Total Solar Eclipse: 21 August 2017

For up to 2 1/2 minutes on the afternoon of Monday August 21, 2017 the sky will go dark, the stars will come out, and the beautiful solar corona will be on display for those along the eclipse centerline.

Link to Google Interactive Map and Path Of Totality Data:

*solar corona courtesy of*
*map courtesy of xavier m. jubier*



Extreme Crescent Hunting Tips

Saber’s Beads: The “string of pearls” arc of illuminated lunar peaks seen prior to the first complete crescent. Note the striking resemblance to the moments just before and after a total solar eclipse. (27 May 2006. raw image credit: maurice collins/ltvt)​

The moonrise before and moonset after each New Moon offer stargazers the opportunity to view the thinnest lunar crescents. There are many websites and apps that provide exact moonrise/set data for any location. Here are some additional tips to maximize your chances of sighting our very young (or old) moon.

Set up at a site with as much altitude as possible overlooking an unobstructed horizon. Optimal sky transparency allows the crescent to be detected and tracked down to, or up from, the horizon. Using a telescope or binoculars (mounted binos are recommended), fine tune the focus on Venus, Jupiter, or one of the brighter stars beforehand. For dusk attempts, have Sol’s setting azimuth on hand- making note after sunset of a random landmark at that position for reference- as well as Luna’s altaz position at sunset thru moonset. Accordingly, for dawn attempts, have Luna’s altaz info for moonrise thru sunrise. As dawn slivers have the advantage of possible detection with dark-adapted eyes, wearing sunglasses during the day prior to sunset attempts is recommended for maximum ‘dusk’ adaptation. Once the crescent is acquired in binoculars, walk the bino down to the horizon/random landmark in consecutive FOVs for the approximate naked-eye altaz. A favorable elongation is important. In the 24 hours before or after New Moon, Luna’s angular separation from Sol can vary by several degrees. With a favorable ecliptic, net elongations (as altitude) of 6° or more at sunset or moonrise offer the best window for detection. Observers nearer to the equator than the poles enjoy a much greater frequency of steep ecliptics. Illuminated fractions of same-age crescents within 24 hours of New Moon can vary by 200% and a full magnitude of brightness due to distance, libration, and sun angle. Slivers near perigee help present a thicker and brighter lunar profile for personal record crescent spotting. Last but not least, don’t always count-out a shallow ecliptic. Occasionally our moon’s extreme northern or southern declination will compensate for a less than favorable ecliptic angle.


Another rare and challenging notch for ones lunar bedpost is to catch the consecutive waning and waxing crescents within 24 hours on each side of New Moon. For example, the July 2008 Buck Moon offered such an opportunity as I was able to spot both the -16.5 hour illumination before sunrise on the 2nd and the +23.5 hour sliver just after sunset on the 3rd. Clean horizons for both windows is a gift in itself.

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[exerpt from Saber Does The Stars by Stephen Saber]


Saturn’s Teasing Tilt

by stephen saber

it’s a pleasant fiction to imagine saturn’s beautiful rings coyly and seductively tilting toward and away from us, slightly by the month and dramatically over a decade. but earth is actually doing the unsung grunt work, carefully pacing itself to fall slightly farther behind saturn in its orbit over the course of each revolution. this allows us the amazing perspective of cycling ring aspects. sorry to dampen anyones fantasy. just something to contemplate at the eyepiece, and while watching the linked vidclip below.

in motion: saturn’s northern ring crossing (jan 2009-sep 2010) at

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[saturn(ish)/jan 2017 courtesy of mobile observatory]


Asterisms: Ally’s Braid

Prolific stargazer and musician Stephen Saber coined the term Ally’s Braid for this beautiful chain of stars running south and east from the Pleiades (aka the Seven Sisters) in the constellation Taurus, describing the asterism as “the flowing locks of Lady Alcyone”. 
Alcyone is the name of the star marked ‘1’ on the map below.

*image courtesy of SDSS*

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Capturing Saber’s Beads

by Jason Prochaska

In May 2006 American astronomer and veteran crescent hunter Stephen Saber was first to note a striking visual similarity between certain very thin lunar crescents and solar eclipse contacts. What made this particular crescent stand out to him was a rare combination of the limb’s staggered profile also appearing far enough away from the sun to be captured in a dark sky (well into nautical twilight) before moonset. Too old, and the crescent appears as a continuous arc. Too young, and the crescent cannot reach sufficient elongation from our sun to be observed in a dark sky. With a favorable libration this creates a nominal window of 18-28 hours before or after New Moon to observe, photograph, or image the phenomenon. As the crescent thickens, the beads become larger with fewer gaps inbetween.
Along with short exposures, an equally important element to capturing Saber’s beads is intent. One must go after the effect with the mindset of producing the eclipse contact resemblance, or, during a total eclipse, capturing the infant crescent similarity. Adding spikes to the staggered brightness peaks also enhances the aesthetics. Finally, following these remarkably thin lunar crescents into low-altitude turbulence near the horizon creates a powerful dynamic to the ‘string-of-pearls’ mirrored lunar aspects.

More common and easier to detect are Saber’s inherited and upgraded precursor beads seen at the horns of older waxing and waning crescents which can be observed to appear then combine with (or detach then fade from) the contiguous crescent rim over hours or even minutes of viewing.
Slowly defocusing these tip beads produces the smokey, overlapping links of “Saber’s chain”. As Stephen mentions, “the more beads, the better- like Mardi Gras…”. Indeed, my own impressions have been that of a cosmic thought bubble.

While the viral properties of the internet have since expanded Sabers beads into the world of literature, music, and the transcendental (representing open-mindedness and increased perspective i.e., experiencing a Saber’s beads moment), the visual dusk and dawn apparitions remain a beautiful celestial sight not to be missed.

Outreach Gone Wild: Listen to Saber’s Beads at YouTube
Also see New Moon: Extreme Crescent Visibility

[reprinted with permission/j.prochaska/starwind.net2012]

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sitting in plato: earth viewed from the moon 

simulated pics as seen from the lunar crater plato *courtesy of celestia*

earth occults the pleiades (messier 45)

earth visits the hyades (caldwell 41)

earth occults saturn

earth occults mars

earth occults sol (total solar eclipse)

a total solar eclipse from earth is seen as a shadow transit from the moon

full shadow transit vidclip at

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saber does the stars at


glass at a glance: orion 25×100 giantview

by stephen saber 

$349 from
instrument arrived promptly, well-packaged, mechanically sound, and in fine collimation.
aluminum case for transport.
bak4/fmc. orion does not skimp on AR coatings- there is barely any reflection at the business ends.
height 17.1 in
weight 10.1 lbs
individual focus
integral mounting post
exit pupil 4 mm
ipd 61-72mm
effective aperture 95mm
eye relief 17 luxurious (as advertised) useable mms
i’m happiest with 12-14mms of UER plus a few more to take advantage of leaving the eyeguards out to block peripheral light. the orion does not disappoint.
large 21mm eyelens diameters also contribute to a comfortable and rewarding viewing experience.

i pay to see out to the field stop, even if the outer fov is just for context. anything less is considered a design flaw and/or a rip-off. those designing noks with 9 or less mms of ER should be subjected to forcibly viewing the fieldstop regardless of ocular bone damage or disfigurement. i keep imagining a think-tank of designers intentionally ignoring every new models’ ER specs and, for kicks and giggles, creating a betting pool as to the final distance outcomes. (“okay boys! who had 11 mms?”)

close focus 100 ft
soft rollback eyeguards
tfov 2.5° (spec )
field sharp to 80%
coma free field 2.0°
nominal positive distortion
afov (spec) 63°
afov (subj) v good. not a spacewalk but a substantial view relative to the limited tfov. fieldstop is well-defined.
false color: present but minimal
ergonomics: braced on my elbows-tripod or reclined, the increased weight actually serves to help stability when held near
the objectives. a heavy-duty tripod is required for best detection and detail.

purchase motivations:
giant bino addicts must have at least one 100 mm or larger horse in their stable. it’s the law. and yes, that’s my collective noun for them, as in ‘a stable of thoroughbred binoculars’. an ‘arsenal’ works, too. again, i also use and recommend giants for high mag handheld training, usually as a warm-up session before powering down to lower mag noks. after spending 15-20 minutes with the 25×100, regardless of the actual physiological stability increase, views thru my 15s and 20s certainly feel lighter and seem steadier- often reaching ‘heartbeat-limited’ stability.

bottom line:
10 lbs of heaven
five star transaction and instrument
highly recommended
*as always, ymmv*

tip of the day: afov direct (star) measurement.
view the left eyelens with your right eye. keeping both eyes open place two superimposed 1x stars at the left and right fieldstop borders, afov is the angular distance between the two stars. divide by tfov for magnification.

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more binocular reviews at:

*photo courtesy of*