Eyepieces - what's next

[Thingo]

Hi everyone,

I've had my telescope now for about a year, it's a William optics Zenithstar 126mm, focal ratio 7.7.

With the telescope I also bought two eyepieces: 

Nagler 31 mm (31x)

Explore scientific 5.5 mm (100 degrees, 176x)

The idea was to get to know the telescope a bit before expanding on an eyepiece collection. I really like both of these eyepieces, however, it is quite annoying that they aren't parfocal. Therefore I have started thinking about replacing the ES with some more naglers and so I would like to hear your view on this. I oftentimes feel like I would want to see a little more than I do with the ES 5.5 and therefore I'm considering the 3.5mm which would give 277x. This is a bit about the recommended 2x the aperture, thoughts?

On the other hand I'm considering the nagler zoom 3-6mm, however, this one is a 50 degree eyepiece and I'm just afraid that I will miss the wider views. Thoughts? 

 

The other question I'm asking myself is whether I should sell the ES and buy a 9 or 11 mm nagler, the primary purpose of this would be to have a parfocal collection of eyepieces. But is it really worth it? I guess I could sell the ES, but no idea how much I could get for it even though it's in pristine condition. 

And as to what I'm trying to see, well pretty much anything. I haven't developed a deep satisfaction from splitting binaries but I really would like to get a "closer" look at the planets and the moon. I really love to just browse with my 31mm nagler as well but can imagine that something around around with a bit more magnification would be really exciting as well. 

Appreciate any thoughts to these questions that you may have. 

Best,

CF

Edited February 25, 2021 by Thingo

[Louis D]

Before you rush off and think all Naglers are parfocal, look at column F under eyepiece dimensions of the Tele Vue eyepiece specifications page.  Notice that the 31mm NT5 is parfocal with the 21mm and 17mm Ethos and nothing else.

I would also investigate the Morpheus line of eyepieces.  They're nearly as wide as the ES-82 and Naglers, have longer eye relief, and are very well corrected at f/7.7.  I have the 9mm and 14mm versions.  The 9mm is pretty close to being an equal of my 10mm Delos.  The 14mm falls a bit behind at the edges, but probably no worse than a 14mm ES-82.

Are you using a tracking mount?  If so, you may be able to get by with narrower fields of view at higher powers since planets, PNs, and double stars tend to be quite small.

[RT65CB-SWL]

Hi @Thingo and a late welcome to SGL. 

For high powers, I think the TeleVue Nagler 3-6mm zoom is a wonderful piece of optical engineering considering its size.
I don't think there is anything else, (zoom e/p wise), you can compare it with.

It maybe worth playing with the Field of View Calculator in the Astronomy Tools tab, then decide before purchase.

[Thingo]

39 minutes ago, Louis D said:

Before you rush off and think all Naglers are parfocal, look at column F under eyepiece dimensions of the Tele Vue eyepiece specifications page.  Notice that the 31mm NT5 is parfocal with the 21mm and 17mm Ethos and nothing else.

I would also investigate the Morpheus line of eyepieces.  They're nearly as wide as the ES-82 and Naglers, have longer eye relief, and are very well corrected at f/7.7.  I have the 9mm and 14mm versions.  The 9mm is pretty close to being an equal of my 10mm Delos.  The 14mm falls a bit behind at the edges, but probably no worse than a 14mm ES-82.

Are you using a tracking mount?  If so, you may be able to get by with narrower fields of view at higher powers since planets, PNs, and double stars tend to be quite small.

Ah, forgot to write that question. I've noticed that it's a type 5 and the others are type 6 and wanted to make sure they are parfocal. Thanks a million for clarifying! Then surely I don't feel committed to the nagler series the same way. What a pity that there are so few eyepieces parfocal to the 31mm, I will for sure not get rid of that one. I've looked at the Ethos, but they are simply too expensive. When I bought the 31mm that was a one-off and I will not spend that much on other individual eyepieces. 

Will have a look at the morpheus series. I notice that there isn't any between 3.5-4mm though which I think will be my focus now..

I'm not using a tracking mount, I'm doing it manually as I want to get more skilled at navigating the sky. 

[AlexK]

What about simply adding parfocal rings?

Personally, I would never part with my 100 deg AFOV EPs for whatever reason.

Also for high mags consider a decent Barlow or the TV Powermate.

Edited February 25, 2021 by AlexK

[Thingo]

4 minutes ago, Philip R said:

Hi @Thingo and a late welcome to SGL. 

For high powers, I think the TeleVue Nagler 3-6mm zoom is a wonderful piece of optical engineering considering its size.
I don't think there is anything else, (zoom e/p wise), you can compare it with.

It maybe worth playing with the Field of View Calculator in the Astronomy Tools tab, then decide before purchase.

Thank you! 😃

Hehe, it feels like everything I do in my spare time is to play around with the field of view calculator 🤣 Thanks for the recommendation on the nagler zoom, I'll see if I can read a few more reviews on it. It's just that the field of the view looks soooo small..

[KP82]

8 minutes ago, Thingo said:

Ah, forgot to write that question. I've noticed that it's a type 5 and the others are type 6 and wanted to make sure they are parfocal. Thanks a million for clarifying! Then surely I don't feel committed to the nagler series the same way. What a pity that there are so few eyepieces parfocal to the 31mm, I will for sure not get rid of that one. I've looked at the Ethos, but they are simply too expensive. When I bought the 31mm that was a one-off and I will not spend that much on other individual eyepieces. 

Will have a look at the morpheus series. I notice that there isn't any between 3.5-4mm though which I think will be my focus now..

I'm not using a tracking mount, I'm doing it manually as I want to get more skilled at navigating the sky. 

As you probably have access to really dark skies in some remote sites in the Alps, you could really push for high mags with your scope. I'd go for something around 7 - 9mm with a 2x or 3x barlow. You may also want something to fill the gap between the N31T5 and your high mag ep, something like a 14 - 18mm.

Edited February 25, 2021 by KP82

[Thingo]

6 minutes ago, AlexK said:

What about simply adding parfocal rings?

Personally, I would never part with my 100 deg AFOV EPs for whatever reason.

Also for high mags consider a decent Barlow or the TV Powermate.

Holy macaroni! I had no idea this existed. THANK YOU!!

[Thingo]

1 minute ago, KP82 said:

As you probably have access to really dark skies in some remote sites in the Alps, you could really push for high mags with your scope. I'd go for something around a 7 - 9mm with a 2x or 3x barlow. You may also want something to fill the gap between the N31T5 and your high mag ep, something like a 14 - 18mm.

Yeah I got some pretty dark skies not too far away from here. I've considered your suggestion as well. Why not use the barlow for the 31 mm though? 

[RT65CB-SWL]

2 minutes ago, Thingo said:

Thank you! 😃

Hehe, it feels like everything I do in my spare time is to play around with the field of view calculator 🤣 Thanks for the recommendation on the nagler zoom, I'll see if I can read a few more reviews on it. It's just that the field of the view looks soooo small..

I used to know a member from my local astro. society/club, (he passed away two years ago), and used the Nagler 2-4mm zoom in the TeleVue 60. He said it was the perfect combination when he was working away from home.

[John]

I use eyepieces with apparent fields from 110 degrees to 50 degrees (which is the Nagler 2mm - 4mm zoom in my case) and, yes, the zoom field of view does seem small but it's quite easy to adjust to that even with scopes mounted on undriven alt-azimuth mounts, as all mine are.

My "in between" eyepieces in terms of field of view are Tele Vue Delos and Pentax XW's which give you very good optical quality and a decent field of view and comfortable eye relief.

With my 130mm refractor I don't use the 100/110 degree eyepieces very much to be honest. The Delos / XW's / Nagler zoom get the bulk of the use with that scope, as they have tonight in fact

 

[Louis D]

37 minutes ago, Thingo said:

Why not use the barlow for the 31 mm though?

Because you need to use a telecentric magnifier like a Powermate at long focal lengths (above 20mm or so) to avoid vignetting and pushing out the exit pupil causing blackout issues.  This then leads to a very long and heavy moment arm in the focuser/diagonal which can be difficult to balance in an alt-az mount at high altitudes.  You're generally better off to buy a comparably compact and lighter 13mm to 16mm 82 to 100 degree eyepiece instead.

If the Ethos are too expensive, you might want to investigate the 100/110 degree eyepieces marketed as APM/Myriad/Stellarview/WO/Lunt/etc.  They've been getting very good reviews at reasonable prices.

[Thingo]

After spending an unhealthy amount of time with the Field of View Calculator, reading countless of reviews and forum threads, and considering the input I got in this topic, I woke up this morning with the realisation. I have made my decision:

I will...

1. Keep my current eyepieces, the nag31T5 and the ES100 5.5mm.

2. Buy the nagler 3-6 zoom and the nag13T6.

3. Get a pair of simple binoculars that have gotten good reviews: Opticron Adventurer 10x50 T WP. I have about 3-4 months to try these out and whether they will be sufficient for the observation I aim to do during my upcoming travels to the bortle 1 skies in the north of Sweden this fall. Regardless of the conclusion I come to, these binoculars will likely be useful also when I'm observing with my WO Z126 and if I against all odds find them completely useless, they are not a huge investment. 

Finally, I want to link to a forum post I found at CN that I found very useful to determine what eyepieces I "should have": https://www.cloudynights.com/topic/70718-how-to-choose-eyepieces-3-methods/
Different methods give you different recommendations, but by using several it's easier to come to a conclusion IMHO. Over the last year since I bought my telescope I have managed well with two eyepieces, now I up that till four. Perhaps I will see a need to upgrade it further in the future, but for now, this will cover the "blind spots" that I have realised that I have in my equipment. 

Edited March 20, 2021 by Thingo

[mikeDnight]

There's still room for one more eyepiece - a 17.5mm Morpheus. You'll love it! But be careful, as you might end up replacing your 13mm Nagler with the Morpheus 12.5. They are a thing of beauty!

Edited March 20, 2021 by mikeDnight

[Mr Spock]

On 25/02/2021 at 19:19, Thingo said:

This is a bit about the recommended 2x the aperture, thoughts?

I wouldn't worry about this with refractors. Apart from floaters, my 80mm ED holds x200 really well. As long as the image isn't too dark for you, it should be fine. 

 

[Thingo]

21 minutes ago, mikeDnight said:

There's still room for one more eyepiece - a 17.5mm Morpheus. You'll love it! But be careful, as you might end up replacing your 13mm Nagler with the Morpheus 12.5. They are a thing of beauty!

I deliberately started with only two eyepieces because I wanted to create that feeling that I really need more - if it would ever come. Now going from 2 to 4 is a pretty big step already and I was considering long and hard whether I would start by buying one more, but to go to 5 eyepieces is out of question at this stage. Let's see what the future has to bring, perhaps I will see a need for an additional eyepiece in the range you mention 😉

[mikeDnight]

29 minutes ago, Thingo said:

I deliberately started with only two eyepieces because I wanted to create that feeling that I really need more - if it would ever come. Now going from 2 to 4 is a pretty big step already and I was considering long and hard whether I would start by buying one more, but to go to 5 eyepieces is out of question at this stage. Let's see what the future has to bring, perhaps I will see a need for an additional eyepiece in the range you mention 😉

You have sound reasoning!  When I started out in this hobby four decades ago, most people were lucky to have three good eyepieces. These were usually Kelners, Plossl's or Orthoscopic's. Al Nagler was just beginning to influence the astronomy world back then, and I knew no-one who could afford one of his eyepieces. Today of course, many observers have cases full of different types of eyepiece for different purposes. I've done that myself over the years, but found that I would generally return again and again to three or four special ones. One that really proved very special was my 20mm Nagler. That eyepiece was a perfect deep sky match for a 4" or 5" refractor.

[Thingo]

7 hours ago, mikeDnight said:

You have sound reasoning!  When I started out in this hobby four decades ago, most people were lucky to have three good eyepieces. These were usually Kelners, Plossl's or Orthoscopic's. Al Nagler was just beginning to influence the astronomy world back then, and I knew no-one who could afford one of his eyepieces. Today of course, many observers have cases full of different types of eyepiece for different purposes. I've done that myself over the years, but found that I would generally return again and again to three or four special ones. One that really proved very special was my 20mm Nagler. That eyepiece was a perfect deep sky match for a 4" or 5" refractor.

Thanks Mike! And what you write about how you generally return to 3-4 special eyepieces is what I read in the forums all the time. That, and obviously the cost, are the reasons why I'm very hesitant when it comes to increasing my collection.