Category Archives: Astronomy

Blog posts about astronomy

Moons – not Earth’s, but Jupiter’s … proudly presenting: the Galileans

Taking good pictures of astronomical objects is quite challenging. Especially if you don’t own highly advanced (and very expensive) equipment.

For quite a long time I thought that the only celestial object which is in my reach to take good images of, was the Moon. Here is one of the better Moon images that I have taken:

Full Moon photo (taken 2011-03-19, ca. 20:30 CET), may be one of my best yet

Over time, both my skills and my equipments advanced a bit. And I managed to take pictures of almost all the planets out to Saturn (not counting planet pictures taken through web-based observatories like GRaS). There are:

Photo of Mercury rising over nearby house (taken today, January 18)

Venus (probably my best planet picture so far):
Photo of Venus, taken through telescope (image is mirrored)

Mars (the red dot on the left; certainly my worst planet picture so far, but for the purpose of completeness …):
Mars next to the Moon

… and Saturn:
Photo of Saturn, taken 2011-04-02 ~22:15 CEST (2 days before opposition)

I didn’t have a picture of Jupiter yet, but that is rather coincidental, as Jupiter is the brightest planet just after Venus and certainly an easier target than Mercury, Mars or Saturn.

Today I not only completed this collection by adding a picture of Jupiter, but also passed another milestone. My first pictures showing Natural satellites (colloquially known as moons) other than Earth’s Moon. Here is Jupiter with (from left to right) Io, Europa and Ganymede:

Jupiter with Io, Europa and Ganymede

To complete the Galilean Family, I took another one showing Io and Callisto (the little dot quite some distance outside):

Jupiter with Io and Callisto

Last but not least, this is what they looked like in Stellarium (Stellarium is what actually allows me to tell which dot is which moon).

Jupiter with Io and Callisto

Neptune, Vesta, ISS, Endeavour space shuttle, and a mag. -8 Iridium Flare

What makes a great observation night? You get to see a lot of things that you don’t get to see every day.

This night (morning of May 31, 2011) was good weather and good sight. Basically I put out the binoculars because I went to see Neptune and asteroid 4 Vesta again, which I already observed yesterday.

Neptune isn’t spectacular, it looks just like an arbitrary star and if you didn’t know its exact position, you would never recognize that it is Neptune. I use primarily Stellarium which has always been reliable and serves the purpose of letting me know where to find a particular object very well. So it also left no doubt that what I was looking at was indeed Neptune.

The same was true for Vesta yesterday. I knew its position based on Stellarium, and it was particularly easy because it was located very near to star ι Cap. (Iota Capricorni), which is easy to find. And since it was where I assumed it to be, there was no reasonable doubt left that I was looking at anything different.

But the great thing especially about observing an asteroid is when you have a chance to look for it on 2 consecutive days, especially if it is that near to a significant star. One can see how it changed its location and that’s real evidence that it is not just an arbitrary star (even though it looks just like one).

Here is Vesta’s position of yesterday at 3am local time:

Location of Vesta 2011-05-30 03:00

And here is Vesta’s position today:

Location of Vesta 2011-05-31 03:00

That’s just what I’ve seen. Take this lesson: while what you are seeing may seem boring, to know what you are looking at can be very fascinating. Even though a dot in the sky may look just like the thousands other dots, it can be something very different … and to find and identify (and eventually track) them is a rewarding thing to do (in my opinion).

But there was more this night. It’s always a good idea to take a look at to watch out for special observation opportunities. And this night delivered HUGE opportunities.

First thing was a Magnitude -8 Iridium Flare at 3.17am. Iridium Flares are pretty common and there is one (or more) to see almost every night. But such with mag. -8 – which is almost as bright as an Iridium Flare can get (about 17 times brighter than Venus at its brightest) – don’t show up that frequently, maybe once in a week or two. And more often than not, either the weather isn’t good or you just forget to check them out. So if there actually is such a bright one during a night that you do observing (and don’t forget to look them up at Heavens Above), you are quite lucky. And this was quite a mighty one, one of the best I’ve seen.

But the real jewels were yet to come.

The STS-134 mission is nearing its end and the space shuttle Endeavour undocked from the ISS just yesterday. This is even more significant as the space shuttle program is coming to an end, and it’s likely the last opportunity ever to see what I had the chance to see tonight (saying this with a tear in one eye, but also with a little smile as it’s time for new challenges beyond low Earth orbit).

Heavens Above showed me that the ISS was about to pass at ~3.34am this night (only 17 minutes after the Iridium Flare). When a space shuttle is on its way back to Earth, you can assume it to show up just a few seconds ahead of the ISS. There was something else that Heavens Above showed me which was very interesting. The path of the ISS led just below the very bright and significant star Deneb Algedi (δ Cap. or Delta Capricorni):

ISS path 2011-05-31 03:34
Deneb Algedi is the star in the center of the chart, right next to the 03:34:30 marker (which is the time the ISS passed it)

So I knew exactly where to look and where to point my binoculars too, which I could prepare even before the Endeavour/ISS pair showed up. I only had to wait until I could see them with the naked eye (very easy since they are both very bright), go to my binoculars, wait until they show up below Deneb Algedi, and follow their ways. An easy job even for a moderately equipped and modestly experienced amateur astronomer like me, but very rewarding.

But the really big deal about this all is that you a) neither need a big budget and b) nor need many years of experience to do just what I am doing. My Omegon Nightstar 25×100 binoculars cost € 299.00. Other than that you need only a PC and an internet connection, which you are likely to have already, if you are reading this. And last but not least, a little bit of passion for what’s going on above us.

Videos of Moon and Saturn

Today I took videos of both the (near full) Moon and the (little past opposition) Saturn through my telescope.

First the Moon:

This one was captured with my old Kodak EasyShare C813. A camera which I bought 3 years ago for $120.

And here is Saturn:

The camera that I used on Saturn is my new Casio EX-H30. This one is capable of producing much brighter pictures, which is very helpful for Saturn, but not for the Moon (when I tried it on the Moon I got just a big bright spot, but hardly any surface features recognizable).

The weird movements of Saturn are partially the Earth’s rotation (when Saturn moves from right top to left bottom), and when I turn around on the scope. I also tried different zoom levels. However, the more I zoomed in, the more Saturn got blurred.

Saturn’s prime time for this year is already over, but the next candidate is on his way. In 2-3 months, Jupiter will begin to be in a position where I will be able to take pictures and videos of it. I’m excited to find out how much detail (and hopefully all of the Galilean Moons) I will be able to capture.

Don’t blindly rely on your sources when observing

Today was not a perfectly clear night, but good enough for some observations. Recently I found that the asteroid 6 Hebe is approaching opposition and therefor makes a good observation target, so I tried my luck finding it.

The source which I used was The position where 6 Hebe was specified to be was RA 0h 30.6m, DE -14° 25′ (J2000). I fired up Stellarium (of all astronomical software that I know, Stellarium resembles what one can really see through binoculars or scopes the best), looked up this position, tried to find a path how to find this position (the star Diphda was a great starting point, it was easy to hop to 6 Hebe’s position from there), and searched this spot with my binoculars. Thanks to Diphda it didn’t take me long to find it.

But whoops, where I expected to find 6 Hebe, there was nothing. Instead, just a little bit further to the left there was an object just as bright as 6 Hebe was supposed to be, and according to Stellarium, there was no star of this brightness at this place. So was this 6 Hebe? I pretty much thought this has to be 6 Hebe, but it was basically just a guess, I had no evidence to support this.

What could I do to know for sure (or at least as sure as I can be)? I remembered NASA’s HORIZONS Web-Interface which allows to track basically every solar system object which is known. There I found that its supposed position is RA 0h 31.47, DE -14° 21′ 11.8″ (J2000). I checked this spot in Stellarium, and voilà – that was exactly where I saw the object which I thought must be 6 Hebe. Evidence enough to confirm.

See this Stellarium screenshot to see the discrepancy:

On the right end of the blue bar is the spot where I expected 6 Hebe to be, on the left is the spot where I actually found it. So the discrepancy is around 20-25 arc minutes, or ~ 2/3 of the diameter of the Moon.

My web-based observatory images (Pluto, Jupiter, Saturn, Uranus, Orion Nebula)

There are some web-based observatories which allow normal people like you and I to rent a telescope somewhere on this planet for a short period of time and quite reasonable amount of money, to take some pictures. Not only is the available equipment superior to the scopes that many people have at home (at least to me this applies for sure), these scopes are most often located on very favorable places up on a mountain, far from city lights and likely good weather conditions. One of these web-based observatories is Global-Rent-a-Scope or short GRaS, where I made my first steps.

They have telescopes in Australia (which adds another advantage: you can take pictures of the Southern Sky, even if you live in fairly high Northern Latitudes; this is also true the other way around of course), Spain (this one is relatively new) and the one which I’ve been using for my tests so far, Mayhill, New Mexico at 32° 54′ 3.60″ N, 105° 31′ 26.41″ W.

My latest achievement was to take 2 images of dwarf planet Pluto, the first on August 23, 2010 at 05:25 UTC and the second on August 27, 2010 at 03:11 UTC. I cut the images to show the same area of the sky, so you can open the images in new browser tabs, switch back and forth between them, and I think you should be able to spot the “pixel” which is Pluto that has changed its location significantly, while the surrounding stars stay at the same positions:

pluto-gras-20100823052500  pluto-gras-20100827031100

If you didn’t manage to spot Pluto, here is the same sky area with Stellarium (an awesome piece of astronomical software … Open Source and available for all the major platforms):

pluto-stellarium-20100823052500  pluto-stellarium-20100827031100

You can also view the original Pluto image of August 23 and the original Pluto image of August 27. The unedited Stellarium screenshots are also available, for August 23 and August 27.

This is something which I could never do with the binoculars and the telescope which I have at home. Pluto, with a magnitude of around 14, is beyond my capabilities (whether it's limited by my technical capabilities or just my skills is yet to be found out).

Here are some more images which I have taken through scopes provided by GRaS (all in Mayhill, NM).

Orion nebula on March 29, 2010 at 4:06 UTC

orion_nebula-gras-201003290406  orion_nebula-stellarium-201003290406

Saturn on March 29, 2010 at 8:52 UTC with Saturnian moons Titan, Enceladus, Dione and Rhea visible

saturn-gras-2-201003290852  saturn-stellarium-201003290852

Jupiter on August 20, 2010 at 5:09 UTC with Jovian moons Callisto, Io, Ganymede and Europa visible

jupiter-gras-201008200509  jupiter-stellarium-201008200509

Uranus on August 20, 2010 at 6:35 UTC with Uranian moons Titania, Umbriel and Oberon visible

uranus-gras-201008200635  uranus-stellarium-201008200635

Dolphins in the Sky

A cloudless night sky is truly amazing, but have you expected to see a dolphin in the sky?

What you see here is the Summer Triangle (all Southern hemisphere residents, please apologize), but did you notice the group of stars left to Altair?

This group of stars is the constellation named “Delphinus” (as can be guessed easily, it’s the Latin word for Dolphin), which can be observed best at almost all latitudes around late spring and early summer (in fact it can be seen almost around the year, but that’s the time of the year that you find this constellation highest in the sky).

So what is this all about? You may have heard that 2009 is the International Year of Astronomy. So there is astronomy, there is a dolphin and we all know that a dolphin (named Sakila) is the mascot of MySQL. Can that be brought together? Sure thing!

Hereby I declare that my contribution to the International Year of Astronomy shall be a series of articles that combine the fun of astronomy with the fun of MySQL. I am by no means a professional astronomer, it is only a little more than a year that I intensified my interest in astronomy (which had been dozing inside me all my life). What ignited the fire was that I stumbled over some great software, and I’d like to especially mention Celestia and Stellarium (Stellarium being what created the 2 images above). Now prepare for the good news: they are free (not only gratis, but Open Source as well) and available for Windows, MacOS and Linux (chances are good that your distribution includes them already). By installing them and exploring all their features (don’t forget to download the manuals! … they have a huge amount of functionality almost too much to discover all on your own) you are making the first big step into this fascinating world!

You don’t need much to do astronomy. A PC (or Mac), some software, an Internet connection (have I mentioned Wikipedia yet?) and a pair of binoculars will do. No more do I have. And chances are good that you have them as well. If you live in a big town or city, you may want to find an observation spot a bit outside of the urban area. You probably won’t need to drive hundreds of kilometers or miles though. I live in a small town (with plenty of street lights nearby) and can still spot celestial objects and features such as the Saturnian rings, Saturn’s moon Titan, the Galilean moons, all planets, some asteroids and dwarf planets such as Ceres, Vesta, Juno, Pallas or Nebulas, Star Clusters and Galaxies only with binoculars, all from my backyard. Don’t let more advanced astronomers who spend thousands of bucks for their hobby scare you. You need much less to get started, but if you like you can of course expand your budget without boundaries.

Watching the sky is only part of the fun. Many things are often observed but never much thought about. For example, have you ever wondered why in winter the moon is much higher in the sky than in summer? By getting involved in astronomy, many things like these become crystal clear and help you to get a deeper comprehension of the incomprehensible (imagine billions of galaxies each containing billions of stars spread across billions of light years). But there are even more interesting discoveries awaiting you. Did you know that you can calculate the position of any celestial object based on its coordinates for exactly your location for any time? Sure you know that it’s possible, but did you think that it’s fairly easy if you have some hints available? Much of astronomy is about data and mathematics and where data comes into play, there is also a playground for MySQL. Here is where the circle closes, but stay tuned for more exciting articles to come.