Top 3 criteria for choosing an eyepiece

[25585]

What are your top 3 criteria when choosing an eyepiece to buy? Do they change with focal length & purpose?

Mine are price, usable eye relief & field of view in that order. 

[MarsG76]

Quality, FOV than price... The way I see it, is if I skimp of quality due to price, I'll end up paying twice.... 

[bingevader]

Ba bling ba bling.

Cha ching cha ching.

Oh, that's only 2!

[Louis D]

In general, these are my primary criteria for monoviewing:

1. Usable eye relief of at least 17mm
2. Price less than $500
3. Apparent field of view not less than 60 degrees

For binoviewing:

1. Upper barrel width no wider than about 35mm
2. Usable eye relief of at least 17mm
3. Apparent field of view of not more than 65 degrees

Price still plays into binoviewing, but aside from Zeiss eyepieces, pairs obeying the above criteria aren't all that expensive.

[planetman83]

1. Apparent FOV.

2. Good coma correction.

3. Size, weight.

[Ags]

1) Want! 2) Need! 3) Must have!

[Louis D]

24 minutes ago, planetman83 said:

1. Apparent FOV.

2. Good coma correction.

3. Size, weight.

For criteria 2, only the long discontinued Pretoria eyepiece will meet that requirement.

[niallk]

1. Green lettering on black... 

2. A free silvery logo sticker

3. 100° afov, reasonable eye relief, well corrected, high transmission, not obesely heavy

[Paz]

Mine are probably.. 

1. Eyerelief 19mm+

2. Good quality well corrected views.

3. Consistent weight of eyepieces in a set as far as possible.

[celestron8g8]

Quality , AFOV , price . I prefer also if possible to be Parfocal and or Plossi . I’m poor so no high end $$$ EPs’ . Can’t afford them . I’m well pleased tho with my Plossis’ and original Celestron Ultima line . 

[BillP]

#1 - Price.  If they are outlandishly priced, then I don't care how good they are.  About $250 USD is the most I am willing to do for an eyepiece, and that amount hurts.

#2 - AFOV (size & correction) - I don't divorce the off-axis correction from the AFOV size.  They both go hand-in-hand IMO and if the off-axis is too terrible then the AFOV really is not as expansive as contended if the outer region is so bad as to look diseased.  And of course, the off-axis correction is also tightly coupled to the focal ratio and design of the telescope.  So if the eyepiece is destined for my f/4.7 Dob then it may lose on criteria #2, but if it is for my f/8 Apo then it may be just fine.  So I need to evaluate the AFOV criteria in connection with the scope it is intended for.  So I do not require the off-axis to be "perfect", just clean enough to not be distracting.  Some mild aberrations are ok IMO since I tend to spend most of my observing in the center of the FOV and I do not usually "observe" something if it is too near the field stop and I just move it to the center for better scrutiny.  So the off-axis just has to be clean enough so that I will take note of interesting stuff there to center and observe and I am mostly happy.

#3 - Ergonomics - I am bothered by large and heavy eyepieces.  So again, no matter how fantastic the eyepiece is optically, if it is a pain to use on the scope because of its weigh and overly large and cumbersome to handle, I generally will not want it.  Now with ergonomics goes eyeball ergonomics as well.  So if the eyepiece is very difficult to hold eye position easily (varies depending on the person), then I am likely not to want it.  Longer eye relief is a plus for me, but I do not mind short eye relief either so that aspect is not so critical for me unless it feels like I need to be unnaturally close to see the entire AFOV peripherally -- often an issue if the eye lens is more strongly concave.

[dweller25]

#1 - Eyerelief - the more the better

#2 - Good to excellent feedback from other astronomers

#3 - Price

[25585]

Feedback is quite valuable, for trying an ep out anyway.

@JohnI owe gratitude to for his reviews that resulted in my buying XW 10 and 7mm eps, also AP diagonal, 120 ED PRO. Various posters for the excellent Vixen LVW 22mm, my FC100DL Tak frac, TS bino viewer.

@BillP, I agree eye positioning is as important as relief. This is tricky. I have found some eps, usually shorter FL, with long enough eye relief, but a too-narrow projection up to my eye. The Pentax XW 5 and 3.5 are such gor me, bettered by Vixen LVWs of that FL as an example. 

An aspect for spectacle wearers is also contact with the ep rim. Metal might scratch, rubber smears so hover height and head sway need to be allowed without any or little loss of FOV. 

 

 

[RiponJas]

The three important factors. 

1. Permission from the wife

2. Permission from the wife

3. Have I got any money left the wife hasn't taken?? ? 

[michaelmorris]

On a purely technical basis, for double star observing -

On axis performance

Off axis performance

Colour correction

[John]

As a certified "occularholic" my top 3 criteria are:

1. Do you really want it ?

2. Do you really, really want it ?

3. Do you really, really, really want it ?

 

[AstroPhil]

1. Focal length / AFOV

2. Quality, comfort, eye relief, reputation....

3. Price, up to a point ?

...which is why I have so many XW's, as for me they hit a real sweet spot of being very nice to use, good spec, and a good price.

[Charic]

The criteria I follow  would be to choose the first eyepiece to match the focal ratio of the scope, this provides my high power eyepiece, the AFOV is important ( I prefer about 60°) as is the eyerelief, then  brand/cost  is next!

The second eyepiece focal length would match that of twice the focal ratio, my medium power eyepiece,  and my wide angle, low power eyepiece would derive from multiplying my eye entry pupil size in mm, by the scopes focal ratio. Anything else a bonus!

[Ben the Ignorant]

Why stop at three criteria? I study all the criteria in every eyepiece, and not all have the same number. Weight, for example, matters a lot in 100° eyepieces because they are so heavy and unbalance telescopes, but short focal 82°'s like my Explore 4.7mm and TS 4mm have a weight that does not count because it's so low.

[LukeSkywatcher]

Price, price and price. 

[Space Hopper]

1. Will they perform with a bino-viewer ?

2. Are they black with green stripes ?

3. Can i get them at 10% discount (or even 20%) ?

[Moonshane]

Mine depend on the use but in general

No chromatic aberration

Sharp across the field

Excellent build quality

[F15Rules]

The top 3 for me purely on a technical basis would be :

1. Optical quality

2. Optical quality

3. Optical quality

but, back in the real world, this has to be tempered to be more realistic:

1. The best optical quality I can afford - here and now ( that can vary with financial circumstances - how often does something really desirable come up for sale just after we have just bought something else?)?

2. Will I use it if I buy it? It's very easy to buy something on a whim and then hardly use it - which, if it's a used item, could deprive another person from acquiring something they would really love to use..?

3. Will the purchase give me better views than I get with my current equipment (based on research and peer reviews)? If not, am I buying it just to "keep up with the Jones's?"?

I've learnt the above lessons the hard way, through personal experience. Nowadays I try to be much more measured in what I buy and when..?

Dave

[Saganite]

Love point three Dave, though they all 'chime' with me. 

I bought a 13mm Ethos a year or so back  because I thought 'I have to have one'. It was amazing, but  I seldom used it, and I don't miss it. A couple of 13mm Naglers in a bino is far superior....IMHO. 

[Moonshane]

This sort of thread is always going to generate diversity of response. My method of avoiding massive prices is to buy used and restrict the field of view. But that said, my preference is for the 60-70 degree field anyhow. If I have less money then I buy the eyepiece with the three characteristics I stated and if this means it has a narrower field then I really don’t mind. My eyepieces have all been under £250, all but one has been £200 or less with most are between £50 and £150. Only once did I breach £250 when I paid £260 for a brand new 26mm nagler when there was a 20% off offer at the time. I sold this to help fund something else – I think it was my PST mod.

I generally have to save or sell to buy but accept this as a discipline. ?