Hi Tim - thanks for the answer:


Quote Originally Posted by tkerr





Generally, it's usually a matter of the Aperture of the objective lens.
A majority of astroimages are done with a telescope, but not all. I guess it depends on what you are trying to accomplish. A camera lens is usually smaller and will give you a wider field of view. Using the 100-400mm gives me more flexibility than using a fixed focal length telescope. But the telescope has a larger aperture and longer focal length which will have greater light grasp and resolving power.(Greater Detail), and increased image scale.


BTW, you don't need a telescope mount to take pictures of the night sky. You will if you want to do something like these two pictures, but there are other things you can do also.

I've been out all weekend and only now have the opportunity to reply. I was referring specifically about capturing magnified images of galaxies, nubulae etc. I remain a little confused about two things though.


Quote Originally Posted by tkerr


Generally, it's usually a matter of the Aperture of the objective lens.



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However a Canon 600mm f/4 hasa bigger aperture than the telescope you used, which was 600mm f/7.5 if I read it right. I have no idea which is more expensive. The canon lens is not cheap.


Then you said:


Quote Originally Posted by tkerr
BTW, you don't need a telescope mount to take pictures of the night sky. You will if you want to do something like these two pictures, but there are other things you can do also.

but that was my main point of surprise because the second shot was not from a telescope but instead a Canon 100-400mm f/5.6, yet it shows what I typically thought required a long focal length.


In my limited exposure to telescopes I've encountered the term "light bucket" which was explained to me as "not a particularly long focal length but very large aperture to capture the light". My expectation would be a focal length not dissimilar to a telephoto camera lens but a monster aperture. Conversely if it were simply this description then I don't know why people wouldn't use these "light bucket" style telescopes more often for land based photography, yet I don't believe they do...


I understand your reference to the telescopes being prime lenses when compared to a camera's zoom lens. I'd expect these long+stacked exposures are sensitive to distotions that are lesser in prime lenses.


Great video. Nice alternate use of your obvious skill at time-lapsefor stacking!


Paul