Some problems with telescopes

1, generally speaking, the aperture is 1.5 times, but a good objective lens can be enlarged to twice the aperture. The focal length is related to multiple, and the focal length of objective lens/eyepiece is equal to multiple, so the focal length is also related to the maximum magnification. For example, the aperture of your mirror objective is 100mm, and the focal length is 3000 mm. If you use the eyepiece of 15mm, you can only get 200 times. If it is less than 15mm, it is more than 200 times.

2. Although the mirror has no chromatic aberration, it is very suitable for photography, but the mirror has chromatic aberration. Generally speaking, the middle part of the photo is normal and the edge part will be distorted. You need an aberration correction mirror, which is not cheap.

The reflection of 3 150 aperture can be amplified by up to 300 times. If the focal length is long enough, the planet can be observed with a slightly larger wide-angle eyepiece, and the aperture of 150 is not small enough to focus light, and some brighter nebulae can also be observed.

4. It is said that the focal length is related to the multiple, and the longer the focal length, the greater the multiple (when the focal length of the eyepiece is fixed).

In addition, SLR plus telescope, as long as the exposure time is appropriate, will not hurt the camera.

Besides, it doesn't matter if you want to shoot with a small caliber upstairs. It's actually very important. If the aperture is small, the exposure time should be prolonged. If it is extended from 5 minutes to 10 minutes, it is still a trivial matter, but if it is extended from 2 hours to 4 hours, it is not a trivial matter, especially if it is extended for one minute in winter, it will be frozen for one more minute. Long exposure time is always bad for (digital SLR) cameras. In addition, wasting time and freezing are trivial matters, and prolonged exposure time will increase a lot, which is no small matter. The noise that could have been eliminated by 1-2 dark field will increase after the exposure time is extended with a small aperture. You don't want to do such boring things as shooting 10 dark field.