Good suggestion, Cameron. I've had problems getting DSS to produce a decent image with the various comet modes in the program. But I may try waht you suggest with the new lens.
So how dark does the sky need to be (avoiding reflection of light from buildings etc)? How would Li know that I could take great photos without having to go way out into the country where there aren't even animals?
Ralph Thompson wrote:
I would have never thought of Copperopolis as no light pollution... It's not THAT far in the sticks....
I guess it depends on your definition of sticks, Ralph. In my community, we're blessed with no streetlights, no town lights, the the neighbors are spaced fairly far apart---I live on 4 acres. The nearest town of any size that would produce light pollution is 20 miles away with numerous hills in the way. In fact, the astronomy club from Stockton (about 45 miles to the west) uses a nearby area as a "dark site." These shots were taken from my driveway.
jforkner wrote:
Got me. I assumed it is the diameter of the objective---I just used the filter size for the lens.
Jack
Yes, I know that "Clear Aperture" of a photo lens means something slightly different (and is more complicated to calculate) than that of a Telescope Objective. However, I would presume that the angular resolving power still is somewhat dependent on the diameter of the front lens elements.
In any case, my main point is that photographiaclly, it looks like the 100-400 II is very similar to the Televue 76 - a very highly regarded (small) astro telescope.
matanuska wrote:
Yes, I know that "Clear Aperture" of a photo lens means something slightly different (and is more complicated to calculate) than that of a Telescope Objective. However, I would presume that the angular resolving power still is somewhat dependent on the diameter of the front lens elements.
In any case, my main point is that photographiaclly, it looks like the 100-400 II is very similar to the Televue 76 - a very highly regarded (small) astro telescope.
I checked it out and the clear aperture is the focal length divided by the f ratio.
That would give the TV 76, (with a clear aperture of 76mm and f/6.3), a 480mm focal length. Jack's photos at 400mm 5.6 would give his lens a clear aperture of just over 71mm.
The lens at that setting and the scope are indeed similar in specs.
I've been interested in trying some Astrophotography, and just got through reading numerous on-line tutorials; all of which recommended fast, WA lenses.
Never thought of using 5.6mm Tele., but your results sure show that it works just fine!
I've been interested in trying some Astrophotography, and just got through reading numerous on-line tutorials; all of which recommended fast, WA lenses.
Never thought of using 5.6mm Tele., but your results sure show that it works just fine!
Leigh
Common amateur telescopes used for astrophotography range anywhere from f/4.5 to f/11. That type of work usually involves long, guided exposures and image stacking. It's a somewhat different mindset from what is found in the "normal" terrestrial photographic world.
I have one of these mounts/drive kits on order, well, still back ordered...
I was wondering, what other bits and pieces do I need?
I was going to try both my FujiFilm X-E1 and Canon 5DMkII.
I have the RSS L bracket on both of these, of course.
I have all kinds of lens, and I have the version I of the Canon 100-400.
Though, I do have the 200/1.8L, heh, I don't think it would support that much weight.
*8^)
Oh, I do have an FD 500/4.5 L I use with the X-E1 body, it's very light weight.
I should get the mount for this converted to EOS, hmm...
I drilled a 1/4" hole in the dovetail bar and mounted the lens to it using a 1/4-20 bolt. Be sure to locate the hole so the bolt will not interfere with dovetail---I drilled mine 3" from one end. Just make sure the bolt length is not too long.
All set for the eclipse. Too bad about the partial for you; we get a total.
