Some problems with telescopes

1, generally is said to caliber 1.5 times, but good quality objective lens can be magnified to caliber 2 times. Focal length and multiplier related, objective lens focal length / eyepiece focal length = multiplier, so the focal length and maximum magnification also has a certain relationship, for example, your mirror objective lens caliber 100mm, focal length of 3000mm, then you can only use 15mm eyepieces in order to get 200 times, less than 15mm will be more than 200 times that won't work.

2, although there is no chromatic aberration reflector this is very suitable for photography, but the reflector has aberration, in common parlance, is the middle part of the photo is normal, the edge of the part of the aberration, to use the aberration correction mirror to work, that thing is not cheap.

3, 150 aperture reflector maximum magnification of 300 times, if the focal length is long enough, with a slightly larger wide-angle eyepiece can observe the planets, 150 aperture is not small enough to collect light strong enough, you can also observe some of the brighter nebulae.

4, the above said focal length and magnification related, the longer the focal length, the greater the magnification (eyepiece focal length is fixed in the case)

Additionally, DSLR plus telescope as long as the exposure time is appropriate, will not harm the camera.

Additionally, upstairs said to photography caliber does not matter, in fact, it is very so-called, caliber is small, the exposure time to be longer, if 5 minutes to extend to 10 minutes is still a small matter, but 2 hours to extend to 4 hours is not a small matter, especially in the winter to extend a minute to more than one minute to be frozen a minute, and the exposure time is always long on the (DSLR) camera is not good, and in addition to wasting time and freezing is a small matter, that Longer exposure time will increase a lot of noise, which is not trivial, originally with 1-2 dark field can be eliminated noise, with a small aperture to increase the exposure time after the dark field to increase the number of sheets, you do not want to do shoot more than 10 sheets of the dark field of such a boring thing, right.