Google Eclipse Map Page

Hybrid Solar Eclipse of -1938 Aug 25 (1939 Aug 25 BCE)

Fred Espenak

Introduction

This page features an interactive Google map [1] showing the regional visibility of the Hybrid Solar Eclipse of -1938 Aug 25. The Google map allows the user to zoom and scroll the map as desired. Clicking the cursor on any location will immediately generate a prediction of the eclipse circumstances from that location. The small global map to the right is for reference and illustrates the overall visibility of the eclipse (for an explanation of this map's features, see Key to Solar Eclipse Maps).

The interactive Google map below uses the Web Mercator projection to display the eclipse track. The large saddle-shapped region is the path of the Moon's penumbral shadow.This is the geographic region from which a partial eclipse can be seen. The northern and/or southern penumbral shadow path limits are plotted as green curves. The magenta loops represent the locus of all locations where the partial eclipse begins or ends at sunrise or sunset. Inside these regions the partial eclipse is in progress at sunrise or sunset. An orange curve also appears inside this region and represents the locus of all locations where the partial eclipse is at its maximum phase at sunrise or sunset. The Key to Google Eclipse Maps illustrates a map with each of these curves. You MUST be somewhere within the region enclosed by these curves in order to see the partial eclipse. Outside this region no eclipse is visible.

The narrow track running through rhe penumbral shadow is the path of the Moon'sumbral (or antumbral)shadow. This is the geographic region from which the total (or annular)eclipse can be seen.The northern and southern path limits are blue and the central line is red. You MUST be somewhere within the central path (shaded zone framed by the blue lines) to see the total (or annular)phase of the eclipse. The eclipse is longest on the central line (red). The yellow lines crossing the path indicate the position of maximum eclipse at 10-minute intervals.

The red marker labeled GE is the point of Greatest Eclipse. The green marker labeled GD is the point of Greatest Duration. This is the location where the total (or annular)eclipse lasts the longest along the entire path. In this case, the Greatest Duration is 00m27.9s. This prediction does not take into account the mountains and valleys along the edge of the Moon. For the sake of speed and simplicity, the effects of the lunar limb profile are NOT used in the predictions and map presented on this page.

You can be hundreds of miles from the theoretical point of Greatest Duration and still enjoy totality (or annularity)lasting within a second of the maximum possible (as long as you stay within several miles of the central line). It's much more important to watch the weather forecasts a day or two before the eclipse and choose a location with the best chance of a cloud-free sky during the eclipse.Good weather is the key to successful eclipse viewing - better to see a shorter eclipse from clear sky that a longer eclipse under clouds [2].

Google Maps uses the Web Mercator projection, and therefore cannot accurately show areas around the poles. As a consequence, eclipse paths at high latitudes will appear highly distorted and may degrade into a series of straight line segments.

Note: Your web browser must have Javascript turned on in order to see a solar eclipse path plotted on Google Maps. See compatible browsers for more information.


Map centered on (latitude, longitude):
Cursor position (latitude, longitude):
Distance from last marker: 		Show marker on click
 Large map
Time Zone:

User Directions

The zoom buttons (the 'plus' and 'minus' buttons to the lower right corner of map) are used to change the magnification [3]. The user's cursor can be used for navigating around the map. Just hold the left mouse button down while the cursor is on the map, and drag the map around to reposition it.The two map buttons (top left) let you switch between map view and satellite view.

Click anywhere on the map to add a blue marker. A pop-up window appears above the marker with the calculated eclipse times and duration of totality (or annularity)for that location (see explanation of Eclipse Circumstances below). The 'x' in the upper right corner of the pop-up window closes the pop-up window. Additional markers can be placed anywhere on the map. Move the cursor over a marker to reveal a pop-up window with the eclipse times for that position. The predictions in the pop-up window can also be displayed in a new web page via the Eclipse Times Pop-up button (just below the map and to the right). You can select and copy this infomation to paste into a word processor.

All the markers can be removed by using the Clear Marker button (below the eclipse map). Choose the Large Map check box to produce a bigger map (hint: enlarge the browser window to its maximum size before selecting the Large Map check box). This option is especially useful to users with large monitors.

Below the lower left corner of the map are three readouts. The first gives the geographic coordinates (latitude and longitude) of the map center while the second gives the geographic coordinates of the cursor. The third line gives the distance of the cursor from the last marker. For more information, see Google Eclipse Map Instructions.

Eclipse Circumstances

When you click on the map a blue marker is added and a pop-up window opens giving the Eclipse Circumstances calculated for that location. The predictions in the pop-up window can be divided into two sections.

In the top part of the window, the decimal Latitude and Longitude of the marker are given. The Eclipse Type (either total, annular or partial) seen from that position is given. The duration of Totality (or duration of Annularity) lists the length of the total (or annular) phase in minutes and seconds. The Eclipse Magnitude is the fraction of the Sun's diameter eclipsed. The Eclipse Obscuration is the fraction of the Sun's area eclipsed.

The bottom part of the window consists of a table listing the times for important stages of the eclipse. The Event column lists eclipse phase, followed by the date and time (both in Universal Time). Finally, the Altitude and Azimuth of the Sun is given for each event. The altitude is measured from the horizon (0°) to the zenith (90°). The azimuth is measured from due North and rotating eastward (North = 0°, East = 90°, South = 180°, and West = 270°).

Below the lower left corner of the map is a drop-down menu labeled Time Zone. By default, the Time Zone is set to UT1 (GMT/London). This is the time zone used in the Eclipse Circumstances pop-up window described above. The drop-down menu offers the user the choice of twenty-four different time zones around the world. After choosing a new time zone,click on a marker (or create a new one). The Eclipse Circumstances pop-up windows will now display eclipse times for this new time zone.

Important Note: The eclipse predictions in this interactive map DO NOT include the effects of mountains and valleys along the edge of the Moon. Such corrections for the lunar limb profile may change the contact times and eclipse durations by ~1-3 seconds. The exact location of Greatest Duration may also change by ~10-20 kilometers.

Footnotes

1. Other interactive Google eclipse maps include those by Xavier Jubier and Bill Kramer.↩

2. An excellent source for weather prospects for upcoming eclipses is meteorologist Jay Anderson's Eclipsophile Eclipse Weather Page. ↩

3. This web page approximates the curved eclipse path by using a series of straight line segments. To maintain the validity of this approximation, the maximum zoom level is limited to ~1 mile/inch (~0.7 kilometers/centimeter). This is done to prevent over-interpretation of the eclipse path accuracy.

Links for the Hybrid Solar Eclipse of -1938 Aug 25 (1939 Aug 25 BCE)

Links to Additional Solar Eclipse Predictions

  • Home - home page of EclipseWise with predictions for both solar and lunar eclipses

Eclipse Predictions

Predictions for the Hybrid Solar Eclipse of -1938 Aug 25 were generated using the JPL DE406 solar and lunar ephemerides. The lunar coordinates were calculated with respect to the Moon's Center of Mass. Although the predictions are first calculated in Terrestrial Dynamical Time (TD), they are then converted to Universal Time (UT1) as presented here. The parameter ΔT is used to convert between the two times (i.e., UT1 = TD - ΔT). For this eclipse ΔT has a value of 44916.5 seconds. The uncertainty in ΔT is 3473.0 seconds corresponding to a standard error in longitude of the eclipse path of ± 14.51°.

The eclipse predictions presented here DO NOT include the effects of mountains and valleys along the edge of the Moon. Such corrections for the lunar limb profile may shift the limits of the eclipse path north or south by ~1-3 kilometers, and change the eclipse duration by ~1-3 seconds.

Acknowledgments

Some of the content on this website is based on the book Thousand Year Canon of Solar Eclipses 1501 to 2500. Special thanks for the indispensable assistance of Bill Kramer (www.eclipse-chasers.com) in developing this web page. All eclipse calculations are by Fred Espenak, and he assumes full responsibility for their accuracy.

Permission is granted to reproduce the eclipse data on this page when accompanied by a link to this page and an acknowledgment:

"Eclipse Predictions by Fred Espenak, EclipseWise.com"

The use of diagrams and maps is permitted provided that they are unaltered (except for re-sizing) and the embedded credit line is not removed or covered.

Please visit the Acknowledgments Page for additional information.