Category Archives: Observing


Orbital mechanics is a very interesting topic.

Usually when you see an orbital track displayed on your computer you see a nice sine-wave pattern.

Take the International Space Station for example or perhaps the newly launched Sentinel-3B.

Then we have geostationary satellites like GOES-17, oh yes it is orbiting.

Have a look at the seemingly odd orbit of the recently launched TESS.

Thanks to N2YO for those great links and check that site out – great stuff!

Scott Manely has a good video out: T”he Most Confusing Things About Spacecraft Orbits”

May Skies

Hubble’s Tonight’s Sky May 2018

If you have good skies you should be able to catch the peak of the Eta Aquarids. The best time to catch these bits of debris from Halley’s Comet is 06 May in the hours before daylight.

The Morning Sky

If you get a chance to look at the sky before daylight you will be treated to (R to L): the Moon, Jupiter, Saturn, and Mars all lined up across the sky. Provided the moonlight does not over whelm Saturn and Mars they all will be visible at the same time.

Jupiter in particular will be very bright so so worries there. You should also be able to see a few of the giant planet’s moons.

The above graphic is from Stellarium showing the line-up before sun rise (click to see a larger version).

Hopefully you won’t be clouded in, I think I am going to be.

Also apparently there is some ridiculous claims this line up is going to cause an increase in volcanism and earthquakes. In a word: NO. That’s just plain crazy.

What’s Up for April

Ahhh, April the temperatures are moderating and it is becoming more comfortable to be outside. Usually a lot of moisture in the air but still good viewing.

I can’t even get into the N2YO site at times – busy. Tiangong is very close to coming in, predictions are 01 April (tomorrow) at 16:45, I will update this later as the estimates become more clear.

Oh and the internet problems are still going on; although there is a work order in, I don’t expect resolution until Monday. I did have an epiphany of sorts and am connecting through my phone and it seems to be working.

Tiangong-1 Coming Down

The Chinese space station Tiangong-1 is losing altitude at an ever increasing rate as the station and the Earth feel that mutual attraction. Of course Earth is going to win.

Right now the station is at about 221 km and losing about 0.20 km per orbit.  Yesterday that loss per orbit was about 0.13 km.

Currently the estimate is 03 April plus or minus a week.  Looking at ESA’s estimate above  the orbit is going to continue the increase in downward motion until  Tiangong-1 feels the increasing density of our atmosphere and begins to slow down appreciably.  When that happens we reach a tipping point of sorts and the spacecraft or what is left of it (yes there will be pieces) will pitch steeply and eventually hit the Earth.

Where will that tipping point be?  That’s the big question.   We are about to find out the answer.

You can follow orbital decay on  I think we are just days away.


It’s the Messier Marathon

Ever just gone outside with a telescope and took a look at all the different Messier objects viewable? Give it a try, even a decent pair of binoculars can be used in some cases. Pretty fun.

I might get to go out later tonight being I should have clear skies for a change. The weather has not be very co-operative in that regard lately.

NASA – In mid-March, skywatchers in the northern hemisphere can try to observe all 110 objects from the Messier catalog in one night. To celebrate the Messier Marathon, NASA’s Hubble Space Telescope is releasing 12 new images to add to its extensive collection of Messier objects observed by Hubble.

View Hubble’s full Messier catalog (excellent!).

View the original Messier catalog at SEDS (I love SEDS!)

See Mercury and Venus

You might be able to catch a look at Mercury and Venus together just after sunset tonight.

Mercury and Venus will only be about a degree and a half apart when they appear together this evening. The image shows about where to look, basically note where the sun sets and let that be your guide and be sure the sun HAS SET if you plan on using binoculars (like I will) for the observation, you can severely damage your eyes if you accidentally look at the sun!

Now all I need is clear skies!

The image is not my backyard sadly, it is the standard background for Stellarium.

The Diamond Ring

ESA brings us this wonderful image of a solar diamond ring for Valentine’s Day. This one is from the Solar Eclipse of 21 August 2017 photographed by during an eclipse expedition to the USA as part of ESA’s CESAR (Cooperation through Education in Science and Astronomy Research) educational initiative. CESAR engages students in the wonders of science and technology – astronomy in particular.

As it happens there will be a solar eclipse tomorrow. This eclipse will be visible to most of Antarctica and southern regions of Chile and Argentina, I know we have readers from the very south of Argentina so here is a map showing when and approximately what you will see.

The map and more information from Wikipedia here.