December 18, 2017

The Early Astronomers: A Brief History of Astronomy.

Ye ‘ole telescope…(Photo by Author).

(Editor’s note: The following is an essay wrote by yours truly in the quest for a science teaching degree. Now that said degree has come to fruition, our writing can be immortalized forever in a re-vamped blog format).

Astronomy is one of man’s earliest pursuits for knowledge. Once we began living in organized communities and brute survival and safety wasn’t a constant and overriding concern, we began to look up and ponder our place in the cosmos and contemplate the workings of the heavens above us. [Read more...]

AstroChallenge: Bagging Omega Centauri from Mid-Northern Latitudes.

Omega Centauri as seen from Arizona. (Image Credit: Mike Weasner/Cassiopeia Observatory).

The Magellanic Clouds. The Tarantula Nebula. Sure, the Southern Hemisphere skies have all the “good stuff…” but did you know that in the summer months, YOU may be able to nab one of its crowning glories? [Read more...]

05.04.11: Student Tool Aids Astrophysicists.

  

Spectral Energy Distribution for Epsilon Aurigae. (Credit: NASA/JPL CalTech/D. Hoard).

We love it when we can put the words “students,” and “astrophysics discoveries” in the same sentence. Recently, students from San Mateo and Hillsdale High School in partnership with NASA and San Mateo College unveiled a new educational tool for budding astrophysicists. [Read more...]

AstroEvent: The Passage of 61 Cygni.

A Finderchart for 61 Cygnus (Photo & Graphic created by author).

   To the naked eye observer, the positions of the stars will appear pretty much the same on the day you die as the day you were born; stellar motion doesn’t add up to much over the span of a human lifetime. This week, however, we’ll look at an interesting configuration that just might show some changes through the telescope over the coming years; 61 Cygni. No less an authority than Burnham’s Celestial Handbook lists 61 Cygni as “historically one of the most interesting objects in the heavens.” A good double star for small telescopes, 61 Cygni lies within a few degrees of the bright star Deneb and is currently placed high in the west for northern hemisphere observers immediately after sunset.  Sometimes known as Bessel’s Star or Piazzi’s Flying Star, 61 Cygni attracted the attention of astronomers around 1800 after Giuseppe Piazzi noted a large proper motion for the pair of 5.22” per year towards a direction of position angle 52°. This is extremely fast, currently the seventh fastest known. The pair itself is just above the naked eye visibility threshold at about +5.2 magnitude, and are currently separated by 30+ arc seconds in its 653 year orbit. In fact, the pair of orange-hued stars will reach maximum apparent separation around 2100 A.D., and thus will continue to separate throughout our lifetimes. An interesting fact about the pair came to our attention via a letter published in the November 2010 Sky & Telescope magazine submitted by Richard Stanton of Three Rivers, California: Component A of the pair is currently “flying by” a distant 11th magnitude background star, and tracking its motion over the next few years could provide an interesting challenge. The constellation Cygnus is well placed in the summer months, but you can start acquainting yourself with the pair tonight. The coordinates of the pair are;

Right Ascension: 21h 06m 54s

Declination: +38° 44’ 45”

The background star should currently be approaching a position angle of 26° and a separation of 5” the summer of 2011 and will be at its closest apparent approach on the following year at a separation of less than 3”. Sketching or tracking the pair would be an interesting exercise in observing proper motion… an even more intriguing feat would be to construct a stop motion animation of the motion of the pair. Do give 61 Cygni a look over the next few years, and marvel at the slow change of movement in the heavens!

The astroword for this week is: Proper Motion. This is the apparent shift of stars against the background as seen from our particular vantage point in space. As we wheel about the core of our galaxy, nearby stars appear to slowly shift in position due to their differing relative motion. The measured proper motion is cumulative between the observed stars’ true radial motion and that of our own solar system; generally, the higher the proper motion, the nearer the star is to us. Think of observing a flock of birds passing by; the birds closer will appear to move faster. It was this fact that brought 61 Cygni to the attention of astronomers in the early 19th century; it wound up on a short list of target stars due to its large proper motion, as it was suspected to be nearby in the galactic hood. It achieved historical notoriety in 1838, when Friedrich Wilhelm Bessel successfully measured its stellar parallax at a tiny 0.29” (this was over the span of six months!) giving 61 Cygni a distance of 10.3 light years, close to the accepted value of 11.4. 61 Cygni was the first star to have its stellar parallax measured, and is now known to be the 14th nearest star system from our own Sun. As you look at the tiny pair this holiday season, remember its place in astronomical history and the role it played in discovering that the universe was indeed a vast place!   

 

AstroEvent: the Leonid Meteor Shower.

 

 

Looking East at 3 AM. (Created by Author in Starry Night).

  This week, be on the lookout for the meteor shower that can roar like a lion, but this year will probably meow like a kitten. The infamous Leonid meteors peak on the morning of Wednesday, November 17th. This shower has been known to produce storm intensity outbursts with a zenithal hourly rate (ZHR) in access of +1,000 roughly every 33 years, which last happened in 1999 & 2000. [Read more...]

AstroEvent: A Challenging Dawn Conjunction.

Saturn & Mercury on closest approach. (Created by the Author with Starry Night).

Saturn & Mercury on closest approach. (Created by the Author with Starry Night).

 

   Set your alarm clocks; one of the closest but most challenging planetary pairings of the year happens this week in the early dawn skies. Mercury and Saturn will be within 1° degree of arc separation the morning of October 8th. Saturn is fresh from superior conjunction behind the Sun, and Mercury is currently undergoing a dawn apparition. Both will fit well in a binocular field of view or a low power eyepiece. The pairing will rise about 45 minutes prior to local sunrise, which for middle northern latitudes will occur around 7:45 AM local. [Read more...]

Astro-Challenge: Spy a Microquasar.

Artists' Conception of SS 433. (NASA/CXC/M. Weiss).

Artists' Conception of SS 433. (NASA/CXC/M. Weiss).

 

   So, you’ve seen everything the night sky has to offer? You say you’ve seen all breeds of eclipses and deep sky objects, and have grown tired of showing the neighbors Saturn and the Ring Nebula? Well, we’ve got a challenge for you. This week’s object will require dark skies, a good finder chart, and a generous aperture telescope.  About 4 degrees northwest of the 3rd magnitude star Delta Aquilae lies +14.1 magnitude SS 433. [Read more...]

AstroEvent of the Week: Spotting Iridium Flares.

 An Iridium Flare graces the dusk. (Photo by Author).

Photo by Author.  

   Looking up at the dawn or dusk skies, it’s not uncommon to see a satellite brighten, flare up, and the abruptly disappear from view. What you’ve just seen is an Iridium flare, a glint of sunlight off of a refrigerator sized satellite panel. Motorola launched this series of 66 communications satellites in 1997 through 1998 and they are currently owned and operated by Iridium Communications, Inc. [Read more...]

Astro-Event: A Planetary-Galactic Pairing.

An interesting pairing of Saturn & NGC 4073. (Created by the Author in Starry Night).
An interesting pairing of Saturn & NGC 4073. (Created by the Author in Starry Night).

 

   This week’s astro-challenge may test your skills as a “visual athlete;” a close visual conjunction of the planet Saturn and the galaxy NGC 4073.  This unique event comes to us via the computations of reader Ed Kotapish. On the evening of July 25th, both planet and galaxy will be in a 1 degree field of view. The challenge is twofold; Saturn sits at magnitude +1.1, while NGC 4073 is about 10,000 times fainter at magnitude +11.4. Add into the mix a Moon just a day from Full, and you’ve got a definite challenge… telescopes of 6” inches aperture or larger need only apply. [Read more...]

Astro-Event of the Week-Redder than Red: V Hydrae.

This week, we here at Astroguyz are going to introduce you to a star that isn’t on the top 10 star party faves, but perhaps should be; V Hydrae. [Read more...]

Astro-Event: An Asteroid Occults a Bright Star.

One of the best occultations of a bright star occurs this week for observers along a line from western Canada down the U.S. west coast. At around 10:00 UT, on the morning of April 6th, 14th magnitude asteroid 824 Anastasia will occult, or pass in front of, the bright +2.5 magnitude star Zeta Ophiuchi for up to 8.6 seconds. This is a rare event in that the occulted star will be visible with the naked eye! Stellar occultations give us the rare opportunity to profile the shape of an asteroid; if enough folks are lined up along the graze line and make and submit accurate observations, a chord map of the “shadow” of the asteroid can be plotted. Binary asteroids have even been discovered by amateur astronomers using this method! Anyway, if you’re located anywhere along the predicted path and the sky is clear, don’t miss this rare event!

[Read more...]

02.04.10- Cassiopeia A: A Quark Star?

The supernova remnant Cassiopeia A holds a compelling astrophysical mystery. Located about 10,000 light years away, this strong radio source was identified in 1947 and remains the most recent galactic supernova known. One slightly odd fact revolves around Cas A; despite its having burst about 325 years ago as seen from Earth, no reliable records exist of the event. Evidence of the event may have been obscured by intervening galactic dust.  Some intriguing indications show that John Flamsteed may have misidentified the supernova as a sixth magnitude star in Cassiopeia during one of his surveys, but now Cas A may be the home of a even more bizarre denizen; a quark star. This theory stems from the fact that the remnant host appears to be only 10 km across, smaller than your average neutron star. At that density, neutrons loose all individual identity and merge into a huge ball of quark strange matter, a “strange” object indeed. First spotted by the Chandra X-Ray observatory in 1999, this “quark star” would be the first of its kind. Of course, an alternative hypothesis, put forth by Wynn Ho and Craig Heinke of Southampton University, states that we’re merely seeing a normal neutron star of about 25 km in diameter shining through a carbon atom haze. Does astrophysics need to get any weirder?

16.03.10:Relativity Triumphant over Bizarre Binary.

For years, a unique binary system has plagued Einsteinian physics. DI Herculis (DI Her) is a seemingly innocuous binary star about 2,000 light years distant. Type B stars each about five times the mass of our Sun, these stars are in a mutual orbital embrace about 0.2 A.U. apart. Visually, the system is at magnitude +8.5, and the orbit is inclined along our line of sight so that mutual eclipses occur every 10.55 days. First recorded in 1900, this feature allows the systems’ mass, luminosity and orbital characteristics to be known to a high degree of precession. For the past several decades, however, astronomer Ed Guinan at Villanova University couldn’t shake an odd effect; namely, periastron of the two stars is advancing at a rate of only ¼ what’s predicted by Einstein’s theory of general relativity. Is an unseen companion lurking in the DI Her system, or is it Albert himself who was wrong? Prediction of such anomalies as the precession of the perihelion of Mercury is one of the great cornerstones of relativity.  In a massive system such as DI Her, this effect should be even more pronounced. Like the Pioneer anomaly, several would-be theorists have pointed to this discrepancy as a potential chink in the relativistic armor…

Enter Simon Albrecht of MIT. Using a 1.93-meter telescope to obtain a high-resolution spectrograph of the two suns, a bizarre fact has become apparent; both stars are tipped on their rotational axes, giving them an orbital “kick” at their closest approach. This configuration adequately accounts for the relativistic anomaly. Apparently, DI Her underwent a close passage of another star or massive object sometime in its history. Guinan is relieved, but will no doubt continue to receive a flood of email from alternate-gravity theorists!

Object of the Week; Gamma Arietis.

Double stars are often overlooked as astronomical targets, but tend to hold up well under light polluted, urban skies. I often show folks bright doubles at star parties to great effect, and a mental vocabulary of about a dozen or so can add to the usual crowd pleasers such as the Moon and bright planets. One of my favorite fall targets is Gamma Arietis, in the constellation Aries, the Ram.

[Read more...]

05.10.09 The 3rd Annual Great World Wide Star Count!

Tired of the deteriorating sky conditions in your neighborhood? Remember a childhood when the Milky way was visible in your backyard, such as it was in our native rural northern Maine? Now there is something that you can do about it. The Great World Wide Star Count wants you to measure the limiting magnitude from your locale in an effort to document light pollution. Its simple; if you can locate the constellation Cygnus in the northern hemisphere and Sagittarius in the southern, then you can participate. No equipment is required, just your eyes, and a tutorial is included on the site. This is the third year around for the Star Count, and we’ve participated here at Astroguyz for the last two years running. It’s great fun to see the reports from various areas, as well as were the astronomers are! This year, the dates run from October 9th to the 23rd, and you can enter reports from multiple sites…put your town on the map! Post Anti-Light Pollution slogans! Show the neighbor the damage that vintage “Battle of Britain” anti-aircraft spotlight is causing! We prefer to document our impressions of the sky for later entry via digital voice recorder, but you’ll no doubt settle on your own system. Now is the time to try a “dry-run” a night or two before the Count starts Friday…anyone thought of posting observations via Twitter? What would be really great is to get reports from such off-the-wall locales such as Thule, Greenland or Poipet, Cambodia…do your part to raise light pollution awareness in your neighborhood!

AstroEvent of the Week: 27.04.09: Epsilon Aurigae.

The American Association of Variable Star Observers wants you to help gather data on a very enigmatic astronomical object; the variable star Epsilon Aurigae. This seemingly ordinary star varies in a very peculiar way. The primary is a type F0 super-giant star, and what is known is that every 27.06 years an unseen mass dims its light from its usual +3.0 magnitude to about +3.8 for about a year.

[Read more...]

AstroEvent of the Week:29th-September 5th, 2008: Spot Neptune!

Now, to spot a planet that was first located mathimatically.

Now that the Moon is out of the sky this week, it’s a good time to add the outer most gas giant to your “been there, done that” list! First spotted in 1846 by Johann Galle & Heinrich D’Arrest, Neptune’s position was first deduced by the French Mathematician Le Verrier, who himself hated the “grittiness” of rank and file observational astronomy. [Read more...]

Astro event of the Week, August 12-18, 2008: See a Triple Conjunction!

Alas, poor North America! We miss out of both this months’ eclipses! But I give you as an Astro consolation of sorts; a rare triple planetary conjunction!

On the evening of August, 15th, the planets Mercury, Venus, and Saturn will span an area of less than 2 degrees, a nice binocular view. [Read more...]