A Double Star Puzzle

What well-known double star has a companion that appears to orbit the primary once every 24 hours?

The answer is a well-known star that looks like a single star to our naked eye but is actually a binary system with a smaller companion star. The companion star is visible in a telescope and appears to orbit the primary once every day. If you view this system through a 24 hour period, perhaps in Winter from above the Arctic Circle where it remains dark all day, then the companion would trace one complete orbit around the primary and end up back where it started. If you are impatient then scroll down to the video below for the answer.

Albireo – one star blue and the other golden – as captured by Tom Wildoner in July, 2015. Visit Tom’s blog, Leisurely Scientist.

A double star is a pair of stars that appear close to each other as viewed from Earth, especially with the aid of a telescope. In binary systems, the stars are physically bound together by gravity so they are in orbit around each other. Binary stars are important to astronomers as knowledge of their motions allows direct calculation of stellar mass.

The star Alberio, the head of swan in the constellation Cygnus, is considered to be one of the most beautiful double stars. It is a binary system with the brighter gold star and the dimmer blue star orbiting around their common center of mass.

The video below shows the answer to the double star puzzle produced by simulating the binary system using the SkySafari app.

Polaris, the north star, is a binary system with a companion SAO 305, also known as Alpha Ursae Minoris B or Polaris B. If you pay attention to the date/time at the bottom of video then you can see that SAO 305 does, in fact, appear to orbit Polar once every 24 hours.

But the puzzle is a deception, of course, because all the stars that we can view from the Northern Hemisphere appear to orbit Polaris every 24 hours as seen in the following video with a wider field.

These “orbits” appear because of the rotation of the Earth rather than the motion of the stars.

But the universe keeps things interesting – In 1929, another very close companion was found near Polaris making it a system of three stars that are gravitationally bound together.

Credit: This puzzle came from Glenn Chaple‘s Oberving Basics column in the May issue of Astronomy Magazine, published Tuesday, April 2, 2019.

Catch SpaceX’s Satellite Train Speeding Past Deneb

A SpaceX Falcon 9 rocket recently launched the first set of 60 Starlink satellites. News broke last Friday night that Dr. Marco Langbroek captured a video of a train of these satellites over in the Netherlands shortly after the launch.

There is a chance to see this satellite train over Vancouver and the Lower Mainland on the night of June 3rd around 11:07 pm PDT as they pass close to Deneb, the brightest star in the constellation Cygnus. The charts below, plotted for SFU’s Burnaby campus, can help locate the satellites but they might be best viewed in binoculars.

Other opportunities to view this satellite train can be found on the heavens-above website.

There is lots of concern and debate on the how Starlink satellites might be harmful to astronomy.

Help us Measure Light Pollution in BC

At Astronomy Day we showed people how easy it is to use phone apps to measure light pollution. Now it is your turn to help us measure the sky glow and light pollution in BC through a campaign called #MeasureTheSkyBC – all you need is your phone and your eyes.

The page MeasureTheSkyBC has more information on the apps and the campaign. You can win prizes by using an app to take a measurement and submitting it via email to [email protected] from June through September 2019. The next two weeks are a great time to start taking measurements as the waning Moon will be less-and-less illuminated until new Moon on June 3rd.

Cover of SkyNews Magazine

Early-bird bonus: be one of the first five to submit a measurement and we’ll send you a free issue of Canada’s SkyNews Magazine that features an article on fighting light pollution.

Light Pollution affects more than just Astronomy – checkout the light pollution section of our website and Five Reasons to Care for its effects on wildlife, human health, and the economy. Or find out more by watching the SUPERnova Episode3 video below on YouTube.

Congratulations to Kelvin Dueck for the Prime Minister’s Award on Teaching Excellence

RASC Vancouver congratulates Kelvin Dueck, a Pitt Meadows secondary physics, science and math teacher, on his receipt of a 2019 Prime Minister’s Award for teaching excellence in STEM.

Kelvin Dueck teaches physics, science, and math to Grades 9 through 12 students at Pitt Meadows Secondary. His teaching achievements and his willingness do almost anything to get his students engaged have been recognized with this award.

RASC Vancouver worked with Kelvin when he recommended one of his students to take part in an astronomy project on Cepheid variable stars with some of our junior members. We also held a solar viewing party at his school.

Kevin’s motto

“Mistakes are expected, respected, inspected and corrected”

encourages students to discover physics for themselves rather than mindlessly memorizing equations. He will do almost anything to get his students engaged, including going skydiving to teach lessons on the physics of free-fall.

More details on Kelvin’s achievements and award are available on the Government Of Canada’s website.

A Good Adieu to Galaxy Season

I was fortunate to spend a few nights under wonderfully dark skies at Manning Park last week. The first night was a bit of a disaster with trying out some new astrophotography equipment, so I switched to visual observing on the second night with the goal of observing some Messier Galaxies, M59, M60 and M89, that I had not yet checked off my Messier observing list.

I was joined by Hayley Miller, RASC’s event coordinator, and we started setting up near the boat launch at Lightning Lake around 8:30 pm. It is a gorgeous site with the lake in the foreground and mountains in the background.

Image of Lightning Lake observing site.
Observing Site – Lightning Lake at Manning Park

We had the area largely to ourselves with just one car in the parking lot and the silence was only disturbed by a few ducks and geese out on the lake. To the west, a beautiful sliver of the 4-day old Moon was heading down towards the mountains.

We watched the brighter stars (Capella, Vega, Arcturus, Spica, Castor and Pollux) and constellations (Cygnus Lyra, Bootes, Virgo, Gemini, Ursa Minor and Ursa Major) pop in to view until around 10:30pm when the skies had turned truly dark – the skies at Manning Park are Bortle class 2 and I measured the sky quality as 21.6 with a unihedron sqm-l.

I then turned my Edge HD 8 scope towards my target galaxies in the Virgo cluster. The north-east part of the constellation Virgo is littered with galaxies.

Virgo galaxy cluster
The Virgo Cluster of Galaxies. Image credit: Rogelio Bernal Andreo, APOD Aug 4th, 2015.

Early March to Mid-April is known as Galaxy Season because of the sheer number of galaxies in the Virgo cluster and the close-by constellations of Coma Berenices, Canes Venatici, and Leo. The image below is a visual explanation for why this time of year is known as Galaxy Season.

Imaging-worthy galaxy locations by optimal viewing date. Image credit: Charlie Bracken

Each red dot is an imaging-worthy galaxy. The Y-axis shows the galaxy’s declination and the X-axis shows the best time of year to observe the galaxy – that is, the time of year when it crosses the meridian at midnight.

I spent the next two hours galaxy hopping through the Virgo Cluster, Coma
Berenices and a little way into Leo. My scope was mounted on a Stellarvue M2 alt-az mount which was easily pushed from one target to the next. My original targets, M59, M60, and M89 were easy to find but I also spent time on M88, M90, M100, M85, the Coma Pinwheel Galaxy, the Siamese Twins, NGC 4503, M87 (with its black hole), Markarian’s Chain, and others. Anything down to magnitude 11 was easy and I’m sure better eyes than mine would easily have gone much deeper.

The night was a wonderful way to say adieu to Galaxy Season for this year. The waxing Moon will interfere with observing faint galaxies until the next new Moon on June 3rd and by then there is only about one hour of true darkness between the end of Astronomical Twilight at 12:35 am and the start of Twilight on the “next day” at 1:45 am. So goodbye to galaxy season but I expect to say hello to some summer Globular Clusters, double stars, and to spend more time on solar observing.

The Jim Bernath Collection Featured at Astronomy Day

“One person’s trash is another person’s treasure – especially if you are collecting old space junk” – excerpt from an interview of Jim Bernath by Flash News, July 1998).

The Jim Bernath collection of astronomy and space artifacts will be featured at this year’s Astronomy Day and Science Rendezvous – Saturday 11:00am to 3:00pm May 11th at Simon Fraser University’s Burnaby campus. Come, see, and touch meteorites, pieces of tile from the space shuttle, the iconic Canadian logo and flag produced for the Canadarm, and other space memorabilia. Parts of the collection are shown in the video below but it is a hands-on display best experienced in person at Astronomy Day!

Jim was a member of RASC since 1975 – that is 44 years. To many, he was known as “Mr. Space of Canada” and a self-described “Specialist in NASA and the Space Shuttle Programs”. Unlike many collectors, Jim didn’t keep his artifacts private but instead chose to display and share them with the public. Jim regularly traveled with his van of curiosities across Canada and the United States. He would set up displays in schools, auditoriums, and malls – wherever he could find a crowd.

At the RASC General Assembly in October of 1981, Jim was one of the recipients of the Best Centre Display. Jim was a regular in presenting his display at our annual Astronomy Day events. Adults and especially kids buzzed around his display tables and loved to hear him explain all of the details of missions and memorabilia.

2018’s International Astronomy Day event was Jim’s last time with us. His fragile health precluded him from bringing the last few pieces of his displays to the event. Instead, Jim was setup next to the tables for the Jim Bernath Collection and he spent the entire afternoon giving away autographed posters of space and the space shuttle with a line-up of children waiting to meet him. He was a rock-star and it was a great send off for him because sadly, shortly after the event, Jim was admitted to long term care and passed away a few months later.

Over the past few years, RASC Vancouver began to acquire pieces of Jim’s displays and created RASC Vancouver’s Jim Bernath Collection to carry on his legacy. It has now become an integral part of our outreach programming.

“His warm charm, wit, and his love of all things astronomical will be missed. Thank you Jim for your generous service on Earth.” – Pomponia Martinez, past-president of RASC Vancouver.

Parts of this article are taken from a tribute to Jim Bernath by Suzanna Nagy, the past president of RASC Vancouver, that will appear in a upcoming issue of the Journal of the RASC.

ISS Solar Transit on May 1st, 2019

The ISS transits the Sun and a prominenceon 2015 August 21st.
Image Credit: Thierry Legault
http://www.youtube.com/watch?v=jmRw6IMo9Uo …

Save the date solar observers! On Wednesday morning, May 1st 2019, the International Space Station is predicted to make a three-star transit of the Sun around 09:40:00 am – the time will vary somewhat based on your location.

The transit should be visible for a narrow 6.2 km slice over the lower mainland ranging from Bowen Island and proceeding south-east over Maple Ridge. The Trottier Observatory at Simon Fraser University is located within 0.16 km of the center-line of that slice.

Warning: Protect your eyes when solar observing!

Never look directly at the Sun. Always use a proper solar filter specifically designed and approved for solar observation, available at astronomy stores; that meet the requirements for ISO Standard 12312-2:2015.

The web site https://transit-finder.com is a fantastic resource to get predictions of ISS solar and lunar transits. Just select your location on a map it it will provide you with ISS transit predictions over the next 10 days.

The transit on May 1st only lasts 1.26 seconds so don’t blink. Also, the ISS is fairly small at 0.41 arc-minutes – about the same angular size as Jupiter – so you will likely need a telescope, with a proper solar filter, to spot it.

More details for observing from near the Trottier Observatory at SFU from the transit-finder.com site:

★★★ Wednesday 2019-05-01 09:41:05.64 • Solar transit

ISS angular size: 41.22″; distance: 670.38 km
Angular separation: 0.6′; azimuth: 110.3°; altitude: 35.9°
Center line distance: 0.15 km; visibility path width: 6.19 km
Transit duration: 1.29 s; transit chord length: 31.7′

R.A.: 02h 34m; Dec: +15° 08′; parallactic angle: 36.3°
ISS velocity: 24.7 ′/s (angular); 4.81 km/s (transverse)
ISS velocity: 5.60 km/s (radial); 7.38 km/s (total);
Direction of motion relative to zenith: 176.0°
Sun angular size: 31.7′46.2 times larger than the ISS

Imaging a Black Hole (effects) with a Small Telescope

Hmmm….thinking about how to image a black hole with my telescope after last week’s release of the first black hole picture. I have a relatively small Celestron EdgeHD 8 inch (200 cm) telescope and a ZWO ASI 178 cmos camera for imaging. Imagers know that matching the angular size of a target to angular resolution of a telescope/camera is an important consideration, so I did that for the b\lack hole and my equipment.

The Hamburg Observatory released a nice image of the region around the black hole and its containing galaxy, M87, that shows some angular sizes.

The region around galaxy M87 and its black hole with angular sizes
Angular sizes of the region around the galaxy M87 and its black hole vs the Moon
Image credit: Hamburg Observatory, EHT collaboration, VLBA image – C. Walker, VLA image – F. Owen, LOFAR image – F. de Gasperin

I added the full moon for some additional context but a quick summary is:

  • The full moon has an angular size of about 1,900 arc-seconds
  • The galaxy M87 has an angular size of about 400 arc-seconds in visible light, and a somewhat larger size in radio frequency observations.
  • The event horizon of the black hole is about 25 micro-arc-seconds!

My telescope/camera combination has a theoretical image scale of roughly 0.25 arc-seconds per pixel (Astronomy Tools has an online image scale calculator). So that means that the event horizon would cover

25 micro-arc-seconds / 0.25 arc-seconds/pixel = 0.0001 pixels

or one ten-thousandth of a pixel! Not likely to be visible, especially since the Earth’s atmosphere typically limits the practical resolution to about 1 to 2 arc-seconds.

Never the less, M87 is still a cool imaging target because it is possible to catch a jet of plasma shot out from the galaxy at relativistic speeds.

Image og galaxy M87 with relativistic jet
The Galaxy M87 with its relativistic jet pointing almost straight up.
Image credit: Ken Jackson, April 20th, 2019, Coquitlam, BC.

The above image was taken using a Celestron Edge HD 8 and ASI 178 camera in poor conditions – heavy light pollution in Bortle class 7 skies from my front yard in Coquitlam and a full moon rising in the east. It is just a single 30 second exposure. Still the jet can be seen pointing almost straight up from the galaxy!

The jet is thought to be powered by the black hole at the galaxy’s core and its surrounding accretion disk of material. In 1999, observations from the Hubble Space Telescope measured the speed of M87’s jet at four to six times the speed of light. This faster-than-light speed is actually an illusion caused by the relativistic velocity of the jet: the time interval between light pulses emitted by the jet is less than the actual interval due to the relativistic speed of the jet moving in the direction of the observer.

So we can’t see the black hole directly with smaller telescopes but we can see one of its cool effects.