The scale of a tilted photograph of focal length f taken from an altitude H, along the plate parallel through principal point is
f/H sec θ
f sec θ/H
f/H
f/H cos ½θ
Correct Answer :
A. f/H sec θ
Related Questions
Right ascension of a heavenly body is its equatorial angular distance measured
Westward from the first point of Libra
Eastward from the first point of Aeries
Westward from the first point of Aeries
Eastward from the first point of Libra
In field astronomy, the quantities observed are entirely
Lengths
Angles
Heights
All of these
In a spherical triangle ABC right angled at C, sin b equals to
sin c sin B
cos c cos B
tan c tan B
sin c cos B
The distance between the minor control point and the principal point should be equal to
Base line of the left photograph of stereo pair
Base line of the right photograph of stereo pair
Sum of the base lines of stereo pair
Mean of the base lines of the stereo pair
The following points form a pair of homologous points:
Photo principal point and ground principal point
Photo isocenter and ground isocenter
Photo plumb point and ground plumb point
All the above
The altitudes of a circumpolar star at culminations are 70° and 10°, both culminations being north of zenith. The latitude of the place, is
80°
70°
60°
40°
In a tropical year, the numbers of sidereal days are
365
365.2224
365.2422
366.2422
The altitude of a heavenly body is its angular distance, measured on the vertical circle passing through the body, above
Equator
Horizon
Pole
None of these
The principal line is the line joining the principal point and
Nadir
Isocenter
Perspective centre
None of these
The difference in longitude of two places expressed in time is equal to the difference in their
Sidereal time
Apparent solar time
Mean solar time
All the above
If a star whose declination is 60° N culminates at zenith, its altitude at the lower culmination, is
10°
20°
30°
40°
The position of a heavenly body on the celestial sphere can be completely specified by
Its altitude and azimuth
Its declination and hour angle
Its declination and right ascension
All the above
The sidereal day is the time interval between two successive upper transits of
Mean sun
First point of Aries
First point of Libra
The polar star
Parallax bar measures
Parallax
Height
Parallax difference
Height difference
The hour angle of the heavenly body for Greenwich meridian equals the hour angle of the body for any other meridian + longitude:
Mean sun
True sun
Vernal equinox
All the above
A star is said to elongate
When the star momentarily moves vertically
When the angle at the star of the spherical triangle is 90°
When the star's declination is greater than the observer's latitude
All the above
The relief displacement of a building 72 m high on photograph is 7.2 mm and its top appears 10 cm away from principal point. The flying height of the camera, is
500 m
1000 m
1500 m
2000 m
According to Napier's Rules of circular parts for a right angled triangle, sine of middle part equals the product of
Tangents of two adjacent parts
Sines of two adjacent parts
Cosines of two adjacent parts
Both (a) and (b) above
To have greatest coverage of the area, the type of photography used, is
High oblique
Low oblique
Vertical
None of these
Pick up the correct statement from the following:
Centre of the celestial sphere is taken as the position of the observer
Centre of the celestial sphere is taken as the centre of the earth
Stars move and maintain their relative positions
All the above
The foot of the perpendicular on the picture plane through the optical centre of the camera lens, is known as
Isocenter
Principal point
Perspective centre
Plumb line
Circumpolar stars
Rotate round the North Pole
Rotate round the celestial pole
Remain always above the horizon
Are seldom seen near the pole star
Pick up the correct statement from the following:
The vertical plane containing the zenith, the station of observation and the celestial pole is the observer's meridian plane
The angle between the direction of star in vertical plane and the direction of the star in horizontal plane is called the altitude of the star
The complement of the altitude of star is called the zenith distance of the star
All the above
The main object of the astronomer to obtain
Astronomical latitude
Astronomical longitude
Astronomical bearing
All of these
The relation between the air base (B), photographic base (b), flying height (H) and the focal length (f) of a vertical photograph, is
B = bH/f
B =f/bH
B = b/fH
B = H/bf
The station pointer is generally used in
Triangulation surveying
Astronomical surveying
Hydrographical surveying
Photogrammetric surveying
Homologous point is
Photo principal point
Ground principal point
Ground isocenter
All the above
At upper culmination, the pole star moves
Eastward
Westward
Northward
Southward
The shortest distance between two places measured along the surface of the earth, is
Length of the equator between their longitudes
Length of the parallel between their longitudes
Length of the arc of the great circle passing through them
None of these
The equation which is obtained by multiplying each equation by the coefficient of its un-knowns and by adding the equations thus formed, is known as
Observation equation
Conditional equation
Normal equation
None of these