@blackhole3553
Great! Thanks for posting
@frans_d7989
If you use a slow scopes to view the same image as a fast scope, the image on the slow scope will be larger meaning that the image is covering more area in the eyepiece, if the same eyepiece is used for both. For example, if the image is 2 times larger than on a fast scope, its area is 4 time (2^2), meaning the same amount of light of the object has to cover 4 times the area that it did on fast scope for the same amount of light producing and a darker image in the eyepiece.
@jpastroguy
One important piece of information is the relationship between focal ratios. How much faster is an F4 vs. F6? There must be a formula. And it can affect decisions on which telescope to buy.
@arturonavarrosanchez7162
Thanks !!
@as1919troboy
great information
@69Atho
So much incorrect information in this video. Varying the f-ratio of a constant aperture has little or no affect on real S/N, except in certain limited circumstances. The relationship of exposure-time and f-ratio only holds true for equivalent focal lengths, which means the aperture must be varied to produce a given f-ratio. The “CCD f-ratio myth” originates in people’s experience with film-based photography, where the exposure-time/f-ratio relation is practically considered a “law of nature”. But that “law” is actually a consequence of some peculiar properties of film emulsions that largely do not affect CCD imaging.
@colelacey2875
Thanks, very helpful
@grugbug4313
Solid! Top KEK! Peace be with you.
@primoroy
The "length" the light travels is incorrect. Slow telescopes are dimmer because the magnification is higher.
@moritzheintze7615
The tricky detail: most telephoto lenses are shorter than their focal length. How? they have a built-in teleconverter or Barlow lens. The same applies for SCT's.
@larrywiseman5534
love your videos. Question? is it okay to leave a telescope outside i. e. overnight in the heat or the cold if its completely covered?
@rdallas81
You can stack photos to bright the objects
@ronm6585
Thank you.
@atluangapachuau
very helpful...
@fadzilgoh2411
Good info
@astroabhi_09
Osummm ❤
@Xindian_mapping_n_Edits
If mak has f/15 is it too bad
@valentinotera3244
Do the obvious party ratio
@kushalgokhale9114
0:23 Focal length of what? In a refractor telescope there are two lenses.
@TheAlienTechs