was with a PowerMate (4 elements) + Paracorr (5 elements) + 8mm Ethos (9 elements). It looked like a Christopher Go or Damian Peach image, only sharper. Full technicolor, too. No more light scatter than I saw in the eyepiece by itself. Different colors on each moon, and albedo features on Ganymede. The keys: great optics and stunningly perfect seeing. Lens count? Not very important, it seems, at least with optics of that quality.
Thanks Don.

I did some dark site viewing a few nights ago and tried the barlow out and I came to the same conclusion.

A decent barlow is a good accessory.

Greg.
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  #27  
Old 03-03-2021, 01:36 AM
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OneCosmos (Chris)
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I have the Ethos 21mm and 13mm. In the 16” SDM THE 13mm was my go-to EP for nebulae and I suspect in the 28” (TechnoFusion mirror from Normand Fullum & 1/30 lambda secondary), it may be the 21mm but as I have so far only had one hour or so at the eyepiece I don’t know yet.

I did briefly use my Nikon 17mm Nav HW 102 degree EP and thought it slightly sharper and more contrasty than the Ethos.

I need to consider my higher power tools for planetary and lunar. I do have a Vixen LVW 8mm and I do have the 2x powermate.

So here’s a question I’ve been wondering about for higher powers to view small objects like planets do you really need 100 degree views? Wouldn’t the Delos prove better?
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  #28  
Old 03-03-2021, 08:11 AM
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Originally Posted by OneCosmos View Post
I have the Ethos 21mm and 13mm. In the 16” SDM THE 13mm was my go-to EP for nebulae and I suspect in the 28” (TechnoFusion mirror from Normand Fullum & 1/30 lambda secondary), it may be the 21mm but as I have so far only had one hour or so at the eyepiece I don’t know yet.

I did briefly use my Nikon 17mm Nav HW 102 degree EP and thought it slightly sharper and more contrasty than the Ethos.

I need to consider my higher power tools for planetary and lunar. I do have a Vixen LVW 8mm and I do have the 2x powermate.

So here’s a question I’ve been wondering about for higher powers to view small objects like planets do you really need 100 degree views? Wouldn’t the Delos prove better?
You don't NEED 100°, but it does give you a lot more time viewing before needing to push the scope.
Now, if your scope tracks, you are freer to use much narrower eyepieces, like TeleVue Delites (one of my favorites), or.........
But narrower won't give you a better image necessarily. That will depend a lot on the eyepiece.
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  #29  
Old 05-10-2021, 01:57 PM
Herbs (Herbert)
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Originally Posted by GUS.K View Post
Hi Greg, not sure about being the best, but they are nice eyepieces. The 12mm is about $170 cheaper than the 13 Ethos.
Using mainly with an 18 inch F4.5 and paracorr, views were similar through both, clean to the edge, and the sky background was slightly darker and detail in galaxies slightly better in the ES (the spiral of NGC 1566 and core detail in NGC 1365 were more pronounced). I'm favouring the ES as the immersive view is hard to beat.
Just check the price of 12mm ES 92, it's now jumped 50% about $200 more than 13 Ethos, is it actually worth the extra $$ above Ethos?
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  #30  
Old 05-10-2021, 02:18 PM
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Just check the price of 12mm ES 92, it's now jumped 50% about $200 more than 13 Ethos, is it actually worth the extra $$ above Ethos?

Don mentioned recently that ES have been experiencing price hikes across the board due to various factors, pushing up prices considerably.
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  #31  
Old 05-10-2021, 03:43 PM
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Just check the price of 12mm ES 92, it's now jumped 50% about $200 more than 13 Ethos, is it actually worth the extra $$ above Ethos?
They are good eyepieces, but very overpriced, there are cheaper options.
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  #32  
Old 08-10-2021, 10:44 PM
yoda776 (Matt)
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I still like and prefer my views in the Nikon NAV HW 17.5 eyepiece over my ethos. Just that bit sharper.

Its all relative to preferende, experiences you've had and among other things how good your eyesight is.

I have qatched ES eyepieces become more expensive over time and they have either gotten better over time or just plain more expensive! I always thought they were over similar calibre to Meade UWAs, although nit really worked with them much admittedly.
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  #33  
Old 09-10-2021, 12:09 AM
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Originally Posted by gregbradley View Post
That's a great write up thanks Martin.

My wife and I were able to see quite clearly the 5th and 6th star in the Trapezium the other night with the AP130GT and a 9mm Morpheus eyepiece.

I'd never seen them all before.

Greg.
A good catch. Now to see the G, H1, H2, I, J, K, and L stars.
[there are many more than just the 6 stars there.
At least 16 of them can be seen in this image:
https://apod.nasa.gov/apod/ap180805.html ]
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  #34  
Old 10-10-2021, 06:27 AM
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Originally Posted by Don Pensack View Post
A good catch. Now to see the G, H1, H2, I, J, K, and L stars.
[there are many more than just the 6 stars there.
At least 16 of them can be seen in this image:
https://apod.nasa.gov/apod/ap180805.html ]
Thanks Don.

That would seem to need a very large dob to see those faint stars.

Greg.
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  #35  
Old 11-10-2021, 02:37 AM
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I've seen the G, H, and I stars with the 12.5", but haven't gone any deeper.
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  #36  
Old 11-10-2021, 06:36 AM
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I’ve seen two well away from the long axis of the Trapezium using a 10.1” f6.4 Newtonian (with mirror I had professionally refigured by Suchting). One was obvious, the other on the threshold as I recall. I thought I was seeing things and then realised I was; more stars!

I cannot remember what magnification I was using although I did use my 12mm T4 Nagler a lot back then but it could have been another eyepiece. Contrast is amazing with this mirror and stars are so tight (exceptional seeing required).
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  #37  
Old 12-10-2021, 10:22 PM
ausastronomer (John Bambury)
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Originally Posted by gregbradley View Post
Thanks Don.

That would seem to need a very large dob to see those faint stars.

Greg.
Hi Greg,

You need reasonable aperture over 10" and obviously the bigger the better, but at least as important is good seeing and a well cooled and collimated telescope.

I've done down to I in my 14" and 18" scopes several times, and reasonably common in the 25" Obsession. One night at Coona under superb conditions with the 25" and a 12mm Nagler, I had "stars everywhere". I am only familiar with them down to "I" and had no finder chart, so not sure what was what, but easily the best view I have ever had of the trap.

Cheers
John B
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  #38  
Old 13-10-2021, 01:03 PM
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Hi Greg,

You need reasonable aperture over 10" and obviously the bigger the better, but at least as important is good seeing and a well cooled and collimated telescope.

I've done down to I in my 14" and 18" scopes several times, and reasonably common in the 25" Obsession. One night at Coona under superb conditions with the 25" and a 12mm Nagler, I had "stars everywhere". I am only familiar with them down to "I" and had no finder chart, so not sure what was what, but easily the best view I have ever had of the trap.

Cheers
John B
Wow, sounds like a very memorable experience. I've never owned a Dob and I am interested in getting one. What would you recommend? I am thinking around the 12 inch size and not too heavy.

Greg.
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  #39  
Old 13-10-2021, 03:48 PM
ausastronomer (John Bambury)
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Wow, sounds like a very memorable experience. I've never owned a Dob and I am interested in getting one. What would you recommend? I am thinking around the 12 inch size and not too heavy.

Greg.
Hi Greg,

I know you've always bought hi quality refractors and are well aware that you "get what you pay for" with optical equipment.

What's your rough budget and timeframe? Do you just want to get something "reasonable" so you can use a dob and see if it's something you want to put more money into to get a good one down the track for visual use, or do you want to dive in at the deep end and get a high quality one straight off. Obviously a $2,000 12" Skywatcher or GSO isn't the equal of a 12" Zambuto mirrored SDM with Servocat. A $10k plus SDM isn't 5 times better than a $2k Skywatcher, or GSO, but it is certainly better in every respect, including optics, smoothness of motion, tracking and longevity. You can also get a mass produced Asian built scope pretty quickly. You will wait a couple of years for an SDM with a Zambuto mirror. SDM's do come up 2nd hand on Icetrades "occasionally" at bargain prices.

Cheers
John B
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  #40  
Old 13-10-2021, 04:50 PM
m11 (Mel)
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I would highly recommend if you can to see one in the flesh and if possible get involved in the setting up of the dob. This will give you a feel of how it is to live with one and if the bulk or weight is an issue at all for you.

You can also try your eyepieces to see how you like the view as well before spending.
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