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Another Ethos for my NP-101 (F5.4) refractor?

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#1 RickM.

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Posted 30 June 2020 - 11:57 AM

I currently have:  ES82 30mm. (18x);  Ethos13mm. (42x);  Ethos 4.7mm. (115x);  Ethos 3.7 (146x).  Would another Ethos be desirable?  At some point I’ll likely swap out the ES82 30mm.  for a Nagler 31T5.


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#2 havasman

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Posted 30 June 2020 - 12:17 PM

Try the 21E before you commit to the 31T5.

 

Because the strength of that scope is its widefield performance and the 21E is a killer in it.


Edited by havasman, 30 June 2020 - 04:49 PM.

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#3 Jon Isaacs

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Posted 30 June 2020 - 12:20 PM

I currently have:  ES82 30mm. (18x);  Ethos13mm. (42x);  Ethos 4.7mm. (115x);  Ethos 3.7 (146x).  Would another Ethos be desirable?  At some point I’ll likely swap out the ES82 30mm.  for a Nagler 31T5.

 

Are those your only eyepieces?  

 

Eventually I would want something between the 13mm and the 4.7 and probably two somethings, the 8 mm and the 6 mm.  And eventually I would want the 21mm.  

 

Jon


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#4 sanbai

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Posted 30 June 2020 - 12:46 PM

I agree with Jon, the priority is to fill the gap between 13 and 4.7.

Higher power require more fine tuning than low/mid one, so that points to the 6 mm.

On the other hand, the 8 mm would sit really in between the 13 and the 4.7 mm

 

I would also consider the 21mm if you are more into true wide fields. It sits well between the 13 and the 30/31 mm. The 21 will provide true field very similar to the 31, although the exit pupil difference should be noticeable. If you are not under dark skies, the 21 mm can provide more contrast due to the higher magnification.

 

There is also a minimalist alternative: Get a 2x Powermate. Then, you get:

 

13 mm: 42x

13mm + PM: 84x

4.7mm: 115

3.7 mm: 146x

4.7 mm +PM: 230x for extreme use

3.7 mm + PM: probably useless except to get big airy discs.



#5 TomK1

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Posted 30 June 2020 - 01:17 PM

Other than a larger field of view, why not an 8 mm Delos and 3 mm Delite.   Almost same total $ and you'll probably use 180x more than 230x mentioned above.   I would want something higher than 146x.  

 

Regarding high power comment, I only have a Genesis SDF and never viewed through a NP-101, so I don't know how much sharper the optics are on your scope.   180x is usually my borderline for loss in sharpness.  

 

Wide field viewing is nice.   I cut the cord at 3 ethos (13/8/6) and bought them primarily for use with my 11" dob.  As it turns out, the 6mm at 241x with dob is pushing it and I probably would not have bought the 6 mm knowing what I know now.   However, luckily I have the refractor and use the 6mm in it quite often.  Expensive lesson considering I bought new, but all is well.



#6 NC Startrekker

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Posted 30 June 2020 - 02:17 PM

Try the 21E before you commit to the 31T5.

Expensive, but I tend to agree with Dick on this one.  If you are set on replacing your ES 30mm, then the 21 Ethos is a versatile choice.  It is a bit more versatile than the 31mm Nagler because you get almost as wide a field but with the benefit of more magnification.  This is advantageous if you are not observing from a dark site.  The greater magnification will darken the sky relative to the stars improving contrast for suburban/urban observing.  On the other hand, if you observe routinely from relatively dark sites, the 31mm Nagler and the NP-101 are a match made in Heaven - quintessential TeleVue!

 

As far as another focal length goes, you seem to have most bases covered.  Some might suggest something between the 13mm and the 4.7mm.  But, the NP-101 is a short focal length scope so the jump or gap there is not as significant as it might be in most other scopes.

 

So, you are pretty well set right now.  Your seemingly minimalist set of eyepieces covers most needs from wide field to moderately high power.  No need to change unless you are just looking to spend money.  But, this is the Eyepiece Forum, so I'm sure you are going to get plenty of advice on ways to spend your money!  wink.gif 


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#7 Jon Isaacs

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Posted 30 June 2020 - 02:29 PM

Expensive, but I tend to agree with Dick on this one.  If you are set on replacing your ES 30mm, then the 21 Ethos is a versatile choice.  It is a bit more versatile than the 31mm Nagler because you get almost as wide a field but with the benefit of more magnification.  This is advantageous if you are not observing from a dark site.  The greater magnification will darken the sky relative to the stars improving contrast for suburban/urban observing.  On the other hand, if you observe routinely from relatively dark sites, the 31mm Nagler and the NP-101 are a match made in Heaven - quintessential TeleVue!

 

As far as another focal length goes, you seem to have most bases covered.  Some might suggest something between the 13mm and the 4.7mm.  But, the NP-101 is a short focal length scope so the jump or gap there is not as significant as it might be in most other scopes.

 

So, you are pretty well set right now.  Your seemingly minimalist set of eyepieces covers most needs from wide field to moderately high power.  No need to change unless you are just looking to spend money.  But, this is the Eyepiece Forum, so I'm sure you are going to get plenty of advice on ways to spend your money!  wink.gif

 

Myself, I would never replace the 30mm ES with the 21mm Ethos, as you say, the 31mm Nagler and the NP-101 are what this scope is all about.  The combination of the 31mm Nagler and the 21mm Ethos is one I like but the 21mm Ethos provides a 3.9 mm exit pupil which is just too small for a low power wide field scope.  

 

For me, the step from the 13mm at 42x and the 4.7mm at 115x is far too great, a 2.4 mm exit pupil with a 2.4 degree AFoV to a 0.87 mm exit pupil with a 0.95 degree TFoV, there's a lot of room in there, a lot stuff to see.

 

Jon


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#8 NC Startrekker

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Posted 30 June 2020 - 03:22 PM

Myself, I would never replace the 30mm ES with the 21mm Ethos, as you say, the 31mm Nagler and the NP-101 are what this scope is all about.  The combination of the 31mm Nagler and the 21mm Ethos is one I like but the 21mm Ethos provides a 3.9 mm exit pupil which is just too small for a low power wide field scope.  

 

For me, the step from the 13mm at 42x and the 4.7mm at 115x is far too great, a 2.4 mm exit pupil with a 2.4 degree AFoV to a 0.87 mm exit pupil with a 0.95 degree TFoV, there's a lot of room in there, a lot stuff to see.

 

Jon

Jon, my caveat was the degree of light pollution where the OP generally observes.  No argument with your statement, "...the 31mm Nagler and the NP-101 are what this scope is all about."  That's exactly what I said.  However, if light pollution is an issue, I suspect that if the OP had both the E21 and the N31 in his kit, the E21 would see far more scope time.



#9 RickM.

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Posted 30 June 2020 - 05:51 PM

Are those your only eyepieces?  

 

Eventually I would want something between the 13mm and the 4.7 and probably two somethings, the 8 mm and the 6 mm.  And eventually I would want the 21mm.  

 

Jon

Yes, Jon, they are my only eyepieces.

 

Rick



#10 RickM.

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Posted 30 June 2020 - 05:53 PM

I agree with Jon, the priority is to fill the gap between 13 and 4.7.

Higher power require more fine tuning than low/mid one, so that points to the 6 mm.

On the other hand, the 8 mm would sit really in between the 13 and the 4.7 mm

 

I would also consider the 21mm if you are more into true wide fields. It sits well between the 13 and the 30/31 mm. The 21 will provide true field very similar to the 31, although the exit pupil difference should be noticeable. If you are not under dark skies, the 21 mm can provide more contrast due to the higher magnification.

 

There is also a minimalist alternative: Get a 2x Powermate. Then, you get:

 

13 mm: 42x

13mm + PM: 84x

4.7mm: 115

3.7 mm: 146x

4.7 mm +PM: 230x for extreme use

3.7 mm + PM: probably useless except to get big airy discs.

The 2x Powermate is an interesting idea.



#11 RickM.

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Posted 30 June 2020 - 06:03 PM

Expensive, but I tend to agree with Dick on this one.  If you are set on replacing your ES 30mm, then the 21 Ethos is a versatile choice.  It is a bit more versatile than the 31mm Nagler because you get almost as wide a field but with the benefit of more magnification.  This is advantageous if you are not observing from a dark site.  The greater magnification will darken the sky relative to the stars improving contrast for suburban/urban observing.  On the other hand, if you observe routinely from relatively dark sites, the 31mm Nagler and the NP-101 are a match made in Heaven - quintessential TeleVue!

 

As far as another focal length goes, you seem to have most bases covered.  Some might suggest something between the 13mm and the 4.7mm.  But, the NP-101 is a short focal length scope so the jump or gap there is not as significant as it might be in most other scopes.

 

So, you are pretty well set right now.  Your seemingly minimalist set of eyepieces covers most needs from wide field to moderately high power.  No need to change unless you are just looking to spend money.  But, this is the Eyepiece Forum, so I'm sure you are going to get plenty of advice on ways to spend your money!  wink.gif

I like the idea of an Ethos 21 and Nagler 31.  I might have to acquire them over time, given the cost!


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#12 RickM.

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Posted 30 June 2020 - 06:05 PM

Myself, I would never replace the 30mm ES with the 21mm Ethos, as you say, the 31mm Nagler and the NP-101 are what this scope is all about.  The combination of the 31mm Nagler and the 21mm Ethos is one I like but the 21mm Ethos provides a 3.9 mm exit pupil which is just too small for a low power wide field scope.  

 

For me, the step from the 13mm at 42x and the 4.7mm at 115x is far too great, a 2.4 mm exit pupil with a 2.4 degree AFoV to a 0.87 mm exit pupil with a 0.95 degree TFoV, there's a lot of room in there, a lot stuff to see.

 

Jon

Would you recommend the 6 or 8 Ethos if I decide to only buy one, Jon?



#13 Jon Isaacs

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Posted 30 June 2020 - 08:04 PM

Would you recommend the 6 or 8 Ethos if I decide to only buy one, Jon?

The 6mm provides 90x, the 8mm provide 67.5x.  

 

The 13mm with a 2x Power mate would be 6.5mm and 83x.  

 

I guess I would want both eventually, it would be a question of which one first, 

 

Jon


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#14 russell23

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Posted 30 June 2020 - 08:33 PM

Would you recommend the 6 or 8 Ethos if I decide to only buy one, Jon?

I find with my 102mm SV Access my favorite deep sky magnification is ~90x.  With the 102mm f/7 that is the 8mm Ethos which I have found to be outstanding.  For yours that would be the 6mm Ethos.   I would get the 6mm and if later on you are able to get the 8mm then great.

 

I made the same decision between the 6mm and 8mm and felt I would use the 8mm at 89x more than the 6mm at 119x based upon exit pupil.



#15 imtl

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Posted Yesterday, 01:22 AM

I personally have the combo of 31mm Nagler then 17-10-6-3.7mm Ethos. I think the steps of exit pupil and magnifications are very suiting for me. The 17mm and the 6mm are just heavenly. The others as well of course. 

At a dark site, the Nagler 31mm and the NP101 are just pure perfection of widefield views of the skies.


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#16 RickM.

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Posted Yesterday, 06:04 AM

I find with my 102mm SV Access my favorite deep sky magnification is ~90x.  With the 102mm f/7 that is the 8mm Ethos which I have found to be outstanding.  For yours that would be the 6mm Ethos.   I would get the 6mm and if later on you are able to get the 8mm then great.

 

I made the same decision between the 6mm and 8mm and felt I would use the 8mm at 89x more than the 6mm at 119x based upon exit pupil.

That’s good to know, Russell.



#17 RickM.

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Posted Yesterday, 06:17 AM

I personally have the combo of 31mm Nagler then 17-10-6-3.7mm Ethos. I think the steps of exit pupil and magnifications are very suiting for me. The 17mm and the 6mm are just heavenly. The others as well of course. 

At a dark site, the Nagler 31mm and the NP101 are just pure perfection of widefield views of the skies.

The 6mm Ethos seems to be a popular choice.  This is the first mention of the 17.



#18 sanbai

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Posted Yesterday, 12:28 PM

The 6mm Ethos seems to be a popular choice.  This is the first mention of the 17.

I have the Nagler 31 and the Ethos 17, BUTmy next step is the Apollo 11.

For you the Ethos 21 makes makes more than the Ethos 17 because it sits more in the middle between 31 and Ethos 13 you already have.

Usually there are two combos for those who only want 3 Ethos eyepieces in the lower power side: 21-13-8 or 17-10-6. Both combos play well with the Nagler 31.

 

Going from 31 to 17 is a larger step, but that's fine for me in low power and I still have the Naglers 22, 17 and 13 as backup if I want some fine tuning (rarely). In your case the Ethos 17 would require some swaps, or accumulating more eyepieces. In any case, the 21 is your best first option if you go towards low power.

 

One must also say than the Ethos 17 receives even more praises than the 21 mm  and the 13 mm... but all them should be nothing shorter than truly awesome for your eyes.



#19 rkelley8493

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Posted Yesterday, 01:00 PM

I currently have:  ES82 30mm. (18x);  Ethos13mm. (42x);  Ethos 4.7mm. (115x);  Ethos 3.7 (146x).  Would another Ethos be desirable?  At some point I’ll likely swap out the ES82 30mm.  for a Nagler 31T5.

If you wanna go with another Ethos, I'd say either the 21 or 8 would work nicely with what you currently have. Either of those will make a good step in magnification to your current lineup. Is weight a factor? What type of mount do you use?

Explore Sci 92º 17mm could be another option, but it's a massive eyepiece. The 17 Ethos is a little more streamline, but both of these have that WOW Factor. 

22T4 Nagler would be another good choice. It fits in well between your ES 30/82 and 13 Ethos, it's a very immersive & comfortable eyepiece to use, and it's about half the price of the 21 Ethos.


Edited by rkelley8493, Yesterday, 04:50 PM.

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#20 leviathan

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Posted Yesterday, 01:18 PM


Usually there are two combos for those who only want 3 Ethos eyepieces in the lower power side: 21-13-8 or 17-10-6. Both combos play well with the Nagler 31.

I had 21-13-8 combo with Nagler 31, but found that I prefer T5 to E21 almost all of the time.


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#21 turtle86

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Posted Yesterday, 02:34 PM

Try the 21E before you commit to the 31T5.

 

Because the strength of that scope is its widefield performance and the 21E is a killer in it.

 

Another vote for the 21E.  I have an NP101 myself and agree that the 21E is a killer in it.  Really looking forward to panning the Summer Milky Way with that combo.


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#22 russell23

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Posted Yesterday, 02:46 PM

I think we also have to keep in mind what the OP already has:

 

31mm Nagler: 18x

13mm Ethos: 42x

4.7mm Ethos: 115x

 

So if you add another Ethos which provides the greatest benefit?

 

21mm Ethos: 26x

17mm Ethos: 32x

8mm Ethos: 68x

6mm Ethos: 90x

3.7mm Ethos:145x

 

I would add the 6mm Ethos and the 1.6x Nikon barlow before the 21mm or 17mm Ethos.  The 1.6x Nikon is excellent with my 8mm Ethos and could be used with the 13mm, 6mm, and 4.7mm without overlaps:

 

31mm Nagler: 18x

13mm Ethos: 42x

13mm x 1.6: 67x

6mm Ethos: 90x

4.7mm Ethos: 115x

6mm x 1.6: 144x

4.7mm x 1.6: 184x

 

I think that is a much bigger gain with an NP101 than the 21mm or 17mm Ethos. 



#23 ianatcn

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Posted Yesterday, 02:48 PM

With my TV127is I use the 31 Nagler for lowest power then go up to the 17 Ethos then 13 Ethos.  The 31 Nagler is a dream to use on this telescope,  So, I would go the same route again if I was starting out.  I think you have the higher powers nicely covered.   


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#24 imtl

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Posted Yesterday, 03:51 PM

I think we also have to keep in mind what the OP already has:

 

31mm Nagler: 18x

13mm Ethos: 42x

4.7mm Ethos: 115x

 

So if you add another Ethos which provides the greatest benefit?

 

21mm Ethos: 26x

17mm Ethos: 32x

8mm Ethos: 68x

6mm Ethos: 90x

3.7mm Ethos:145x

 

I would add the 6mm Ethos and the 1.6x Nikon barlow before the 21mm or 17mm Ethos.  The 1.6x Nikon is excellent with my 8mm Ethos and could be used with the 13mm, 6mm, and 4.7mm without overlaps:

 

31mm Nagler: 18x

13mm Ethos: 42x

13mm x 1.6: 67x

6mm Ethos: 90x

4.7mm Ethos: 115x

6mm x 1.6: 144x

4.7mm x 1.6: 184x

 

I think that is a much bigger gain with an NP101 than the 21mm or 17mm Ethos. 

I think it very much depends on how dark your skies are. If you are more than bortle 4-5 the Nagler 31mm with the NP101 will give you washout skies. That is where the Ethos 17mm really kicks in. (or the 21mm for that matters).


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#25 russell23

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Posted Yesterday, 04:02 PM

I think it very much depends on how dark your skies are. If you are more than bortle 4-5 the Nagler 31mm with the NP101 will give you washout skies. That is where the Ethos 17mm really kicks in. (or the 21mm for that matters).

Sure but he already has the 31mm Nagler and is looking to add an Ethos.  To me there is no reason to add the 21mm or 17mm Ethos if the 31mm Nagler is being kept - especially if looking to get the most out of the scope.

 

Now if the 31mm Nagler is needed for another scope then maybe you add the 21mm or 17mm if you no longer want to use it with the NP101.  But the 31mm is there and if it stays the 6mm makes the most sense as the next Ethos to add. 

 

And really if you have the 13mm Ethos at 42x, then the 17mm Ethos at 32x is not doing too much for you either.  So the 31mm Nagler provides the widest TFOV and then the 13mm makes sense as the next jump just based upon exit pupil & magnification.  After that both the 8mm and 6mm could make sense but in my experience the 90x of the 6mm Ethos does more for deep sky in terms of balancing image scale and image brightness.  The 8mm Ethos as a jump from the 13mm in that scope is kind of in the no-mans land where you might as well blow by it to a higher magnification.  

 

Why not skip the 6mm as well and go to the 4.7mm?  The reason is that once you get below a 1mm exit pupil you start to get some objects suffering due to the dimmer image.  So the 1.1mm exit pupil you get with the 6mm avoids that problem.  So I think having both the 6mm and 4.7mm makes sense with that scope.


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