Copyright (c) S. Waldee 2014 - All Rights Reserved

Faint Fuzzy Observations

   140 - A Very Nice Jupiter, From Home

Posted: 3/8/14:
I read some very interesting posts and reviews by the remarkably skilled and experienced southern California telescope maker and planetary observing expert, Daniel Mounsey: and put his advice to the test, getting one of my all-time BEST views of Jupiter, right at home.  [Note: Mars drawing added at the end, in update.]

Light Polluted Skies May HELP Planetary Viewing!

This seems like an almost absurd claim; after all, don't amateur astronomers always scream for less light pollution? Well...not Daniel Mounsey. He observes the planets to best advantage at a place called Charlton Flats, near the famed old observatory on Mt. Wilson, overlooking Pasadena: at a height of 5,500 feet above sea level. The air in that remarkable locale has laminar flow: which means that it moves in an even homogeneous sheet, without small pockets of fluctuation. Mt. Wilson seemed almost heaven-sent to the astronomers of the turn of the 20th-century, who revelled in the quality of the planetary images they studied in the 60-inch George Ritchey reflector telescope. Even Edward Barnard was impressed: and he had discovered the fifth moon of Jupiter, Amalthea, on the very first night he was assigned to use the mighty 36-inch Clark refractor at Mt. Hamilton (400 miles to the north) back in 1892. Both mounts Hamilton and Wilson are legendary for the superb astronomical seeing, which sometimes approaches a perfect "10 out of 10" on the Pickering Seeing Scale.

O'Meara drawing of Saturn's spokesI've confirmed the unbeatable seeing quality of Mt. Hamilton while observed Saturn through the 36-incher at Lick Observatory (one night in the late summer of, I think, 1987, just after my wife finished performing at one of her "Music of the Spheres" concerts), and we both were able to perceive Saturn's spokes with that glorious instrument. My friend Sue French has also seen them, soon after astronomy writer Stephen J. O'Meara first documented them by eye before they were later confirmed by the Voyager space probe. O'Meara discusses the spokes (shown in his drawing, at left) in this video, via YouTube, explaining that in visual observing, as opposed to digital imaging, "there are very fine moments where everything becomes just pristine, and sharp."

The human eye/brain resolves and quantifies visual details in tiny slices of time that may be no longer than about 100 milliseconds. Though the air pockets between the observer's telescope objective, and the very edge of the earth's atmosphere, are in constant flux, under meteorological circumstances benefiting from little or no jet stream flow and with low local moisture, the deep columns of air may occasionally settle down: but only in very brief flashes of time. As one watches a highly magnified planet or star, this 'flickering' may be readily perceived, even in the most modest equipment. The phenomenon is perhaps even more annoying in a LARGE aperture scope, which looks through a wider column of air. And, if the telescope tube contains heat currents (and the objective or mirror has not cooled to the outside ambient temperature), the instrument itself contributes turbulence. Very modern professional and amateur techniques may be used to acquire short-exposure and high-resolution (but rather low contrast) snaps of planets, which can be 'stacked' as a series of transparent images, building up the contrast and detail: almost equalling the "perfect" instants of clarity perceived by the human eye, but with more vivid colors and enhanced extremes of light and dark.

Thus, in recent decades we have witnessed such remarkably skilled amateurs as Britain's Damian Peach, whose website features still images and animations that stagger the imagination: done as if he's privileged to own his VERY own Hubble Space Telescope, but created with high quality yet "commonplace" commercial amateur scopes you could buy (such as a Celestron C-11.) Damian, like Mounsey or me, lives in a region where the air flows off the ocean in a stable laminar sheet (at the Norfolk coast of the UK), which is why HIS images are always the sharpest and clearest, beating almost any other such amateur work: almost as if there is no Earthly atmosphere at all!  The light pollution in most of the UK is as bad, or worse, than just about any place in the United States: but the images of Peach, or Pete Lawrence, prove that some places in continental Britain indeed do offer first-rate air: if only for the planets, not requiring the pristine darkness that is necessary for penetrating into the deep sky.

Daniel Mounsey, an observer from the Los Angeles area, for some years made and marketed high-end astronomical observers' accessory cases; he now works in sales at Woodland Hills Telescopes, his hobby being contruction and use of high-resolution reflector telescopes, mostly for planetary observing. He has also written many informative posts and reviews for the Cloudy Nights website (now, unfortunately, offline due, as of early March 2014, to a current project to reorganize their site; presumably they will be returning at some future date. I was, however, able to get some of his older HTML pages and PDFs by using this Internet Archive Wayback Machine backup of his menu of contributions.) I have previously downloaded many of Daniel's articles, perusing them closely to glean his always pertinent and thoughtful remarks about telescopes, eyepieces, and observing techniques: I consider him one of the two or three LEADING experts featured by that website.

I don't have one of Daniel's now-offline posts at hand but remember exactly what I read just last week: he explained that light pollution could, in a way, HELP planetary observers. The reason? You see more detail with daytime-type (photopic) vision, which utilizes the central cones of the retina, adept at discerning fine detail. When you dark-adapt for optimized night type (scoptic) vision, you employ the more sensitive rods of the retina, whose detection capabilities are improved by at least a factor of one thousand, with the buildup of a chemical enhancing dimness detection, in the absence of bright light. The usual advice for deep sky viewers is to wait at least a half-hour for this dark adaptation process to complete; but laboratory study has shown that it may continue to increase (at least slightly) for as long as four hours before reaching absolute maximum sensitivity. Thus, I -- for one -- prefer to do LONG deep sky observing sessions until at least 3 am, and -- if the objects are best situated in the sky -- might often see things with a clarity and strength that other amateurs, eschewing this practice, simply cannot believe. They might scoff at my perceptions of faint objects with 'theoretically too-small telescopes'; but if they don't build up profound dark adapation, and wait til the sky has the steadiest air and least stray light, they might NEVER see these same things even in much larger scopes!

When I do deep sky sessions, I nearly never look at the planets. One glimpse of Jupiter or Mars in even a 4-inch scope will nearly instantly collapse my dark adaptation. And, I was perturbed that the famous British observer James Mullaney recommends you start your dark adaptation process by looking at the bright planets: the very thing that sets dark adaptation back to 'zero'. Whereas, I avoid the planets all night, until the very end of the session. Just as it gets lighter, I glance at them: as the gloaming and loss of a dead black background helps the eye cope with the contrast extremes.

Mounsey has worked all that out to a fine procedure. While he does prefer to use high-altitude Charlton Flats, he says that he nonetheless may employ fine, still nights at home, when his superb instruments (fine-tuned, and cooled and acclimatized precisely) give him wonderful results, in a sky blazing with light pollution.

And, HE'S QUITE RIGHT!

I Observe The Planets, Mostly, From Home in San Jose

While some nights at my private mountaintop observing site north of Santa Cruz, at 3,400 feet in altitude, offer Pickering 8 or 9 seeing, and I can get absolutely best planetary resolution, I still prefer to look at the planets from home, at about 200 ft. above sea level, in the "heat island" of San Jose. Of course, I really cannot do any satisfactory deep sky viewing from home -- maybe the best things to be achieved are a few of the Messier objects, even with big scopes -- but, I have a lot of scopes, so why not use them at every possible opportunity?

Planetary observing removes ALL the burdens of dark adaptation. No more eye patches, no red goggles, no black cloth over the head, no waiting 45 minutes with the eye shut off to the sky... and no worry about having to use only a red light to look at charts!

Mounsey insists that planetary and lunar observing is better with light pollution, and though I had long been aware that such experts recommended looking at planets at dusk, or even when using ambient lights, I'd never gone quite as far as I did last night (Friday 7 March 2014) in following such advice.

Not only did I not pay the slightest attention to those fussy rules about dark adaptation; but I even looked DIRECTLY and FREQUENTLY at the awful, blinding low pressure sodium vapor streelights all around my neighborhood; and did not flinch, close my eyes, or look away in a frenzy, when cars passed through the neighborhood, sweeping their penetrating halogen beams right across my vision.

The result? BETTER detail discernment!

Stephen sketching Jupiter with 4.7 inch scope

Above, the Old Man sketches Jupiter back in July of 2009, registering a Jovian collision. This picture shows my Orion 120 mm aperture f/8 Sky View Pro achromat refractor, a good telescope but supplied originally on an inadequate mount; now I have put it onto a formidable structure that is much steadier:

Improved mounting for 120 mm Sky View Pro

I took the 120 mm scope's original German equatorial head and attached it (as shown above) to an extension pier, bolted on top of a very massive and rugged Meade field tripod; and then added the RA and dec motor drive kit for the EQ-4 type head, so that my instrument would stay centered on a planet by tracking the sidereal drift (explained in this article; go down to the addendum, "Clock Drive for 120 mm f/8 Refractor".) But, even this was not good enough for me...

Original German equatorial head, atop new extension pier mounted on an old rugged Meade field tripod

...so I devised a way to increase its stability by adding flexible packing straps (with tightening clutches) used for securing cargo in the back of a truck or trailer. You may read about the adapting project here.

NOW I had something of which to be proud! This combo of gear gives me a rock-steady mount, good object tracking, and fine images. Of course, the achromat telescope is not perfectly color-corrected; but I have to admit that at my age, the color fringing is less objectionable than it would have been, say, forty years ago. (My wife, however, has a brand-new lens in her right observing eye, to replace one that deteriorated due to a cataract; and SHE now sees very strong and vivid blues and violets! So, Regina complains about faint color fringing that I can barely ever discern; but, on the other hand: my "original equipment manufacture" lenses are near-perfect, with crystal sharpness, at least if I overcome my nearsightedness by readjustment of the scope's focuser... for I have NO trace of cataracts!)

The final touch? Improve your perception: follow Mounsey's methods!  And so, on the night of Friday 8 March 2014, as I took out the dinner scraps, I happened to notice the incredible steadiness of San Jose's air, with barely any twinkles in the (few) stars that shone in the sky above my house; and it felt almost summery, with a delicious smell of new vegetation growth wafting from the plants in our front yard: at last we'd had some nourishing rain here in California, during this bleakly-dry winter.

I simply had to try the Sky View Pro on Jupiter! (I had been looking at the planet, occasionally, with just my lowly, free 76-mm Newtonian reflector on occasion, but never quit seemed to hit upon a night with perfectly stable air.) But, tonight surely was THE night for it.

And... it certainly was! I studied mighty Jove from 10 to nearly midnight, in awe of the crisp detail and the lack of the usual shimmering. The Galilean moons were PERFECT round pearls, almost entirely steady: you could see differences of diameter and albedo. I was picking up loops and festoons in the Jovian belts, and long bright white patches, plus small oval spots. I had to attempt to draw it all!

I am NO planetary artist. And, I chose not to do an expanded scale drawing (with a template of about 3 or 4 inches in diameter, as suggested by the experts, enabling one to register very fine details with a pencil, vastly larger than in the original perceived scale) but rather to register the actual complete eyepiece field of view. I experimented very briefly with oculars, and determined that I could use nearly 200x, which often is too much magnification for Jupiter in this scope. I put in my Orion 5 mm Stratus (with 68 degree apparent field of view), which has wonderful eye relief and ease of use, not being at all fussy with respect to exact axis of pupil placement. I've often tended to use this eyepiece on Jupiter, with this instrument or my 10" f/4.7 Orion Sky-Quest Dob (though, to tell the truth: the ocular has one small defect: if you place Jupiter JUST outside the field stop, you can see a distinct and unpleasant flare. But this never occurs with bright Jupiter IN any part of the visible field!)

Rather than showing my drawing 'au naturel' (a la Jaakko Saloranta, who always prefers to give his drawings as black marks-on-white) I decided to get fancy, and colorize it. After scanning my pencil sketch, I reversed the picture to negative mode, but reverted just the central part -- Jupiter only -- to positive mode; and then changed its monochrome image to a very slightly warmish hued tone. Then I made the eyepiece field background dark blue-gray, to resemble the sky as I actually perceived it:

SRW sketch of Jupiter at 192x, with Orion 120 mm f/8 achromatI spent well over an hour studying Jupiter in this manner: reveling in the moments of absolute crispness and clarity, which came much more frequently than normal. As I watched, my eye tended to get somewhat dark adapted, and after a few minutes of staring, I did notice that I would start losing a sense of depth and sharpness; so I 'obeyed Mounsey' in effect: I forced my eye to transition back to photopic vision...BY STARING DIRECTLY AT THE AWFUL STREETLIGHT!

Then after two or three seconds, I'd go back to Jupiter. Yep: it was now sharp again!

I alternated this way many times, and built up a fine sense of what the stable details were in the Jovian aspect; then I got out paper and pencil, and made my drawing, which was worked on for at least 15 minutes.

I determined that I did prefer to shade my eye/eyepiece with my hand (using an eye patch on my left, non-observing eye) though I made absolutely no effort to avoid seeing the considerable ambient light in the driveway (strong enough to allow me to read with perfect clarity my Sky & Telescope Pocket Atlas.) But, on previous occasions when I've tried to make a planetary drawing, I have tended to take more care to avoid light; not this time! And I definitely confirmed the Mounsey methodology. You can almost "glory" in your bath of awful stray light: as it keeps your eye in the most acute mode.

After I finished the drawing (which did not capture ALL of the fine detail I perceived, though -- on the other hand -- it does show much 'darker' Jupiter markings than I sensed; it was almost impossible for me, with limited experience, to render them entirely accurately) I then decided to make some further experiments. Both Mounsey, and eyepiece expert Bill Paolini, have asserted that to discern some kinds of detail, one might prefer to use single-coated eyepieces. Mounsey has done a very extensive series of field tests; and surpriingly, he often prefers to use the old, relatively cheap, Edmund Scientific RKE (modified Kellner) types, which used to cost as little as $25 on the used market--until HIS praise became known; now they're much more pricey!

Paolini has recommended the simpler, cheaper eyepieces for viewing the puffy nebulosity of M-42; but I just cannot confirm this assertion, by my own tests: see the section titled "Update: Bill Paolini Speaks" at the end of this article.

So, now it was time to test Mounsey's eyepiece theories. I do not, at present, have any RKE types; but I have kept some very cheap oculars that were supplied with the following instruments: a $69 Celestron 50-mm spotter; a $99 Celestron First-Scope reflector, and a Celestron 70-mm spotter; and an inexpensive Sky-Watcher 70 mm f/10 refractor. These are all single-coated, and some have very simple and old-fashioned designs: Huygenian and symmetrical Ramsden and Kellner topologies.

So, I tried them in place of the somewhat costly Orion Stratus. To use them and get about the same magnification, I dug up from the scrap pile a $10 surplus single-coated Barlow I had purchased at a clearance sale; it turned out to have VERY sharp resolution but, sadly, rather poor contrast, so I never used it, favoring instead my pricey Orion three-element, fully multicoated Barlow.

The only reason I hung on to that Barlow was that by my actual careful measurements, it had a magnification factor of 1.6, an odd one not matched by any of my other, better Barlows.

Well! It turns out that I got even BETTER resolution, surpassing the 5 mm Stratus, with a very cheap 8 mm Huygenian, plus the 1.6x Barlow: for an equivalent eyepiece focal length of 8 divided by 1.6, or 5 mm, same as the Stratus. And, it looked BETTER on Jupiter! I repeated this same type of comparison with several other cheap eyepiece/Barlow combos, also using a $17 budget 2.5x Barlow I bought years ago from Owl Optics. The result: either AS GOOD as the Stratus; or just very slightly ENHANCED detail and sharpness that were slightly superior!

However, in all of the tests with the Huygenian type, I could see more "lateral color" (see this article on ocular aberrations), and had greater viewing difficulty due to the poor eye relief, so you win a few--and lose a few.

Once again: score for Mounsey. In fact, had I spent an hour scrutinizing Jupiter with the best optional choices, instead of that 5 mm Stratus, I just might have been able to put in a BIT more pinpoint Jovian cloud detail in my drawing (though not being able to get nearly as nicely 'deep' and entrancing view of its field, registering all four of the Galilean moons plus stars well away from the planet. I lost all those things in the cheap, narrower field eyepieces.)

There is an actual technical explanation for this: I was now using FEWER GLASS ELEMENTS than with the Stratus. Not all cheap eyepieces have good lenses; the ones that I had kept DO have excellent sharpness; though their fields of view are narrow; some have more lateral color; and they all have much poorer contrast on faint deep sky objects.

Try these kinds of experiments, and see if you think Mounsey and I are spouting hot air--or if we are on to something!

Meade 3 inch Newtonian on old, massive Meade GEMUpdate:  The new Moon period of March 2014 has been disappointing for astronomy, due to cloudy and drizzly weather here in the SF bay area (but... we needed the moisture, so what the heck!)

I took advantage of this period, when I'd have set aside time for astronomical observing, to work -- instead -- on further refurbishing of my old, used Meade German equatorial mount. I had given up the idea of using it with the scope with which it was originally sold (a Meade 8" SCT), which seriously overpowered the tripod. Would it work with a lighter instrument?

I tried my old Bushnell 76 mm f/9 Newtonian, a scope given to me a while ago by a friend (see here), and which turned out to have exquisitely sharp optics, to my great surprise. And, would you believe it? The darned Meade GEM isn't even stable with THIS lightweight scope! Despite my best efforts, it shakes and twitches, even with a Newtonian tube attached that weighs only a third as much as the Meade SCT. But, this did give me a chance to test it on Mars, which at the moment subtends a diameter of less than 15 seconds of arc. It was rather agonizing to focus with my 2.5 mm TMB/Knight-Owl eyepiece (which yields 280x in this scope--and the image is still perfectly sharp, without a sense of mushy empty magnification!); but being rather surprised at the details I could see, I quickly made a crude sketch, during an early cold and rather damp morning when the clouds had dispersed out to the horizon. (Normally I am more careful about documentation but on this occasion I did not date the drawing; I think it was on Saturday morning, 29 March 2014. Now, about only 4 or 5 days later, I've forgotten precisely; but the Weather Underground online station close to my home registers lower moisture on that morning, so this must be the date: as either side of the 29th, the humidity is 95% or above at that hour: indicating the drizzly weather.)

Here is the sketch:

Mars, drawn by SRW at very high magnification with a mere 3 inch Meade NewtonianA few caveats should be added to help interpret this result for beginning observers. First: I had just collimated the scope, employing a laser to line up the mirrors roughly, followed by a critical star alignment on Polaris, to get the Airy disk looking nice and symmetrical. (This is NOT easy to do on the Bushnell, which has had a rebuilt primary mirror cell to facilitate easier alignment than the 'stock' original.) Second: though the air was really quite steady at best moments, as usual the disk of Mars boiled, twitched, wobbled, and flickered constantly: so the drawing records one's impressions of the best brief glimpses of clarity, preceded by perhaps 10 minutes of close observation. Therefore in a sense, it's a 'composite' view: one's recollection of steadiest looking slices of time. Third: normally one reads the commonplace recommendation to "use only up to 50x per inch of aperture" for highest resolution views. However, in rare telescopes that have very sharp optics (especially small aperture instruments) one CAN go much higher than this, fruitfully, given best moments of good seeing. I've done lots of experimentation on Saturn, Jupiter, and Mars with this scope and find that I can definitely see more detail if I exceed 50x per inch of aperture (which works out in practice to a 4.8 mm eyepiece, for about 146x at 49x per inch of aperture.) But with the 2.5 mm TMB ocular, I obtained a whopping 93x per inch of aperture; yet, it definitely helped show more surface detail than a "recommended maximum magnification" of 146x. Thus, we must realize, as our sophistication grows as trained observers, that the "rules" that are always offered so sternly in books and forums are only useful up to a point.  I always find that actual experimental results are to be preferred to mere rote rule-following. - srw, 4/1/14 -- and, no: this is NOT an April Fool's Day joke.

 


 

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