Bob Trembley

About Bob Trembley

Bob is a lifelong amateur astronomer, the Outreach Officer for the Warren Astronomical Society, and a volunteer NASA/JPL Solar System Ambassador. Bob does a lot of astronomy outreach - he lectures about astronomy and space science, and sets up his telescopes at schools, planetariums, conventions, and other venues. From 2014-2016, he was the editor of the Warren Astronomical Society's newsletter.

Bob is fantastically interested in asteroids and near-Earth objects (NEOs), and a HUGE fan of Kerbal Space Program; he is determined to improve the teaching of astronomy and Space History throughout Michigan, and the U.S.

Rocket in Flight
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In the Sky This Week – August 1, 2017

Venus is still high in the eastern morning sky; the constellation Orion appears a bit higher each morning. The southern sky is filled with objects this week: the waxing gibbous Moon accompanies Jupiter and Saturn for several days. The Moon will appear very close to Saturn on the evening on August 2nd. The constellation Cetus appears in the predawn sky to the southeast. Cetus is depicted as a sea monster in Greek mythology, but is often referred to as “the whale” today. I know several astronomers who had a copy of H.A. Rey’s “The Stars: A New Way to See Them” when they were young – I still have my copy! I was overjoyed to see that Stellarium has a starlore set depicting constellations as drawn by H.A. Rey in his book. The constellation Cetus in Stellarium as drawn by H.A. Rey in his book “The Stars: A New Way to See Them.” The sky overhead – Aug 1, 2017 … Continue reading

In the Sky This Week – July 25, 2017

Venus is still bright in the eastern predawn sky, but a little bit lower each morning. The constellation Orion is rising with the dawn; a little more of the constellation visible each morning. A wafer-thin waxing crescent Moon will be visible for a short time after sunset in the west on July 25th. Jupiter is visible low in the southwestern sky, and will be a little lower in the sky each evening after sunset. Saturn is high in the southern sky, and is a great target for telescope observers. Jupiter will be a scant 3° South of the Moon after sunset on July 28th. The Moon will be at First Quarter on the evening of July 30th, surrounded by Jupiter and Saturn, and the Southern Delta Aquariids Meteor Shower peaks on July 29-30th; this would be a great evening to host an astronomy outreach event! Apps used for this post: Stellarium: a free open source planetarium app for PC/MAC/Linux. NASA … Continue reading

Southern Delta Aquariids Meteor Shower 2017

The Southern Delta Aquariids is a strong shower best seen from the southern tropics. North of the equator, the radiant is located low in the southern sky – rates will be less than if seen from further south. This shower produces good rates for about a week centered on the night of maximum. These meteors are usually faint and lack persistent trains; few fireballs can be expected. Peak: July 29-30 Active from: July 21st to August 23rd Radiant: 22:40 -16.4° (see image above) Hourly Rate: 16 Velocity: 26 miles/sec (medium – 42km/sec) Parent Object: P/2008 Y12 The moon will be a waxing crescent, rising shortly after midnight. Source: American Meteor Society … Continue reading

In the Sky This Week – July 18, 2017

Venus continues to dominate the morning sky in the east, but appears slightly lower in the sky each morning as it pulls ahead of us in its orbit. The waning crescent Moon will appear near Venus the the star Aldebaran on the mornings of July 19th and 20th. The New Moon will be on the 23rd. Jupiter and Saturn appear in the south-southwestern sky after sunset; Jupiter will appear slightly lower in the western sky each day as the Earth pulls ahead of Jupiter in its orbit. The constellations Pegasus and Andromeda appear low in the northeast sky after sunset; the wispy cloud of M31, the Andromeda galaxy, makes a good target for telescope observers. M31 is the nearest major galaxy to the Milky Way. It is 2.5 million light years distant, and heading straight at us; in a little over 4 billion years, it will collide with the Milky way, and the two galaxies will merge into a large … Continue reading

Jupiter’s Great Red Spot from Juno

The Juno spacecraft made its seventh close approach (perijove) to Jupiter on July 10th, flying directly over the Great Red Spot. The raw images from the mission are publicly available, and have been post-processed by several different individuals. The results are as beautiful as they are varied. This stunning image, processed by Seán Doran, was featured on the Astronomy Picture of the Day on July 15, 2017: Here are some more examples of post-processing from the imaging community: This image was processed by Jason Major, who runs the fantastic Lights in the Dark website; the image was used in this post by NASA. This video was created using the NASA’s Eyes on the Solar System app shows the Juno spacecraft coming up on the Great Red Spot; I knew the storm was big, but I’ve never seen it from this perspective… it’s BIG! This video gives you a good idea of how close the Juno spacecraft gets to Jupiter during … Continue reading

In the Sky This Week – July 11, 2017

Venus continues to be the “morning star” in the east, and will appear very close to the red giant star Aldebaran – the “eye of the bull” in the constellation Taurus. On the 11th, Venus will be 3◦ north of Aldebaran, over the course of the week, Venus’ day to day change in position relative to Aldebaran will be very noticeable. In the west, bright stars Vega and Altair are the last to fade in the oncoming dawn. On the 11th, a waning gibbous Moon will be rise in the east before midnight, and set in the west around 9:00 AM. On the 18th, a waning crescent Moon will rise shortly after 2:00 AM, and be visible until it is lost in the glare of the rising sun after 6:00 AM. The Moon will be at third quarter on the 16th, and will be visible from about 1:00 AM – 1:00 PM.* Jupiter and Saturn are visible in the southern sky … Continue reading

In the Sky This Week – July 4, 2017

Venus is the bright morning star in the eastern sky, attended by the Pleiades star cluster, and the bright star Capella to the northeast. The southern sky is adorned with several jewels this week: the Moon appears high in the southern sky before sunset as a waxing gibbous – a few days past first quarter. Jupiter and Saturn are both visible, as are the bright stars Antares and Spica. The full Moon will be on July 9th. The bright star Altair (featured in the classic SF film Forbidden Planet) rises in the east followed by the constellation Sagittarius to the southeast. Sagittarius is recognizable by “The Teapot” asterism low on the horizon. Sagittarius has several interesting deep sky objects to observe using telescopes; something cool you can do with the public during nighttime observing sessions is point to the Teapot’s spout and say “that’s where center of our Milky Way galaxy is!” Before dawn, the constellation Hercules sets in the west, and “The … Continue reading

In the Sky This Week – June 27, 2017

Venus remains high in the eastern morning sky, the Pleiades star cluster appears between Venus and the star Capella. The Moon is a waxing crescent, appearing in the west after sunset. Jupiter is high in the southwest, and Saturn is low in the southeast sky after sunset. There will be a conjunction of the Moon, Jupiter and the star Spica on the evenings of June 30th and July 1st. Here is the current positions of the planets in the solar system: Also in In the Sky This Week Weekly post on what you can see in the sky. In the Sky This Week – June 22, 2017 In the Sky This Week – June 27, 2017 In the Sky This Week – July 4, 2017 In the Sky This Week – July 11, 2017 In the Sky This Week – July 18, 2017 In the Sky This Week – July 25, 2017 In the Sky This Week – August 1, 2017 … Continue reading

Could “Planet Nine” be Considered a Planet?

I got to wondering: given the International Astronomical Union’s (IAU) current definition of a planet, if a hypothesized “Planet Nine” were to be found in the outer reaches of our solar system, could it (or anything in that region) be considered “a planet?” The IAU definition of a planet is a celestial body that: (a) is in orbit around the Sun. (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape. (c) has cleared the neighborhood around its orbit. An astronomical units (AU) is a unit of measurement equal to the mean distance from the center of the earth to the center of the sun – 149.6 million kilometers. The Kuiper belt is a disc-shaped region of icy bodies in the solar system – including dwarf planets such as Pluto – and comets beyond the orbit of Neptune. It extends from about 30 to 55 AU. A trans-Neptunian object (TNO) is any … Continue reading

In the Sky This Week – June 22, 2017

The planet Venus appears high in the eastern morning sky; the bright star Capella, to the northwest, is the last star to fade with the oncoming dawn. The waning crescent Moon will vanish amid the morning haze to the east, to reappear in the west as a waxing crescent after dusk on June 25th. The Summer Triangle is an asterism formed from the three stars Altair, Deneb, and Vega, the brightest stars in the three constellations of Aquila, Cygnus, and Lyra. They can be see in the eastern sky before midnight. Jupiter is high in the southwestern sky after dusk, and sets in the west around 1:30 AM. Saturn appears high in the southeastern sky after dusk, is at its highest around midnight, and sets in the southwest just before dawn. Directly overhead, the Milky Way flows through the constellations Cygnus and Aquila (if you live in a city – trust me, it’s really there… drive out of the city … Continue reading

Kepler Team Releases Catalog with 219 new Exoplanet Candidates

The story of the Kepler space telescope is a saga of discovery, heartbreak, and redemption. Launched in 2009, Kepler’s mission was to search for Earth-size and smaller planets orbiting nearby stars, and to estimate how many stars in the Milky Way have such planets. Within the first few weeks of observations, five previously unknown exoplanets were found orbiting close to their parent star. Over the next few years, thousands of planetary candidates were discovered. In July of 2012, one of the telescope’s four reaction wheels failed; these are a type of flywheel that keep the spacecraft pointed at its target, and the telescope needs three to function properly. In May of 2013 a second reaction wheel failed, ending new data collection for the original mission and putting the continuation of the mission into jeopardy. In November of 2013, a new mission plan dubbed K2 “Second Light” was devised – by balancing “light pressure” from the Sun on spacecraft’s solar panels to act as a … Continue reading

Asteroid Day 2017

It’s June, Asteroid Day approaches! Asteroid Day is a global coalition of scientists, astronauts, physicists, artists, musicians and concerned citizens that have come together to focus the world’s attention on the nature of asteroids, and the solutions that could protect all life on Earth from future asteroid impacts, and inspire the next generation. Since the summer of 2015, worldwide Asteroid Day events have been held on June 30th, the date of the historic Tunguska Impact Event of 1908. The founders of Asteroid Day drafted the 100X Declaration. In short: Over the last decade and a half, we’ve discovered a LOT of near-Earth asteroids, and continue to do so. Some of these asteroids can potentially impact the Earth. Some of these asteroids are large enough that an impact would be “a bad thing.” We need to accelerate the discovery and tracking of Near-Earth Asteroids to 100,000 per year within the next ten years. We need to get government, private and philanthropic organizations … Continue reading