Journal of the Amateur Astronomers Association of New York

October 2015 Volume 64 Number 10 ISSN 0146-7662

Space Dust:

By Richard Brounstein

On Earth, dust is a nui-sance. It accumulates all over our possessions on display shelves, books we haven’t read in awhile, furniture, and pictures on our desk. No matter how much dust you remove, millions of little particles are pa-tiently letting gravity overcome electromagnet-ic forces and atmospheric

pressure before settling onto your pristine surfaces. It blows through the atmosphere and restricts our vision and causes some of us breathing problems. Dust storms range from be-ing disruptive to agriculture to being downright dangerous to human life.

Elsewhere in the Universe, dust can also be troublesome. It blocks our view of astronomical phenomena, interferes with space probes and other equipment that we send off the Earth and interferes with our exploration of the Universe. But dust isn’t all bad. It also helps us explore the universe. It helps shape the galaxies and is part of the beauty of some celestial objects. It is also essential for life.

Dust in our Solar System

Any small particle floating between planets is dust. There is no exact definition for the size of a particle for it to be dust or not dust. If it is smaller than a millimeter, then it probably is. As empty as space is, the most common thing you will encounter travelling through the solar system are dust parti-cles. Most likely, these particles are bits of rock from aster-oid collisions or pieces of ice ejected from comets that shape beautiful tails and feed the Leonid and Perseid meteor show-ers every year.

Little bits of matter speeding through space at thousands of km an hour in Earth orbit damage space stations, space probes and satellites. A tiny spec slamming into an object at 28,000 kph has the equivalent energy of a small explosive charge. Manned spacecraft need stronger hulls more than ever because of tiny bombs that might slam into the craft.

20th ANNUAL AAA STARFEST Saturday, October 17th: Central Park , Sheep Meadow @ 67th Street

GOOD OR BAD?

Apollo astronauts found that dust from the moon caused prob-lems for equipment, negatively affected their health and got caught in the joints of their spacesuits making them harder to use. When they would get back into their lunar module and remove the suits, the dust filled the air and got into their lungs. Apollo 17 astronaut Harrison Schmitt said moon dust smelled like gunpowder. The Moon’s silicon dust is abrasive like glass and can cause breathing problems. NASA knows that they must prevent dust from accumulating into the filtered environ-ment when we eventually return to the Moon or residents will be battling serous health problems whenever equipment comes from the lunar environment into the human environment.

Dust storms happen on Mars as well as Earth. Bits of dust create problems in machinery for any number of landers and rovers exploring the red planet. In 2010, particles of Martian soil from dust devils covered the photovoltaic solar panels

powering the Opportunity rover exploring near the equator of Mars. This blocked enough solar ener-gy to stop its mission tem-porarily. Thankfully, the winds turned favorable and cleaned off the panels and the science mission re-sumed.

The dust on Mars is much more poisonous than moon dust. Martian soil contains toxic metals such as arsenic and chromium. Future colo-nists will need powerful filters to clean the air of any human habitat or suffer dire consequences. On the plus side, if enough concentra-tions of these heavy metals

exist, mining heavy metals on Mars will make it possible to manufacture complex machines and electronic devices and cool video games. Modern conveniences depend on materials that were once dust.

Dust can be beautiful, though. It provides most of the ma-terial for the stunning rings of Saturn as well as rings of Jupi-ter, Neptune, and Uranus. And more than that, all the objects in our solar system were tiny grains of dust made up of various heavy elements before gravity and collisions formed our solar system objects. Our Sun, in fact, was created out of a cloud of gas and dust 5 billion years ago. (Space Dust, cont’d on page 4)

NASA.gov

A piece of dust 10 microns across

NASA.gov

Total Lunar Eclipse

NASA.gov

The Butterfly Nebula is a central exploding star surrounded by dust and gas that gives it the butterfly shape.

October 2015

Follow veteran sky watcher Tony Faddoul each month, as he points our minds and our scopes toward the night sky.

WHAT’S UP IN THE SKY AAA Observers’ Guide

By Tony Faddoul

October’s Evening Planets: Saturn will be in Libra the Scales for one hour after sunset. Neptune is in Aquarius the Water Bearer and Uranus in Pisces the Fish all night. Dwarf planet Pluto is in Sagittarius the Archer until 10 PM. October’s Evening Stars: Spot the Summer Triangle of Vega in Lyra the Harp, Deneb in Cygnus the Swan, and Altair in Aquila the Eagle until around 1:00 AM. Bright Capella in Auriga the charioteer will be up all night. Spot the stars of constellations Andromeda, Cassiopeia, Perseus, Cepheus, Draco, Sagittarius, Pega-sus, Aquarius, Aries, Taurus, Pisces, Capricornus, and the two Dippers.

October’s Morning Planets: Find bright Venus be-tween Cancer the Crab and Leo the Lion around 3 AM until sunrise. Mars and Jupiter will be in Leo the Lion from 4 AM until sunrise. Mercury is in Virgo the Vir-gin in around 6 AM in the middle of October. Uranus will be in Pisces the Fish until sunrise. October’s Morning Stars: Spot the Winter Triangle; Sirius, the brightest star viewed from Earth in Canis Major the Great Dog, Betelgeuse in Orion the Hunter and Procyon in Canis Minor the Small Dog. Spot Ca-pella in Auriga the charioteer, Aldebaran in Taurus the Bull, and the stars of Aries, Gemini, Orion, Pisces, Peg-asus, Andromeda, Cassiopeia, Cepheus, Draco, Per-seus, and the two Dippers.

Oct 4 Last Quarter Moon at 5:05 PM

Oct 8 Mercury is Stationary, sunset

Oct 9 Jupiter is 3° north of the Moon, sunset

Oct 11 Moon at apogee (252,520 miles away)

Oct 12 New Moon at 8:06 PM

Oct 20 First Quarter Moon at 4:30 PM

Oct 22 Orionid meteor shower peaks, pre-dawn

Oct 26 Venus is 1° south of Jupiter, pre-dawn

Oct 26 Moon at perigee (221,740 miles away)

Oct 27 Full Moon at 8:05 AM

Times given in EDT

Octobers “Skylights”

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AAA Events on the Horizon

OCTOBER 2015

Saturday, October 3 Observing at Brooklyn Museum Plaza 9:00pm, PTC

Tuesday, October 6

Observing on the High Line 7:30pm PTC

Saturday, October 10 Observing at North-South Lake, Haines Falls 8:00pm

MPTC

Sunday, October 11 Observing at North-South Lake, Haines Falls 2:30am

MPTC

Tuesday, October 13 Observing on the High Line 7:30pm PTC

Wednesday, October 14

AAA Fall Astronomy Classes at Cicatelli Center, Manhattan, 6:30—8:30 pm M (Fall classes sold out)

Next Class Oct. 21 Registration required at: http://www.aaa.org/education AAA Members Only. New classes begin Winter / Spring

Friday, October 16

Lecture at the American Museum of Natural History 6:15pm P

Saturday, October 17 Urban Starfest in Central Park, 20th Anniversary

Sheep Meadow @W67th St. 7:00pm PTC

Observing at Great Kills, Staten Island 8:30pm PTC

Tuesday, October 20

Observing on the High Line 7:30pm PTC

Friday, October 23 Observing at Carl Schurz Park 7:00pm PTC

Tuesday, October 27

Observing on the High Line 7:30pm PTC

Friday, October 30 Observing at Floyd Bennett Field 8:00pm PTC

[Cancelled] Observing at Parkchester, Bronx 8:00pm

Saturday, October 31

[Cancelled] Solar Observing, Poe Park, The Bronx 11:00am

M: Members only; P: Public Event; T: Br ing telescopes / binoculars; C: Cancelled if cloudy.

For location and cancellation information visit: www.aaa.org

Photographing the Aurora Borealis

By Stan Honda

Success as a night sky photographer often depends on the preparation you do before you ever set up your tripod and camera. Last March, I had the good luck to photograph the aurora borealis, one of the most astonishing natural events I’ve ever witnessed. Just for good measure, it occurred a mere 12 hours after I saw my first total solar eclipse on March 20 in the polar archipelago of Svalbard.

Before the trip I had read about exposures for aurora photos. Aurora photographers recommend keeping shutter

speeds as short as possible since the lights tend to move quickly and long exposures blur the structure of the aurora. The Travel Quest tour I was on offered one free night of auro-

ra viewing. I signed up for three extra nights to make sure of a sighting since I had never seen the northern lights.

After two nights of intermittent clouds and little ac-tivity, the sky was clear on the night after the eclipse. Our viewing site had two warming huts, essential for the sub-zero temperatures. At 78 degrees north latitude, the Big Dipper was high overhead, pointing to Polaris nearly at zenith. Just before midnight a broad faint green light appeared in the southeast. It grew from the horizon, and people came out of the huts.

I had already set up my camera and tripod so they would be ready if the lights came. I used a Nikon D810 cam-era with a 14-24mm zoom lens set at 14mm. I had done some test shots the previous hour, and the stars looked good using an exposure of 15 seconds, f2.8 at 1600 ISO. These settings were fine for the first few photos. As the aurora grew in size, I realized it was moving fast so I raised the ISO to 3200 and shortened the shutter speed to 8 seconds.

The lights grew even greater, forming a classic coni-cal shape. In a matter of minutes the lights had grown to en-compass much of our view of the sky. It was incredible. I checked the exposure on the camera screen once, then contin-uously shot photos since the aurora changed so rapidly. It soon expanded beyond the frame of my lens, looking like an explosion of green. I contemplated changing to a 16mm fisheye lens, which takes in 180 degrees from side to side, but realized I would lose valuable shooting opportunities.

At one point the aurora moved directly overhead, much to the delight of the crowd. We craned our necks, and I quickly pointed the camera straight up, not even looking through the viewfinder to compose. The shapes changed con-tinuously and I shot as many photos as I could in the short

October 2015

time. In less than an hour the show was over. I realized I bare-ly felt the bitter cold.

When I viewed the pictures on the computer, I saw some purple strands of light mixed in with the green. I had seen only green with my eyes, but since digital cameras are more sensitive to red light than the human eye, the camera must have picked up the faint purple light in the sky.

Looking ahead, during the whole month of October there will be a very nice conjunction of three bright planets. The good news is you should be able to see and photograph them easily from New York if the sky is clear. The bad news is they rise during the pre-dawn hours. The planetarium soft-ware Stellarium shows that Jupiter, Mars and Venus will rise almost in a straight line on Sept. 30. Jupiter, at the bottom of the trio, will clear the horizon at 4:39 a.m. Add about 30 minutes to these times to see the bottom planet at 5 degrees above the horizon, enough to clear distant buildings if you are in the New York area (and to get more sleep!) Initially they will be about 15 degrees apart.

On Oct. 9 the planets rise with a waning crescent moon, which should make a remarkable sight and a very nice photograph. Jupiter rises at 4:13 a.m. and the grouping will be 10 degrees apart. You’ll just need a moderate telephoto lens to get all four objects in one frame. Find an interesting landmark to include in the foreground of your picture, such as a distant building or tree or the skyline. It will still be dark for over an hour as the group rises, and you’ll still be able to get great photos as the sky brightens just after 6:00 a.m. Mars and Jupiter will be less than 1 degree apart on Oct. 18 (rising at 3:46 a.m.) and both will be 5 degrees from Venus. Jupiter will “pass” Mars as they reform into a more or less straight line for a few days. On Oct. 25 the plan-

IN LONGYEARBYEN, SPITSBERGEN

Stan Honda

Stan Honda Aurora in Longyearbyen, Spitsbergen on March 20. Nikon D810, 14-24mm lens, 15 sec., f2.8, ISO 1600

Explore more night sky photography at www.stanhonda.com stanhonda@gmail.com.

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Photographing the Aurora, (cont’d on Page 4)

4

October 2015

Space Dust, (cont’d from Page 1)

It is only through dust that we have pristine samples from a comet here on Earth. In 2004, NASA’s Stardust spacecraft collected samples of comet dust and returned them to Earth in 2006. Unlike the full rocks from the moon, it was much easier to collect dust particles for direct study.

Interstellar Dust

Dust prevents us from exploring much of the Milky Way Galaxy. Interstellar dust blocks our view of stars from most of the galaxy. That’s why if you want to observe starts in the oth-er side of the galaxy, we need to use infrared light sensitive detectors. Infrared can penetrate space dust. When the James Web Space Telescope launches in 2018, humans will learn much more about our galaxy because it operates in IR.

In 2014, interstellar dust also interfered with efforts to dis-cover gravity waves generated way back at the beginning of the universe. This would’ve helped prove cosmic inflation. Unfor-tunately, the dust in our galaxy interfered and the results were inconclusive. Gravity waves still probably exist but we need to keep searching for the evidence.

On the positive side, dust helps us understand the shapes of galaxies and nebula clouds. It is not just the light from the stars that show us the galaxies. It is the dust throughout the galaxy that is lit up from those stars that make it visible. Dust helps reveal the shape of galaxies.

Conclusion

Despite all it’s problems, space dust is important. It helps us to explore. It creates our stars and solar systems. It makes it pos-sible for heavy elements and complex carbon compounds to exist on Earth. Dusty particles eventually became part of all life forms. Dust is the building blocks of all life. Dust is what we all were and what we will each someday become. We are all bits of dust.

CALL FOR WRITERS

The Amateur Astronomers Association of New York’s

journal Eyepiece is looking for dedicated writers to

contribute articles covering lectures, seminars, and

observing events around town, as well as current topics

in astronomy and astrophysics.

Interested? Please submit a short writing sample to Amy Wagner at editor@aaa.org.

Eyepiece Staff October Issue

Issue Editor: Rori Baldari Copy Editor: Richard Brounstein

Editor in Chief: Amy Wagner

Contributing Writers: Richard Brounstein, Tony Faddoul, Stan Honda,

Eyepiece Logo and Graphic Design: Rori Baldari

Administrative Support: Joe Delfausse Printing by McVicker & Higginbotham

Hello AAA Members! We are celebrating the 20th anniversary of Starfest on October 17th, at Central Park’s Sheep Meadow. Bring your friends and family, there will be talks, raffles and observing.

Our Lecture Series for 2015-2016 starts this month, featuring David Eicher from Astronomy Magazine, presenting “The New Cosmos: Answering Astronomy’s Big Questions” on October 16th. Check the full Lecture Series schedule at: http://www.aaa.org/lectures1516

We resumed Astronomy Classes, with “AAA Fall Astrono-my Class: Astronomy Basics” which sold out very quickly and two more classes scheduled for this coming winter and spring.

All of our observing sites, including directions and maps can be found at http://www.aaa.org/observing

Please note that our calendar updates very often and the best way to see our current full calendar is at http://aaa.org/calendar Marcelo Cabrera President, AAA president@aaa.org

A Message from the AAA President

The Amateur Astronomers’ Association of New York Info, Events, and Observing: president@aaa.org or 212-535-2922

Membership: members@aaa.org Eyepiece: editor@aaa.org

Visit us online at www.aaa.org.

ets (rising at 3:40 a.m.) are in a triangular shape just 3 degrees apart. If you have a longer telephoto (200-300mm on a crop sensor digital camera), you’ll get nice tight shots of the trio. But zoom back slightly to get some of the skyline and you may find you have a better shot. By mid to late October the group rises earlier. On Oct. 25 Jupiter and Venus will be level with each other about 1 degree apart. After that date Jupiter “passes” Venus but the show con-tinues into early November. For all of these shots, make sure you have a sturdy tripod for your camera and lens. The expo-sures will probably be around one second or more so you’ll need steady support.

Richard Brounstein’s monthly column tests the limits of our imagination. Join him each month, as he stretches the boundaries

of imagination to present new, fascinating concepts.

Stan Honda is a professional photographer. Formerly with Agence

France-Presse, Stan covered the Space Shuttle program.

He shares his night sky images and explores his passions for

astronomy and photography.

Photographing the Aurora, (cont’d from Page 3)