Photography methods of direct focus photography

The first step in direct focus photography is to set up your telescope. This action includes: setting up the telescope, camera, guide equipment, etc., locking them on the equatorial mount, and balancing the right ascension and declination axes. Balancing this action is extremely important and can be a huge factor in the success of your photo shoot tonight. The next step is to correct the polar axis. The polar axis is equal to the earth's rotation axis. If you can align it very accurately with the North Pole, it will be really difficult to take a bad picture.

The third step is to guide. The most troublesome part of direct focus photography is the guide. When we arrive at the observation site, set up the equatorial mount and telescope, connect the camera, and align the polar axis, it is not possible to press the shutter button. As mentioned before: Because the earth rotates, an equatorial mount is necessary. However, the equatorial mount is not the Earth. The operation of the motor and the correction of the polar axis cannot be completely equal to the rotation of the Earth, so errors will occur. This error will show up in the photo, so we need to use another telescope - the guide scope to view and correct this error (because after the single-lens camera presses the shutter, the image cannot be seen in the window, so you cannot use the telescope during shooting. do this). That is to say, after we set up the instrument, we have to use the guide mirror to find a bright enough star near the photographed celestial body, put it into the field of view of the guide star monitor, and then use a high-power eyepiece to guide the star from the beginning to the end of the exposure. , stare at the star and correct for the offset you see (aka the equatorial mount's error). Every picture must be like this. The longer the focus, the more careful and careful it is. Think about it, you have to stare at the guide monitor for hours on a cold night, you can't go there, you can't do anything, and you have to fight off sleepiness! This is really not what people should do.