Rosetta spacecraft’s last few days

Posted on September 21, 2016 by Benoit Guertin

After over 12 years Rosetta will be decommissioned by sending it down to impact with comet 67P/C-G. This fate was decided as the comet is moving away from the sun, beyond the orbit of Jupiter and the solar panels will not generate enough power to keep the spacecraft operational. Even “hibernation” is not a possibility as heaters are still required to keep the critical systems idling. Hence mission control will send commands in the next few days such that on September 29th a series of maneuvers will send it on a impact trajectory with the comet. As the comet’s gravity is rather weak (1/10,000 of Earth’s) it will most likely not be a fatal impact. However the Rosetta will be instructed to shutdown upon contact with the surface in order not to “pollute” the deep space communication network with spurious and uncommanded signals. This is expected to happen on September 30th 10:40 GMT.

So where is comet 67P/C-G? Travelling towards the orbit of Jupiter, in constellation Virgo, opposite to the sun from Earth’s perspective. Normally an event like this would be timed to be observable at night from Earth such that telescopes can gather scientific data. But at apparent magnitude 20 (to compare, Pluto has a mean apparent magnitude of 15) it will be very difficult to observe. And the impact is not expected to generate a large plume of dust. Therefore it will be up to Rosetta to record and beam back to Earth as much data during the descent before shutting down for good.

Rosetta and comet 67P/C-G position on September 30th

Reference: ESA

Dark Nebula – Barnard 142 and 143

Image

In my previous post I captured a hint dark nebula Barnard 142 and 143. But as the lens drifted out of focus, I could only use a few frames (14 out of 60). At the next clear sky I aimed Altair in the constellation Aquila with the goal to capture a good 60 frames in-focus to once again capture Barnard 142 and 143.

Dark Nebula Barnard 142 and 143 near Altair (Aquila)

The entire image scaled 40% (the above is a crop) is available here.

Canon XTi
50mm F3.2 ISO800
59 x 30sec (29.5 minutes of integration)

Wide Angle on Constellation Sagitta (Messier 71 and Messier 27)

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The fall is a great time for wide-angle photography of the night sky. The Milky Way passes overhead which provides a chance to capture some dark nebula. Unfortunately after I had everything setup the 50mm Canon lens drifted out of focus; I only got about 2-3 frames with decent focus. By frame 14 of 60, it was too out of focus to even register (align) with software. When set to manual focus that lens is way too loose.

But I managed to capture a hint of my first dark nebula at the bottom half of the image. Those immense molecular clouds that block out the background stars. In the following millions of years, these clouds will collapse to create start nurseries and new solar systems.

Messier 71 (Globular Cluster) and Messier 27 (Planetary Nebula) near constellation Sagitta

Globular cluster Messier 71 and planetary nebula Messier 27 are identified in my image around the constellation Sagitta. I’m surprised at how “bright” and blue that nebula turned out.

Photo Details:
Canon XTi (ISO 800)
Canon 50mm F3.2
14 x 30 sec

2016 Harvest Moon

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A Full Moon near the autumn equinox? Well that’s a Harvest Moon. While the Moon over the horizon can look rather large, there’s some disagreement whether the 2016 Harvest Moon should also be a Super Moon. I’ll let them sort it out while I snap a few pictures…

2016 Harvest Moon – Benoit Guertin

Photo details:
Combined a short and long exposure with Canon XTi
85mm F5.6 1/250sec (ISO200)
61mm F5.6 0.5sec (ISO400)

Autumn – Darker Skies and No Mosquitos

Posted on September 16, 2016 by Benoit Guertin

I hadn’t taken the telescope out since April. With other projects and hobbies I just didn’t bother setting up the equipment. But a few nights ago looking at a dark blue evening sky I noticed a nice crescent Moon and a triangular star formation over the horizon. The kids weren’t in bed yet so I grabbed my gear and made a quick set-up for observation with the 80ED telescope.

After an observation of the Moon, spending time examining the lights and shadows across the lunar craters and valleys I looked at the triangular star formation and suspected that at least one was a planet. Slewed the telescope over and discovered Mars. Tried different eye pieces and settled for an Orion Edge-On 9mm planetary with Televue 2x Barlow.

With the kids off to bed I changed the set-up for webcam imaging before Mars could dip below the horizon. Follow up processing that evening wasn’t very rewarding. Mars is some distance with Earth therefore appeared rather small compared with other times I pointed the telescope and with the heavy atmospheric turbulence imaging at such a low altitude it blurred the scant details I could have captured.

But that evening I broke the ice and got the gear out. And since I’ve been enjoying the night sky when weather permits. With the galactic plane crossing the sky it’s a great time for wide angle shots. It’s also much faster to set-up and more forgiving to an incorrect polar alignment. I got three photo sessions to analyze and hope to have some good shots to show in the next few days.

Autumn, with cooler nights, dark skies and no mosquitos it’s prime time to enjoy the night sky.