Tag Archives: photo

DSLR astrophotography from La Palma

I was lucky enough to get one last observing run at the Mercator Telescope on La Palma, so I spent another eleven nights at the telescope last month, bringing up my totals to 139 nights there (and to 232 overall at international observatories). Since my contract at the Institute of Astronomy ended on the 30th of September, this number will not change anymore :(

Anyway, to make the most out of my last payed trip to the Canaries, I decided that it was time to bring my heavy duty photography equipment with me again, but instead of shooting more time lapse movies, I wanted to do some more serious astrophotography, so I also bought (and then brought along) a compact sized motorised equatorial mount (a Sky-Watcher Sky Adventurer). I mounted the tracking mount on my good old Manfrotto tripod, and used an extra Manfrotto ball head to support and enable easy pointing of my Canon EOS 6D. You can also see the Canon TC-80N3 timer I was using to automate the image acquisition sequence so I did not have to press the shutter release button every two minutes. (Small note: I enabled mirror lock-up and used the 2 second self-timer setting in the camera, so when the TC-80N3 timer gave the signal, the mirror locked up, and 2 seconds later the actual exposure started, eliminating any unwanted vibration from the movement of the mirror. This meant setting an exposure time of 122 seconds on the TC-80N3 timer when I wanted an actual exposure time of 120 seconds.)

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While I have done some very basic astrophotography before (and of course time lapse videos), I never had a tracking mount, so I was always limited in terms of exposure time by the Earth’s rotation. Also back then my DSLR was a Canon EOS 7D, that had worse noise levels than my current Canon EOS 6D, which meant that I could not really go above ISO 1600… But now with a better camera, a tracking mount, and a good amount of research before my trip, I was ready to step up my game.

My first few nights were lit by the bright Moon (I arrived just the day after Full Moon), so I spent the short amount of dark time before moonrise to experiment with the mount, my two lenses, and the camera settings. It took me four nights (of very little dark time) to figure everything out, but starting with my 5th night, my camera was outside from the beginning of the astronomical twilight until moonrise (which happened later and later as the days went by). I found out that I prefer taking more zoomed-in photos, so instead of using the Canon 16-35mm f/4 L IS USM lens, I went for the Canon 50mm f/1.4 USM lens. None of these lenses are really made for astrophotography, meaning that wide open they have a pretty bad coma towards the corners of the image on a full frame sensor, therefore I had to stop the lens down to f/4 to get a result that I was happy with. I used ISO 3200 (after reading a lot about ISO levels for astrophotography here), and an exposure time of 120 seconds (to expose the images to a good overall brightness). As a comparison, in 5 to 10 seconds the stars would already move away enough (thanks to Earth’s rotation) that they would appear as short lines instead of circles on the photo without a tracking mount, (see, e.g., my attempt from a few years ago here). After a good polar alignment (which was pretty uncomfortable with such a low mount, but I managed), I had zero issues with the tracking. Even after one hour, there was basically no shift in the stars’ positions, so I was very happy with the whole setup.

To make one picture, I took 30 to 50 120 second exposures of the same spot of the sky (accounting for a total exposure time between 3600 and 6000 seconds), and also ~30 dark and bias frames for proper calibration (no flats since I have no dirt on my sensor, the vignetting at f/4 is negligible, and taking properly illuminated flats with a DSLR is a mess anyway). Then I processed these in AstroPixelProcessor (really great and pretty much self-explanatory software, with a 30 day trial version!), and at the end I saved an average (or median) image to improve the signal to noise ratio of the images. Finally, I used Adobe Lightroom to do some final adjustments mostly on the curves and colour of the photographs. To show how much this process means for the results, here is a comparison of a selected region from a final processed image, and the same area from a single 120 second unprocessed RAW exposure out of the 30 that were used to create it.

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It is a quite impressive improvement. I liked doing this so much that I would definitely get more into astrophotography if I did not live under one of the most light polluted skies of the world here in Belgium… :D :( Anyway, below is a selection of the images I made on La Palma, and you can find more on my Flickr (at even higher resolution). Since even these 8 resized to ~50% weight in at ~40 MB, you will have to click after the first one for the rest.

1) The centre of the Milky Way, looking towards Scorpius, Sagittarius, and Ophiuchus, with Saturn in the very centre of the image, and many bright and dark nebulae visible around the field of view. A sum of 30 exposures of 120 seconds each.

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A weekend in the Netherlands with my parents

Last week my parents flew over for the long weekend, and we spent the first two days visiting the most touristic sights in and around Leiden. (On the last day we did a very long walk across previously unexplored and new parts of Leuven). Our first stop was at the UNESCO World Heritage Site of the windmills in Kinderdijk.

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Here we had a nice walk discovering the area, except for the first few hundred metres where the path along the small channels was packed with tourists from all over the world. Afterwards we drove to our hotel in Leiden, checked in, and almost immediately went for a walk (leaving the car in a nice new underground parking garage that was opened only two days earlier). Of course first we had to refill our energy reserves, so we went for pancakes in a “pancake house” (Pannenkoekenhuys Oudt Leyden). They were excellent (and huge)! Then we walked around the centrum, and among others we also made it to the top of the Burcht van Leiden (an old fortified point overlooking the city, providing great panoramas).

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The next morning we drove to the tulip gardens of Keukenhof right after a not too early breakfast. We arrived there around 11:15, and luckily we still got into the (otherwise amazingly well organised and coordinated) parking without a problem. People coming just a half hour later were not that lucky anymore, because by that time everything was full. It turns out that we managed to visit on one of the busiest days the park has ever had. This was pretty evident inside, since there were people everywhere, but there were also so many flowers and it was really so extremely beautiful, that it made up for the otherwise alarmingly high tourist-density to the full extent. Of course it was basically impossible to take photos without including a Chinese family or a Russian couple in the background, but I did my best to still get some nice pictures. It was definitely worth a visit, but I would recommend going during the week and maybe when the weather is a bit less perfect :D

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Holidays in the Black Forest

Last week we spent five full days in the Black Forest in Germany. We stayed in the quite village of Hinterzarten (which can be reached by train from Leuven via Liege – Cologne – Freiburg), did three not too heavy but rather scenic hikes around the region (to the highest point of the Black Forest, to a nearby lake, and through the local gorge), and also visited the city of Freiburg. We were quite lucky with the weather, it was perfect for the hikes, as it was mild, sunny, and it only rained for an afternoon. I had way too many slices of schwarzwald cake, and plenty of nice food in the local restaurants/hotels (except for the first day, when we visited the Italian place nearby), and Clio was very happy to be outside in a nice forest. Unluckily during our stay the Belgians got also kicked out of the European Championships, but yeah, you can not have everything :D

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Holidays in Boston – Part 3

Thursday the 24th we first headed to the Harborwalk facing the Waterfront to take pictures of the Boston skyline in the morning sunlight. Then after a quick sandwich and salad lunch, we visited the New England Aquarium. This was the first time that I have been to a proper aquarium ever, and it was awesome. Clio loves fishes (and that is an understatement), so for her it was almost as good as going to Disneyland. We could even pet some animals in the ‘ray and shark touch tank’. We spent more than 3 hours here! Afterwards we still walked through Chinatown and spent some time in the Public Garden (surrounded by hundreds of squirrels) before taking the subway home in the sunset.

On the morning of the 25th we started with a visit to the Science Museum. It was all right, especially the more interesting interactive elements, although I was a tiny bit disappointed with their collection overall. It’s not like the science museum in London… I think this one might be more fun for smaller children. But then after a lunch break (BBQ Pulled Pork Sandwich for the win!) and buying a few more GoPro accessories (that are so much cheaper in the USA), we went kayaking on the Charles River. There was quite some wind, but the water was not too rough, especially inside the Storrow Lagoon along the Esplanade. The view towards the city was really nice and we enjoyed our time in the sunshine a lot. I am sure if we lived somewhere in New England, I would have a sea kayak.

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Saturday was our last full day, and the first day when we were not exactly sure what to do. After quite some thinking we decided to go to South Boston. We walked along the Harborwalk from the John F. Kennedy Presidential Library and Museum all the way up to Castle Island. The weather was still nice, although the wind got quite strong, so we were happy to warm up with a hamburger and a hot dog at the end :) Then we took a bus towards Downtown to find a place that had happy hour for oysters (for Clio).

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Then Sunday morning we still had a nice brunch (where I had a gigantic breakfast pizza) at the MIT before going to the airport. The flight was uneventful, especially since we were sitting on the left side of the plane and thus we did not get to see the total lunar eclipse happening on the other side… And unluckily there were no northern lights on our side either. We arrived home on the afternoon with some serious jet lag. Clio tried to fight it with some sleeping, while I tried to stay awake playing FIFA 16 on the PS4…

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To sum it up, we had a really nice time in Boston, it was really worth going. I spent quite some time making a selection of the hundreds of photos I had taken there, so if you are curious to see more than the very strict selection of this blog post, then head over to my Flick gallery. Thanks for reading!