SmartPhoneTripod

Using a tripod with your smartphone to record the eclipse

If you don’t have a photographic tripod, you may be able to borrow one from a friend or neighbor; it should be high enough so you can easily get your head under the smart phone to see its display, even when the Sun is high in the sky, as it will be especially from Wyoming to Tennessee. A folding chair is useful, so you can get low enough to look at the screen. If you need to wear glasses to see the screen, wash them before the eclipse, since small dirt specks on them can catch sunlight and confuse the view. If the photographic tripod does not hold the camera high enough, you might put it on a table, or on the roof of your vehicle, to get the phone high enough. If you want to buy a tripod, there are some that will raise high enough that cost in the range of $25 to $60; I give some recommendations at the end of this Web page. You need a small mobile phone tripod, such as the Promark one available for $10 from K-Mart (Wal-Mart has similar units); the small spider tripod is not very useful, but the small frame that securely holds the smart phone can attach to any photographic tripod, or its quick-release pad. Throughout the eclipse, keep the recording smart phone (“B” if there are two at your station) in the small frame, which in turn should be kept secured to the quick-release pad of the tripod, so the smart phone can be quickly attached or released from the photographic tripod at any time. The pictures below, from left to right, show: 1.) The Promark smart phone holder (right) attached to the tripod quick-release pad (left); 2.) The smart phone, with the telephoto lens, secured with the Promark holder to the tripod quick-release pad; and 3.) Everything in 2) now attached to the tripod head. For observing the Sun at high altitude, the altitude adjust and tightening bar (lower right of 3) should be pointed in the same direction as the telephoto lens, as shown in the picture at upper left, where I’m using it with my right hand, accomplished by rotating the square-bottomed quick-release pad by 180° of what is shown in 3).

 

 

 

 

 

 

 

A YouTube video shows how to record the eclipse using a smart phone attached to a tripod, but it has much general information that is covered better in (and superseded by) the later information here . There is another YouTube video showing the recording that was made with the smart phone “B” used in that video. As noted previously, you can ignore the part about imaging the geographical coordinates with the smart phone app, if you just take a couple of still pictures of your observing site with location tagging enabled.

Two minutes before the time of central eclipse for your station (that time will be provided for your area and should be known to 10 seconds accuracy or better), smart phone “A” should have the accurate time (from an app like Emerald Time or Smart Time Sync) on its display, unless you have another source for accurate time noted previously. Then with smart phone “B”, touch the video camera symbol to start the video recording. Point smart phone “B” so that it records the display of “A” showing the accurate time; it only needs to be recorded for about 10 seconds. Next you should attach “B” to the tripod and aim it at the Sun, to start recording the eclipse (we want you to record for two minutes, or more, centered on the maximum eclipse at your location, that is, have “B” pointed at the Sun, and continue with the video recording (do NOT press the square that will stop the recording, keep it recording, until the end, noted below), starting no later than one minute (60 seconds) before the central eclipse time for your location. During the minute surrounding the central eclipse (that is, starting 30 seconds before the central eclipse time), it will be safe to look at the eclipsed Sun by naked eye. The brightness will be changing rapidly, and we want you to call out when you think the last bright part of the Sun disappears, leaving only the red or pink chromosphere visible, and again when the chromosphere brightens and is overwhelmed as the bright surface of the Sun reappears. These are called “2nd contact” and “3rd contact”, respectively, the start and end of the total eclipse. That’s all that the observers lined up at the edges of past eclipses could do; we want to compare the visual impression with the recorded one. As soon as the Sun becomes too bright to comfortably look at, start using the eclipse glasses, to see the now expanding crescent of sunlight. As soon as the time is one minute (60 seconds) later than the time of central eclipse, remove smart phone “B” from the tripod and again image and record the Source time of A’s Smart Time Synch display, for 10 seconds (or Emerald Time, or another source of accurate time, as discussed previously). After that, you should press the red square to stop B’s video recording; if all has worked as described, you have made a recording that will be part of the overall best-observed eclipse in history.

Binocular viewing: Use of the tripod will leave you free to enjoy the eclipse experience, perhaps looking at the totally-eclipsed Sun briefly with a pair of binoculars. Be careful, viewing with binoculars is only safe when the bright part of the Sun has disappeared, which may be only for a few seconds at your location – if the remaining part of the Sun is too dazzling or uncomfortable to look at, immediately turn away and use the eclipse glasses to safely view the eclipse by naked eye.

A word of caution – if the weather is calm (little or no wind) during the partial phases, just before and during the total eclipse, the cooling temperature of the atmosphere can cause a rather strong “eclipse wind”. Therefore, I recommend that you hang a weight (a sizeable rock, water bottle, or other object) in a net, or with string, rubber bands, or blue painter’s tape, low at the center of the tripod, to increase its stability in the case of wind.

Tripod sources: The tripod I’m using is a Sunpak 9002TM tripod/monopod, but I could find it for sale only at superiorphotonic.com for $65; even Amazon says “currently unavailable”. An inexpensive tripod that will probably work about as well is the Amazon Basics 60-in. Lightweight Tripod with Bag, $23.49 plus shipping, at https://www.amazon.com/AmazonBasics-60-Inch-Lightweight-Tripod-Bag/dp/B005KP473Q/ref=pd_lpo_sbs_421_t_2/146-5218444-7067204?_encoding=UTF8&psc=1&refRID=ZJ64CTNCEFWPEW8CN200 .

David Dunham, International Occultation Timing Association, dunham@starpower.net .