February 26, 2017

A Supercell Thunderstorm Cloud Over Montana

Is that a spaceship or a cloud? Although it may seem like an alien mothership, it's actually a impressive thunderstorm cloud called a supercell. Such colossal storm systems center on mesocyclones -- rotating updrafts that can span several kilometers and deliver torrential rain and high winds including tornadoes. Jagged sculptured clouds adorn the supercell's edge, while wind swept dust and rain dominate the center. A tree waits patiently in the foreground. The above supercell cloud was photographed in 2010 July west of Glasgow, Montana, USA, caused minor damage, and lasted several hours before moving on. via NASA http://ift.tt/2kZHgUH

February 24, 2017

NGC 3621: Far Beyond the Local Group

Far beyond the local group of galaxies lies NGC 3621, some 22 million light-years away. Found in the multi-headed southern constellation Hydra, the winding spiral arms of this gorgeous island universe are loaded with luminous blue star clusters, pinkish starforming regions, and dark dust lanes. Still, for astronomers NGC 3621 has not been just another pretty face-on spiral galaxy. Some of its brighter stars have been used as standard candles to establish important estimates of extragalactic distances and the scale of the Universe. This beautiful image of NGC 3621, is a composite of space- and ground-based telescope data. It traces the loose spiral arms far from the galaxy's brighter central regions for some 100,000 light-years. Spiky foreground stars in our own Milky Way Galaxy and even more distant background galaxies are scattered across the colorful skyscape. via NASA http://ift.tt/2lzQ2as

February 20, 2017

Almost Three Tails for Comet Encke

How can a comet have three tails? Normally, a comet has two tails: an ion tail of charged particles emitted by the comet and pushed out by the wind from the Sun, and a dust tail of small debris that orbits behind the comet but is also pushed out, to some degree, by the solar wind. Frequently a comet will appear to have only one tail because the other tail is not easily visible from the Earth. In the featured unusual image, Comet 2P/Encke appears to have three tails because the ion tail split just near to the time when the image was taken. The complex solar wind is occasionally turbulent and sometimes creates unusual structure in an ion tail. On rare occasions even ion-tail disconnection events have been recorded. An image of the Comet Encke taken two days later gives a perhaps less perplexing perspective. via NASA http://ift.tt/2m0u7dZ

February 18, 2017

Penumbral Eclipse Rising

As seen from Cocoa Beach Pier, Florida, planet Earth, the Moon rose at sunset on February 10 while gliding through Earth's faint outer shadow. In progress was the first eclipse of 2017, a penumbral lunar eclipse followed in this digital stack of seaside exposures. Of course, the penumbral shadow is lighter than the planet's umbral shadow. That central, dark, shadow is easily seen on the lunar disk during a total or partial lunar eclipse. Still, in this penumbral eclipse the limb of the Moon grows just perceptibly darker as it rises above the western horizon. The second eclipse of 2017 could be more dramatic though. With viewing from a path across planet Earth's southern hemisphere, on February 26 there will be an annular eclipse of the Sun. via NASA http://ift.tt/2kJzVUb

February 16, 2017

The Tulip and Cygnus X-1

Framing a bright emission region, this telescopic view looks out along the plane of our Milky Way Galaxy toward the nebula rich constellation Cygnus the Swan. Popularly called the Tulip Nebula, the reddish glowing cloud of interstellar gas and dust is also found in the 1959 catalog by astronomer Stewart Sharpless as Sh2-101. About 8,000 light-years distant and 70 light-years across the complex and beautiful nebula blossoms at the center of this composite image. Ultraviolet radiation from young energetic stars at the edge of the Cygnus OB3 association, including O star HDE 227018, ionizes the atoms and powers the emission from the Tulip Nebula. HDE 227018 is the bright star near the center of the nebula. Also framed in the field of view is microquasar Cygnus X-1, one of the strongest X-ray sources in planet Earth's sky. Driven by powerful jets from a black hole accretion disk, its fainter visible curved shock front lies above and right, just beyond the cosmic Tulip's petals via NASA http://ift.tt/2lVUygT

February 11, 2017

Solar System Portrait

On Valentine's Day in 1990, cruising four billion miles from the Sun, the Voyager 1 spacecraft looked back one last time to make this first ever Solar System family portrait. The complete portrait is a 60 frame mosaic made from a vantage point 32 degrees above the ecliptic plane. In it, Voyager's wide angle camera frames sweep through the inner Solar System at the left, linking up with gas giant Neptune, the Solar System's outermost planet, at the far right. Positions for Venus, Earth, Jupiter, Saturn, Uranus, and Neptune are indicated by letters, while the Sun is the bright spot near the center of the circle of frames. The inset frames for each of the planets are from Voyager's narrow field camera. Unseen in the portrait are Mercury, too close to the Sun to be detected, and Mars, unfortunately hidden by sunlight scattered in the camera's optical system. Closer to the Sun than Neptune at the time, small, faint Pluto's position was not covered. via NASA http://ift.tt/2l4F6lk

February 10, 2017

Melotte 15 inthe Heart

Cosmic clouds form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are scattered in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrowband and broadband telescopic images, the view spans about 15 light-years and includes emission from ionized hydrogen, sulfur, and oxygen atoms mapped to green, red, and blue hues in the popular Hubble Palette. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - The Heart Nebula. IC 1805 is located about 7,500 light years away toward the boastful constellation Cassiopeia. via NASA http://ift.tt/2kb8Ii1

Crescent Enceladus

Peering from the shadows, the Saturn-facing hemisphere of tantalizing inner moon Enceladus poses in this Cassini spacecraft image. North is up in the dramatic scene captured last November as Cassini's camera was pointed in a nearly sunward direction about 130,000 kilometers from the moon's bright crescent. In fact, the distant world reflects over 90 percent of the sunlight it receives, giving its surface about the same reflectivity as fresh snow. A mere 500 kilometers in diameter, Enceladus is a surprisingly active moon. Data collected during Cassini's flybys and years of images have revealed the presence of remarkable south polar geysers and a possible global ocean of liquid water beneath an icy crust. via NASA http://ift.tt/2kSnEkD

February 7, 2017

Azden AZ-61 6m FM HT - Tip #13 - Specifications

This is an article in a series regarding the vintage Azden AZ-61 6m FM Transceiver.

In its day, the AZ-61 provided a unique product to radio amateurs.  Radio collectors love specifications.

AZ-61 Specifications

  • Reception frequency range: 46.000 - 54.000MHz
  • Transmission frequency range: 50.000 - 53.995MHz
  • Antenna Impedance: 50 Ohms
  • DC Power Input Voltage: +3VDC to +16VDC, negative ground
  • Current consumption (receiving): ~150mA; when squelched: ~48mA; in the Battery Saver mode: ~28mA; in APO mode: ~100uA
  • Current consumption (transmitting): High power: ~1.5A; Low power: ~500mA
  • Dimensions (with BP-11 installed): 65mm x 174mm x 33mm
  • Weight: ~550g (including BP-11, antenna, hand strap, and belt clip)
  • Operating temperature: -20 deg. C to +60 deg. C
  • Transmitting power output: High: 5W; Low: 0.5W
  • Modulation: Variable Reactance Modulation
  • Maximum Frequency Deviation: +/- 5Khz
  • Spurious Output: -60dB or less
  • Built-in Microphone: Electret capacitor type (Impedance: 2k ohms)
  • Receiver method: Double conversion super-heterodyne type
  • RF Sensitivity: FM: Better than 0.16uV for 12dB SINAD
  • First IF Frequency: 16.9MHz
  • Second IF Frequency: 455KHz
  • Squelch sensitivity: 0.1uV or less
  • Selectivity: +/- 6KHz min. (-6dB); +/- 15KHz max (-60dB)
  • Audio Output: 250mW min into 8 ohms with 10% distortion

Photo of the Azden AZ-61 hand held transceiver
Azden AZ-61 HT

Good DX and 73, NJ2X

Other related articles on NJ2X.COM:
Azden AZ-61 6m FM HT - Tip #1 - How to program the radio
Azden AZ-61 6m FM HT - Tip #2 - disabling "the beep"
Azden AZ-61 6m FM HT - Tip #3 - 1993 review article
Azden AZ-61 6m FM HT - Tip #4 - rebuilding the battery pack
Azden AZ-61 6m FM HT - Tip #5 - how to reset the radio
Azden AZ-61 6m FM HT - Tip #6 - Automatic Power-Off
Azden AZ-61 6m FM HT - Tip #7 - VFO Mode
Azden AZ-61 6m FM HT - Tip #8 - Frequency Step
Azden AZ-61 6m FM HT - Tip #9 - Scanning
Azden AZ-61 6m FM HT - Tip #10 - Dual Watch

© Michael W. Maher and NJ2X.COM, 2017. Unauthorized use and/or duplication of this material without express and written permission from this blog’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to Michael W. Maher and NJ2X.COM with appropriate and specific direction to the original content.

January 31, 2017

Where to See the American Eclipse

Are you planning to see the American Eclipse on August 21? A few hours after sunrise, a rare total eclipse of the Sun will be visible along a narrow path across the USA. Those only near the path will see a partial eclipse. Although some Americans live right in path of totality, surely many more will be able to get there after a well-planned drive. One problem with eclipses, though, is that clouds sometimes get in the way. To increase your clear-viewing odds, you might consult the featured map and find a convenient destination with a historically low chance (more blue) of thick clouds overhead during totality. Given the large fraction of Americans carrying camera-equipped smartphones, this American Eclipse may turn out to be the most photographed event in the history of the world. via NASA http://ift.tt/2jR3xiW

January 28, 2017

N159 in the Large Magellanic Cloud

Over 150 light-years across, this cosmic maelstrom of gas and dust is not too far away. It lies south of the Tarantula Nebula in our satellite galaxy the Large Magellanic Cloud a mere 180,000 light-years distant. Massive stars have formed within. Their energetic radiation and powerful stellar winds sculpt the gas and dust and power the glow of this HII region, entered into the Henize catalog of emission stars and nebulae in the Magellanic Clouds as N159. The bright, compact, butterfly-shaped nebula above and left of center likely contains massive stars in a very early stage of formation. Resolved for the first time in Hubble images, the compact blob of ionized gas has come to be known as the Papillon Nebula. via NASA http://ift.tt/2ke3QIc