How to shoot the sun with astronomical telescope

Generally, when shooting the sun with a popular astronomical telescope, in order to obtain the image brightness suitable for the camera terminal, it is necessary to configure a dimming/filtering device at the objective lens.

Among the white light dimming/filtering devices, the Baader Planetarium is the most cost-effective. It has two specifications, the density is 3.8 and 5.0 respectively. The density of 3.8 is mainly used for solar photography, and the corresponding light transmittance is about 65438+ 16. This kind of camera is used to shoot photographic equipment, and its density is not enough to protect eyes from injury during visual inspection. The light transmittance corresponding to density 5 is one in 100,000, which is used as a solar filter for naked eye observation. If used for visual inspection, a density of 5.0 must be used.

Budd membrane is a kind of solar filter. Different from other similar products, Budd film can reduce light and harmful radiation without reducing the contrast of the subject. In other words, using Budd film as a solar filter can get better image quality, and even record sunspot activity on the surface of the sun easily. The appearance of Budd film is silver film.

The camera terminal configuration for photographing the sun is no different from that for photographing the stars. You can use a single-lens anti-halo to obtain a direct-focus optical path (see the figure below), or you can use a card holder or a mobile phone holder to fix a card machine or a mobile phone to shoot. However, it is difficult to avoid strong stray light interference during the day, so the expected effect is far less than that of direct focusing method.

SLR direct focusing optical path

SLR direct focus object

cardholder

Of course, if you have a professional CCD or electronic eyepiece, you don't have to worry about the camera terminal. These devices can achieve better expected results.

By the way, all of the above are full-band white light modes, because Budd film is a broadband dimming device with flat amplitude-frequency characteristics. If you want to shoot color light with a specific wavelength, you need to configure corresponding narrow-band filter equipment, such as prominence mirror. In this way, we can get a certain level of image of the sun surface for more professional viewing and research.