The plane at right angle to the zenith-nadir line and passing through the centre of the earth, is called
Rational horizon
True horizon
Celestial horizon
All the above
Correct Answer :
D. All the above
Related Questions
From the principal point the horizon point lies on the principal line at a distance of
f tan θ
f sin θ
f cot θ
f cos θ
To obtain photographs of an area of 1000 m average elevation, on scale 1 : 30, 000, with a camera of 30 cm focal length, the flying height is
4000 m
5000 m
6000 m
7000 m
Pick up the correct statement from the following:
Ursa Minor's remains always north of pole star
Polar star remains always north of Polaris
Polaris remains always north of Ursa Minor's
Ursa Minor's pole star and Polaris are the names of the same star
The true and mean suns occupy the same meridian at the same time on
April 15
June 14
September 1
All the above
In a spherical triangle ABC, right angled at C, sin b equals
sin a cos A
cos a sin A
tan a cot A
cot A tan a
The angle between the axis of earth and the vertical at the station of observation is called
Astronomical latitude
Astronomical co-latitude
Co-declination of star
Declination of star
On vertical photographs, height displacement is
Positive for points above datum
Negative for points below datum
Zero for points vertically below the air station
All the above
Pick up the incorrect statement from the following:
Latitudes north of the equator are taken as positive
Latitudes south of the equator are taken as negative
Longitudes east of Greenwich are taken as negative
Longitudes west of Greenwich are taken as positive
The method of surveying by triangulation was first introduced by the Dutchman Snell in
1600
1615
1630
1650
The declination and right ascension of the sun becomes 23° 27' N and 90° respectively on
March 21
June 21
September 21
December 22
The position of the sun when its north declination is maximum is known as
Vernal equinox
Autumnal equinox
Summer solstice
Winter solstice
The meridian of a place is
A great circle passing through the place and the poles
A great circle whose plane is perpendicular to the axis of rotation and it also passes through the place
A semi-circle which passes through the place and is terminated at the poles
An arc of the great circle which passes through the place and is perpendicular to the equator
Homologous points are
Opposite corners of a photograph
Nodal points of the camera lens
Corresponding points on the ground and photograph
Plumb points of stereo pair of photographs
If α, H, A and δ be the altitude, hour angle, azimuth and declination of a circumpolar star at its elongation, in latitude λ, the following relation holds good
cos H = tan λ/tan δ
sin α = sin λ/sin δ
sin A = cos δ/cos λ
All the above
The maximum error in radial line assumption, is
h/H f tan θ
h/H f² tan θ
h/H f² sin θ
h/H f cos θ
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
The solar tidal force divided by lunar tidal force is
1/3
1/2
3/4
5/4
The elevation of the star at elongation is obtained by
sin α = sin φ cosec δ
sin α = sin φ sec δ
sin α = cos φ sec δ
sin α = cos φ cosec δ
Rotation of the camera at exposure about its vertical axis, is known as
Swing
Tilt
Tip
None of these
The great circle whose plane is perpendicular to the axis of rotation of the earth, is called
Equator
Terrestrial equator
0° latitude
All the above
A star in northern sphere is said to transit
When its altitude is maximum
When its azimuth is 180°
When it is in south
All the above
23 cm × 23 cm photographs are taken from a flying height with a camera of focal length of 3600 m and 15.23 cm respectively. A parallax difference of 0.01 mm represents
1 m
2 m
4 m
8 m
At lower culmination, the pole star moves
Eastward
Westward
Northward
Southward
The latitude of the observer's position, is
Elevation of the elevated pole
Declination of the observer's zenith
Angular distance along the observer's meridian between equator and the observer
All the above
Polaris is usually observed for the determination of the latitude when it is
At culmination
At elongation
Neither at culmination nor at elongation
Either at culmination or at elongation
Pick up the in-correct statement from the following:
Apparent solar time is measured from the lower transit of the true sun
Mean solar time is measured from the lower transit of the mean sun
Sidereal time is measured from the lower transit of the first point of Aries
Sidereal time is measured from the upper transit of the first point of Aries
The altitude of a circumpolar star is maximum when it is
At east elongation
At upper culmination
At west elongation
At lower culmination
The latitude of a place was obtained by subtracting the declination of a star from its zenith distance, the observed star was between
Horizon and equator
Zenith and pole
Equator and zenith
Pole and horizon
Pick up the in-correct statement from the following:
Correction for refraction is always negative
Correction for parallax is always positive
Correction for semi-diameter is always negative
Correction for dip is always negative
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