Sunday 17 February 2013

Movie: Why the Russian Super Meteor was not related to asteroid 2012 DA14 - explained with the help of an orange

Dutch note: een Nederlandstalige versie van deze video is eerder hier gepost.

Added Note: the reality is slightly more complex than I present it in the video, as objects that graze just past the earth limb are slightly deflected by earth gravitation and can end up on (low) northern latitudes. Latitude 55 N is out of the question though, and as this added detail might make the story too complex I decided to leave it out.

Filmpje: waarom de supermeteoor boven Rusland niets te maken heeft met planetoide 2012 DA14 - uitgelegd met behulp van een sinaasappel

Note to English readers: an English version of the Dutch language video below is posted in a separate post here.

Toegevoegde noot: Het is in werkelijkheid iĆ©ts complexer dan ik hier doe voorkomen, omdat een langs de rand van de aarde scherend object door de aardse zwaartekracht iets wordt afgebogen en er zo dus wel fragmenten op (lage) noordelijke breedtegraden terecht kunnen komen. Maar 55 Noord is echt buiten de mogelijkheid, en ik heb dit er daarom maar uit gelaten omdat het anders misschien te complex werd.

Saturday 16 February 2013

On national television about 2012 DA14 and the Russian super meteor

Yesterday was a crazy day, that started as soon as I woke up, opened my e-mail and saw the messages about the Russian super meteor event. Next, my telephone was red-hot from phone calls, and my e-mail and twitter flowed over from private messages by persons and news media seeking information.

I got two TV crews visiting me, plus a radio reporter, and I turned down a couple of other media requests.

At 22:00 (10 pm) Dutch time I was Live in the broadcast of 'Nieuwsuur', a prominent news program on Dutch national television channel Nederland 2. Through a satellite connection, I was interviewed by the news anchors in the studio, while I was standing next to my telescope in my courtyard. The topics were both the Russian event and the 2012 DA14 asteroid fly-by.

 TV van in the street

screenshots from the live Nieuwsuur broadcast

The video (in Dutch) can be seen here. It starts directly with my item.

I was also interviewed by a regional TV and radio station, TV West. The video of that TV appearance (again in Dutch of course) can be viewed here [link fixed: it initially erroneously linked to the Nieuwsuur item]: my item starts at 3:40 in the video.

TV West filming my explanation

Screenshots from the TV West broadcast

Radio reporter interviewing me

Friday 15 February 2013

[updated] HUGE fireball over Russia this morning! Not 2012 DA14 related.

A HUGE fireball has appeared over Chelyabinsk, Russia, this morning. And with HUGE I mean: HUGE. Apparent brightness rivalling the sun, and very strong sonic booms leading to glass damage and people being wounded by flying glass. This must have been a seizable object entering the atmosphere.

Phil Plait, the "Bad Astronomer" has very good coverage including some amazing videos here, so I will refer to him for imagery and the general story (apart from two I include below: one showing the meteor, the other one the arrival of the shock wave).

Below, I will briefly explain why this fireball cannot have been a fragment of 2012 DA14, the ~50 meter wide asteroid that will pass very close to earth coming evening (Feb 15, 2013).

First of all (and Phil Plait points this out as well), the fireball in Russia came from the wrong direction. Several of the videos show it appearing in the east near the rising sun, coming from a N-NE direction. That is the wrong direction: fragments of 2012 DA14 are on a south-north trajectory.

What is even more important: fragments of 2012 DA14 could never enter the atmosphere as far north as latitude 55 N (Chelyabinsk). Fragments in orbits similar to that of the asteroid, have a theoretical geocentric radiant at declination -81 degrees, i.e. almost at the southern celestial pole. They hence approach earth from due south. This means that the northern hemisphere is out of reach of these fragments: the northern hemisphere represents (as seen from these approaching fragments) the "far side" of the earth.

[video added 18/02/2013]

[added 18/02/2013] In the above video I explain this more visually, with the help of an orange. In reality, it is slightly more complicated than I present it in the video, as objects grazing the earth's limb are actually slightly attracted by earths gravity and can end up a little bit over the line between "front" and "far" side of the earth. Ending up at latitude 55 N is nevertheless out of the question.

The funny thing is that the latitude of Chelyabinsk and the approach direction of 2012 DA14 (and fragments in a swarm around it) are well established facts, even if the trajectory of the Russian fireball is less so at the moment. So it is quite nice that from the encounter geometry with the 2012 DA14 orbit and the latitude of the Russian meteor alone, we can actualy already exclude a connection between the two with a quite strong certainty.

Fragments in 2012 DA14-like orbits and the Russian fireball itself are also too fast to be temporarily captured in earth-orbit, so that is no explanation either.

This fireball was not man-made space junk either. Besides coming from an unlikely direction, it is too fast and much too bright for that.

These are amazing times: the reentry of a Russian rocket stage seen from NW Europe on the evening of the 13th, then this hughe meteoric fireball over Russia this morning, and a close pass of asteroid 2012 DA14 tonight. Wow!

Wednesday 13 February 2013

Fireball over NW Europe of the evening of 13 February 2013: Re-entry of a Soyuz r/b

Reports are pouring in of a very long duration, bright fireball near 22:15 CET (21:15 GMT) seen from Belgium, the Netherlands and Germany. Reports indicate 30-40 seconds visibility, and an "explosion" halfway, and some reports indicate sonic booms.

This fireball was with a high degree of certainty the re-entry of a Russian Soyuz 3rd stage, #39083 (2013-007B), the 3rd stage from the Soyuz that launched the Progress cargoship Progress-M 18M towards the ISS on February 11th.

USSTRATCOM issued a TIP message indicating decay at 21:15 +/- 1 m UTC near 49N, 13 E.

Below is a quick map (made using Orbitron) of the trajectory and approximate position of the re-entry.
click map to enlarge

Time, general description and reentry data all fit quite well.

Monday 4 February 2013

OT - a new telescope and imaging the moon

Since 18 November I have done little in terms of satellite observing, for reasons outlined below. Therefore, a post that is slightly OT - but still astronomical in topic.

Generally bad weather over the past two months - lots of clouds, and even snow mid January - is one primary reason for my inactivity on the satellite observing front. Another is that mid-winter isn't the best period of the year at 52 N due to the "winter blackout" of many objects in LEO. Third, I am occupied these months by a few other things, including the "Super Secret Project" which I obviously can't talk about yet (but is very exciting).

The generally bad weather over December and January meant that I could not yet fully use my new toy. Near the start of December, I obtained myself a new telescope, partly with the proceeds of the Van der Bilt Prize. The telescope is a Celestron C6 Schmidt-Cassegrain (15 cm f=1500) on an SGT Advanced Goto equatorial mount. Here is me showing it off:

For quite a while I wanted a slightly bigger and optically better telescope than the simple Meade ETX-70 and small and very old 4.5" Newton I already had, yet found it just too expensive. The extra money from the Van der Bilt Prize meant it became just feasible for me to finally buy something better.

Since I have no option for a permanent setup and live small, it could not be a very large and heavy setup, so I choose this 6" Schmidt-Cassegrain (the mount is heavier than I expected though). Even though I have not been able to use it extensively yet, I so far like it very much!

Twice in January I could test it out on the moon. Here are some images shot on January 22nd. First, an old-fashioned single shot photograph of the moon disc (C6 prime focus with F6.3 flattener/reducer, and Canon EOS 60D, 1/160s at ISO 200). Seeing was quite mediocre, the air was not quite steady (the image was "wavy" as if reflected on the surface of water):

click image to enlarge

I also used the HD movie capabilities of my Canon EOS 60D to shoot a few short movies, and then stack frames from these movies using Registax. This results in a dramatic increase in detail. The images below are each the result of stacking 200 movie frames, selected out of movie sequences of ~550 frames each, and are my first ever experiments with Registax (which is quite complex to use for a novice):

click images to enlarge

Southern highlands: Clavius and Tycho

Northern part of Mare Imbrium with Sinus Iridium,
Plato and Vallis Alpes

Mare Humorum, Mare Nubium, with Gassendi
and Bullialdus

One of the intended primary goals for this telescope will be to observe asteroid occultations, with the WATEC 902H video camera plus GPS time inserter attached to it.Satellites are not the primary goal of this new instrument.