August 2017 solar eclipse preparation

Discussion in 'Nature' started by rod_sorensen|1, Jan 12, 2017.

  1. With the incredible opportunity for USA residents to view a total solar eclipse in August, I'm starting to make preparations to be able to view AND photograph the eclipse. I thought I'd start by outlining what I'm thinking so far and then ask questions and hopefully get some advice from several of you experts here. As far as equipment, my plan is a Nikon 600mm f4G with 1.4 or 2.0 teleconverter, D800 or D300, and a Gitzo 1548 tripod. It looks like I can get a 52mm solar filter for the non-totality part of the eclipse and I will shoot sun pictures in advance to get some exposure data. A couple years ago, I purchased an old Astro-Physics 70mm refractor with a motorized equatorial mount, but it is heavy and awkward and I have not used it at all for photography to this point. I'm thinking it would not be the best option considering its characteristics and the fact that I will need to travel several hours to a viewing location (likely IL, MO or NE) and probably stay in a motel the night before.
    My questions are as follows: (1) Would a full frame or crop body be optimal? I have been considering a D500 and might upgrade to that if I'm going to use a crop sensor. (2) Am I blowing it by not using the telescope that I have? i.e. Should I get that ready for photography and plan on taking it with me, having an appropriate location, setting it up, etc.? (3) Since almost all locations along the eclipse line have about a 30-40% chance of overcast, what is the best way to strategize where I will drive and how I will get lodging at the last minute? (4) Is there any advice on how I should be thinking in terms of possible locations, whether I should explore them beforehand, etc.? (5) Since totality is only going to last about 150 seconds and since I will want to make sure I can really fire away especially during that interval, I'm assuming I should have a clock mount of some sort and are there any ideas about the best set-up for that?
    I'll probably have more questions as I prepare myself for this.
     
  2. Hi Rod,
    I would recommend solar film in front to the lens vs. a 52mm filter. The lens will concentrate sunlight (and infrared heat) into an area 1/8 the area of a 150 mm front filter. Keep the heat out of your lens.
    During totality, the corona will extend several solar diameters beyond the solar disk. This site has some tables on lens focal lengths and exposure: http://www.mreclipse.com/SEphoto/SEphoto.html
    Immediately before and after totality, you'll see the diamond ring and Baily's Beads. This is where you want the filter off and start shooting brackets until totality ends and you put the filter back on.
    The motorized equatorial mount will allow you to keep your ISO relatively low during totality.
    Have a second body with a fast wide angle lens to capture some of the other eclipse phenomena, landscapes, and the goings on of eclipse parties if you are in a group.
    Regarding weather, watch the fronts and cloud cover in the weeks ahead of the event and plan to alter you destination based on what is developing in the days ahead of the eclipse. I'm batting 50% for the eclipses I chased. As totality nears, the temperature drops which changes cloud formation.
    Regarding location, your target area will experience the eclipse with the sun near its zenith, so any location clear of clouds will do.
    Good luck!
     
    John Di Leo and dcstep like this.
  3. With regard to the Astro-Physics mount, the 70mm telescope objective size makes me question whether the 600mm + camera weight is too much for the mount. Astro-Physics does make good mounts, so experiment and determine if you can achieve good balance and rigidity mounting the telephoto on the mount. Since eclipses exposure times are a few seconds or less, polar alignment is not critical for good images. Practice alignment using a level and compass. Shoot some lunar images in the same exposure time range as eclipse totality to verify that your technique is adequate. If you get motion blur, raise the ISO to shorten exposure time.
     
  4. I am not familiar with that 600mm lens - - - - but - - - - in all the excitement of setting up, don't forget to check your INFINITY focus as many long lenses focus beyond infinity.
    That messed me up in the late 70's when I photo'd an eclipse. Taught me a valuable lesson about lenses. I would hate to see this happen to anyone else . . .
    Hopefully all you others out there are experienced and not as inattentive as I was.
     
    John Di Leo likes this.
  5. Manual focus, with a piece of tape to lock the ring, and manual exposure is recommended.
    Regarding using a mount with a clock drive, using the "500 rule" (500 / focal_length = max exposure in seconds) shows that a fixed mount can be used if moderate ISO is used. A solid tripod should be sufficient for all but the longest telephotos.
     
    John Di Leo likes this.
  6. As far as lodging is concerned you should check what the cancellation policy is for where you want to stay and make multiple reservations. You should have a pretty clear idea what the weather will be three days before and then make your choice and cancel the other reservations. Motel 6 allows cancellation the day of the reservation.
     
  7. Great thread and thanks to the experienced hands for chipping in. I've got two follow-on questions:
    • I'm assuming that I'll need to DYI my own front mount solar filter for my Canon 500/f4 II. Has anyone built such a rig and could they share some pix?
    • What are typical exposure settings? I hand hold shots of the moon all the time. I own a sturdy tripod, but usually leave it in the trunk. I wonder why I'd need it for the sun.
    [​IMG]Waxing Gibbous Moon by David Stephens, on Flickr

    Handheld, ISO 800, f/8.0 and 1/1000-sec.
     
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  8. The "maximum" spot is about 2 miles SSE of my house. (my bedrooms are already filled up, so don't ask).

    Carbondale has always been "centrally located" as in "equally far from anyplace", but this is our 2:39 of fame, for sure
    . Skyscape-63-solar-eclipse-.jpg
    1963 partial solar eclipe, sorta ​
     
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  9. One of the most interesting shots of a solar eclipse, at least during the buildup and aftermath of totality, is to look on the ground!

    If you haven't ever seen it, the pattern of sunlight during a partial eclipse filtered through the leaves of a tree will most likely surprise you. A great demonstration of the 'pin-hole camera' effect!
     
  10. +1 on experiencing the "ground effects" during a total eclipse. Shadow crescents, wavy lines moving across the ground, owls and other night creatures becoming active, and the overall "spookyness" of the event is really worth pulling away from the long lens and having a look around. Have a camera with a fast wide to normal lens to capture these effects, video may be the best medium.

    On solar filters for telephotos, I order film from Thousand Oaks Optical and tape it onto a cardboard tube that fits over the lens shade. The tube can fabricated from posterboard or other bendable material. You want the cardboard tube snug, but not too tight. The filter must be removed just before totality and that is the point where you have to work fast to capture the diamond ring and Baily's beads as the moon blocks the sun's disk. Once in full totality, you have have up to 2-1/2 minutes to capture the corona. It may extend further than the frame for long telephotos (my 400mm EFL should be about right for the extended corona). As totality ends, adjust your exposure for Baily's beads and the diamond ring. Bracket, bracket, bracket. Once the diamond ring flashes, put the filter back on.

    WRT exposure, there are many sites that cover recommended settings for total eclipses. Study them. Remember to shoot in manual and bracket. Pre-totality and post totality shots of the crescent sun can be practiced with your filter on days ahead of the event. Immediately before totality, and during totality, use recommended settings and bracket, bracket, bracket.

    Tracking mount ... nice to have if it is sturdy enough for your long telephoto. Check your planned exposure brackets with the rule of 500 to determine if a tracking mount is really necessary. (IMO, a very sturdy fixed tripod and head trumps a trembling tracking mount). You should be shooting wide open or down one stop (the bigger the aperture, the more potential resolution) so you may not need tracking with sufficient ISO. Test with the moon.
     
  11. John, about how many stops does the solar filter film absorb?
     
  12. David,
    I went ahead and spent the money for these glass filters from Spectrum Telescope for my telescope and binoculars. Likely will also get one for my Nikon 600mm.
    Product Categories Glass Solar Filters
    They absorb 99+% of the suns rays. Not sure what that would amount to in f-stops, but I think handheld wouldn't work.
    I'm a rookie to solar eclipse photography, but have read a LOT trying to get myself prepared. John obviously has the useful REAL experience.
     
  13. Much darker than my 10x ND filter. Darker than my #12 welding shade. It's sunny today so I'll go out and test.
     
  14. In my last response, I also neglected to specify that I am assuming the TOTAL eclipse is what I will really want good images of. That will be in near darkness, so I would think a tripod is definitely mandatory then.
     
  15. Yes, you'll need a tripod for totality. Exposures will be below what is hand-holdable for long telephotos. The question then becomes "is tracking needed" to compensate for the Earth's rotation. That's where the rule of 500 comes into play with your lens choice and ISO decisions.

    Regarding the Thousand Oaks solar film density, I just ran a quick test on a Sunny 16 day. My test target was a grey porch floor in the sun an hour ahead of zenith. All exposures were at ISO 100. Manual exposure adjusted so the histogram spike was centered on the scale. EV values were determined using the chart at scantips.com

    No filter 1/1000 sec @ F8 EV 16
    Hoya NDX400 1/3 sec @ F8 EV 8
    Solar film 15 sec @ F8 EV 2

    Best exposure for the solar disk (brightness at Zone 6) using the solar film: 1/2500 at F8.
     
  16. Rod, thanks for the link, which I will use, very soon. John, thanks for the testing and references.

    Totality, clearly can be hand held. I'll probably have the tripod for partials, then lift the rig off at totality.

    If you leave a little room and shoot the sun in the middle of the frame, it'll be very simple to align things later. At f/4 and 7 or 8 seconds, you're not going to get noticeable smear, are you? I shoot stars at 25-sec. and the movement is just starting to show. Of course, the sun is a lot closer star, so maybe I need something like ISO 800, f/8 and 1/800-sec., which is how I shoot the moon.
     
  17. dcstep, you have it backwards. The tripod is required for totality. For my 500mm F8 mirror lens, my bracketing centers at 1/15 sec at ISO 400. If the corona is very extended (we can hope), the longer exposures capture the faint gas out to the edge of the frame.
     
  18. 500mm at f/4 and ISO 800 would equal 1/60-second, plus four stops of IS means hand holding is possible. With the tripod already there and such a slow moving (relative to us) subject, I'll probably use the tripod. ;-)

    So it's sounding like we'll blow out the corona near the moon in order to get enough light from the extremes.
     
  19. Bracket, bracket, bracket. :)
     
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  20. Good info above; this is my 5th, I think. I am using a 750 f/8 Bausch and Lomb telescope with tripod on a full frame. That website for Mr. Eclipse is chocked with excellent info. I may have another camera set up with a wide view. A couple of bits of advice:
    1) find the sun in your viewfinder well before Diamond Ring. The longer your lens the narrower angle of view and you do NOT want to spend valuable seconds hunting for the sun. Of course use a filter for your search.
    2) re ground effects. As mentioned there are the pinhole camera effects form leaves in the trees, but any "pinhole" will do, like making a small opening with your fingers and projecting that. If you use a piece of cardboard, have another piece to project upon.
    But the OTHER ground effect are the shadow bands...they are VERY cool, video would catch them best I think...they move fast.
    From Wiki...
    Shadow bands are thin wavy lines of alternating light and dark that can be seen moving and undulating in parallel on plain-coloured surfaces immediately before and after a total solar eclipse.[1] They are caused by the thin slit-like solar crescent illuminating the Earth's atmosphere moments before and after the eclipse totality.[2] Their movement is caused by atmospheric winds.[3]
    In 2008, Dr. Stuart Eves suggested that shadow bands might be caused by infrasound, which involves the shadow of the moon travelling at supersonic speed, which in turn produces low frequency sound that humans cannot hear. Due to this, he theorized, the movement of the moon creates a shock-wave in front of the shadow, which causes shadow bands. Dr. Eves said, "If proven, it would be something of a revelation that eclipses are a sonic as well as an optical phenomenon." Professor Brian Jones stated, "The [accepted] theory works; there's no need to seek an alternative."[4]
    Shadow bands have been noted throughout history:

    • In the 9th century AD shadow bands during a total solar eclipse were described for the first time--in the Völuspá, part of the old Icelandic poetic edda.[citation needed]
    • In 1820, Hermann Goldschmidt of Germany noted shadow bands visible just before and after totality at some eclipses.[5][6][7]
    • In 1842, George B. Airy, the English astronomer royal, saw his first total eclipse of the sun. He recalled shadow bands as one of the highlights: "As the totality approached, a strange fluctuation of light was seen upon the walls and the ground, so striking that in some places children ran after it and tried to catch it with their hands."[8]
     

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