Today we’ll discuss the choice of the best objects for astrophotography according to your equipment. Astronomy lovers say: “There is no such photographer who would not dream of becoming an astrophotographer.” Indeed, although the process of visual observation is a unique, incomparable pleasure, various reasons prompt people to take up astrophotography.
Someone wants to share the beauty of the heavens with others; someone wants to see more: after all, during visual observations, even the brightest and most interesting objects of deep space look ordinary-looking gray specks, and the dimmer ones are not visible at all. Even a small telescope will show them in color with details imperceptible to the human eye when photographing. And in the images of planets, you can often see more small details than visually. Experienced amateur astrophotographers get pictures as good as pictures from the Hubble Telescope.
Of course, there is not enough good equipment to achieve significant results, and the subsequent processing of the obtained initial images plays an almost important role. But processing skills come with experience, and it is better to acquire a telescope for astrophotography right away. There are not so many clear nights to be wasted fighting the recalcitrant “iron.”
Who Are The “Planets” And “Deep Sky” Guys?
Usually, astrophotographers specialize in types of photography as “planets” (shoot the moon and planets) or “deep-sky” (shoot galaxies, nebulae, star clusters, comets, etc.). Depending on this, the equipment used, image processing methods differ, and the requirements for shooting conditions are often opposite.
So, if you need a calm atmosphere for shooting planets and the moon (even if it is not very transparent), the so-called “sing,” then transparency and lack of illumination are essential to get good pictures of deep-sky objects calm of the atmosphere is not crucial.
Consider astrophotography of deep-sky objects (DSOs) or deep-sky objects. All DSOs have very low surface brightness, so even with the largest telescope, the human eye sees them in black and white and does not see all the details of their structure.
In contrast, a film or camera sensor can accumulate light falling on it for several minutes when shooting with long exposures. At the same time, colors and small details invisible to the eye begin to appear in the picture.
With digital photographic equipment and the subsequent computer addition of a series of images, the total exposure time can reach tens and even hundreds of hours. In general, modern astrophotography is unthinkable without the use of computer processing of images.
But although image processing is an exciting lesson with its secrets and nuances, this is a separate, huge topic. We will not touch on it in this article, especially since the source materials for processing still need to be obtained. Consider the astrophotography equipment requirements for astrophotography.
Which Mount Is Suitable for An Astrophotography Telescope?
A good mount is almost more important than a telescope (lens) and a camera for high-quality astrophotography. So, a small telescope or even a photographic lens on a rigid mount will allow you to get excellent pictures. In contrast, even a 10-inch telescope without a good mount is entirely useless for astrophotography.
The mount should be driven in both axes and the ability to control from a computer – this will allow auto-guiding.
The fact is that even the toughest and most accurate mounts lead the telescope somewhat unevenly; during visual observations, we do not just notice this. But during photography, tracking errors accumulate, and the stars in the image lose their round shape, become dashes or ticks. It becomes more pronounced the longer the focal length of the lens.
The computer monitors guidance errors using an auto-guide. It adjusts the operation of the mount drives to eliminate them in time. In general, a smaller telescope on a more stable mount is preferable to a more aperture but unstable telescope.
What Is the Recommended Lens Aperture?
The telescope for practical astrophotography should be as fast as possible (have a relative aperture of f/6 – f/4) – this allows you to collect more light from celestial objects in a shorter period. Usually, for deep sky astrophotography, either a small semi-apochromatic mounted on a mount with auto-guidance is used – as a compact travel tool if the volume of luggage is limited, or a reflector with an aperture of 200-250 mm on an equatorial mount.
The telescope should have an electric focuser or at least a two-speed Crayford focuser – if, during visual observations, small focusing inaccuracies are compensated for by the lens of the eye, and we will not even notice them. When using a telescope for astrophotography, this will lead to a blurred image.
Features of Shooting Deep Space Objects
Deep-sky objects are usually taken in the direct focus of the telescope, while it is used as the lens of a DSLR. For this, a corresponding threaded T-ring is attached to the camera. Which, in turn, is screwed onto the thread on the focuser of the telescope.
The most popular among amateurs is Canon SLR cameras, but you can also use them if you already have another camera.
For deep-sky astrophotography, it is highly desirable to drive away from city lights. In conditions of strong illumination at exposures longer than 30 seconds, the brightness of the sky background increases too much, and it is impossible to get any high-quality images.
An exception is shooting through narrow-band filters, but they cannot replace the dark suburban sky.
Features of Lunar-Planetary Shooting
Lunar-planetary photography has its characteristics, and it often happens that an experienced deep sky photographer cannot even get a photo of the moon through a telescope. The fact is that the moon and planets are very bright objects, and when shooting them, you do not need a long exposure. Usually, they are filmed with webcams or unique astronomical cameras; then, the video is split into separate frames and folded using special software.
There are special adapters for 1.25″ diameter, with which the webcam is installed instead of the telescope eyepiece. Also, when shooting planets, black-and-white cameras are often used using light filters, respectively, of red, green, and blue colors, and subsequent channel-by-channel addition to obtaining a color image.
In lunar-planetary imaging, the requirements for the accuracy of telescope guidance are not so high; minor errors are compensated for during processing. In principle, the first photos from a telescope can be obtained even with manual guidance, but it is still better to use a motorized mount.
A telescope with the largest focal length is needed to increase the size of the planet’s disk on the camera matrix. To magnify it, 3x and even 5x Barlow lenses are used, while the equivalent focal length of the system can reach up to 10 meters.
Question: Which Telescopes Are Suitable for Taking Pictures of The Moon?
Answer: A variety of telescopes are used for astrophotography of planets; the most common are Equatorial Reflectors. In this case, the larger the aperture, the more details, and fine details will appear in the picture.
Suppose you want to get your first photo through a telescope as soon as possible. In that case, you should try shooting the moon – this is the most contrasting and relatively simple object, and sometimes even a single frame is enough to get a high-quality picture.