“7 Minutes of Terror”

Posted on December 26, 2020 by Benoit Guertin

The folks at JPL created a short film showcasing Perseverance’s critical descent phase for the Mars landing. If everything goes according to plan, we shall have a new rover on Mars at 3:40pm EST on February 18, 2021.

Perseverance is currently “cruising” at 84,600km/h through space with Mars as a target. To give you an idea of what kind of speed that is, here are a few benchmarks:

The fastest commercial jet: the Concord flying at Mach 2.04 is just under 2,200km/h
Space Shuttle re-entry speed: 28,100km/h
Voyager 1, leaving our solar system : 61,500 km/h
Parker Solar Probe (fastest man-made object) : +250,000km/h

Perseverance was launched on July 30th, 2020 from Cape Canaveral Air Force Station, Florida, on top of a Atlas V-541 rocket.

Animation of Mars 2020’s trajectory around Sun, Data source: HORIZONS System, JPL, NASA

The only way the rover will be able to decelerate from its current cruising speed is by plunging into the Martian atmosphere at the right angle and using the atmospheric friction to slow it down. That “7 minutes of terror” is the time the rover will spend on re-entry, from approaching Mars at the right angle, to landing in the desired spot on the Martian surface.

Lots of steps need to go right, timed correctly to have a successful landing. Only 22 of the 45 landers sent to Mars have survived a landing. The US is by far the country with the most success (sorry Russia, you’re space program is awesome, but you suck at landing on Mars)

Glancing up at the night sky that February 18, 2021 evening will be very easy to spot Mars, but also the Pleiades star cluster (Messier 45). Mars will be about 5 degrees north of a almost half-illuminated moon. And if you keep looking higher up by 10 degrees you’ll see the famous open star cluster nicknamed the Seven Sisters, also used as the Subaru emblem.

The Great Comet of 2020 That Never Was

Posted on April 19, 2020 by Benoit Guertin

Back in March, the astronomy crowd was buzzing about a possible”naked-eye” comet expected in late May 2020. Comet C/2019 Y4 (ATLAS) was first detected at the tail end of December as a very dim magnitude 19.6 object and by mid-March it had brighten to an easy telescope target magnitude of 8. Those not familiar with the magnitude scale, going from 19.6 to 8 is not a doubling in brightness, but around a 4000 times increase!

That dramatic increase in brightness help fuel the hype for the Great Comet of 2020, and there were two other factors that got people excited:

It would be visible at dusk from the Norther Hemisphere, hence within easy viewing to much of the world population.
It was following a similar orbital path as the “Great Comet of 1843“, suggesting that it was from the same original body and could potentially provide the same viewing spectacle. That 1843 comet was visible in daytime!

Well all that went south when the comet’s breakup was observed in late March after peaking momentarily at magnitude 7. It began to dim, along with any hopes of a Great Comet repeat. Below is a graph showing the the original (grey line) and revised (red) comet brightness forecast (dots being observed measurements) on this chart created by Seiichi Yoshida (comet@aerith.net)

Comet C/2019 Y4 (ATLAS) Brightness – Copyright(C) Seiichi Yoshida

Comet C/2019 Y4 is expected to make its closest approach to the sun on May 31st, however most experts believe it will disappear (disintegrate) before that date. Seeing that I had a small window of opportunity to capture the comet I decided to try my luck last Saturday evening.

Below is an extremely processed (and ugly) image that I got by combining 25 photos (15 seconds each at ISO 3200) using my Skywatcher 80ED scope. The photo just about makes out the distinctive blue-green hue and elongated shape of a comet. It is around magnitude 10, very diffuse and about 147 million km away from us the day this photo was taken.

Comet C/2019 Y4 (ATLAS) on April 18, 2020 – Very faint at about magnitude 10. Imaged with 80ED telescope 25 x 15sec

I pushed the image processing so hard that I was able to pick up faint magnitude 13 galaxies!

On to the next comet!

Telescope: Skywatcher 80ED
Camera: Canon 80D
Image: 25 x 15sec at ISO3200 (6 minutes)

Ending the Year with Betelgeuse

Posted on December 30, 2019 by Benoit Guertin

A few days prior to the holiday break there was news of Betelgeuse dimming to an all-time low, potentially signaling the start of the process that will transform this star into a Supernova. What? Wait a minute… A star in our own galaxy exploding? But that hasn’t been observed since 1604!

Remnant of SN1604 – last galactic nova (NASA)

There are plenty of novas at any point in time, they just happen to be in galaxies far away (cue Star Wars intro). During those few days or weeks of otherworldly explosions these stars become the brightest object in their host galaxies.

SN2018ivc in galaxy NGC 1068 (Credit: Bostroem et al., 2019.)

So if we can see them when they are millions of light years away, what would an exploding star just 700 light years away, like Betelgeuse, look like?

Well if we base ourselves on SN1604 it will be visible to the naked in eye for three weeks, including during daytime. SN1604 was 20,000 light years away, while Betelgeuse is at a fraction of that, so most experts anticipates that it would be as bright as a full Moon.

Now before we go crazy anticipating when Betelgeuse, a red super-giant, will explode, let me present some information to put everything in perspective.

Betelgeuse is a red super-giant of class M1-2 in the constellation Orion, 2nd in brightness just after Rigel. Betelgeuse is one of the largest start we can see when glancing up at the night sky. If Betelgeuse was our Sun, it would engulfed all planets up to Jupiter. Stars of that size aren’t like the nice Smith Ball of fire we imagine our Sun to be. They are more like a loose ball of foam, constantly bubbling and bloating from the incredible heat created in the inner core. If you are starting to think unstable, you are partly right.

Betelgeuse is also a well documented variable star, meaning it periodically varies in brightness.

Recorded Brightness of Betelgeuse Over the Years (credit: AAVSO)

So while it is at an all-time low compared to its known ~425 day cycle, it also has a ~5.9 year cycle, and this episode just happens to be a combination of both lows. So no need to panic… for now.

Betelgeuse will one day end as a type II supernovae, probably not for another 100,000 years. Until then we can all glance up during these cold winter nights at how easily the Orion constellation can be spotted and enjoyed. The three bright stars marking the belt and the hour-glass figure is easy to find. Take a few moments to look at Betelgeuse as on a galactic scale it will be gone tomorrow.

Betelgeuse Red Super Giant in Orion (Benoit Guertin)

Coming this March – Reentry of Chinese Space Station

Posted on January 7, 2018 by Benoit Guertin

Its inevitable, what goes up must come down. On average there is one large piece of equipment that re-enters our atmosphere every week. Some are controlled and planned decommissioning of satellites after their useful life. They are purposely commanded for re-entry and burn-up in the atmosphere to avoid adding debris to our already crowded space orbits or worse, cause a collision with another satellite creating an enormous field of debris. Other objects that re-enter are left to fall on their own such as discarded rocket bodies and old satellite that ceased to operate long ago or malfunctioned and can no longer be controlled.

Tiangong-1 : First Chinese space station launched in 2011

This coming March the 8,500kg (18,700lbs) Tiangong-1 Chinese space station is coming back to Earth. Launched in September 2011 and used for two manned missions, it suffered a malfunction and the Chinese have not been in control of it since 2016. The space station has been in a decaying orbit ever since, and now below the 300km altitude where Earth’s atmosphere is causing the space station to slow down due to aerodynamic drag it will soon make its re-entry.

Delta 2 rocket fuel tank surviving re-entry near Georgetown, TX, on 22 January 1997

Now there is no need to panic. Most of Earth is ocean, and we’ll probably not see anything let alone have a piece of it land in a city. However as this is a fairly large body, there is a good chance not all pieces will burn up and some may make it to the surface.

This isn’t the first time a space station makes a re-entry. The American Skylab at 77 tons re-entered in 1979, and Russian Mir (120 tons) made its re-entry in 2001.
For the Mir re-entry, Taco Bell even got it onto the re-entry buzz by anchoring a large

: Taco Bell target for Mir re-entry (2001)

target off the Australian coast along the planned re-entry track, and should Mir crash into it there would be free tacos for all Americans. The fast food chain even took out an insurance policy just in case it would happen.

In early January 2018, Tiangong-1 is orbiting at an altitude of around 270-290km (to put that into perspective, ISS is at a 400km orbit) and in a 45 deg orbit, hence the re-entry will be within those latitudes. The green area in the map below is where Tiangong-1 could make a re-entry, and also marks where the re-entry could be observed.

Tiangong-1 ground coverage – http://www.aerospace.org

It’s still too early to determine the time and location of potentially crash site, as Earth’s atmosphere is influenced by space weather and swells based on our Sun’s moods, which alters the drag force on the space station. However various space centers and organizations will continue to track the space station the coming weeks to improve the prediction.

You can follow everything at Aerospace.org for up to date information and predictions.

What could the re-entry look like? Below is a video shot by NASA of the Japanese Hayabusa spacecraft during a controlled re-entry on June 13, 2010

Red Dwarf Spaceship Spotting?

Posted on November 21, 2017 by Benoit Guertin

The big news this week is the first recordings and observations of an interstellar object. Of the 750,000 asteroids and comets that have been cataloged up to now, every one of them originate from within our solar system. This object detected by the Pan-STARRS1 telescope and named A/2017 U1 or “Oumuamua”, a Hawaiian word for scout or messenger from the distant past, came from another part of our galaxy. Based on measurements made from multiple ground-based telescopes it is believed to be rather long and of a deep red color . Below is an artist’s rendering of this extra-solar visitor. While a comet would have generated some type of coma or tail travelling near the Sun, no such activity was recorded, hence it’s believed to be an asteroid-type object.

Artist’s impression of the interstellar asteroid `Oumuamua

Credit: ESO/M. Kornmesser

Measurements over multiple nights allowed to establish the trajectory, which clearly shows that it did not originate from the Oort cloud or other asteroid/comet rich fields surrounding the Sun. While the discovery was made only on an October 19 image, its closest approach to the Sun was September 9th.

Diagram showing the trajectory of A/2017 U1 (ESO/K. Meech, et al.)

Now I thing they got it all wrong. What they picked-up was the Red Dwarf mining ship swinging by our neighborhood!

Red Dwarf mining vessel owned by the Jupiter Mining Corporation (BBC)

ESO Press Release

My photo in this week’s SkyNews

Posted on November 20, 2017 by Benoit Guertin

Today I got an e-mail from Gary that a photo of the Big Dipper that I had submitted a few months ago got selected for this week’s column on SkyNews. Couldn’t be happier. I wish all my weeks could start this way.

My photo featured on SkyNews

Astrophotography is a combination of equipment, experience, location/timing and luck. With this photo I just happen to hit everything right and was lucky.

Using the best equipment helps, but for this photo it was the simplest of setup: my very worn Canon Rebel XTi DSLR with a zoom lens set to 17mm F4 mounted on an old steel camera tripod my father used in the 60s. So nothing special, and within everyone’s reach.

OK, for the next part I had experience on my side. It allowed me to pick the right camera settings, but was also lucky as my photo viewing was limited to that small LCD screen on the camera. I had no laptop to fully explore and review the photos and make the necessary adjustments. Even the focus was reviewed through the small camera LCD. That night I only took 4 images with 20 second exposure crossing my fingers that I would have something worthwhile once back home.

And then there is the post-processing on the computer, which is a lot of trial-error. In image processing doing steps A + B will not give you the same results as performing B + A. We all have our “recipes” for what produces good results, but every photo ends up being a unique project. With this one, I knew there was good potential.

Finally there is the location and timing. I was up in cottage country, away from city lights, and a clear sky. However there was a full moon rising, couldn’t wait too long as the sky would start to brighten. A Big Dipper low in the sky next to the trees framed everything very well.

Thanks Gary and SkyNews for selecting my photo. For all the experimentation that I do with the camera, once in a while I get everything right. I’m just happy someone noticed and said “Hey, that’s a great photo we could use.”

Large Asteroid to Pass Near Earth

Posted on April 16, 2017 by Benoit Guertin

On April 19th a considerable sized asteroid will pass about 4.6 lunar distances (1.8 million km) from Earth. While there is no chance of it impacting our planet, this 650m asteroid was only discovered three years ago, and it will be the closest encounter of a large asteroid since asteroid Toutatis in September 2004. The next predicted fly-by of a large asteroid is 2027 with 800m wide 1990 AN10.

The expected magnitude could reach up to 11 during the close approach, hence a decent sized scope will be required, and due to the rapid movement may be hard to locate and track.

Sky chart for asteroid 2014 JO25 covering April 18th to 20th 2017

And as a bonus, comet PanSTARRS (C/2015 ER61) will also make its closest approach to Earth on the 19th, but 10 times farther away as the asteroid. I should be visible with small telescopes or binoculars in the constellation Aquarius in the dawn sky.

Source: NASA/JPL

Comets for 2017 [updated 16-APR-2017]

Posted on December 26, 2016 by Benoit Guertin

Below are some of the comets to keep a watch for in 2017 as they should be observable with small scopes and even binoculars.

45P/Honda-Mrkos-Pajdusakova
Currently observable low in the evening at around magnitude 8 and will continue to brighten to magnitude 7 in January and then fade rapidly, including a approach to within 0.08AU of Earth on February 11th, as well as passing within a few degrees of globular cluster M3 shortly after.
Photo from January 6th.

C/2016 U1 ( NEOWISE )
Currently observable at magnitude 9 and predicted to brighten to magnitude 7 in mid January. Discovered on October 21, 2016. Not visible in the southern hemisphere.

C/2015 V2 ( Johnson )
Faint at magnitude 12, and will continue to brighten until mid 2017, with good chances of observation.

C/2015 ER61 ( PanSTARRS )
Should brighten to magnitude 7 spring of 2017, unfortunately not very visible to the northern latitudes. However it will cross many NGC and Messier objects throughout the first half of the year.

2P/Encke
Expected to brighten to magnitude 6-7 around at the start of March, overall visible for about 45 days. For those in the northern hemisphere, best observations will be the end of February.

41P/Tuttle-Giacobini-Kresak
Expected to brighten to better than magnitude 6 in early April. A good opportunity for wide-field photo as it passes 5° of M92 at the end of April.
Photo from April 13th.

References:
Comet Chasing
Seiichi Yoshida’s Bright Comet Listing (and future listing)
Paper by the British Astronomical Association

JunoCam – Revealing Jupiter from New Angles

Posted on December 20, 2016 by Benoit Guertin

JunoCam onboard the Juno spacecraft is providing us with some great pictures of the Jupiter cloud top, but from the rarely seen polar angle. Pretty much all spacecrafts that have visited Jupiter did so with a fly by along the equatorial plane, which is also the same plane we observe Jupiter here on Earth. However with the Juno spacecraft, we now have a chance to enter into a polar orbit and take pictures of the polar regions.

Part of the reason behind JunoCam is to get the amateur astronomer community participating in selecting what parts of Jupiter the camera should be snapping pictures, and of processing the raw images. The image below was captured by JunoCam during Juno’s 3rd swing around Jupiter at a distance of about 37,000km. The south polar region is on the left.

Jupiter - December 11, 2016 JunoCam - Juno Spacecraft

NASA, JPL-Caltech, SwRI, MSSS; Processing: Damian Peach

The above was the PeriJove3 encounter (3rd pass), and voting on the next PeriJove4 will take place between January 19th and 23rd 2017. This is where the community can propose and vote for Points of Interest to photograph with JunoCam during the rather quick (2 hours) close pass with Juno. You can even submit images of Jupiter taken with your equipment to help plan the Points of Interest.

Ref: JunoMission