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19 Pan for planets?

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#1 Moonglum

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Posted 16 January 2014 - 06:42 PM

A fellow in another post mentioned how he thought a 19 Pan was pretty much the equal of his 20mm TV plossl in clarity and contrast. I myself always wrote off the 19 Pan for planets because of it's reportedly high Rectilinear Distortion, but then I realized I would only be using it at F18 and slower. So my question is, at F18 and slower, will Jupiter become distorted at the very edge? Or does the extreme slow focal length negate this effect entirely?
I ask because I mostly hand-track with heavily barlowed refractors on alt/az these days, and could really use the extra field.

Kirk

#2 youngamateur42

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Posted 16 January 2014 - 06:45 PM

From what I've heard, the Panopics and other wide field eyepieces are not optimum for planetary observations. I have before, but Plossls, othoscopics etc are better

#3 JustaBoy

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Posted 16 January 2014 - 06:46 PM

The distortion is a product of the eyepiece Only and is unrelated to the telescope it is used in.

#4 Starman1

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Posted 16 January 2014 - 08:03 PM

A fellow in another post mentioned how he thought a 19 Pan was pretty much the equal of his 20mm TV plossl in clarity and contrast. I myself always wrote off the 19 Pan for planets because of it's reportedly high Rectilinear Distortion, but then I realized I would only be using it at F18 and slower. So my question is, at F18 and slower, will Jupiter become distorted at the very edge? Or does the extreme slow focal length negate this effect entirely?
I ask because I mostly hand-track with heavily barlowed refractors on alt/az these days, and could really use the extra field.

Kirk

RD doesn't distort planetary images like you think. Usually, a distorted planet is the result of AMD (Angular Magnification Distortion), of which the Panoptic line has nearly zero.
The issue you might have with the 19 Pan is that, like the 24 as well, it tends to have some lateral chromatic issues which are not an issue for DSOs, but might be obtrusive on planets. But, at f/18, you'd likely run into a lot less of that than we f/3-f/6 scope owners. In my f/12.8 Mak, said chromatic spread only occurs right near the edge, which is certainly not where you're likely to be viewing a planet.
If you panned (pun intended) the planet so it never left the central 75% of the field of view, you'd probably find the 19 Pan seeing-limited, just like every other 19mm eyepiece, and without any lack of sharpness not due to the atmosphere or the scope itself.

#5 Scanning4Comets

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Posted 16 January 2014 - 08:41 PM

"I don't always use my 19mm Pan for planets, but when I do, I make sure I don't pan around in circles"

LOL

#6 BillP

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Posted 16 January 2014 - 09:04 PM

A fellow in another post mentioned how he thought a 19 Pan was pretty much the equal of his 20mm TV plossl in clarity and contrast.


The 19 Pan was by far my favorite of the Panoptic line. I used to give it a go every now and then for planetary. While it is a good performer, not up to what a Plossl or Abbe can do made to the same level of excellence as the Pans IME. It's not to say that it is impossible for both the 19 Pan and 20 Plossl to show the same planetary performance, just depends on how much the optical chain may be masking things, or the atmosphere, or the physiology of the observer at the time. So not doubting their observation at all. But this has not been my experience in my optical chain under my skies. The 20 Plossl and 19 Pan (each Barlowed with a TV 2x or 3x to get to planetary magnifications), always showed the 20 Plossl doing an easily better job on planets.

Now one thing I have noticed on the occasion when I have used very long focal ratio telescopes, is that EP performance on-axis definitely changes for my eye. So always the possibility that the two designs get closer to each other, and if the water vapor or particulates in the atmosphere are at a level that any difference between the two is overwhelmed by atmospheric scatter, then indeed easy for the two to look like they are performing equally. Anything is possible...why consistent performance difference over time is really needed to make a firmer conclusion. For me consistently better performance for planetary always went to the Plossl when I had both lines. 19 Pan though and 16T5...really sweet little packages :) Miss them both.

#7 Eddgie

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Posted 16 January 2014 - 09:53 PM

I used one a lot for planets when I owned the C14 and loved it. I did not really feel like it was any less capable than the TV 20mm or 17mm Plossl. Only used it at the center of the field though. Not sure how it would work if you left a planet drift to the field stop.

Dude, maybe you should be spending your money on a mount with a motor... LOL.

#8 Jeff Morgan

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Posted 16 January 2014 - 11:00 PM

I love Panoptics as much as anyone, but you can do better for planetary. Depends upon how much planetary is a passion for you, at f/18 virtually anything is possible provided it's a quality build. And by "quality" we're not talking Zeiss, but University Optics or better.

#9 Moonglum

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Posted 16 January 2014 - 11:19 PM

I get the feeling that most who have replied here, indeed most on CN in general, have never spent serious time hand tracking planetary with anything other than a Dob. Under the Jetstream, as probably over half of us live, we are limited to what, about 175X to 225X on most evenings? How can the most critical on-axis view matter that much on these nights? I would rather be able to lift and move about the tree lined backyard my 115 triplet, binos and eyepieces, Macrostar and heavy wood surveyor's tripod at will. Only if the atmosphere supports over 200x do I bring out my 8 inch scope and EQ6. And for the 8 months of the year with no snow on the ground this works out to 3-4 nights (that I can stay up late) a year. My reality for now, and probably why so many new astronomers get discouraged and give up after realizing the regular time commitment required to set up things like tracking mounts.

A 4-5 inch bino'd apo on a alt/az packs an incredibly viable punch under the Jetstream. The convenience factor cannot be over-stated. For Jupiter at 150X 50 degrees is perfect. For Saturn and Mars approaching 200X a 70 degree field becomes mandatory.

Guerilla astronomy it must be, in and out as quick as possible.

#10 BillP

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Posted 17 January 2014 - 09:10 AM

I like that..."Guerilla Astronomy!" :lol:

You make a great point that is most often totally ignored when people give advice. No one really considers the operating conditions, and most advice is to get the Ferrari, even when the driving conditions may be mostly a mud track :lol:

An APO on an Alt-Az, binoed or not, is a beautifully portable, extremely capable, and at the ready machine. And while tracking mounts can be a pain, there are some relatively painless ones. I alternate my APO on alt-az or tracking, depending on my mood. The tracking mount I chose was the iOptron Minitower Pro. I exclusively use it in battery operation as I find easy to get a few months out of the set even when observing a lot. Setup on it is virtually nothing as just point it straight up, turn it on, then tell it to go to your first object. That object is always visible in a low power eyepiece, so then you just use the sync command to center the object and that they gets the alignment perfect for the evening. So I never waste time doing a 1 or 2 star alignment and just go straight to my first observing target. It is also very small and light so no more bulk than the alt-az.

Anyway, for Astro Guerilla Warfare, the iOptron tracking mount is also a viable weapon system ;)

#11 Bill Barlow

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Posted 17 January 2014 - 11:19 AM

I, like you, use manual altaz mounts from UA, the Unistar series. I have never owned a computerized/motor driven mount and don't plan to. I like the simplicity/ease of setup and like finding/tracking objects myself. I use a C14 on the UA Unistar deluxe with the 7" duel clamping saddle on a CGE tripod with vibration pads and it works great. So there is no wrong way to observe, to each his/her own depending on their mount of choice. I guess I am a gorilla like you.

Bill

#12 vahe

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Posted 17 January 2014 - 12:05 PM

I use a pair of 19-Pans for high power lunar binoviewing with my long focus Maks, it produces spectacular lunar close ups, 260x, with my 8” Mak.
The curvature of field is very pronounced in this eyepiece, more than any eyepiece that I have owned.

Planets are problematic with this eyepiece due to reflections caused by the deeply concave eye lens, acting as a spherical mirror the eye lens produces very sharp ghost image of the planets image reflected back into it from the eye, this ghost image of planet can be critically focused by adjusting the eye position.

Rectilinear distortion is not a problem for a tiny object seen at the center of field.

All in all, I do not use the 19-Pans for planets for the reasons cited.

Vahe

#13 Moonglum

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Posted 17 January 2014 - 09:03 PM

Bill, thanks for adding to my astro lust list. Why the pro over the Mini tower II ? Just the heavier tripod? I've a feeling I'll be keeping my eye on these I options for a while. I'm having a vision of mounting my SV102T and binos, which is surprisingly short with the 1.7 glaspath installed before the diagonal for a resultant 1.6X -doh!...and a pair of those swanky new 6mm Tak orthos, for 215X traking on Saturn. Could be bliss.

Vahe thanks for the tip on the 19 pans. Too bad planet-wise but you've really got me excited for the Moon. In my 15.5 Mak they will give me 200x, but if the 19 Pans come to focus in the big Mak with the 1.5+ glaspath, I'll get 250x, which should be usable most nights on the Moon. Also I've recently discovered the benefits of placing the glaspath correctors before the diagonal in my refractors, and as BillP would say, a Gestalt thing sort of happens when Binoviewing this way. Eye-relief seems optimum for the eyepiece itself, if that make sense, unwanted reflections disappear, and even the two field stops merge easier. This is with corrector before the diagonal, and just as important is to elevate the binos themselves 20mm or more off the top of the diagonal. So maybe this will reduce or even eliminate the planet reflections in the refractor. In the Mak I wouldn't want to increase the back focus anyway.

Bill Barlow... I mounted my 8 inch Mak 25lbs on both my dual jaw Unistar and my Dual jaw Macrostar. It was a little more stable on the Macrostar. So Macrostar for planets and the bent arm Unistar for deepsky viewing overhead. These are good quality, relatively inexpensive mounts. But how big must a finder be to view deepsky with a 3900 fl scope undriven? You must use encoders...

And finally... Don. Thanks for sharing your hands-on experience with the Pan 19....and thanks for well...just being you. No thread on clouldnights seems complete without your contribution.

#14 johnnyha

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Posted 18 January 2014 - 03:26 AM

Jupiter appeared to stretch out quite a bit as it got nearer and nearer the edge using my 19 Pans in my binos at around f18 in a refractor. That's why I eventually sold them even though I think they are great eyepieces.

#15 rguasto

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Posted 18 January 2014 - 01:09 PM

Yes. Just like a sterling plossl.






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