Under the sky of Tenerife: behind the scenes of a time-lapse journey to the stars

April 30, 2018

Here's my journey into capturing some of the world's most detailed time-lapse shots of the milky way and into continuing to pave the way for innovative astrolapse techniques.

 

 

Before going deep into the details and technical stuff, you should probably take a watch at the movie if you haven't done it yet: 

 

 

If you have been following my work over the past few years you would know that I found a field of astronomy and astrophotography that I've gotten extremely passionate about: ASTROLAPSE - the art of timelasping the night sky. I know this sounds completely nerdy but it can produce some of the most stunning views and helps show the gems of our universe in a very unique and visual way. Now astrolapse is not brand new (but still young!) and ever since the dawn of digital photography people have started shooting night scapes and producing stunning time-lapses of wide-angle scenes of the milky way moving against a foreground. The photographic gear has gotten better since and now we can get crisper films but to me astrolapse had never really evolved...until now! While the whole span of our home galaxy is still impressive to gaze at, it was time for me to show something else and to create some variation. There are three ways of doing so since we are stuck on Earth: changing your focal length, changing your perspective from which you are shooting, changing your shooting technique. It has been long journey of learning, investing, making sacrifices and experimenting (for more details on these new techniques I invite you to read my article: click here). After the success (but also challenges) experimenting in La Palma last November to get stunning views of the winter milky way, I was more than eager to apply these new skills (and avoid past mistakes) to the most photographed and famous part of the galaxy: the core! So it could seem like traveling to Tenerife would be a nice relaxing vacation as it was originally meant to be, but why not do both: enjoy the island's beauties and activities while creeping my way up the volcano at night like an astro vampire thirsty for the night sky?
 

 

Located at the heart of the Canary islands- around 200km off the shore of Morocco and Western Sahara, Africa, Tenerife is a volcanic island full of wonders. It belongs to Spain and harbors the country’s highest peak, Pico Del Teide culminating at 3718 meters above sea level. The island benefits from a wide variety of climates due to the different levels of altitudes and air currents. Lower altitudes generally get a layer of low rolling clouds produced by the vicinity of sea water. The north of the island often gets rain and therefore a more temperate sub-tropical climate whereas the southern tip is very mediterranean, desert-like even, with lots of cacti due to the low amount of annual precipitation. The higher you climb the slopes of the crater the drier the soil and vegetation get and the more barren it becomes. This area is called ‘Corona Forestal’, meaning the forest crown, and is mainly populated by pine trees. The El Teide national parc is delimited by the primary crater mountain ridge which offers peculiar conditions for a scares and very endemic fauna and flora to survive. You really get a feeling of emptiness and mystery in that very lunar landscape. The primary goal of this short film was of course to showcase this unique variety and biodiversity (did you see the bunny and the lizards?), but also the extremely unique mood of the crater, which only brings us closer to the heavens!

 

 

This short’s timeline is built around one fictional day. It starts with the beautiful sunrises above the sea of clouds. Then embark on a journey around the island, visiting the Cacti of the south or the humid forests of the north. As the day unfolds we progressively climb the volcano to witness the magic of sunsets from the crater. There you can experience many twilight phenomena. For one the sun hanging right above the ‘Calima’- this cloud of dust and sand from the Sahara, giving beautiful colors. You can also appreciate the extremely fast twilight with Venus and the thin-crescent moon in the Earthshine setting on the western shore in the zodiacal lights, this strange pyramidal column of light coming from the sunlight being refracted into tiny interplanetary dust particles. From this moment when colors and light are fading away you are in for quite a show! 

 

 

WHY TENERIFE TO PHOTOGRAPH THE CORE?

 

I stayed on the island two years ago at the exact same period of the year and I was just beginning my astrolapse journey. Back then I was stunned by how well you could see the stars and how beautiful my milky way pictures looked. I even compiled a short film about the island: 

 

 

Notice what I called the movie back at the time: 'The darkest crater'. It's partly true and partly erroneous and this will bring me to my point. After progressively getting better and learning so much about how to improve astrophotos, I realized back then that my shots weren't so sharp, had tons of coma and chromatic aberration, were too noisy and had too much light pollution in them. I was in shock because I had read so many times that Tenerife was one of the best places in the world to photograph the milky way and my pictures still looked gorgeous (at least to the novice Adrien). As you get more and more into astrophotography and even more so astrolapse (where you want to optimize your shooting conditions as you can only take a series of single exposures), you start getting picky… After my astro trip to La Palma (another of those Canary islands even more famous for its dark skies) last November I got excellent footage but I was also able to draw some compelling conclusions that the skies there were not THE absolute best in the world. For starters Tenerife’s light pollution (LP) is far from being insignificant when you do single picture astrophotography. It’s as if you were shooting in a rural area and you still get the yellow glow almost all around the island, although mostly around the southern tip and Santa Cruz in the North. Climbing up the crater makes it a bit better but you still cannot avoid it. I had to use a square light pollution filter to counter that. Look at the LP map (Red, Orange, yellow, even green is bad!):

 

The following photos have been taken without a light pollution filter to give you an idea: 

 

Some areas are a bit better (you can get the milky way between zones with LP, especially if you stand in the northern part of the crater as the third photo suggests) but you can easily see that most of the picture will be affected by it. Nevertheless LP appears dimmer (I would say about 30%) when there is a blanket of lower clouds and that happens quite often so that's good news. LP affects your astrophotos in several ways. Firstly it drowns everything in an annoying glow that is hard (impossible even) to suppress. It cancels out the little contrasts there are from the light of the milky way and instead of the landscape being illuminated only by stars, you get a flatter distribution of light. Then LP produces one more obstacle by reflecting in dust particles and humidity in the air. You will consequently have to apply more noise reduction also because you're going to want to increase your contrasts more in post-production.  

 

One other challenge to shoot timelapse up there was the multiple noise-enhancing factors like dust, sand and airglow, and you can barely do anything about them. On the last night the 'Calima' was raging on! Another big issue was the wind. The regular gusts made it very difficult when I was tracking the shots to get better sharpness and exposure, but also when I was using motion control. I got a lot of shakes and even if daytime scenes were easily corrected in post-processing, I had to throw away 20% of the night time sequences because too many shakes on a long exposure sequence cannot be corrected. One last challenge is that I had to deal with was fatigue. As I never know what I'm gonna get, I wanted to make the most of every moment on the island and shoot as much as possible. By that I mean literally from 5pm till 7am every day! I would usually start by driving an hour up to the crater, do some scouting around and shoot as I found spots. I would also search for night time shooting locations and settle there for the night. In the morning right before dawn I would drive down an hour and go to my hotel to sleep a few hours (4-5) and take advantage of the sea, the sun and the pool. It's really challenging but if you wanna get the best of both worlds and still enjoy yourself, you gotta do it! 

All those challenges aside I was able to shoot great night sequences (with perhaps a bit more LP than La Palma) and it is safe to say that Tenerife still remains a tremendous location to gaze at the night sky, probably better than most in your own country!

 

 

As I am following my journey into finding innovative sequences and techniques, this trip was the perfect occasion to test out these new skills on a part of the sky I was eager to capture: the center of our home galaxy and its many astronomical treasures. I had planned the trip for about a week using some apps (Star walk, Sky Guide, Sky Live) and google maps to see what was visible in the sky, when and from where. That way I would come prepared knowing approximately where the celestial events would take place. Here's how I planned it. First I would figure out an interesting object to shoot and how I would shoot it (focal length, tracking, static...). It requires a lot of imagination and a good knowledge of the night sky but the possibilities are endless. Then comes the time to determine how these objects will move in sky relative to an interesting foreground.  Choosing your foreground can almost only be done right there on the spot. You can try and google Earth it as it now comes in 3D but to estimate the right height and shapes of things like trees or mountains, you would need to be there in person. That's why the day scouting phase takes so much time and is invisible in the movie! You can always improvise on-location if you spot interesting foregrounds. Now comes the time to set up your camera and shoot! Remember that nothing comes easy especially in astrolapse and you may have to make multiple attempts before starting to get nice results. I am detailing the process of the Orion setting behind El Roque de Garcia pinnacles scene:

1) I remembered the beautiful pinnacles at El Roque de Garcia in the crater 2 years prior. So I imagined an interesting object that would pass behind it so that I could get the two together.

2) The pinnacles are not very tall nor wide so no matter what I was going to shoot (milky way or something else), I would probably need a medium format like 50mm or 85mm. I needed to keep in mind that both those lenses have a shallow depths of field at night and also a very long focusing distance (especially the Samyang 85mm f1.4), so I would need to be at least 10 meters away from it. 

3) After going there during the day and looking at my StarWalk app, I saw that Orion was visible right after sunset and still quite high in the south-west, since only the north part of El Roque is accessible by foot (the rest is off-limits). 

 

4) One night I decided to stay there after sunset in the company of a fellow astrophotographer (Peter Colley). I still needed to figure out what focal length I would use and for that I needed my (short) experience from La Palma. I knew that the only way to really bring out detail and colors of Barnard's Loop and the red nebulosity in the Orion region was to track the sky. The problem was that if I did so the foreground would move, introducing motion blur as well. I also asked myself if I would be able to see the foreground long enough for it to be interesting. All these considerations helped me locate an idea spot. It was awfully windy that night as well and I was lucky to find a perfect location behind a bush and facing the 10-meter pinnacle due south-west! 

5) I set up my canon 6D astromodified to capture the H-alpha emissions, mounted on the Vixen Polarie to track the sky and a light pollution filter (one other essential to increase contrasts and reduce the effects of LP). Another challenge was the relentless flashes of car lights producing flicker on the rocky formation but it eventually turned out to illuminate it anyway!

 

Above are two shots derived from the scene at 50mm (Sigma f1.4). The first one is the RAW files straight out of the camera, at ISO 6400, f2.5, 14 seconds (tracked). Notice that the magenta color is created because of a color shift coming from the astromodification. The right-hand side picture is the corresponding processed JPEG. I am quite happy with the result although the wind forced me to shoot at that precise spot and it would have been great to shoot a bit left of that to get a better framing. However I still got the Rosette nebula and Christmas tree cluster (top left corner) and the whole of Orion (with the head), hence the need for 50mm! Hang on, I'll get to the processing part later for another scene! 

 

 

WHAT SUBJECTS FOR THE APRIL NIGHT SKY IN TENERIFE? 

 

After twilight in April, you can witness the ‘winter part’ of the milky way setting on the south-western shore along with the famous Sirius, Orion constellations and its nebulae (Orion, Running Man, Flame, Horse Head, Rosette).

It’s also a good time to peek at Vela, the Gum nebula and the Carina nebula. I tried shooting the gum nebula and the Carina nebula but they were too close to the horizon and just above a source of LP so they didn't give usable timelapse for this movie. I will wait until I go to southern hemisphere locations to get them higher in the sky. 

Around midnight you can watch Jupiter rise in the east followed by the head of Scorpius (Pi Sco, Dschubba and Acrab), announcing the rise of the milky way. About 15 minutes later a very interesting region would lift up: The Antares region.

 

 

This region located in Scorpius offers a beautiful palette of colors because of reflection nebulae (clouds of gas and dust reflecting the light of a passing star; in this case a blue one (Rho Ophiuchi), a yellow one reflecting the light of Antares (super red giant)), and emission nebulae emitting red light (around Sigma Scorpii and Tau Scorpii). All of this contrasts well with some dark dust lane seemingly coming straight from the core of the milky way. Rho Ophiuchi was too good to pass on and I had the idea of framing it ever since I started astrolapse. Was I going to be able to get enough detail and colors in one shot to make an interesting time-lapse out of it? Most astrophotographers would tell you it is impossible unless you stack multiple exposures! But here's to prove them wrong. For the first time in timelapse you will be able to gaze at the beautiful colors and shapes of the nebulae of Rho Ophiuchi along with Messier 4, and especially a signature shot of this area photobombed by some red and green airglow, making the yellow, pink and blue gas clouds literally change color!

 

 

I love to watch satellites fly under these colored nebulae even if there is no foreground! The shape of this subject is also quite interesting to frame as it resembles a flying ghost! I shot this scene at 135mm to get maximum detail using the awesome Samyang 135mm f2 mounted on Canon 6D modded (to get the H-alpha). I also tracked it with a LP filter (Pure night from Lonely Speck) to really get the best out of every single shot. However this shot was extremely challenging because of LP, airglow and sand from the Sahara. Antares gets quite high in the sky but those nebulae are quite faint so I had to expose for 17 seconds to get a good amount of light and stop down to f2.8 to get good sharpness. I am extremely happy with this key scene because it has never been managed/thought of before. I can't wait to try it again in better shooting conditions when Antares is right above head! Here's an exclusive stack from 40 frames of this timelapse to show you how you can increase detail just by stacking exposures (and also to reveal the true beauty of this region).

 

 

After Antares there really was something that I had been eager to get with these new skills: the core of our home galaxy in high detail. There is something so fascinating about this area probably because you can see it with the naked eye when you do think about the several billion stars in this downtown neighborhood, which in turns puts everything into perspective. Finding other habitable planets and other sources of Life has also been our struggle and hope but it still holds its share of mysteries to unravel, partly because of the immense distances and the dark clouds of gas blocking the blinding light of the bulge. I knew that the core would rise almost horizontally 30 minutes after Antares. I traveled and hiked to several locations to get the shots at different focal lengths.  Now this is where I needed to be creative and innovative because tons of people get wide angle shots. So I got some with my Sigma 14mm f1.8 lens along with either the panning mode of the Vixen Polarie or the motion control system Syrp Genie 3-axis, and spent the rest of my time to shoot at longer focal lengths.

 

 

I yet have to try 35mm but I started at 50mm, which I think gets stunning results, and then all the way to 135mm. I tried both untracked sequences (for example the milky way rising behind the fixed telescope to give a perspective effect) and tracked sequences. As much as I like simple setups I have to say that the tracked sequences give the most astonishing results (though a mobile foreground). I shot the core rising from different locations and when it was at its highest in the sky (around 4-5am), I would simply shoot it without any foreground. The latter sequences have also never been attempted (to my knowledge) and in any case displayed! This is where I don's quite know why others have never thought of capturing it like this before because the view is just mesmerizing: 

 

 

Look at how well you can see the fine structures in the dark clouds, and also the nice contrasts of lights and shadows! The Lagoon nebula (big pink area) and the Trifid nebula (pink and blue dots) also turned out quite detailed! You can really get a sense of what's going on there: the battle between the million stars trying to cast their light and the dark clouds trying to block it. In the movie you might also notice that those tracked scenes are slightly moving whereas they are supposed to be fixed. It comes from the fact that the Vixen Polarie is quite hard to polar align with the North Star because I have to aim with my eye through a whole in the dark and manage to get the star perfectly at the center of this whole. It can never be perfectly aligned manually so this slight misalignment is big enough to give a slight movement over the whole sequence (> 1 hour), but too insignificant to affect each individual pictures taken around 15 seconds of exposure (absolutely pinpoint sharp stars!). However I really took advantage of this movement and I really like that it gives a bit of motion so that the sequence is more pleasant to watch. Before getting into the processing part, here's a quick stack of 25 exposures only from the 135mm core scene: 

 

 

In my movie you can also watch many other wide angle shots of our home galaxy rising and hanging above the crater at various locations, whether it is above the Caldera, or the white dunes of Minas de San Jose, or even the many basaltic pinnacles of the craters. On top of that I also featured a 50mm shot of the Cygnus region and its nebulae, the Eagle and Shield region, The tail of Scorpius up to Norma with the Cat’s Paw nebula, the War and Peace nebulae, and the Prawn nebula all bathed in airglow...

 

 

HOW TO PROCESS RAW FILES FOR A NICE NOISE-FREE ASTROLAPSE?

 

This is the section a lot of you have patiently been waiting for! How do I post process my timelapse sequences to maximize detail, minimize noise while preserving a stunning quality? For this short demo I will exclusively be using Adobe Lightroom. I will be explaining how to process this milky way shot taken with the Canon 6D modded, Sigma 50mm f1.4 at f2.8 (for sharpness), ISO 6400, 16'' exp. time, tracked with Vixen Polarie and contrast-enhanced with the Matt Aust LP filter. The idea was to get a very clean shot of the core as high as possible in the sky to limit distortion, diffraction and noise. I still wanted a foreground reference hence the trees to the far right of the picture. Here's one of the final pictures: 

 

 

In order for you to get this type of shot there are several things to keep in mind and to really grasp because a slight mistake in post-process can ruin your final sequence. I personally made a lot of those mistakes in the past (and even for this film!) but I figured you should know the do's and don'ts so that you can avoid these mistakes in the first place! 
 

1) Understand your sequence. This one is of utmost importance because if you can't really comprehend how the light and noise behave you can end up with a terrible result. Back home you have to ask yourself and remember what the shooting conditions were that night: was there a lot of light pollution? Was there a lot of haze or humidity in the air? Was there any other hurdles along your sequence (This is where you should quickly look through your RAW files)? Determining all this will help you make up your mind about how much you should process your shots. 

 

2) Don't try and overprocess! This one IS the most important of all things. Your sequence needs to be pleasing the eye and kept as harmonious and natural as possible (that last term is of course very subjective and I remind everyone that they are free to do whatever they like, I am just giving you some tips, not telling you how to think!). If you increase the contrasts too much you might lose some data and end up with a way too noisy scene. Remember that even if noise isn't that visible in a single frame it might be revealed in a film as those imperfections move from frame to frame. In the same mindset don't ever touch the 'dehaze' button as it only brings up much noise (hence the necessity of planning your shot well). Colors should not be tempered with too much either. You can of course change the white balance following your taste, along with vibrance, saturation (each individual channel) or even the hues (be careful about color hues and luminance as changing it will bring you nasty color noise and undesired artifacts such as lines and washed out areas...). Now one of the secrets that I have kept until now was about clarity and sharpness. I find that a lot of people push those sliders too much hoping to gain more details while at the end of the day they are left with more noise and halos than anything else! You would be surprised to know that I actually reduce clarity in most of my shots, especially the tracked shots. As the stars appear pinpoints they pack a tremendous amount of light that is too contrasted and this will in turn distract the viewer from the main subject: the fine nebulosity of our home galaxy. Reducing clarity and 'lights' (a bit!) helps bring this phenomenon down (you lose a slight bit of details in the process) and you start seeing nebulae and dust clouds pop out in the background more! That's how I am able to get those Orion shot because if it weren't for a reduced clarity you wouldn't see Barnard's loop as clear as this. You will also need to apply some noise reduction (probably more than in your usual shots) but I would advise not to reduce it too much just yet (know that there are other ways of reducing it when you put together your final production). 

PROCESS

 

1) Import you RAW files into Lr. 

 

2) Start editing the first picture of your sequence in the 'Develop' module. First play around a bit with the white balance (try and remember what it looked like that night, was it warm or cold, was the moon present or not?). I personally have to rebalance my pictures because the astromodification draws the WB to the magentas and yellows, hence the temp. at around 2100K and the tint at -81. I always like to use a WB as neutral as possible. To do so, temporarily put the saturation and vibrance to max (it will help you see the color changes better) and adjust the WB sliders until you have a homogeneous blend, then put saturation and vibrance back to normal by double clicking on the cursor). Then try bumping up a notch the exposure. Most people tend to underexpose their night shots to the point of losing so much details and data. Look at the histogram in the right-hand corner, it will tell you the distribution of the light. What you want is a spread out histogram that is higher in the left side but no part of the graph should go 'out-of-bounds', which means you have clipped data by either bringing up the 'Whites/highlights' and bringing down the 'Blacks/shadows' too much. Find the right balance between highlights, shadows, whites and blacks but remember to be gentle with them! They can also be adjusted in the 'Tone curve' section if you prefer working with the curves. The overall goal is to have a nice but not overblown light coming from the bulge of our milky way, detail in the dark lanes (that's why the blacks should not be cranked down too much). Keeping a reasonable amount of grey scale and blacks will also help you make noise less visible, and I feel like it looks more natural anyways! Notice that I also reduced clarity to around -20 for the overall shot. This helps me keep the brightest stars from distracting the viewer too much and bring out details in the background nebulosity a bit. Also notice that I absolutely do not touch the master vibrance nor saturation! 

 

For colors, I head down to the individual channels. I did not touch the 'Hues' nor the 'luminance' of each color channel because it tends to give horrendous results. I just try bringing up the reds of the H-alpha while reducing the saturation of the oranges (light pollution) and the blues (background sky). Then I go all the way down to 'Camera calibration' and change the primary color hues there to my liking. This will help restoring the 'true colors' (if there ever are some) of the milky way after they are tampered by LP and airglow. 

For noise reduction I head to 'Luminance' and apply a first 40% NR. I also increase color noise reduction a tad because playing around with the primary colors will have introduced some band color noise. I leave sharpness to 25% which is enough to my liking. You can also edit in the camera and lens profiles which will help you control chromatic aberration, distortion and vignetting. 

When you're done keep the first picture selected in the develop module and select all the pictures of the sequence (Ctrl or Cmd + A) and click on the 'Sync' button in the bottom right corner of your screen. In the pop-up dialogue box, tick all and click on 'Synchronize' to apply all those modifications to the whole sequence. 

And there you have it! I personally use a special Lr timelapse + plugin that lets me apply different changes to different keyframes and then blend the settings between those keyframes because sometimes you encounter changes in exposure or color balance between the frames. This plug-in helps me smooth these changes out. Try export just one picture to see how it looks like individually (I remind you though that it's not because it looks good on still that it will necessarily look good on film!). When you're satisfied with the result export your files in JPEG (exporting in TIFF will have you end up with several hundreds of Go of data for just one sequence!) at 100% quality. JPEG is not a lossless format, but let's be honest, it's still more than enough anyways! After your sequence is exported, you can assemble it in any software that you like (There exists some free ones for Mac and PC) and edit your sequence in post-processing in FCPX or Adobe Premier Pro (This will be the subject of another tutorial!). 

As a conclusion to an unforgettable trip and one more amazing astro-experience, Tenerife remains one of the world's key spots for astrophotography and astronomy. There is no denying though that Tenerife's skies are not THE best in the world because of the ever growing light pollution and the regular dust clouds from the Sahara. I was still able to produce some extremely satisfying clips and all in all I got pretty much all that I had imagined in my mind (and more!). I was more than surprised about how much details I could get in the Antares region and the core of the milky way, which give me even more ideas for future clips when the core will be higher in the sky (southern hemisphere). I would like to thank you all for the amazing support and encouragements you have given me over the past day since the publication of this short film because this keeps me going and gives me inspiration. If you have further questions or commercial inquires about all this please shoot me an email at adphotography2410@gmail.com. In the mean time stay tuned on social media because I am far from being finished publishing amazing pics from this incredible island! 

 

 

 

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