75 replies to this topic

[wrvond]

Eyepieces, just like cars, are built using variables within certain constraints. For example, all cars (generally speaking) have four wheels. Different cars have different size wheels within the constraint of having four wheels. You, as the user can choose what size wheel (or tire) you want on your car. A 17" wheel is going to give you more torque than a 20" wheel (all else being equal) but a 20" wheel is going to give you better fuel mileage than a 17" wheel. You don't ponder the "why" of this, you accept it and move on.

 

Some people like long eye relief (due to glasses for example) others like short eye relief. I like to rest my eyebrow against an eyecup so I prefer a shorter eye relief.

Some people like an eyecup, some prefer no eyecup at all.

Some people feel that an AFoV of 50° is like looking through a soda straw. Some feel that 100° is too wide to comfortably take in the entire view. I prefer 82° myself.

Some people only like eyepieces with orange lettering on their barrels. Some like blue. I like green.

 

There are a host of parameters (or variables) to choose from. With experience we determine what our personal preferences are and make our selections accordingly.

I have owned well over 200 eyepieces and have tried many, many more than that. Experience has led me to select just ten eyepieces for mono viewing:

 

 

I once had a binoviewer that I kept individual focal length eyepiece pairs for. I eventually sold it and the EPs. Recently I purchased another binoviewer but this time I decided to go with a pair of Baader zooms rather than individual focal lengths. Convenience and economy has changed my priorities. 

 

 

[ChristianG]

It weighs in at 13.3 oz which I assumed it weighed more, it felt heavier, need to try it in the telescope, visual means more than weight.

Hi.

 

If you peel off the round stickers with the Celestron logo, this exposes the screws holding the 'eyeguard', which is responsible for a good chunk of the weight and size of the eyepiece. Of course, without it, there is no more guide for the eye, and you have to find a suitable cap for the top lens (I used a binocular objective cap). You get used to placing your eye in the right place by gently holding the black eyepiece core in your hand. I did this to a 23 mm and also to a 19 mm. Some images (from another CN fellow):

 

https://www.cloudyni...minos-eyepiece/

 

Good luck.

 

--Christian

[newbeeDavid]

Well looking at the photo seems many of my Tele Vue purchases are good choices, assuming yours are, and I feel pretty good about your choices, from what I read for specs and feedback reports of the Nagler 5 and 6 eyepieces they ar pretty good choices even at their age.. Being new I am sure I miss any flaws but am overly pleased. Just found a 3 mm. ES 52° AFOV that is also a brand that seems to get good praise on CN  so I bought it, mag is a bit high for both the Orion 8" xt and my grandsons Meade 102mm,  418x on the dobsonian and 200x on the refractor. Will get it this weekend so we will see, bought it for primarily planets in this solar system and some distant universe views my grandson sees on Stellarium he's going for his next step finding them may be interesting,my next education step.

[SeattleScott]

Televue currently produces T5 and T6 Naglers. The T1/T2’s are the old ones. Sure, there have been improvements over time. Better coatings, easier eye placement, more eye relief in some cases, and generally smaller/lighter. Just look at a 9T1 versus a 9T6, or 20T2 versus 20T5. They have gotten smaller over time. But the old ones generally had good edge correction across their very wide fields.

ES is a bit different . They have products at different price points to appeal to different audiences. Some of their stuff tried to compete with Televue. Other stuff is for more bargain/value shoppers.

[newbeeDavid]

Other than it being 52° AFOV 3mm and argon purged how would I tell what I bought?

[Starman1]

Televue currently produces T5 and T6 Naglers. The T1/T2’s are the old ones. Sure, there have been improvements over time. Better coatings, easier eye placement, more eye relief in some cases, and generally smaller/lighter. Just look at a 9T1 versus a 9T6, or 20T2 versus 20T5. They have gotten smaller over time. But the old ones generally had good edge correction across their very wide fields.

ES is a bit different . They have products at different price points to appeal to different audiences. Some of their stuff tried to compete with Televue. Other stuff is for more bargain/value shoppers.

The Nagler T4 22mm is still current.

[Dave Mitsky]

A 3mm eyepiece is going to produce a rather tiny exit pupil of 3/5.9mm or 0.51mm, with your Dob.  You're probably going to be seeing a lot of "floaters".

 

The 8" Orion SkyQuest XT8 Plus has a focal length of 1200mm.  The true field of view at 400x is going to be very small, about 13 arc minutes, necessitating constant nudges to keep an object in view.
 

https://www.telescop...yquest-xt8-plus

[Dave Mitsky]

Another issue with using a 3mm eyepiece that produces that much magnification is whether the astronomical seeing will ever support using it.  The northeast is not known for having excellent seeing.
 

http://www.damianpeach.com/seeing1.htm
 

http://www.damianpea...m/pickering.htm
 

https://skyandtelesc...ing-the-seeing/
 

https://www.skyatnig...nomical-seeing/

[SeattleScott]

Other than it being 52° AFOV 3mm and argon purged how would I tell what I bought?

The 52 AFOV line is a budget line for ES. It isn’t made to the same standard as their flagship ultrawides and hyperwides.

That being said they should have greater eye relief in short focal lengths than a standard 52 AFOV Plossl. So you get that, and argon purging.

But if I was willing to live with 52 AFOV and wanted the sharpest possible view, I would be looking more at something like Televue Plossls, Tak TPLs, Tak TOE, etc. Most of those have poor ER in short focal lengths though. If I wanted good ER in short focal lengths, I might look at Vixen SLVs. Even those have a somewhat sketchy reputation regarding baffling, and aren’t generally held in the same regard as Televue/Tak. But I would trust them more than the ES 52 AFOV series.

Truth is, the ES 52’s aren’t real well known. They are expensive for 52 AFOV, so not many people buy them. What few reviews I have seen suggest they are fairly mediocre, and mostly you are paying for the long ER at short focal lengths, and the argon purging. But yeah, not a lot of reviews to go off of, especially from veteran stargazers who really know their eyepieces, and have other eyepieces to compare them to.

Ultimately I’m sure they are fine eyepieces that do the job, like most eyepieces. I just don’t know how well they compare to competitors, or if there are better options with similar performance for less money. Or better performance for same money. Personally, for 50 AFOV with usable ER, I like the pseudo Masuyamas. Parks Gold, Orion Ultrascopic, etc. Yesterday I saw a set of five of them listed in Classifieds for $250. Vintage eyepieces, but premium Japanese quality. Very sharp. Yeah, they aren’t wide AFOV, and they don’t have 20mm ER. That’s why they usually sell for around $70. I trust the quality of these more than SLVs or ES 52s. So I won’t be getting any ES 52’s.

[SeattleScott]

Ok I was curious so I looked up some reviews and came across this thread:
https://www.cloudyni...ientific/page-3

It took awhile to get any comparisons to high quality eyepieces, but eventually someone provided that information. It sounds like the 52’s are pretty sharp and mostly have good edge correction. Sounds like there are some issues that baffling when viewing bright objects, which is what I recalled from reading about them before. A reviewer (who really liked the 6.5mm) suggested it was a better DSO eyepiece than planetary. But in general it seems like they are good performers, not giving up much to Pentax and Nikon (other than AFOV and in some cases ER). Which could make them a good value, considering the cost of Pentax and Nikon.

[scotsman328i]

 

The only true 2" Tele Vue Nagler eyepieces currently available are the 31mm Type 5 and 22mm Type 4.  The 17mm Nagler type 4, 20mm Type 2, 20mm Type 5, and 26mm Type 5 are no longer in production.

The 9, 11mm, and 13mm Nagler Original, the 12 and 16mm Nagler Type 2, and 12mm Nagler Type 4 eyepieces have hybrid 2" and 1.25" barrels.  They are not "true" 2" eyepieces.

https://www.televue....page.asp?id=214

And…oh man! I’m so fortunate to have bit that bullet over the years and still own pristine Naglers 20T5, 26T5 and the 17T4. I’ll never part with them. Come get them out of my cold dead hands at my estate sale someday. 
 

 

[newbeeDavid]

Trying To get a better handle on eyepieces, the FOV calculator gives me a better concept of the actual FOV for different eyepieces, the part I don't see is the visual quality I seem to be looking more at the Nagler pieces however even there the options: T5, T6, Delite, Delos, Ethos, ETC makes a lot of difference in FOV and I assume visual quality. I have several I purchased on CN classifieds yet having knowledge of age differences and where manufactured would be a part of the purchase. This is where being a novice comes back into play, again I would have to go back to the assumption I am buying quality based on  the manufacturer. I have a decent selection of eyepieces now so it is back to finding the personal preference with eye relief, FOV, and other issues that have been pointed out in this post  to the eyepieces I have listed and if I turn around to sell or keep.

This reminds me of my boating days, the list is endless it just matters what you want to put in weighed against what the outcome is. 

[Starman1]

Trying To get a better handle on eyepieces, the FOV calculator gives me a better concept of the actual FOV for different eyepieces, the part I don't see is the visual quality

Yes, FOV doesn't tell you about the visual quality.  Price does a little, but even then, there are some exceptional bargains out there.

 

I seem to be looking more at the Nagler pieces however even there the options: T5, T6, Delite, Delos, Ethos, ETC makes a lot of difference in FOV and I assume visual quality.

The one thing you can count on from Tele Vue is that there isn't a qualitative difference among their eyepieces, only apparent field and eye relief.

The wider the apparent field, the more expensive the eyepiece--you're almost paying for the weight of the eyepiece, which makes sense when you realize that larger lenses cost more money than smaller lenses.

 

I have several I purchased on CN classifieds yet having knowledge of age differences and where manufactured would be a part of the purchase. This is where being a novice comes back into play, again I would have to go back to the assumption I am buying quality based on the manufacturer. I have a decent selection of eyepieces now, so it is back to finding the personal preference with eye relief, FOV, and other issues that have been pointed out in this post  to the eyepieces I have listed and if I turn around to sell or keep.

This reminds me of my boating days, the list is endless it just matters what you want to put in weighed against what the outcome is. 

Indeed.  The process is almost endless, though it slows down when you are really happy with the eyepieces you have.  I have a rule--if I haven't used it in 2 years, I sell it.

The hard part is the reverse--if you have used all your eyepieces in that period, but you have too many eyepieces, how do you sell one?

The answer for many is to have a large collection of eyepieces.  I have 12 and typically use at least 11 of them every time I'm in the field.  Some are really duplicates, i.e. very close together in focal length, but present very different images of their fields of view.

Sometimes, I like to keep my glasses on so use glasses-compatible eyepieces down to 4.8mm.  Other times, I take them off and use eyepieces that are not glasses compatible from 8mm down to 3.7mm.  It depends on what I am looking for.

A 7mm with a 100° is a fantastic view, but not glasses-compatible.  A 6.7mm with a 79° apparent field is a great image and IS glasses-compatible.  

I guess as long as all my eyepieces fit in one case there is not really any reason to sell one.  But new eyepieces come out all the time, and I might like one of them even more... 

 

 

[daveb2022]

Perhaps it has already been mentioned but there is some good info here:

 

https://www.televue....=TRUE#Eyepieces

[newbeeDavid]

Well that list just put several sites I haven't seen about Tele Vue on my reading list , I have read a lot about Nagler but most info was pre 2015 so I will have to look and see what some of these topics say. If anything my read knowledge is expanding quickly, however practical application isn't. Waiting for weather change in the Northeast but it seems to be locked into winter and wet cloudy skies. I know this is normal but a new hobby gets you wanting, and teaching my grandson as I learn makes it a rewarding challenge.

The eyepieces that I have acquired are now a decent list and range from 3-34 mm with some good AFOV which I am seeing that 80* is a good # the only quest there is if I find ones I have unacceptable and below 68* AFOV seems to be the cut off point but that may change overtime with usage. the reason I use 68* is the out of view drift time for High magnifications, when I set planet views up and have my grandson look, the drift limits view time, but the reverse adjustment throws him for a loop. drift limits time. I am trying to get him to understand following planets the dobsonian is one problem but two scopes are set up with SVBony alt az mounts to try and simplify things for his view time.

[newbeeDavid]

Thanks Dave so far the reading is very beneficial even a lens app that matches eyepieces to scope has good information for my 8" dobsonian vs my 102 mm refractor.

[raghavanb]

2” format has nothing to do with how much light. 2” format has to do with how wide the view is.

Your 9mm Nagler has nearly just as wide of a view as the current Type 6 model. It is basically an ultrawide eyepiece, 2” or not. The AT 9mm hyperwide is even a 1.25” eyepiece.

Yes, the marketing is perhaps deceptive in that it isn’t a true 2” eyepiece. Just a 1.25” eyepiece with an extra 2” barrel for convenience. But 2” format is meaningless for a 9mm eyepiece anyway, except for perhaps the monstrous ES 9mm 120. Even with that, 2” format feels like a design choice, and likely not necessary to enjoy the whole 120 degree view.

Marketing apart, am I losing light presented by a 2" secondary barrel of my Newtonian OTA when I employ a 1.25" eyepiece to view the same?

I realize this must be a newbie question that may have been answered in the past, thank you for your patience!

Edited by raghavanb, 14 February 2025 - 07:52 AM.

[Starman1]

Marketing apart, am I losing light presented by a 2" secondary barrel of my Newtonian OTA when I employ a 1.25" eyepiece to view the same?

I realize this must be a newbie question that may have been answered in the past, thank you for your patience!

To answer the question, you need to state aperture, f/ratio, and distance from secondary center bolt to top of focuser plus 18mm to guess location of the scope's focal plane.

[SeattleScott]

Marketing apart, am I losing light presented by a 2" secondary barrel of my Newtonian OTA when I employ a 1.25" eyepiece to view the same?

I realize this must be a newbie question that may have been answered in the past, thank you for your patience!

No, objects will not be dimmer because you use a 1.25” eyepiece. The view will be narrower, but the target won’t be dimmer because of 1.25” format.

In practice, 1.25” eyepieces almost always provide dimmer views than 2” eyepieces, simply because 1.25” eyepieces are typically higher magnification. But comparing my 2” 70 AFOV 30mm eyepiece with my 1.25” 50 AFOV 30mm eyepiece, the view looked identical other than the view in the 2” being wider.

[WillR]

That is the information I was looking for, the terminology of "not true 2" is the most defining answer. Not expecting glass to be 2" but also not expecting a 2" eyepiece to have glass smaller than 1.25" diameter the purpose I assume is more light not less or equal to 1.25" eyepieces.

Think of it as a 1 1/4” eyepiece that can be used in a 2” focuser. This makes it possible to swap out a true 2” eyepiece with a 1 1/4” eyepiece without having to use a 2” to 1 1/4” adapter. It’s for convenience only.

 

The field stop is the limiting the factor in an eyepiece’s FOV. It is only in the longer focal lengths where a true 2” eyepiece is needed.

[WillR]

These responses are getting me to where I started, trying to understand 2" optics compared to 1.25" and understanding higher mag and AFOV I am constantly using the FOV calculator App trying to get eyepieces that fit my planetary viewing for my grandson and his growing request list which starts with Andromeda then leads to Nebulas and Binary stars, eight and the sky is his hobby.

Ok, you are overthinking this. You‘ll drive yourself crazy. For planetary you want short focal lengths eyepieces. TFOV is irrelevant because even Jupiter will fit with lots of room around it in the narrowest FOV. It is less than 1’across.

 

I hope the Televue Naglers are for you. They are pretty big and heavy for an 8 year old, and dropping one would not have a happy outcome. As he learns to swap out eyepieces, I would suggest a few Paradigms or similar.

[WillR]

The 23 Luminos is chunky. It is January so it would be a good time to put it in a diet if it is too big and heavy for your preferences. I have a slimmed down Meade 24mm SWA for example.

Scott is referring to taking off the outer shell which is purely cosmetic. It’s called decloaking I believe. You can find plenty of topics on it.

[newbeeDavid]

Yeah we'll skip the "decloaking"  idea and the Naglers and any others are my hands only. I noticed one Tele Vue Nagler 9mm I purchased through CN had been dropped the 2" ring shows misshapen and a small skuff like it was on asphalt or Cement. Have not used it yet so not sure if it shows visual damage , examining I can see nothing in the glass are there other issues that should concerning me? Should I have it looked at by the manufacturer?

Edited by newbeeDavid, 15 February 2025 - 08:43 AM.

[WillR]

Yeah we'll skip the "decloaking"  idea and the Naglers and any others are my hands only. I noticed one I purchased through CN had been dropped the 2" ring shows misshapen and a small skuff like it was on asphalt or Cement. Have not used it yet so not sure if it shows visual damage , examining I can see nothing in the glass are there other issues that should concerning me? Should I have it looked at by the manufacturer?

Just try it out.

[newbeeDavid]

That's what I figured  if weather will allow. This weekend brings another snowstorm.