Mercury transit - We, the Earth, the Sun, and the planets between us

Imagine that you are waiting in your car for someone, and suddenly a fly walks over the front window. You see the fly, but also a building in the background. It seems like a giant fly that is walking over this building with doors and windows. You imagine that? We could call this a 'fly transit'. Now imagine that the front window is 5 meters away from you. You still see the fly walking over the building but it looks pretty small.
The first situation symbolizes the Venus transit, and the second the Mercury transit because Venus is much closer to Earth than Mercury. The big difference is that these planets do not walk over a window. They just seem to hang in space and turn around the Sun. They have a little higher velocity, but much shorter paths around the Sun (orbits). This is why they turn in fewer days around the Sun, and we can see them moving across the Sun from time to time. Wow! Imagine Earth, Venus and the Sun 'hanging' in space and turning around each other. The gravity of the Sun is the only thing preventing us from floating away! These transits are a beautiful and visible proof that we, and other planets, turn around the Sun.


Mercury transit 2016 (May 9)
The big spot is a sunspot and stays where it is. The second -very small- dot is Mercury and moves between these three photos that I took during the several hours of the transit from middle left to lower right. Mercury transits occur quite often (13-14 times a century), but due to different angle of the orbit path, it can also pass the earth without moving between us and the sun (higher or lower). The next transits are in 2019 and 2032. Mercury moves with about 50 km/s around the sun in 88 Days (Earth: 30 km/s in 365 days). It is about 60 million km from the Sun (but varying because of an elliptic path) and about 77 million km from Earth . It is also quite small, roughly 5000 km in diameter compared to Earth with 13000 km.


Venus transit 2004 (June 8)
I took this series with my analog equipment in 2004. Venus appears much bigger than Mercury, just like the fly on the window direct in front of you. I was lucky to observe it so nicely! The 2012 Venus transit was badly visible due to clouds and for the next one we have to wait until 2117 and 2125. Venus transits occur in pairs with 8 years distance, because 13 Venus turns around the Sun is almost exactly 8 Earth turns. 8 Years later, they miss each other because Venus is slightly too fast and orbit tracks have a different angle. In the last picture the 'black drop effect' can be seen: Venus and the Sun visually merge together, instead of two circles perfectly laying on top of each other. This effect was long thought to be linked to Venus' atmosphere, but in 2004 so many picture were be taken around the world that this effect is now thought to be caused by irregularities in the earth's atmosphere and by lower quality optics. Remember that the previous transits were in 1874 and in 1882 and the first few picture were taken! Without knowing, one of the photographers back than, Jules Janssen, wrote history by making the first 'movie'. In 1874 he made a series of Venus transit photos on a wheel, just like the first stop-motion pictures with moving animals made by Eadweard Muybridge in 1878. Notice that they were both scientists trying to documents something very accurately.
Venus moves with about 35 km/s around the sun in 225 Days (Earth: 30 km/s in 365 days). It is about 108 million km from the Sun and about 38 million km from Earth (closest distance, at transit). It is just a little smaller than Earth, roughly 12000 km in diameter (Earth: 13000). For who wants to know: Mercury and Venus can transit the sun at the same time, but this happens not so often, the next time is in the year 69163.

Science and transits
The early observations of Venus transits in 1639, 1761, 1769,1874 and 1882 were used to estimate the distance between Earth and Venus and to the Sun (by solar parallax). If you observe the transit from the northern hemisphere and the southern hemisphere (with a known distance between these points), both transits appear slightly moved up and down to each other on the sun, but measuring this vertical shift appeared to be too inaccurate. The following step was to measure the exact time between start and end of the transits, which is shorter when the transit is lower on the sun. This served a more accurate estimation of the distance between both paths. However, the start and end time were still inaccurate because of the 'black drop effect' in the observation.
The Venus transit of 2012 was used to observe how light properties change when a planet moves in front of the sun. This data is useful to improve the search for exoplanets. Exoplanets are mainly found by looking at stars and changes in the light of stars ("a big planet now moves in front of the star").




Viewing
There are only two safe ways to observe this phenomenon yourself; with approved eclipse glasses directly or by projection on a cardboard. Everything else can damage your eyes! Don 't look into the Sun directly! Sunglasses and welding masks are not safe, neither are the combination of eclipse glasses and binoculars.

Photography
For the pictures of Mercury I used my Canon EOS 7D, a Canon EF 75-300 (1:4-5.6 III) Zoom lens and a Kenko Teleplus 1.4x converter, making 420 mm in total. I used cheap Lumifol foil in two layers to darken the sun. This is a kind of reflecting foil which has microscopic holes in it, reducing the light substantially. This foil is not safe for viewing, since it has no additional layer reflecting UV and IR waves. So I never used the viewfinder for viewing during, but used the locked up mirror instead. The result is, despite tripod and locked up mirror, not perfect. At the same time still satisfying.
NASA can do better, of course
https://www.youtube.com/watch?v=AhWMOkrzKzs

Verbessern von Bienenhotels und Standorte

Warum funktioniert mein Bienenhotel nicht?

Diese Frage kommt oft, und letztes Jahr habe ich die wichtigsten Tipps zur Verbesserung von Bienenhotels auf einem A4 zusammengefasst (pdf) können.

Verschiedene Röhrchen
Bambus ist für mich die Nummer 1; robust, viele Jahre haltbar und bei den Wildbienen sehr beliebt. Der Nachteil ist aber das man immer wieder nach der richtige Größe sucht (Lochgröße 3-9 mm), und das sägen per Hand mühsam ist. Tipp beim sägen: Rundum fast durchsägen und dann brechen. Das verhindert das an eine Seite Faden/spitzen entstehen.
Schilf wird häufig eingesetzt weil er einige Vorteile hat: Es gibt immer welche geeignete Lochgrößen und man bekommt mit wenig mühe viel Masse im Bienenhotel. Wichtig ist aber das der Schnitt sauber ist und der Schilf nicht einreißt und zerdrückt wird beim sägen, was man eigentlich nur mit eine sehr scharfe elektrische Säge hinbekommen kann. Auch verwittert Schilf schneller und soll nach 3-4 Jahre ausgetauscht werden.
Japanische Staudenknöterich und Wilde Karde sind sehr leicht in der Umgang per Hand. Einmal ein Messer im Kreis herum ziehen, knacken (einmal mit Sandpapier schliefen) und fertig. Diese Röhrchen sind nicht so robust wie Bambus, aber den Schilf deutlich überlegen.

Pappröhrchen
Dieses Jahr habe ich Pappröhrchen bestellt (bienenhotel.de), die als Nachteil haben das sie komplett offen sind, und so kaum von Wildbienen angenommen werden. Es wird empfohlen diese in einem Schicht Gips hinein zu stecken, so dass die Hinterseite dicht ist. Selber habe ich etwas experimentiert mit der Absicht in der Mitte ein Art von Verschluss zu machen. Vorteil hierbei ist das die Röhrchen jetzt von beide Seiten benutzt werden können, und leichter austauschbar sind.

 

Hierzu habe ich Stückchen Papier genommen und dieses in stark mit Wasser verdünnter Holzleim getauft, zum Mehrschicht-Dreieck gefaltet und mit einem Stöckchen im Rohr geschoben.

Balkonblumen
Was kann man auf einem kleinen Balkon für Wildbienen tun? Alle Arten von Klee sind beliebt bei vielen Wildbienen und blühen lange. Darum wächst bei mir stinknormaler Rotklee im Balkonkasten. Sehr begeistert bin ich von Steinklee. Vielleicht ist er mit 1 bis 1,5 m etwas zu groß für auf dem Balkon, aber er war den letzten Jahre ein richtiger Bienen-Magnet, der Monatelang geblüht hat und pflegeleicht war. Malven mag ich auch sehr gern, sowie Phacelia und Ringelblumen. Viele andere Tipps finden Sie auf wildbienen.info!

Best of 3D - Part 1

Once in a while, you make a discovery that blows you away. I had this recently when I discovered that I could turn many of my macro photos into 3D images (!). The series that I shot often had slightly moved positions giving exactly the left and right eye information that is needed for 3D vision. This is a selection of the moist stunning results so far, - more to come -. You need a red/cyan glasses which comes with almost any 3d print medium. Maybe you still have one? (Those from back in the eighties also work!)

If not, you can simply take a piece of transparent plastic (product packaging, CD case) and a red and green permanent marker and color two fields. Make sure that you hold the red part for your left eye! It is far from perfect but should should you give something between boring flat and "wow-3d".

                                Romanesco broccoli

                                Clouds

                                Bolete, probably porcino

 

                                Muskroot (Adoxa moschatellina) 

                                Tinder fungus

                                Slime mould 

                                Slime mould close-up

Flying to other solar systems

Flying to other solar systems, would that ever be possible?! Last week, a web-publication appeared in which scientists have came up with a way to do this and formulated 20 challenges in design and material science to make it possible:
http://www.breakthroughinitiatives.org/Challenges/3
If you now think of large spaceships, you are wrong. It concerns so called nanocrafts; little computer chips with a camera, battery and communication device that have a large (4m x 4m) sail to catch laser beams from earth (for initial energy and communication). The advantage of these nanocrafts is that they are so lightweight that they may reach velocities as fast as 1/5 of the light speed! This means that the closest star at 4 light years away could be reached in 20 years. Of course this is optimistic. But wouldn't it be wonderful to reach several of our neighbor solar systems (List_of_nearest_stars_and_brown_dwarfs) within 50 to 100 years?
Some see it as the unavoidable step to discover 'new earths' just in time before ours becomes uninhabitable. Columbus discovered America because Europe was so dirty, overfished and deforested that it was an urgent to find new resources and clean places to start over again. I think, curiosity is still the best motivation to explore and discover and should create new opportunities beside -and not instead of- existing ones (Europe is now more clean, forested and sustainable than 200-500 years ago!).

This example from breakthroughinitiatives nicely illustrates how you set goals in science; by dreaming, extrapolating and definition of realistic small steps!

Origami butterfly

An elegant and simple model that I designed and diagrammed back in 2002 (or so): Origami Butterfly by JE. Sorting out my designs made me clear that there is enough to diagram and share, from jungle animals and plants to flying seeds that really fly. Well, maybe one day...

At least I can share this one with you.

Feel free to distribute! 

Two math questions for bikers: with interesting solutions!

1. When you are biking and you stop for 1 minute to put on a coat and your bike partner goes on, how long will it take before you keep up, by going 2 km/h faster? After what distance do you meet again?
Solution (simplified, ignoring the acceleration phase):
Between begin of stop and re-unite person 1 and person 2 have traveled the same distance (D). During the stop phase (Tstop) person 2 has continued to cycle with velocity 2 (V2). After the stop phase, person 1 has to gain with velocity 1 (V1) the distance that person 2 has cycled during the stop phase. The time required (T) to keep up is hence given by:
T = Tstop*V2 / V2-V1
and the distance:
D = V1*T
So say that the velocity of person 2 is 20 km/h and that of person 2 is 22 km/h to keep up. Tstop is one minute, 1/60 hour. If you use the formula you find that the time needed to keep up is 10 minutes and the distance 3.7 km.
Of course, numbers increase when the base velocity of the trip (and hence person 2) is higher or the time stopped is longer. Every second counts! Better you stop both :-)

2. When you are bicycling in the rain, would it help to go faster?
You are earlier at your endpoint by reducing the total time in the rain, but you also get wetter because you get more raindrops per time unit. By biking faster, do you get wetter, are you getting less wet, or doesn't it matter at all? Does the same apply for walking and motorcycling?
Rain is usually measured as rate in mm/h. After making some calculations on a sketch paper I found out that this problem is independent of surface and distance! The rain rate is normally applied to a non-moving object. The rain "receive rate" depends on the velocity of the object, not on it's surface. An object that moves twice as fast as another, receives twice as much rain per time unit. The rain rate can just be multiplied by the velocity to get the rain receive rate. If you then multiply the rain receive rate with the time required for a fixed distance, you will find that two objects moving with different speeds have received the same amount of rain at the end of the track. So when you are going faster, you are only faster to get dry clothes in a warm house! But if you know the rain is going to stop before you get home, slow down!

Feel free to comment if you have any addition or correction!

360° Panaroma of the Stünz Park in Leipzig

My first post on this blog. So many ideas and almost finished mini-projects. Would the first post be my microscope images of bees and beetles, an R-script, a how-to, my anaglyph 3d photos, or ... ? No. My first post is about a 360 degree panorama that I uploaded to 360cities. It was something I wanted to do for a long time.



It is a set of 48 images that I took in 2010 in the Stünz Park in Leipzig, and thanks to the excellent stitching engine of Lightroom, and my new computer could combine these photos, finally!
You can walk through this panorama in full screen ("toggle full screen", left from shopping cart) and rotate left, right, up and down and zoom in to see full detail. Now, try to count the dandelions and daisies..., enjoy! The arrows have been put in by 360cities and link to other panoramas (better not click on them if you want to stay in the panorama).

This is how I made this 360 degree panorama:
I took 48 photos on a tripod with a 18 mm lens that overlap enough (portrait orientation). Covering 360 degrees with much fewer images is only possible with a wider lens (<18mm) such as a fisheye lens. The photos were stitched together in Lightroom, which worked better than with Photoshop or Hugin, although top and bottom were not complete (because clouds had been moving and I worked without a nodal point adapter). I made some color and contrast adjustments and exported the equirectangular image of this panorama.

 

These are the rough steps that I took in Photoshop for this final version:
* cut the picture in two parts at a vertical line where the new outer border should come, and switch these parts. The previous outer border is now more central, and you can now see what should be a seamless border does not come perfectly out of Lightroom. The geometric fit is good, but you need to correct differences in color and brightness (burn/dodge/clone).
* extend canvas size at the top and bottom region so that the side ratio is exactly 2:1. If the image is 2000 pixels wide and 980 high, it needs 10 pixels at top and bottom more.
* now get rid of incomplete top and bottom. One way is to stretch (layer from background,edit->transform->scale) to top and bottom so that all bad part are gone. A better way is this nice free (32 bit) plugin super cubic:
http://www.superrune.com/tools/supercubic.php
It converts the equirectangular projection to 6 cube faces, or as we need the top and bottom face. You can now use the spot healing brush to complete the clouds and remove the tripod. See the site for instructions how to use and convert back to equirectangular. In this step I also added my site "naturemoods.com".
* After some final adjustments, including sharpening, it is ready to upload at 360cities.com!

But it is also nice to make a "little planet" from the equirectangular image.




This is how:
- use canvas size to make the image square, 1:1
- move the image to the bottom
- use filter -> distort -> spherize, vertical only. This makes the sky longer, and the bottom shorter.
- stretch (edit->transform->scale) make it fill the square
- rotate 180 degrees
- use filter -> distort -> polar coordinates, to make the planet
- with filter -> lens correction you can make the center look smaller. You can apply it several times.
- with filter -> liquify - to make own distortions toward the edges. In my case, I pulled at the top of the big tree to make it look like a normal tree again.
- rote and crop, ready!

Update 2020 - another Panorama
In Autumn 2019 several older trees got damaged and were removed from the park. Apart from the panorama in 2010, I also tried one in 2013 with a cheap ultra wide angle lens (58mm 0.45X Weitwinkel Objektiv Konverter Makro for 35€). This was the first and the last time I used this lens; vignetting was terrible and lens sharpness was only in the center acceptable and colors and contrast were horrible. But it was a wonderful day, with spring flowers everywhere, and as I realized my attempt was a time document with the older trees still standing strong. I therefore did a more rigorous editing and cutting in Lighroom and PS, to get rid of as much 'bad' as possible. In PS I manually edited the clipping masks of each layer to get the most sharp areas. I didn't believe in this for a long time, but result is acceptable.



One additional challenge to overcome was the horizon that was not straight. Photoshop seems to have problems correcting this, but you can easily straighten your panorama with the free software Hugin:
- add image (only one)
- lens type is equirectangular
- go to the panorama preview - press the button straighten
- left click to move/set center
- right click (left or right from center) to change angle from center - straightens horizon
to export from Hugin: go to advanced/expert mode, go directly to Stitcher and export. Do not forget to 'calculate optimal size' for the original dimensions.
You can now further edit in PS, e.g. to edit top and bottom. The free plugin by superrune I proposed earlier is 32 bit, and does not work in 64 bit PS. I considered buying their 64bit plugin for 35$, but I decided to get for a bit more the Flexify 2 plugin from Flaming Pear, which can do 'Nadir and Zenit' editing and incredibly much more projections, from mini planets to origami globes.