Explore Scientific optical quality across ranges

[jetstream]

9 hours ago, alan potts said:

A fair point Gerry I would say that of the 33 that I once had only 16 were bought new which is not even 50% but I feel that I did have rather more than most, my Paracorr Mk2 was new so that sort of saves the day. I do have another problem here though, anything I need new I have to get from Telly House and for one eyepiece they charge 45 pounds for a courier, I will not deal with other European outlets for personally reasons, in anycase there I would have to pay a 30e bank charge for a transfer on top of any transport. So now as my local dealer can no longer help me in that area I tend to look for secondhand from site members. I feel I will have to bit the bullet on my De-lite wants and order as a batch from the UK, new.

Alan

Congrats for the Delites coming! I hear they are VG and with a bit smaller spot size than the Delos. Many eyepieces are going up in price thats for sure, including ES and I'm glad I have all I need pretty much

[jetstream]

10 hours ago, Louis D said:

In the center of the 30mm ES-82, stars simply refuse to focus down to pinpoints

My experience differs from yours Louis- my 30 ES 82 focuses perfectly into pinpoint stars. It has really good contrast but not in the league of the 21E or 20mm Lunt HDC that I own. The 18ES in the collection offers a bit better contrast than my 16T5 Nagler and is also sharper on axis on lunar etc. My 17E beats them both for DSO contrast but the 17E does not offer top tier on axis performance for planetary to my eyes-compared to some fairly good orthos including the 18mm BCO,18mm UO and an 18mm Tak.

[Louis D]

11 hours ago, John said:

Thanks for taking another look throught these Louis and for reporting what you saw.

Are your ES 82's the current design or the earlier "mushroom top" design ?

 

 

The original mushroom top.  It has just enough eye relief to use with eyeglasses.

[Louis D]

4 hours ago, jetstream said:

My experience differs from yours Louis- my 30 ES 82 focuses perfectly into pinpoint stars.

Perhaps they made a change to the optical formula.  I just wish they hadn't recessed the eye lens.

[Piero]

6 hours ago, jetstream said:

My experience differs from yours Louis- my 30 ES 82 focuses perfectly into pinpoint stars. It has really good contrast but not in the league of the 21E or 20mm Lunt HDC that I own. The 18ES in the collection offers a bit better contrast than my 16T5 Nagler and is also sharper on axis on lunar etc. My 17E beats them both for DSO contrast but the 17E does not offer top tier on axis performance for planetary to my eyes-compared to some fairly good orthos including the 18mm BCO,18mm UO and an 18mm Tak.

My ex ES 30mm was pretty much as you described. 

[N3ptune]

I have the 34mm ES 68d, it's a great eyepiece (; I paid 380$ total for it. The closest better equivalent would be the Nagler 31mm which is around 1200$ but I can't afford it... I don't have a choice to be glad ES copied TV to provide good copies to the masses, Otherwise It would not be possible for me to do comfortable astronomy with wide fields well corrected eyepieces. 

It's Corvette for everyone! like at the end of Mr. Deeds 

And this would be everyone.

https://www.youtube.com/watch?v=G_eistbnfeY

[alan potts]

On 19/11/2017 at 16:55, N3ptune said:

I have the 34mm ES 68d, it's a great eyepiece (; I paid 380$ total for it. The closest better equivalent would be the Nagler 31mm which is around 1200$ but I can't afford it... I don't have a choice to be glad ES copied TV to provide good copies to the masses, Otherwise It would not be possible for me to do comfortable astronomy with wide fields well corrected eyepieces. 

It's Corvette for everyone! like at the end of Mr. Deeds 

And this would be everyone.

https://www.youtube.com/watch?v=G_eistbnfeY

I had the full set of SWA, wish I had kept them more than once, the 16mm was a bit short on ER for some but in general it was a fine set of 6. I still feel the 40mm, though very heavy was better in my SC than the 41mm Panoptic, but being a stuggling TVaholic I sold the Meade.

[N3ptune]

12 hours ago, alan potts said:

I had the full set of SWA, wish I had kept them more than once, the 16mm was a bit short on ER for some but in general it was a fine set of 6. I still feel the 40mm, though very heavy was better in my SC than the 41mm Panoptic, but being a stuggling TVaholic I sold the Meade.

Ahh maybe I don't have enough experience yet to desire the very best like you do. But slowly my tastes are refined. I could end up one day with TVs only, we never know...

[Louis D]

12 hours ago, N3ptune said:

Ahh maybe I don't have enough experience yet to desire the very best like you do. But slowly my tastes are refined. I could end up one day with TVs only, we never know...

It doesn't stop there.  Then you start adding Nikon or Docter or Zeiss or Leica where appropriate.

[N3ptune]

On 2017/11/21 at 11:33, Louis D said:

It doesn't stop there.  Then you start adding Nikon or Docter or Zeiss or Leica where appropriate.

I hope to remain in my actual category honestly everything is simple and inexpensive.

[Louis D]

On 11/18/2017 at 16:45, Piero said:

My ex ES 30mm was pretty much as you described. 

I had a look at the moon last night with my 30mm ES-82.  It was plenty sharp in the center just like the rest of my eyepieces, but it had all sorts of issues at the edge.  First, it was hard to hold the image directly.  Second, the image was unsharp, probably due to astigmatism and chromatic aberration.  Third, there was this nasty orange-yellow glow all around the edge when the moon was placed there (ring of fire?).  Probably the last 20% of the view I'd estimate suffered from this.  Taken together, the edge was simply unuseable.  The 12mm and 17mm Nagler T4s did not suffer from this, nor did the 17mm ES-92.  My 30mm KK Widescan clone was just as sharp in the center and had no ring of fire.  I placed my field flattener about 6 inches ahead of it and removed most of its curved field.  At that point, the edge was only suffering from some astigmatism.  The view was much more enjoyable letting the moon drift through the KKWC than throught the ES-82.

[Piero]

9 minutes ago, Louis D said:

I had a look at the moon last night with my 30mm ES-82.  It was plenty sharp in the center just like the rest of my eyepieces, but it had all sorts of issues at the edge.  First, it was hard to hold the image directly.  Second, the image was unsharp, probably due to astigmatism and chromatic aberration.  Third, there was this nasty orange-yellow glow all around the edge when the moon was placed there (ring of fire?).  Probably the last 20% of the view I'd estimate suffered from this.  Taken together, the edge was simply unuseable.  The 12mm and 17mm Nagler T4s did not suffer from this, nor did the 17mm ES-92.  My 30mm KK Widescan clone was just as sharp in the center and had no ring of fire.  I placed my field flattener about 6 inches ahead of it and removed most of its curved field.  At that point, the edge was only suffering from some astigmatism.  The view was much more enjoyable letting the moon drift through the KKWC than throught the ES-82.

As mentioned before, I think your version of ES30 is older than mine. Mine shows the ring of fire, but none of the issues you mentioned in the last 20% of the field. Said this I am not a great fan of the moon with large AFOV eyepieces. I tend prefer <70. For me, the only exception to this rule seems to be the Docter + barlow.

[jetstream]

44 minutes ago, Louis D said:

The 12mm and 17mm Nagler T4s did not suffer from this,

Out of curiosity did these two eyepieces show a thin blue ring at the edge when on the moon? A few years ago I tested a bunch of 82 deg + eyepieces for this.

[cloudsweeper]

1 hour ago, Louis D said:

I had a look at the moon last night with my 30mm ES-82.  It was plenty sharp in the center just like the rest of my eyepieces, but it had all sorts of issues at the edge.  First, it was hard to hold the image directly.  Second, the image was unsharp, probably due to astigmatism and chromatic aberration.  Third, there was this nasty orange-yellow glow all around the edge when the moon was placed there (ring of fire?).  Probably the last 20% of the view I'd estimate suffered from this.  Taken together, the edge was simply unuseable. 

I bought a new ES 30/82 this year, and have detected only a little field curvature, but no astigmatism to speak of.  But the Ring of Fire (when viewing the Moon) came as a surprise, especially as the humble Revelation Astro Superview 30/68 which was being replaced didn't show that effect. 

I ended up keeping the Rev, and use the ES when I want extra TFOV!

Doug.

[Louis D]

1 hour ago, jetstream said:

Out of curiosity did these two eyepieces show a thin blue ring at the edge when on the moon? A few years ago I tested a bunch of 82 deg + eyepieces for this.

I think so.  Pretty much all of my positive/negative design eyepieces show some amount of thin blue line at the edge with the moon.  Some are just thicker, sharper, or more intense than others.  Next time I'm observing the moon, I make a mental note of which do and to what extent.  I know the 10mm Delos is very bright and thin while the XLs are thin and less intense.  The 17mm ES-92 shows some edge effects as well.  By comparison, positive only designs like plossls, Konigs, Panoptics, etc. don't seem to show this effect.  I think of the thin blue line as the light rays being tortured by first being bent outward and then back inward.  Seemingly, some fraction of the edge rays get misaligned leading to the blue line.

[John]

2 hours ago, Louis D said:

I think so.  Pretty much all of my positive/negative design eyepieces show some amount of thin blue line at the edge with the moon.  Some are just thicker, sharper, or more intense than others.  Next time I'm observing the moon, I make a mental note of which do and to what extent.  I know the 10mm Delos is very bright and thin while the XLs are thin and less intense.  The 17mm ES-92 shows some edge effects as well.  By comparison, positive only designs like plossls, Konigs, Panoptics, etc. don't seem to show this effect.  I think of the thin blue line as the light rays being tortured by first being bent outward and then back inward.  Seemingly, some fraction of the edge rays get misaligned leading to the blue line.

Interesting explanation here including a specific post on the older style ES 30 / 82 eyepiece:

https://www.cloudynights.com/topic/530975-what-actually-causes-ring-of-fire-in-31-nagler-and-others/

 

[Louis D]

2 hours ago, John said:

Interesting explanation here including a specific post on the older style ES 30 / 82 eyepiece:

https://www.cloudynights.com/topic/530975-what-actually-causes-ring-of-fire-in-31-nagler-and-others/

 

Thanks for the link.  Notice in Ernest's photo that the exit pupil is poorly defined.  It starts to diverge before it has come to a point, thus it's difficult to pin down the usable eye relief.  I noticed the same thing in my flashlight projection testing.  I also noticed he's using the same version of the 30m ES-82 that I do (mushroom top).  I believe this inability to focus all frequencies to a single point leads to the indistinct star points I see.  They start out as small blue, then white, then red circles as you rack through focus without ever coming to a fine pinpoint because different frequencies are focused at different distances in the exit pupil.

Could someone with the latest version rig up a similar test?  Just project a bright light through the eyepiece in a darkened room and bisect the exiting light cone with a white sheet of paper.