Photographing Mars

Discussion in 'Digital Cameras' started by Kulvinder Singh Matharu, Aug 5, 2003.

  1. I've got a Canon 10D, and am considering photographing Mars (it's
    very bright and close at the moment).

    Is it worth while hiring a telescope? and which one would you
    recommend.

    I have a 400mm zoom, but I gather that this is inadequate and that
    I'll need to at least get a teleconvertor.

    Any tips? Thanks.

    --
    Kulvinder Singh Matharu
    Contact details : http://www.metalvortex.com/form/index.htm
    Website : http://www.metalvortex.com/

    "It ain't Coca Cola, it's rice" - The Clash
     
    Kulvinder Singh Matharu, Aug 5, 2003
    #1
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  2. Kulvinder Singh Matharu

    Tony Spadaro Guest

    If you intend to photograph Mars as anything but a red dot in the black
    sky, you are going to need a telescope. 400 mm isn't even enough to
    adequately photograph the moon. I don't remember what size scope I was on
    the one time I saw any detail on the surface of Mars but I'm pretty sure it
    was 8 or more inches - and probably a 12 inch reflector. A 6 inch reflector
    will give a decent view of Jupiter but it would still be awfully small for
    photography.
    My information is pretty old as I haven't done much planet gazing since
    the 60s but if you were to pick up a copy of Sky and Telescope or one of the
    other astronomy magazines, I would assume you'll find all the details you
    need for photographing Mars this month.
    I should point out that 'very big and very bright' in astronomical terms
    does not mean a whole lot in photographic terms usually.

    --
    http://www.chapelhillnoir.com
    home of The Camera-ist's Manifesto
    The Improved Links Pages are at
    http://www.chapelhillnoir.com/links/mlinks00.html
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    Tony Spadaro, Aug 5, 2003
    #2
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  3. Kulvinder Singh Matharu

    Bob O`Bob Guest


    Well ... yeah -- it is.
    In a few days, it'll be closer than at any time in the last 60,000 years.

    But it'll do it again in another 280 or so.

    I'm not waitin'


    Bob
     
    Bob O`Bob, Aug 5, 2003
    #3
  4. Kulvinder Singh Matharu

    Ron Hunter Guest

    A nice 12" would be feasible, but I rather suspect that getting one
    about now will prove a challenge.
     
    Ron Hunter, Aug 5, 2003
    #4
  5. Kulvinder Singh Matharu, Aug 5, 2003
    #5
  6. To photograph distance planets you need a long
    focal length. Mars will be only about 25 arc-seconds
    in apparent size, so you need a large aperture telescope
    so that it has a small diffraction spot size, and
    a long focal length to spread the detail across
    your pixels.

    The 10D has about 7-micron pixel spacing, so at
    700 mm focal length you would get:
    arctan(0.007/700) = 0.00057 deg = 2.1 arc-seconds per
    pixel. So on the 10D that gives about 12 pixels.
    You really need at least 4 pixels per diffraction
    spot size (because of the RGBG pixels).
    On a 10-inch telescope the diffraction spot size is
    about 0.5 arc-second, so 0.1 arc-second per pixel
    is needed. This is 21 times longer focal length
    than 700mm = 14700 mm. On a 10-inch telescope
    that is f/58! Next: you need a really stable
    atmosphere or turbulence will wipe you out.
    Also a very stable mount that tracks compensating
    for the Earth's rotation. The Earth rotates at a
    rate of 15 arc-seconds/time-second on the celestial
    equator. Focus will be
    critical too. Thus, it is very difficult.
    Anything above f/20 or so should be pretty good
    (5000 mm focal length).

    That said, the 10D is superb. If you can pull it
    together, take lots images trying for the most
    stable air (which may last only a fraction of a second
    every minute or so).

    Good luck.

    Roger Clark
    Photography, digital info, astrophotos:
    http://www.clarkvision.com
     
    Roger N. Clark, Aug 6, 2003
    #6
  7. Kulvinder Singh Matharu

    Luke Guest

    Kulvinder,

    From what I understand as far as the average consumer goes you will be able
    to do much better with film than with any normal digital camera.

    To get a good exposure you need very slow shutter speeds and you will
    generally end up with too much noise in a digital camera. Film doesn't
    really have the same problem, you can take very long exposures and still
    maintain dynamic range.

    CCD's used in astronomy are cryogenically cooled to reduce the dark current.

    For any consumer grade telescope if you want to take a photo which will
    revel detail on Mars one of the major limiting factors will be how still you
    can keep the telescope. You will need a very firm mount and don't go
    anywhere near it whilst you are taking the exposure.

    Good luck, it's a fascinating project, but don't expect miracles unless you
    can get hold of some top notch astronomy kit.

    Luke
     
    Luke, Aug 6, 2003
    #7
  8. Kulvinder Singh Matharu

    DL Guest

    DL, Aug 6, 2003
    #8
  9. Kulvinder Singh Matharu

    DL Guest

    The mount is indeed very important. However, digital cameras have far surpassed
    film for lunar (moon) and planetary (e.g., Mars) work. For planetary, the
    technique is to take a lot of digital images in a short period of time, and then
    combine them. Film still rules for widefield stuff IMHO, though digital cameras
    are catching up.

    Strangely, cheaper digicams and webcams are better for planets than DSLR's as
    you don't get mirror vibration in the former, and you can capture a huge number
    of images in a short time with the latter.

    See also my other post on this topic.

    Dick
     
    DL, Aug 6, 2003
    #9
  10. Kulvinder Singh Matharu

    Luke Guest

    For planetary, the
    What do you use to adjust alignment in recombination? Or do you just stack
    and hope for the best?

    Luke
     
    Luke, Aug 6, 2003
    #10
  11. Roger N. Clark, Aug 6, 2003
    #11
  12. On Tue, 05 Aug 2003 17:56:23 -0600, "Roger N. Clark"

    [snip]
    Thanks very much for the advice!

    Took a hand-held photo of the Moon using my 28-135mm IS zoom lens a
    couple of months go...

    http://www.metalvortex.com/photo_art/moon/index.htm

    I rather like to think that it came out OK!

    --
    Kulvinder Singh Matharu
    Contact details : http://www.metalvortex.com/form/index.htm
    Website : http://www.metalvortex.com/

    "It ain't Coca Cola, it's rice" - The Clash
     
    Kulvinder Singh Matharu, Aug 6, 2003
    #12
  13. Kulvinder Singh Matharu

    Zol. Guest

    Love the composition of that shot - great! Zol.

     
    Zol., Aug 6, 2003
    #13
  14. Kulvinder Singh Matharu

    Lionel Guest

    Nice!
    I'm very impressed. I'll have to try it myself with my 100-300mm 'L'
    lens.
     
    Lionel, Aug 7, 2003
    #14
  15. Kulvinder Singh Matharu

    Paul B Guest

    Actually, noise (in the form of hot pixels) is a problem at longer exposure
    settings. There are several programs in the public domain which can be used
    to extract the hot pixels (by taking a second "black" frame immediately
    after while the same hot pixels are still glowing). One such program is
    called (funnily enough) Blackframe. You can get it from www.mediachance.com.
    The 10D is probably better as it uses a "cooler" CMOS sensor rather than a
    10D.
    In any case, Mars, as the brightest star in the evening sky will not take
    anything like 15 seconds to capture, even at high magnification through a
    telescope.
     
    Paul B, Aug 7, 2003
    #15
  16. Kulvinder Singh Matharu

    Luke Guest

    Lionel you're getting the wrong end of the stick, I'm talking exposures of
    several minutes and longer. This kind of work is totaly alien to the would
    of comsumer photography. That kind of exposure is only possible with a ccd
    if it is cryogenically cooled but it is possible with normal film if you
    have the right sort of camera.

    As DL pointed out earlier the only way you can compete using a digital
    camera is to take lots of individual exposures and average the results.
    However this doesn't help you if the signal level is so low to start with
    that it is down in the amplifier noise.

    Luke
     
    Luke, Aug 7, 2003
    #16
  17. Here are some examples of what the 10D can do in astrophotography.
    It is revolutionary:

    http://www.hostultra.com/~ghonis/050503D10.html

    For 1Ds, D60, check these astrophotos out:

    http://www.pbase.com/jayseejay/messier

    http://panther-observatory.com/deepsky.htm

    http://panther-observatory.com (go to gallery then 2003)

    Roger
     
    Roger N. Clark, Aug 7, 2003
    #17
  18. Roger N. Clark, Aug 7, 2003
    #18
  19. Kulvinder Singh Matharu, Aug 7, 2003
    #19
  20. Kulvinder Singh Matharu

    Luke Guest

    Luke, Aug 7, 2003
    #20
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