Pictures Of the Stars

Discussion in 'Digital Cameras' started by RacerX, Nov 29, 2003.

  1. RacerX

    RacerX Guest

    Ive seen some really nice pictures of the stars and moon and other such
    things, my question is how do i get pictures like these. Ive recently
    purchased a canon Digital Rebel 6.3 Mp SLR with a canon ef 80-200 4.5-5.6
    and an EFS 18-55 3.5-5.6. Is there a Telescope "preferably cheap i just
    spent all my money on the camera and lenses" that can hook up to the camera
    or however you do it, or do i just need one of the huge canon lenses?

    Thanks for any and all help

    Craig
     
    RacerX, Nov 29, 2003
    #1
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  2. RacerX

    Ray Fischer Guest

    There are lots of telescopes that you can attach the dRebel to. The
    weight of the camera and the ability of the scope to handle it is the
    biggest consideration. T-rings are readily available from places such
    as ...

    www.telescope.com

    Cheap? Well, telescopes are like cameras, except more so. Money
    gets you quality, and the cheap stuff is crap.
     
    Ray Fischer, Nov 29, 2003
    #2
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  3. RacerX

    JPS Guest

    In message <N%Rxb.18119$>,
    Remember also how much atmosphere the light has to pass through. The
    sunny-ISO-for-shutter-speed @ f16 rule is designed for close objects
    that lose almost nothing to the atmosphere. f16 will underexpose.
    --
     
    JPS, Nov 29, 2003
    #3
  4. RacerX

    Ron Andrews Guest

    For the moon, the standard exposure is the lunar f/11 rule. This is
    like the sunny f/16 rule for sunlit terrestrial objects, but it recognizes
    that we are used to seeing the moon as something lighter than a medium gray.
    For ASA 200, set the shutter at 1/200 (1/250 is close enough) and the
    aperture at f/11. While you are at it, bracket up and down until you get
    something you like.
    For stars, you can take up to 30 second exposures before you see
    appreciable elongation of the stars from the earth's rotation. I you are
    shooting the big dipper you can go as long as 2 minutes. The longer the
    exposure, the more feint stars you will find. Orion is a favorite subject
    for this kind of picture taking because it is a bold and recognizable
    constellation, it has different color stars, and it as nebulas that will
    easily show up. Here is an example that was shot 2 years ago during the
    Leonid meteor shower (30 seconds, f/1.4, 800 speed film; yes, film still
    works):
    http://home.rochester.rr.com/andrewsfamily/images/2000s Pix/011118MeteorComp2W.jpg
    Here is the larger version of the same image:
    http://homepage.mac.com/randrews4/.Pictures/Misc/011118MeteorComp2.jpg
    Taking pictures through a telescope is very difficult for anything
    other than the moon or the sun (with an appropriate filter). You need a
    clock drive for exposures of several minutes. The exposures you see
    published by NASA are often exposed for several hours. This requires a very
    good clock drive and a telescope that is bigger than the one you are
    shooting the pictures through and attached to it. You look through the
    larger scope and make fine adjustments to keep the attached smaller scope on
    track.
     
    Ron Andrews, Nov 29, 2003
    #4
  5. RacerX

    RacerX Guest

    RacerX, Nov 29, 2003
    #5
  6. RacerX

    cc Guest

    I also plan to get a telescope for some astrophotography. I'm looking at
    a Celestron 5 or 8 reflector with a motor drive and maybe some sort of
    fancy object database but that isn't absolutely necessary (and adds a
    lot to the price). Just a basic telescope, tripod, and motor drive is
    not too expensive, not more than a good quality lens for the camera
    (which the telescope would be in this case). If you want to photograph
    stars, clusters, and galaxies, etc. as opposed to mostly objects within
    the solar system (the moon, planets, etc.), you should get a refector
    and not a refractor to avoid chromatic aberration. Reflectors work well
    for planets and the moon too. Meade and other brands also make good
    reflectors but my experience is with Celestrons at school. With a motor
    drive you can expose for as long as you need to get a good image without
    worrying about the object tracking across the sky because it compensates
    for the rotation of the earth.

    I am curious about your first purchased product, the adapter. It looks
    like it is for one specific brand of telescope or is it for any brand of
    telescope?

    Good luck.
     
    cc, Nov 29, 2003
    #6
  7. RacerX

    gr Guest

    Idiot alert. Buddy... here's some clues for you:

    1. The moon has no atmosphere.

    2. The light reflected from the moon passes through the same atmosphere of
    Earth as the sunlight reaching the "close objects" you talk about.
     
    gr, Nov 29, 2003
    #7
  8. "Idiot alert" indeed...

    HMc
     
    Howard McCollister, Nov 29, 2003
    #8
  9. RacerX

    Ron Andrews Guest

    I've seen this contention often. You can find many exposure
    recommendations for shots of the moon that change with the phase of the
    moon. I don't buy it. Assuming the moon is a diffuse reflector, the sunlit
    part of a first quarter moon is just as bright as the sunlit part of a full
    moon. Sure there is less light, but it is a smaller image of equal
    brightness.
    This discussion is largely academic as anyone shooting the moon should
    bracket liberally.
     
    Ron Andrews, Nov 29, 2003
    #9
  10. RacerX

    JPS Guest

    In message <bqa8n6$208679$-berlin.de>,
    I didn't say it did.
    Yes, but of all the light that gets through the atmosphere directly from
    the sun, the part that lights the sky and makes it blue can still
    contribute to an object's overall brightness. The light from the moon
    that is diffused by the atmosphere does not contribute to the exposure
    of the moon; it simply brightens the night sky around it. See the
    difference?
    --
     
    JPS, Nov 29, 2003
    #10
  11. RacerX

    cc Guest

    Less total light, but approximately the same surface brightness, which
    is what really counts when you consider how much light will reach any
    given pixel (or particle of emulsion). Typically one would open the
    aperture all the way for astronomical shots and adjust only the exposure
    time, since the concept of depth of field is moot (everything's at
    infinity), but I guess for something as bright as the moon you have the
    option of using only the middle of the lens which is better optically.
    Otherwise, even with a motor drive there is still the factor of the
    earth's motion to consider (not to mention vibration etc.) so you want
    to keep the exposure as short as possible.
     
    cc, Nov 29, 2003
    #11
  12. RacerX

    Kin Lau Guest

    It's makes sense because the moon is not flat, but a sphere. Think of
    taking a frontlit vs sidelit picture of any spherical object.
     
    Kin Lau, Nov 29, 2003
    #12
  13. RacerX

    gr Guest

    Don't be ridiculous. The scattering of sunlight in the atmosphere
    contributes to just as much "extra light" lost to space as it does to ground
    illumination.

    There's absolutely no difference between a full-moon exposure and an
    exposure of pavement on Earth.

    There is a difference if the moon is not full, as someone incorrectly
    pointed out. A "half moon" is about a tenth as bright as the full moon,
    spread across an area half as big. So you'll need a couple of extra stops
    exposure if you're shooting a crescent.
     
    gr, Nov 29, 2003
    #13
  14. RacerX

    Ron Andrews Guest

    But if the moon is a diffuse reflector, then the angle of viewing
    doesn't make a difference. The angle of illumination will make some
    difference when you get to the extremes with a slim crescent. For a quarter
    moon, this is insignificant.
     
    Ron Andrews, Nov 29, 2003
    #14
  15. RacerX

    Kin Lau Guest

    The angle of illumination makes _enough_ of a difference. I look at my
    shots of a gibbous moon, and I can see quite a difference from one side
    to another. Here's a link to a nice gibbous moon shot (not mine),
    http://www.netaxs.com/~mhmyers/cdjpgs/7-10daymoons.jpg
    and one of a series of quarter moons
    http://www.netaxs.com/~mhmyers/cdjpgs/4moons.jpg
    and here's the link to the full page
    http://www.netaxs.com/~mhmyers/moon.tn.html .

    Load up the jpg's in your favourite editor, and play with the brightness
    level, and see how much of a difference there is in illumination across
    the shot. If you don't want to lose the detail, then you have to
    compensate.
     
    Kin Lau, Nov 30, 2003
    #15
  16. RacerX

    JPS Guest

    In message <>,
    How did we meet, again? I believe there was a discussion about
    sharpness of pictures, and you posted a link to an example, that wasn't
    sharp at all. I pointed this out to you, and you've been angry at me
    since. If I wasn't the first to mention it, someone else would have.
    You seem to blame me for all the other people who mentioned it, too,
    some of them much ruder than myself.

    And the full moon most definitely *does* under-expose at f16 with the
    1/ISO as the shutter speed, especially if it is near the horizon.
    --
     
    JPS, Nov 30, 2003
    #16
  17. RacerX

    gr Guest

    Here's another clue for you:

    So do daylight scenes, especially when the sun in near the horizon.

    DUH!
     
    gr, Nov 30, 2003
    #17
  18. RacerX

    JPS Guest

    In message <bqbjou$204o0t$-berlin.de>,
    Here's a clue for you: not all of the exposure of a distant mountain is
    from that mountain. What the light reflecting off the mountain loses
    through diffusion, it gains from diffusion of light coming off of other
    objects, and lowers contrast. The moon in the night sky has nothing
    else to gain from; it can only lose light to diffusion; it can't gain
    any from it, because there's not muych else up their with light to
    diffuse.

    Get it yet?
    --
     
    JPS, Nov 30, 2003
    #18
  19. RacerX

    Kin Lau Guest

    I'll take your word for it. All the advice so far on the various
    lunar/astro photography sites have been in agreement on this, and
    looking at your site, I'll take your experience over someone else's
    "guesses".
     
    Kin Lau, Nov 30, 2003
    #19
  20. RacerX

    Kin Lau Guest

    Here in Toronto, the moon's definitely a little lower in the southern
    sky right now. I've tried shooting the moon rising up out of Lake
    Ontario back in September, and you're right about it extra stops needed.
    I couldn't even _see_ the moon until it was a few degrees above the
    horizon, and then only a dull orange. About 15min's later, it was
    _much_ brighter.

    We were on the California coast this July, and couldn't even see the sun
    set into the ocean except for a couple of days. So that absorption rate
    can be much higher.
     
    Kin Lau, Nov 30, 2003
    #20
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