Baseline Contingency Air Observations over Turkey
To observe the total phase of the
eclipse from the air, an aircraft must (1) be
located at the center of the Moon's shadow as the shadow passes over
the aircraft , and (2) the aircraft must be flying a heading to permit
viewing the eclipse out of the cabin windows.
1. The location path of the eclipse varies with altitude above sea-level, but is readily computable. As examples, the latitude and longitude of the CENTERLINE of the path of totality are tabulated as functions of time (UTC = GMT) in following tables for flight elevations of 32,000 ft to 44,000 ft in 2000 ft increments and time steps of 10 seconds along the entire path of totality over Turkey:
DIRECTORY of CENTERLINE FILES:
In addition to time, latitude, and longitude these files give the Duration of Totality (in seconds as would be seen from a STATIONARY observer, i.e., before correcting for the motion of an aircraft), The width of the shadow in kilometers, and the Altitude and Azimuth of the Sun at mid eclipse)
2. The aircraft must be flying on a heading to intercept the Moon's shadow at a specific location on centerline (for a given flight altitude) at the corresponding time. The aircraft heading must be equal (or very close) to the azimuth of the Sun (at mid eclipse) minus 90 degrees (i.e., so the aircraft has a velocity component in the direction of motion of the Moon' shadow, not against it).
3. The aircraft must be flying on that heading for an appropriate mid-eclipse intercept (at least) 3 minutes before mid-eclipse.
1. The location path of the eclipse varies with altitude above sea-level, but is readily computable. As examples, the latitude and longitude of the CENTERLINE of the path of totality are tabulated as functions of time (UTC = GMT) in following tables for flight elevations of 32,000 ft to 44,000 ft in 2000 ft increments and time steps of 10 seconds along the entire path of totality over Turkey:
DIRECTORY of CENTERLINE FILES:
In addition to time, latitude, and longitude these files give the Duration of Totality (in seconds as would be seen from a STATIONARY observer, i.e., before correcting for the motion of an aircraft), The width of the shadow in kilometers, and the Altitude and Azimuth of the Sun at mid eclipse)
2. The aircraft must be flying on a heading to intercept the Moon's shadow at a specific location on centerline (for a given flight altitude) at the corresponding time. The aircraft heading must be equal (or very close) to the azimuth of the Sun (at mid eclipse) minus 90 degrees (i.e., so the aircraft has a velocity component in the direction of motion of the Moon' shadow, not against it).
3. The aircraft must be flying on that heading for an appropriate mid-eclipse intercept (at least) 3 minutes before mid-eclipse.
Baseline planning is predicated
upon following assumptions, which may be somewhat different in actual
detail or implementation:
A) Use of Raytheon Hawker-400 jet aircraft or similar:
- Climb to altitude: 18 minutes
- Cruise 450 kt (833 km/hr)
- Service Ceiling: 45,000 ft.
B) T/O and Landing from Antalya, Turkey (Int'l Airport)
- Lat = 36d 54' E, 30d 48' N
C) Total flight time T/O to Landing = 1 hour
A "BASELINE" Scenario is presented - which closely minimizes the flying distance (and thus time) from Antalya:
Baseline Scenario for Mid-Eclipse Intercept:
i) Flight Altitude = 40,000 ft*
ii) U.T. of mid-Eclipse Intercept = 10:57:50 U.T.
It must be noted that the altitude of the Sun (angular degrees above the horizon) is 53.6 degrees at this location. This SHOULD be observable out the aircraft windows with some neck craning (but needs to be confirmed), in straight and level flight, BUT it would be highly desirable if the aircraft could be banked (tilted) - while still flying on a fixed heading - by whatever amount may be accommodated to "lower" the sun as seen through the aircraft windows. An intercept point chosen later in time (further to the North East) would have the Sun at a somewhat lower altitude - at the expense of additional flying time. For this baseline scenario, a 10:57:50 UT intercept is considered because of the short flight distance. Clearly, that can be adjusted. Note that 1 minute of flying time - parallel to the centerline of the path of totality - (after reaching altitude and nomincal cruise speed) would move the intercept point by appx 7.5 nautical miles along the path of totatlity.
At this U.T. and flight level, the point of mid-Eclipse intercept is:
Mid-Eclipse Coordinates: +37.0477 (+37 02 51.8) North, +31.7632 (+031 45 47.5) East
The azimuth of the Sun at that time is: 206 deg, so the aircraft heading would be 116 degrees.
This is a distance of of only 47 nautical miles (88 km) from the antalya Aiirport. Allowing 18 minutes (as an approximation) for the aircraft to reach 40,000 ft cruise altitude and a point to begin a mid-eclipse minus 3 minute "totality run" can be accommodated in an hour of flight time. It should also be noted, that the aircraft CANNOT be "late", hence, a detail of the plan would be to take-off and reach the location several minutes ahead of time (to allow for "delays" and "hold" by either circling at the "entry point" of the totality run, or fly parallel to the track from that point, and actually turn onto the desired heading at slightly later time (intercepting the center of the shadow slightly later in time). Such adjustments can be made easily in real-time.
AT MINIMUM, for the above intercept, the aircraft would need to be at the start of the "totality run" at 10:55 U.T. Assuming a ground speed of 450 kts (again, a representative speed for planning), this would put the aircraft (before any windage compensation) a distance of 22.5 nautical miles from the point of mideclipse intercept, in a direction 296 degrees from that point (flying toward it, them, on a heading of 116 degrees). Thus, the START of the totality run at mid-eclipse minus 3 minutes is from a location at:
Start of Totality Run: 37d 12.68' N, 31d 20.48'E
(which is 69 nautical miles from Antaya airport, and within a nominal 1 hour flight). Note: At that point (the start of the totality run) would be appx 1m 15s before second contact).
The aircraft would stay on this course until (at least) 3 minutes (to 36d 52.93'N, 32d 11.01'E) after mid-eclipse and then return to Antalya.
The above defines a MINIMUM - success-oriented flight. I ESTIMATE th flight time to be about 53 minutes, but we certainly should build in (I would suggest at leaast) 5 minutes of pre-eclipse contingency in the air. I defer to the flight crew and charter company as to the expectation for an "on time" take-off, as without building in a NECESSARY contingency the clips intercept would be in jeopardy. We MUST be at the tottality run star position at or before (as small needed adjustments can be made in the air) the appointed time, being "late" is not an option as we cannot "make up" a delay.
The above scenario is illustrated below:
A) Use of Raytheon Hawker-400 jet aircraft or similar:
- Climb to altitude: 18 minutes
- Cruise 450 kt (833 km/hr)
- Service Ceiling: 45,000 ft.
B) T/O and Landing from Antalya, Turkey (Int'l Airport)
- Lat = 36d 54' E, 30d 48' N
C) Total flight time T/O to Landing = 1 hour
A "BASELINE" Scenario is presented - which closely minimizes the flying distance (and thus time) from Antalya:
Baseline Scenario for Mid-Eclipse Intercept:
i) Flight Altitude = 40,000 ft*
ii) U.T. of mid-Eclipse Intercept = 10:57:50 U.T.
It must be noted that the altitude of the Sun (angular degrees above the horizon) is 53.6 degrees at this location. This SHOULD be observable out the aircraft windows with some neck craning (but needs to be confirmed), in straight and level flight, BUT it would be highly desirable if the aircraft could be banked (tilted) - while still flying on a fixed heading - by whatever amount may be accommodated to "lower" the sun as seen through the aircraft windows. An intercept point chosen later in time (further to the North East) would have the Sun at a somewhat lower altitude - at the expense of additional flying time. For this baseline scenario, a 10:57:50 UT intercept is considered because of the short flight distance. Clearly, that can be adjusted. Note that 1 minute of flying time - parallel to the centerline of the path of totality - (after reaching altitude and nomincal cruise speed) would move the intercept point by appx 7.5 nautical miles along the path of totatlity.
At this U.T. and flight level, the point of mid-Eclipse intercept is:
Mid-Eclipse Coordinates: +37.0477 (+37 02 51.8) North, +31.7632 (+031 45 47.5) East
The azimuth of the Sun at that time is: 206 deg, so the aircraft heading would be 116 degrees.
This is a distance of of only 47 nautical miles (88 km) from the antalya Aiirport. Allowing 18 minutes (as an approximation) for the aircraft to reach 40,000 ft cruise altitude and a point to begin a mid-eclipse minus 3 minute "totality run" can be accommodated in an hour of flight time. It should also be noted, that the aircraft CANNOT be "late", hence, a detail of the plan would be to take-off and reach the location several minutes ahead of time (to allow for "delays" and "hold" by either circling at the "entry point" of the totality run, or fly parallel to the track from that point, and actually turn onto the desired heading at slightly later time (intercepting the center of the shadow slightly later in time). Such adjustments can be made easily in real-time.
AT MINIMUM, for the above intercept, the aircraft would need to be at the start of the "totality run" at 10:55 U.T. Assuming a ground speed of 450 kts (again, a representative speed for planning), this would put the aircraft (before any windage compensation) a distance of 22.5 nautical miles from the point of mideclipse intercept, in a direction 296 degrees from that point (flying toward it, them, on a heading of 116 degrees). Thus, the START of the totality run at mid-eclipse minus 3 minutes is from a location at:
Start of Totality Run: 37d 12.68' N, 31d 20.48'E
(which is 69 nautical miles from Antaya airport, and within a nominal 1 hour flight). Note: At that point (the start of the totality run) would be appx 1m 15s before second contact).
The aircraft would stay on this course until (at least) 3 minutes (to 36d 52.93'N, 32d 11.01'E) after mid-eclipse and then return to Antalya.
The above defines a MINIMUM - success-oriented flight. I ESTIMATE th flight time to be about 53 minutes, but we certainly should build in (I would suggest at leaast) 5 minutes of pre-eclipse contingency in the air. I defer to the flight crew and charter company as to the expectation for an "on time" take-off, as without building in a NECESSARY contingency the clips intercept would be in jeopardy. We MUST be at the tottality run star position at or before (as small needed adjustments can be made in the air) the appointed time, being "late" is not an option as we cannot "make up" a delay.
The above scenario is illustrated below: