Quote:

---

Quote:

---

Steve:

You might want to rethink the Hamilton-Burr approach or at least amend it with a qualifier. Something like this:

"Ties remaining after the Proctor's scoring will be broken with the Hamilton-Burr thrown-eyepieces-at-thirty-paces-first-blood-wins method UNLESS any such eyepiece is the property of SteveC, in which case the winner will be selected by drawing lots from a hat EXCEPT that by virtue of the generosity of its owner each such SteveC-owned eyepiece shall be given two chits rather than one."

Regards,

Jim

---

Ya know Jim, that's twice.....................................people are going to start believing that I don't think things through and that I'm rather impulsive, but that's not the case here. In every duel, there are "seconds" that represent each side. Use somebody else's EPs. A couple of Ethos would fill in quite nicely as seconds. I mean,....................what else are they good for?

My question for Dan is, since it seems that he has a pretty good arm, would he use a four finger across the Ethos body pitch or the two finger across the lens end over end pitch? I almost got to use the four finger across the body of a 16mm Nagler pitch, when a deer startled the heck out of me one night.

---

There is a pitch in baseball called the "eephus" which is attributed to a pitcher for the Pirates back in the '40s named Rip Sewell. It's considered a junk pitch but the only known home run given up by Sewell was to Ted Williams in an All-Star game.

I am considering a like pitch called the "Ethoses" pitch which you throw by placing your pinky firmly against the field lens and your thumb firmly against the front lens. This is a modified split fingered approach. I have used this several times with a couple I owned which did not perform well in the World Cup. The lob effect was magnificent. I will not go into what happened when the bat...oops over imagination!

--------------------
Dan

20" f/5 Obsession
Antares 1529
Various Naglers, Ethos, UO Orthos
Gone but not forgotten: Meade 5K UWAs & Plossls, WO UWANs, TV Plossls & T6 Naglers, Tak LEs, 13 & 17 Ethos, Vixen LVWs, Orion Stratus, Meade 12" LX200R, TV Genesis and TV102, Meade AR6, WO 80SD. All these helped to get me to what I own today.

The Off Fisher Lane Irregulars

Post Extras:

Quote:

---

As the f-ratio of the scope gets slower, surface accuracy of the eyepiece becomes less impactful, but surface smoothness of the eyepiece (i.e., scratches, dings, rougher polish), becomes more impactful. Would this be a correct restatement of what you meant?

---

Post Extras:

Quote:

---

The latter would refer to the surface roughness of each lens on a small nanometer scale, which would have not only some effect on the image quality but also an effect on light scatter in the eyepiece.

---

No, not unless those photons answer to very weird physics (of which sadly there's quite a lot in even the ATM journal from time to time).

One nanometer is 1/50 of a wavelength. Even ten nanometer is 1/50 (and these are lenses, so there's not the doubling effect of surface error vs. wavefront path length difference).

There's a reason that people need electron microscopes to see things that small. Shorter wavelength. Yes, a contrast phase test can reveal very small detail as well, but that's within the setting of the contrast phase test and quite unrelated to what happens with the wavefront outside of that test.


--------------------

400mm f/4.46 self made Dobsonian on Tom Osypowski equatorial platform
Orion Starblast (114mm f/4 reflector, Alt/Az)

Post Extras:

Quote:

---

Quote:

---

The latter would refer to the surface roughness of each lens on a small nanometer scale, which would have not only some effect on the image quality but also an effect on light scatter in the eyepiece.

---

No, not unless those photons answer to very weird physics (of which sadly there's quite a lot in even the ATM journal from time to time).

One nanometer is 1/500 of a wavelength[of blue light]. Even ten nanometers is 1/50 wave (and these are lenses, so there's not the doubling effect of surface error vs. wavefront path length difference).

There's a reason that people need electron microscopes to see things that small. Shorter wavelength. Yes, a contrast phase test can reveal very small detail as well, but that's within the setting of the contrast phase test and quite unrelated to what happens with the wavefront outside of that test.

---

Well, that depends of the amount of the error.

A 1/10 wave surface inaccuracy (say 50nm) may be invisible to the eye unless it corresponds to a similar 50nm wavelength divot on the other side of the same lens. Then you have a 1/5th wave error. The likelihood is that there will be cancellation, partial cancellation, partial reinfocement, or reinforcement of the error in the wavefront depending on chance.

And though the light cone entering the eyepiece is no larger than the field lens of the eyepiece, that field could be expanded as it passes through the next lens or lens set. Even if the planet subtends a 0.1mm field width at the field lens does not mean it passes through all the lenses as a 0.1mm image.

Plus, the number of elements is higher than 1. If additional elements did not result in increased scatter and wavefront degradation, we'd all be using eyepieces with large numbers of elements to control aberrations. But yet, and quite persistently, planetary observers tend to express preferences for eyepieces with small numbers of elements.

I, myself, have seen optical differences among three of the same model/brand/focal length of eyepiece on the same night/target/scope (a few times in my eyepiece collection past). If the differences were as minute as you imply, I could not have seen consistent, repeatable, differences, and yet I did.

Scratch and dig surface roughness is likely (maybe)to be on the small side compared to one wavelength of blue light. But that does not mean that surface roughness has no effect on the wavefront passage. Yes, it is probably on a much smaller scale than similar errors in a primary or secondary mirror. But the image scale is considerably smaller at the final focal plane than at the entrance pupil, and similar depth/width errors (on the surface of an eyepiece lens) to a primary mirror can have an effect over a larger true field than the errors at the primary mirror.

--------------------
Don Pensack
12.5" Truss Dob, 5" Maksutov, Fujinon Binos
Sustaining Lifetime IDA member

Post Extras:

Quote:

---

Well, that depends of the amount of the error.

---

Quote:

---

A 1/10 wave surface inaccuracy (say 50nm) may be invisible to the eye unless it corresponds to a similar 50nm wavelength divot on the other side of the same lens. Then you have a 1/5th wave error.

---

Quote:

---

If additional elements did not result in increased scatter and wavefront degradation,

---

Quote:

---

Scratch and dig surface roughness is likely (maybe)to be on the small side compared to one wavelength of blue light.

---

Quote:

---

But that does not mean that surface roughness has no effect on the wavefront passage.

---

Again, I did not say this. I said that nanometer scale roughness (which you can still detect in a contrast transfer phase test) doesn't have much of an effect.

--------------------

400mm f/4.46 self made Dobsonian on Tom Osypowski equatorial platform
Orion Starblast (114mm f/4 reflector, Alt/Az)

Post Extras: