e-clipse (i-klips') n. The partial or complete obscuring, relative to a designated observer, of one celestial body by another.
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e-clipse (i-klips') n. The partial or complete obscuring, relative to a designated observer, of one celestial body by another.
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How Does Eclipse Timer Help You?
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Table of Contents - Advanced
Audible Voice Warnings For Eclipse Voice Under the Tools Menu the first voice selection is Eclipse Voice and choosing this will provide voice warnings that are appropriate for a total or partial eclipses of the Sun or the Moon. For Eclipse Voice: The 1st Contact spoken audible warnings played by Eclipse Timer™ are as follows: "First Contact In 60 Seconds"; "40 Seconds"; "30 Seconds"; "20 Seconds"; "10 Seconds"; "5"; "4"; "3; "2"; "1"; 2 Second Warning Tone. The 2nd Contact spoken audible warnings played by Eclipse Timer™ are as follows: "Second Contact In 2 Minutes"; "First Contact In 60 Seconds"; 40 Seconds"; "30 Seconds"; "20 Seconds"; "10 Seconds"; "5"; "4"; "3"; "2"; "1"; 2 Second Warning Tone. The Max/Mid spoken audible warnings played by Eclipse Timer™ are as follows: "Max Eclipse in 10 Seconds"; "5"; "4"; "3"; "2"; "1"; 4 Second Warning Tone. The 3rd Contact the spoken audible warnings played by Eclipse Timer™ are as follows: "Third Contact In 20 Seconds"; "10 Seconds"; "5"; "4"; "3"; "2"; "1"; 2 Second Warning Tone. The 4th Contact the audible warnings played by Eclipse Timer™ are as follows: "Fourth Contact In 60 Seconds"; "40 Seconds"; "30 Seconds"; "20 Seconds"; "10 Seconds"; "5"; "4"; "3"; "2"; "1"; 2 Second Warning Tone. The audible warnings chosen for the Eclipse Voice option were given a great deal of thought and I would like to explain a few things. It was felt that 60 seconds of warning time was ample for 1st Contact and 4th Contact because the EXACT moment of these contact times is not actually visible. Furthermore, most photographic exposures will be taken many seconds or minutes after 1st Contact when an actual bite out of the surface of the Sun is clearly visible, or, many seconds or minutes before 4th Contact when there still is a bite out of the Sun visible. However, for 2nd Contact, it was felt that an additional 2-minute warning would be helpful for photographers to get into position at their equipment. The last 60 seconds of audible warnings before 2nd Contact can be used to choreograph your final photographic chores. For the Max/Mid eclipse point it was felt that only a 10-second warning was necessary to alert observers of the mid-point since special preparations for this point are not needed. However, a 4-second long warning tone was chosen to play after the Max/Mid time in an attempt to get your attention and alert you that this point has passed. This may serve as a reminder to finish your photography and spend some time observing with your eyes! There can be a lot of commotion during totality as the surrounding observers are awed by the event and this four second warning tone was chosen to help get your attention. For 3rd Contact the audible warnings begin at 20 seconds. This was felt to be enough time to prepare to be in a position to capture the photographic events as the Moon moves off of the Sun. A shorter time was chosen to warn for 3rd Contact so that for short duration totalities, the Max/Mid eclipse audible warnings would not overlap with the 3rd Contact warnings. Eclipse Timer™ can effectively time a totality with a duration as short as 52 seconds and have the complete set of voice audible Max/Mid warnings and the complete set of voice audible 3rd Contact warnings. For a totality duration shorter than 52 seconds, with a Max/Mid time programmed, the voice audible warnings for 3rd Contact are dropped out in order since they don’t have time to play. So, the voice audible warning "3rd Contact in 20 seconds" would be dropped when timing a totality with a duration of 51 seconds or less. However, if you choose not to program a time for Max/Mid, you can have the full set of 3rd Contact voice audible warnings for a totality with a duration of 24 seconds. Simply stated, Eclipse Timer™ plays all of the audible voice warnings during totality sequentially starting with the Max/Mid warnings. It will play as many audible voice warning as it has time for. Partial Phase Phenomenon Voice Warnings When Eclipse Voice is chosen, the Partial Phase Phenomenon selection is also active. This selection is only relevant for total, annular or very deep partial eclipses of the Sun. Partial Phase Phenomenon warnings occur between 1st Contact and 2nd Contact. The audible voice warnings that are played are timed BACKWARD from the programmed 2nd Contact time. You only have to worry about programming the correct 2nd Contact time; the software will do the calculations for the Partial Phase Phenomenon. The warnings remind you to observe ambient temperature, ambient lighting, animal behavior and shadow bands. The audible voice warnings for the Partial Phase Phenomenon are as follows: "Forty Five Minutes Until Totality Observe Changes In Ambient Temperature" "Thirty Minutes Until Totality Observe Changes In Ambient Temperature" "Fifteen Minutes Until Totality Observe Changes In Ambient Temperature" "Ten Minutes Until Totality Observe Changes In Ambient Lighting" "Eight Minutes Until Totality Observe Changes In Animal Behavior" "Five Minutes Until Totality Observe For Shadow Bands" The audible voice warnings that were chosen for the Partial Phase Phenomenon were given a great deal of thought. Not all veteran eclipse chasers would agree on when and what was chosen to warn about, so let me explain a little about my selections. Although much is written about the decrease in ambient temperature during a total eclipse of the Sun, the emphasis is usually placed on the time of totality. But in reality the temperature is slowly and steadily dropping during the initial partial phases. Depending on your observing location, the season, the outdoor temperature, relative humidity and wind conditions, it is possible to perceive the change in ambient temperature well in advance of totality. In Africa, in June of 2001, we were amazed to clearly feel the drop in temperature at 30 minutes before totality. Our perception was confirmed by temperature data collected during that eclipse. Therefore, for Eclipse Timer™, I chose to warn you to observe for your perception of ambient temperature change at 45, 30 and 15 minutes before totality. Click on the graph thumbnail below for a full sized graph of the temperature data from the June 21, 2001 eclipse.
Mitzi Adams, Mail Code SD50, NASA, Marshall Space Flight Center, Huntsville, AL 35812 Graph Modified By GMT Note: Temperature Data From African Countryside Recorded Drop From 78° to 58° F (ê 20°) By 10 minutes before totality there is a distinct difference in the ambient lighting and I chose to put a warning about this phenomenon at this time. Much is written about this and the most basic observation is that is it getting darker. However, it is a very interesting and unusual decrease in light. The following are my perceptions of the change in lighting and it is difficult to describe. The overall brightness is decreasing even though the Sun is high in the sky. But the change in brightness is not the same as when, for instance, a thick cloud passes in front of the Sun on a regular day. There is a subtle color change, which to me appeared to be lightly gray. Similar to wearing a pair of very lightly tinted sunglasses with gray lenses or looking through a lightly tinted neutral density camera filter. But because the effect is all around you and you are not wearing sunglasses the scene has an eerie feeling. Another phenomenon at approximately 10 minutes to totality is the change in the appearance of shadows cast to the ground. Very, very little is written about this and I cannot say that in Africa I perceived the changes. Fred Espenak, NASA/Goddard Space Fight Center, was nice enough to explain the effect to me and I am paraphrasing his explanation. On a normal day, the symmetric lighting from a full Sun disk produces shadows that have fuzzy indistinct edges. During the final 10 to 20 minutes before a total eclipse, when the Sun is a thin crescent, two types of shadows can be cast. Shadows that are in line with the crescent of the Sun are still fuzzy. But shadows in the perpendicular direction are much sharper at the edges because the crescent is much narrower than it is high At 8 minutes I chose to warn you to observe for changes in animal behavior. This close to totality, it is becoming dark enough that animals can be fooled into thinking it is becoming nighttime and they will behave as such. There have been reports of bats beginning to fly, birds going to their perches to rest or sleep, grazing animals ceasing to feed and insects beginning to make their nighttime sounds. In Africa in June of 2001, the increase in the number and volume of chirping crickets in the field surrounding us was clearly evident! At 5 minutes before totality there is a warning to observe for shadowbands and what is meant is to "start" to look for shadowbands. They are faint "bands of shadows" or undulations of light that can be see on the ground. Some describe the appearance as similar to the way sunlight moves across the bottom of a swimming pool. Shadowbands are caused by the sunlight rays from the thin crescent of the Sun being bent as the light passes through warmer and cooler cells of air in the atmosphere. The phenomenon will probably occur closer to totality when the crescent is even thinner. However, I wanted to give ample warning to begin to look for them because every eclipse is unique and everyone’s observing location is different. Also, I did not want to put the warning too close to the warnings that will begin for 2nd Contact, because I imagine that the 2nd Contact warnings will move people into position for photography. Back to TopAudible Voice Warnings For Planet Transit Voice Under the Tools Menu the second voice selection is Planet Transit Voice and choosing this will provide voice warnings that are appropriate for Mercury and Venus transits across the Sun or occultation’s of planets, stars and asteroids by the Moon. For Planet Transit Voice, the spoken audible warnings played by Eclipse Timer™ are exactly the same as the warnings for Eclipse Voice, except the Max/Mid warning will say "Mid transit in 10 seconds." Audible Voice Warnings For Galilean Moons - Moon 1st or Shadow 1st Under the Tools Menu the third and forth voice selections are Galilean Moons – Moon 1st and Galilean Moons – Shadow 1st. These two selections provide voice warnings that are appropriate for timing the movement of Jupiter’s Moons as they cross in front of the planet. Depending on the position of Jupiter relative to it’s conjunction you choose either Moon 1st or Shadow 1st. When using Eclipse Timer™ for this function the Contact Times are actually Ingress and Egress times of the moon and it’s shadow. For Galilean Moons – Moon 1st the Time 1 spoken audible warnings played by Eclipse Timer™ is as follows: "Moon ingress in 60 seconds." This is followed by the same countdown of seconds as for Eclipse Voice including the warning tone. The Time 2 spoken audible warnings played by Eclipse Timer™ is as follows: "Shadow ingress in 60 seconds." This is followed by the same countdown of seconds as for Eclipse Voice including the warning tone. Max/Mid spoken audible warnings played by Eclipse Timer™ is as follows: "Mid transit in 10 seconds." This is followed by the same countdown of seconds as for Eclipse Voice including the warning tone. Note that you can choose whether you want to mark the mid-transit of the moon or it’s shadow, but you can’t mark both. The Time 3 spoken audible warnings played by Eclipse Timer™ is as follows: "Moon egress in 20 seconds." This is followed by the same countdown of seconds as for Eclipse Voice including the warning tone. The Time 4 spoken audible warnings played by Eclipse Timer™ is as follows: "Shadow egress in 60 seconds." This is followed by the same countdown of seconds as for Eclipse Voice including the warning tone. For Galilean Moons – Shadow 1st the spoken audible warnings played by Eclipse Timer™ are the same as above but appropriately reversed. Authors: Gordon Telepun and Angela Hartsfield
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