Starry Sky, Orbit, astrophotography Raiders (I)

Astrophysics has a romantic saying: The starry sky is the hometown of every atom in you. MichaelShainblum, a photographer from the United States, has a different kind of feelings about the universe and is good at natural starry photography. The night sky and the Milky Way under his lens are gorgeous and wonderful.

Shainblum said, "Sometimes, the starry sky has the biggest surprise, giving you a great view beyond your imagination."

For the northern hemisphere, from September to October every year, it's the starry sky season for another year. Are you eager to take photos, but are you troubled by not knowing where to start? Starry photography seems to be relatively tall, but in fact, after mastering certain astronomical knowledge and shooting skills, I believe everyone can shoot the most beautiful starry sky. Before sharing, let's enjoy some beautiful pictures of the starry sky.

There are a lot of articles about starry sky shooting on the Internet. I try to combine these fragmented knowledge points with my own experience, sort out the cost series and share them, comprehensively explain the pre-shooting technology and post-thinking, and introduce each step of post-processing in detail with examples.

commonly known as starry sky photography can be roughly divided into two categories: deep space photography (celestial photography) and star field photography. In general, deep space photography refers to photography with the main purpose of shooting deep space objects, which belongs to a professional shooting method, including the moon, the sun, nebulae and star clusters. It can also be divided into two categories: pure deep space celestial bodies and wide-area deep space, which require the use of expensive special professional equipment, such as star guide equipment, equatorial telescope, frozen CCD, astronomical telescope and so on. Star field photography, on the other hand, mainly takes pictures with natural landscape or artificial foreground, while the background takes common starry sky or star orbit as the distant view.

Astronomical knowledge

Why are other people's photos flashing in sky full of stars, and you are interested in taking pictures of the Milky Way, but the stars in the photos are scattered and disappointed? The fundamental reason is that the Milky Way did not appear in the night sky you shot. Starry photography is a special subject, which requires not only exquisite pre-and post-stage technology, but also understanding relevant astronomical knowledge is the key to success.

characteristics and differences of the Milky Way between the northern and southern hemispheres

The Milky Way refers to a milky bright belt across the starry sky. The Milky Way intersects the celestial equator in Aquila and is in the northern hemisphere. The Milky Way draws a band with different widths on the celestial sphere, which is called the galactic belt. Its widest point is 3, and its narrowest point is only 4 ~ 5, with an average of about 2, which is only a part of the Milky Way.

The Milky Way occupies a very important position in China culture. As early as the Han Dynasty, the famous China myth and legend The Cowherd and the Weaver Girl were included in the literature. China was also called Tianhan, Tianhe, Hehan, Yinhan, Xinghe, Xinghan and Yunhan in ancient times.

In fact, you can see the Milky Way at night all year round, but because the silver heart is the brightest and most spectacular part, shooting the Milky Way usually refers to shooting the silver heart in the concept of photography.

Friends who have taken pictures of the starry sky know that the direction and time of the appearance of the Silver Heart in the night sky are different from month to month and from season to season. Careful planning before shooting is the guarantee of success. In the northern hemisphere, the Milky Way, which spans the sky from northeast to south in the summer night sky, is like a rushing torrent. In winter, only the dim cantilever part can be seen, and vice versa in the southern hemisphere. Why is there such a difference in time and orientation? This requires us to understand the relationship between the earth, the solar system and the Milky Way.

generally speaking, the silver heart can be photographed in most parts of the northern hemisphere from March to October, and the silver heart can be photographed in most parts of the southern hemisphere from February to October, and only the cantilever part of the Milky Way can be photographed in other months.

Because of the geographical position and the earth's axis deviation, the shape and orientation of the Milky Way seen in the northern and southern hemispheres are different. Starry photography should conform to the laws of nature, and the scene in the photo should appear at a certain moment in nature. What I want to say here is that it is forbidden to make a joke when PS becomes a picture that does not conform to the laws of nature.

The natural conditions in the southern hemisphere are slightly better than those in the northern hemisphere, and the differences can be summarized as follows:

(1) You can see all the constellations at the equator, and the more you look north, the less you look south, so the Magellanic Cloud in the southern hemisphere is invisible in the northern hemisphere.

(2) April-July is the most suitable season to photograph the Milky Way, when it is spring and summer in the northern hemisphere and autumn and winter in the southern hemisphere.

(3) The shape of the galaxy photographed in the southeast and southwest of the southern hemisphere is reversed, while only the same galaxy can be photographed in the northern hemisphere.

(4) The position of the silver center in the northern hemisphere can usually be well combined with the landscape, but in the southern hemisphere, as the silver center rises to a certain position, it cannot be combined with the landscape, which is not conducive to composition. Especially after dark from August to October, the silver heart in the southeast is far away from the horizon, and it is difficult to combine with the foreground unless there are mountains in the landscape, but the galaxy can be photographed in the southwest, and the shape of the silver heart is reversed.

How to use moonlight to add color to photos

Starry photography is at night, which inevitably involves the moon. Because the brightness of moonlight is very strong, when a bright moon hangs high in the night sky, many stars are covered by the light of the moon, and few stars are visible. The moon is bright and the stars are rare. If you shoot the starry sky in this situation, the moonlight will directly affect the brightness of the Milky Way, and the shooting effect is very unsatisfactory. How to determine the best shooting date and understand the moon phase is a compulsory course for starry sky photography.

according to the shape, there are eight kinds of moon phases. The period is one month, and the sequence is: new moon → waning crescent moon → first quarter moon → convex moon → full moon → convex moon → second quarter moon → waning crescent moon → new moon.

How to avoid too strong moonlight when shooting the Milky Way? First, you can choose to shoot before the moon rises or after the moon sets; Second, during the Emei month, which is also my favorite shooting condition, the moonlight is not very strong, which has little influence on the Milky Way, and at the same time, it can illuminate the landscape and play a role in supplementing light.

shooting conditions

weather

starry sky photography also needs good meteorological conditions, among which cloud cover and atmospheric transparency are particularly worthy of attention. A proper amount of thin clouds can set off the atmosphere, which is an important element to add color to the time-lapse photography picture, but the thick clouds all over the sky are the nightmare of starry photography. Therefore, before making a shooting plan, it is generally necessary to understand and predict the local meteorological conditions in the target area.

Ordinary civil weather forecasts often only cover urban areas, and the information content is not targeted enough for starry sky shooting. We recommend using the website Sunny Clock and its related mobile application "Starry Sky Guide", which can query the forecast information such as cloud cover, transparency, visibility, temperature and humidity in local areas according to geographical location, which is more worthy of reference than civil large-scale weather forecasts. In addition, from the experience, strong winds can often bring clear and transparent weather, and the atmospheric transparency after rain is generally high, which is a good time to shoot.

Location

Geographical location directly affects the light environment, which is of great significance to starry sky photography. Generally speaking, we should choose a shooting location with less light pollution and higher altitude.

The light pollution in the night sky is mainly caused by the light generated by human activities being scattered by dust or water vapor in the low-altitude atmosphere. The easiest way to avoid light pollution is to stay as far away from the light source as possible, which means that starry photographers often look for shooting locations in the suburbs or even in the wild.

Take Beijing as an example. Only about 5 kilometers away from the city center can the Milky Way appear in the sky. Only more than 1 kilometers away from the city center can we truly appreciate its magnificence.

The increase of human activities makes the pure night sky more and more rare, and it is very difficult to completely avoid light pollution. We can choose to avoid light pollution by turning our backs or deviating from the perspective of the city. For example, we should not choose the location in the north of the city when shooting the summer Milky Way in the south sky, otherwise the part of the Milky Way near the ground will be covered by the light emitted by the city. Or do the opposite, use light pollution to render the atmosphere and make it a component of the image. ?

High altitude is another favorable factor for starry sky photography, not to narrow the distance with the starry sky, but to better avoid the interference of the atmosphere; For shooting the starry sky near the city, the elevation of several hundred meters to one kilometer can effectively improve the light environment.

tip: the following websites can be used to inquire about the global light pollution situation:

www.lightpollutionmap.info

/maps/world.html

https://blue-marble.de/nightlights

Time

First, we should determine a large time range, that is, the shooting season of the Milky Way, and secondly.

PlanIt, the APP starry sky prediction software in the mobile phone! For photographers, photohills, Distantsuns, Stellarium, etc. all have very accurate information about the Milky Way and the moon, so you can make careful plans before shooting.

shooting equipment

the pursuit of dim light and the complicated shooting environment in starry sky photography require adequate preparation on the equipment. With the development of technology and the targeted design of manufacturers, more and more equipment can be used for starry sky shooting, which brings more colorful means of expression. Knowing and using all kinds of equipment reasonably can make our shooting get twice the result with half the effort.

after years of development and polishing, digital SLR/mirrorless cameras has perfect functions, excellent comprehensive performance and mature ecosystem, and has a wide range of lens choices, and has always been the main equipment for starry sky photography.

camera

one of the biggest advantages of high-sensitivity full-frame camera over APS frame camera is high-sensitivity image quality. Because the starry sky photography needs ISO32-64 or even ISO128, high-sensitivity expressive force is very important for image quality.

lens

in starry sky photography, large aperture lens has obvious advantages, which can not only reduce noise by using lower ISO, but also improve the brightness of live view and the convenience of focusing and composition.

1 Nikon 14-24mm F2.8 and Zeiss 15mm F2.8 are good shooting lenses for starry sky. Recently, several large aperture fixed-focus wide-angle lenses have appeared on the market, such as Sigma 14mm F1.8 and Old Frog 12mm F2.8, which are all sharp tools for starry photography.

Fisheye lenses with larger viewing angles are also widely used in starry sky photography. These lenses are designed for shooting the sky. Fisheye lenses with circular frames are suitable for recording all-day pictures, and fisheye lenses with diagonal frames can be used to earn a wider view. The unique frame and distortion of fisheye lens can create novel and interesting pictures, and it also requires photographers to have strong control over the images. Wide-angle lens is not always used in starry sky photography, and the reasonable use of medium and long-focus lens can often bring unique effects. The medium focus lens has a large aperture and excellent image quality, which can achieve sufficient exposure and expose the gorgeous colors and rich layers in the central part of the Milky Way.

Of course, these lenses also have some disadvantages, such as high price, poor distortion control, too heavy, etc., so we should consider them comprehensively according to our own situation and ability. In addition to the main lens, I also use Sanyo 14mm/F2.8 to shoot the Galaxy, which is a large aperture wide-angle lens with very high cost performance.

timed cable release

It is also necessary to prepare a timed cable release for shooting the Milky Way starry sky. Because pressing the shutter by hand in a dark environment can easily cause the camera to shift or shake, the camera will automatically shoot after the interval time and the number of shots are set by the timer cable release. At present, Canon's 5DS and 5DR, as well as all Nikon's full-frame cameras and some half-frame cameras have interval shooting function. If the camera you use has interval shooting function, forgetting to bring cable release will not affect your shooting of the starry sky, galaxy and orbit. Some friends like to use the remote shutter, which is really useful when taking selfies, but I suggest that it is more reliable to bring a wired timed cable release.

High-speed memory card

You don't need to take many pictures of the starry sky and the Milky Way itself. However, if you want to shoot a circular star orbit or the delay of the starry galaxy, you need to shoot a lot of pictures, and finally synthesize the star orbit or make a time-delay photography work through the later software. Because the pixels of cameras are getting higher and higher now, it is necessary to prepare more high-speed memory cards. It's best to use raw format when shooting, which is convenient for later adjustment.

tip: 5 rules of starry sky photography

When shooting starry sky, we can use the 5 rules of starry sky photography to calculate the appropriate shutter time in order to ensure that the starry sky does not appear trailing. Simply put, you can get the ideal shutter time by dividing 5 by the focal length (focal length of Quan Huafu), for example:

11mm: 5/11 = 45s

16mm: 5/16 = 31s

24mm: 5/24 = 21s

tripod. After setting up the camera and tripod, be sure to carefully check whether each section of the foot tube has been fixed, and the three footholds should be on the flat ground, not on the edge of some potholes, so as to avoid sliding during shooting and causing displacement of the tripod.

headlights &; Flashlight

In order to avoid light pollution, the shooting places of starry sky photography are in remote areas far away from cities. Lighting equipment is very important in dark environment, and safety is the first principle at all times. This is an accessory that is often taken lightly. Another function of headlights and flashlights is to fill the foreground and help focus. Cable release, GPS, warm clothes and mosquito repellent are also necessary accessories.

galaxy shooting skills

what should we shoot for starry sky photography? Many people think that shooting the Milky Way or the star orbit is a success, and ignoring the landscape is a common problem. At the beginning of this chapter, it has been introduced that Hoshino photography is not astrophotography, but a kind of landscape photography, so it is consistent with the concepts of other subjects in landscape photography. The selection of foreground (landscape) is directly related to the success or failure of the photo. The Milky Way, like the sun and clouds, is just the big environment in the photo, and the composition should be coordinated with the landscape. The most common misunderstanding is to blindly pursue the details of the starry sky and ignore the overall composition of the photo.

In terms of shooting technology, the prophase and anaphase of starry sky photography are more complicated than other subjects. Because light pollution will affect the brightness of the starry sky, we will choose dark areas to shoot, and how to shoot photos with normal exposure in low light environment becomes the biggest challenge. Although long exposure can solve the problem of shooting the landscape, the position of the stars in the sky is not fixed, but rotates relative to the earth because of the autobiography of the earth. If the exposure time is too long, there will be a problem that the stars are "pulled" and the star orbit will be generated. So how to ensure that the stars are not trailing and can be exposed normally? The following is a description of the starry sky and the landscape.

starry sky shooting parameters

First of all, preset the parameters with manual shooting mode M file, and re-set.