Technical information about this photo.

This is a 24 hour picture. I was wondering if it is possible to visualize a full day on a photo. I finally decided to give it a try! The shooting began the morning of December 30, 2010. I started taking photos with the camera on a tripod facing east. The 'day part' is composed of a dozen of shots covering the landscape from east to west and the Sun's course from sunrise to sunset. The Sun's position was recorded exactly every 15 minutes using an intervalometer, with an astrosolar filter adjusted to the camera lens. In one of the shots, when the Sun was near it's maximum altitude, I removed the filter in order to capture a more 'dramatic' shot with the Sun's glare. After the sunset, I took various shots with the camera facing west - northwest in order to achieve a more smooth transition from the 'day part' to the 'night part' of the picture. The 'night part' is also composed of a dozen of shots covering the landscape from west to east. After the 'transition' shots I mentioned above, I took a small startrail sequence, with approximately half an hour duration, and the camera facing northwest. Then at 19.13 local time, I turned the camera to north and I started taking the all-night startrail which lasted almost 11 hours. After the 11 hour startrail I turned the camera to northeast and I shot a half an hour startrail, and finally with the camera at northeast and east some 'night to day' transition shots.

A) Some of the challenges:

-- Preparation. This picture is composed of many shots taken at very different lighting conditions. This requires a very detailed preparation of exactly how and when to take these shots. I have made a written plan of the shooting and also set an alarm clock to be notified whenever I had to change the shooting angle or a camera setting.

-- Patience... I had to stay to the same place, alone for approximately 30 hours. (I was on the spot 2-3 hours before sunrise in order to make the preparations and test shooting and I also stayed 2-3 hours more to the second day in order to shoot a part of the Sun's sequence that I lost the first morning due to clouds. Therefore, this photo represents a 24 hour shot but it is actually more...).

-- Weather - clouds. My plan was to make the shooting at the winter solstice day, achieving the lowest Sun's arc, and the longest startrail duration. The problem is that even for the famous Greek weather it requires a great amount of luck to find 24 continuous hours with clear sky in the middle of winter... This day finally came at December 30 to 31, 2010. I chose Sounio for this project for it's usually stable weather conditions.

-- Cold... At night, I had to stay awake, inspecting the camera lens for moisture every 30 minutes. The temperature was about 3 degrees Celsius, so this wasn't very easy. I was equipped with a hairdryer, in order to use it on the lens in case of moisture but I finally didn't use it because the moisture levels were low.

-- Power the camera. A typical camera battery lasts for only a few hours. I use an adapter to power the camera from a large 12V battery.

-- All night startrail. A lot of things can go wrong here. A thick cloud that passes through the field of view, can ruin the startrail photo. Other possible problems include moisture, windy conditions or even an accidental kick on the tripod or the power supply. Believe me! After many, many hours in the cold and in the darkness one of the most challenging tasks is not to kick the tripod!

-- Photo process. It took me about 12 hours to compose and process a single photo from over 500 startrail, 35 Sun sequence and 25 landscape shots. I have made 'litle planet', startrails and Sun sequence shots before but to be honest I really wasn't sure if all the above can be combined. The software I used: Startrails for the startrails, Ptgui for the little planet and Photoshop for the final touch.

-- Nagging from the wife. Fortunately I was lucky enough for not having such an issue!

B) Equipment:

-- A DSLR camera (I use Canon 550D).

-- A camera tripod.

-- A fast and large memory card for the camera. (4 GB is OK, 8 GB is better).

-- A wide field lens (I prefer prime lenses. They are not as flexible as zoom lenses but they generally provide better quality.) For a relatively small panorama I prefer the Canon EF28mm f/1.8 USM but for large panoramas with fast moving objects (clouds, stars) it is better to use a wider lens like Canon EF 15mm f/2.8 Fisheye

-- An intervalometer. I have the TC80N3 which is the most reliable. The problem is that Canon does not provide an intervalometer for the 'small' DSLR models, so if you have for example Canon 400D, 450D, 550D etc you will need an adapter like this one.

-- An external power source for the camera. I use a large 12V battery which is similar to a car battery. It is better to buy one that it is specifically designed for continuous charge and discharge cycles. So you need a battery charger as well. I also use this adapter to connect the camera to the battery:

-- An astro solar membrane filter for the Sun's disk shots. You may buy the membrane and make your own custom filters using carton.

-- A hair drier to periodically blow hot air to the lens in order to avoid moisture. You may need a second battery and a power inverter for that. You may use the one in the car but it is a bit risky to discharge your car battery...

-- An alarm clock.

-- Mobile phone.

-- Warm clothes. Isothermal clothes and apres ski boots is a good investment for the really cold winter nights.

-- Water - Food.

-- A GPS unit so if you get lost on the mountains, the rescue team will know exactly where to find you!

C) Preparation:

The ideal day for this shot is at the winter solstice day (around December, 21) where the Sun makes the lowest arc in the sky comparing to the other days of the year and also we have the longest night. Seek for an accurate weather forecast and try to find a clear day as near as possible to winter solstice. Make a written plan of the shooting. Have a look at the photo with the annotations to get an idea. If it is necessary set the alarm clock to remind you whenever you have to change a camera angle or setting.
Choose a spot with an interesting foreground and if it is possible with relatively stable weather conditions. From my experience, for example on a top of a mountain you may encounter fog or windy conditions.
Make a checklist. You don't want to ruin the project because you forgot an adaptor or charging the battery.

D) Software:

-- Cartes Du Ciel or similar astronomy software. It contains useful information such as the exact time of the sunrise, the Sun's highest altitude, sunset, lighting of the sky etc.
-- I use this software to compose the startrails photo.
-- Ptgui. It is the photo stitching software.
-- Photoshop.

E) Shooting:

Let's suppose that you start shooting before sunrise. Set the camera on a tripod on the preferred spot and start taking shots covering the area from east to south, including the ground (remember this will be a 'little planet' panorama) . The purpose for this is to obtain the 'morning landscape' shots of the panorama. Just before the Sun appears, turn the camera to the east, secure it tight, take a photo of this position to the landscape without a filter, put the solar filter to the lens, set the intervalometer to take a shot every 15 minutes and then wait. It should take at least 2 hours before the Sun starts to approach the end of your field of view.

At this point you should turn the camera to the new position facing south, secure tight the tripod, and let the camera continue taking shots. Every time you change the camera angle you must remove the filter to take a shot of the landscape. You could do that when the Sun is on the highest altitude to add a shot of the Sun without the 

Again, after 2-3 hours, when the Sun starts to approach the end of your field of view, you change the angle again facing west, remove the filter, take a shot of the landscape, put the filter again and let the camera shoot the final set of the Sun's photos until sunset.

Just after sunset you remove the filter and take landscape shots covering the area from west to south. This is going to be the 'afternoon landscape' shots of the panorama. When the first stars appear, turn the camera west-north and take a few 'transition shots'. These are intermediate shots between the day shots and the night shots to make the transition from the day to night smoother.

At next, you should take shots covering the area from north-west to north-east, (don't forget to include the ground). This will be your night part of the panorama.

About the startrails, in order to achieve a wider startrail and also to make the transition from the trails to the other photos smoother I took a half an hour startrail west-north, an 11 hour startrail at north and finally a half an hour startrail east-north. If you don't have a very large memory card you should calculate the number of shots available in order to adjust the camera settings accordingly. For example if your prefered settings for your startrails is ISO 800 and 30 seconds exposure, consider the fact that if you change it to ISO 400 and 60 seconds exposure you get similar (or even better) results occupying only half memory card space.

For the startrails you set the DSLR exposure to Bulb, connect the intervalometer, set the intervalometer exposure to whatever you choose, interval time to 1 second, number of shots to infinite (00) and start shooting! After the startrails you may shoot some darks for better results after the process. Darks are shots with the lens cap on, with the same settings as the startrail shots. A more detailed analysis about startrails will follow in another tutorial.

After the startrails, before the sunrise, when the stars begin to faint, take some transition shots with the camera facing north-east and you are done!
Congratulations!!! You now have all the material for the 24 hour little planet!

F) Processing:

The first step is to merge the Sun disk shots with the photos taken during daytime. Stack the Sun's disk shots taken at your first angle (east), with your favorite stacking software. I use Startrails for that. Open your first angle shot with Photoshop and apply the stacked image as a separate layer. Remove the black part from the stacked image. There are a number of ways to do that. You can use the 'magic wand' tool to select and then delete the black background. Then select carefully every little disk with lasso tool, invert the selection and use the eraser tool to erase what's left from the black backround. Finally, merge the layers. Repeat the process with the shots taken at noon and afternoon. This is how a stacked Sun sequence looks like.

There is something to consider about the shots taken at noon. They are taken with the camera facing towards the Sun, therefore the landscape may be dark (under-exposed). If previously, during the shooting, you have taken various exposures from the same angle at noon, you can create a High Dynamic Range picture. Another alternative is to just add the missing landscape information (dark), combining the different exposure shots in Photoshop. A simple way: select the landscape with magic wand, copy and paste it as a layer to the noon under-exposed photo, apply if you want 50% opacity to the new layer to hide any visible variations between the two layers and then use eraser tool also with opacity (10-20%) to fine tune any rough edges. It's not an exact science... It requires experimentation and try and error attempts.

You should end up with a number of images ready for stitching as shown here. Due to the fact that images are heterogeneous you will have to add many Ptgui control points yourself. See this image for the other options. You should export the blended image AND the layers because the latter is necessary for corrections at some areas of the stitched image where stitching was not accurate. This is how the initial stitched image should look like and this is one of the layers. The final blending - corrections is done with Photoshop.

Well... That's it! Let me know about your 'little planet' attempts!