Tag Archives: mercator

Four planets and the Moon over the Mercator telescope

I am back on La Palma (again), supervising our Master students at the telescope (again). Although I did not bring the ‘big guns’ from my photo gear this time, I still have my small camera with me. The first night of this observing run was my 100th night at the Mercator telescope :) To celebrate this, here is a picture I took of the beautiful planetary conjunction before Sunrise on the morning of the 11th with my FUJIFILM X100S camera (with an equivalent focal length of 35 mm) set at f/2.8, at ISO 800, and using an exposure time of 10 seconds.


Although the Moon looks full, it is just a thin crescent (which is better visible after clicking on the image), but the dark side is quite strongly lit by light reflected back from the Earth. This is called earthshine. (At the same moment, Earth looks almost full from the surface of the Moon, so there is a lot of Earthlight even on the dark parts.)

Summer observing run on La Palma

I am sitting at the airport of La Palma waiting for my hopefully not very delayed flight to Madrid (a bit of delay is ok, but I still want to make it home today), so I have a bit of time to post. I spent the previous almost two weeks (officially 10 nights) working at our Mercator Telescope, and as this time I did not come without my photography equipment, I also took a few nice pictures in my spare time. It has been so long since I took proper pictures here, that I finally had some new ideas and it did not feel like a burden to take photos. So please enjoy the following selection, and should these be not enough, head over to the full gallery on flickr.


Flying to La Palma, if it’s not on a day when charters fly, you will most likely catch a connecting flight in Madrid. I like the colours of this airport a lot. then after landing on La Palma, it’s a one hour taxi ride up from sea level to 2145 meters to the Observatory. The amount of curves along the way is just crazy, so you should keep your eyes on the road…



At the observatory astronomers stay at the residencia. It is basically a small hotel with cozy rooms that can be made totally dark even during daytime (which is pretty much the most important thing when you need to sleep during the day).


This is the first time that I came here at the beginning of the summer, so I finally got to see the sea of yellow flowers on the mountain. Especially in very clear days (so, basically every day here), they are really beautiful against the deep blue backdrop of the sky.


I made an improved version of my famous transparent dome photo, which took a lot of preparations, and running between the control room an the camera. You can read more about the process in my blog post for the old picture.


I was lucky because Venus and Jupiter came unusually close to each other on the evening sky during my stay, so I had something special to put in the background of the telescope (or the building). Note our new simultaneous three channel (hence the three colours on its sides) photometer (MAIA) on the side of the telescope.


I also got to see the laser of the WHT in action. This was actually already the second time that I saw it, but last October I had no camera with me to take pictures. Also, now I could put the Milky Way in the background :)


When I said Venus and Jupiter had a pretty close conjunction, I meant they had an apparent distance less than the diameter of the Moon! It was an amazing visual sight.



Then of course there is the famous caldera of the island, which is usually filled with a sea of clouds, but there are also a few rare days, when you can see down all the way to the bottom.


On one of the last nights I had some fun with light-painting, writing the telescope’s name with a flashlight on a long-exposure image. BTW the rest of the scenery is lit by moonlight.



Then on the last day, I could still catch our home galaxy rising behind the telescope building in the short dark time between sunset and moonrise.


I will be back in October with the Master students as usual, but probably without photo-equipment. I have taken enough nice pictures for a while.


Back from La Palma

What time of the day is it? I see that it is bright outside, so it must be during the day, but my biological clock is so screwed up again, I could not tell if it was morning or afternoon… I had enough of this jet lag (or observatory lag in this case) for this year, I am really fed up with it. At the end each of the seven nights went by without major problems and with perfect weather at the Mercator telescope, thus the Master students from Leuven and Amsterdam got plenty of data to work with.


It is really exceptional that we had such good meteorological conditions in October. As far as I can recall, there were always at least a few nights lost due to rain/clouds in the past years during the weeks of the master students’ observational projects. This time the students from Amsterdam even gave me a bottle of wine for the help I provided them during the past week! That felt really nice, I have to say. This was the first time I got something like this from students :)


I stayed one more night at the observatory (but not at the telescope) before coming home, which I spent studying my Dutch, trying to go through the lessons I had missed during the past two weeks. Then my taxi to the airport almost did not fit my bike box (we had to leave the trunk open and fix everything with ropes…), and my flight also got a three hour delay. And although I specifically went for a direct connection this time, the leg space is so horribly inadequate on these Thomas Cook flights, that now I really do not know what to do next (because having to change two times with IBERIA is also not one of my favourite things). I wish we could just teleport from one place to the other. The weather back home in Leuven is a bit grey, but this time of the year, this is pretty normal. But it is good to be home again. The rest of this week I will have to catch catch up with my work email, my Dutch class, and try to unpack my bags/bike box… Oh, and sleep…

Comet Lovejoy (C/2013 R1) with MAIA

Since one of the student projects involves imaging comets with the new MAIA camera, and I like to create images for outreach, I present you Comet Lovejoy in false colour.


Creating a colour image with MAIA (which is far from the main purpose – photometry for asteroseismology – of the camera) is a bit more complicated than it was with MEROPE, since the optical paths leading towards the 3 CCDs are different, which – in practice – means, that the images captured by the 3 CCDs do not overlap perfectly. Unluckily these differences are not linear, so you need to do some proper astrometry to align the three channels in post processing, or use the Auto-Align Layers command in Photoshop (which is highly unprofessional, but results in pretty images rather instantaneously). For this RGB image I used the r+i channel as R, the g as G, and a tricky combination (made using black magic) of the two for B (since in u the number of photons from the comet is in the single digit region).

Moon, Venus, Saturn, Mercury, and the ISS


After a week of cycling, I am back again at the Mercator telescope, supervising a group of Belgian and Dutch master students while they are working on their observational projects. This is our second night, and we already saw a quite rare celestial conjunction. The picture above was taken with a FUJIFILM X100S camera set at f/2.8, at ISO 400, using an exposure time of 30 seconds. It shows the Moon and Venus towards the top left, the track of the International Space Station in the centre, and slightly hidden among the hundreds of stars, also Saturn and Mercury towards the lower right, just above the horizon. Use the finder chart here to identify them!