The angle between the direction of star and the direction of earth's axis of rotation is called
Co-declination
Co-latitude
Declination
Latitude
Correct Answer :
A. Co-declination
Related Questions
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
Pick up the incorrect statement from the following:
In truly vertical photographs without relief angles are true at the plumb point
In tilted photographs without relief, angles are true at the iso-centre
In tilled photographs with relief, angles are true at the principal point
None of these
For plane ground the scale of a vertical photograph will be same as that of a tiled photograph along the photo parallel through
Isocenter
Plumb point
Principal point
None of these
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
The Polaris remains below horizon at
10° N
50° N Latitude
Equator
5° S latitude
The height displacement on a vertical photograph
Increases as the horizontal distance increases from the principal point
Increases as the ground elevation increases
Decreases as the flying height increases
All the above
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
In a tropical year, the numbers of sidereal days are
One less than mean solar days
One more than mean solar days
Equal to mean solar days
None of these
In a truly vertical photograph,
Principal point coincides the isocenter
Iso-centre coincides the plumb point
Plumb point coincides the principal point
All the above
Pick up the correct statement from the following:
Aerial photographs may be either vertical or oblique
Vertical photographs are taken with the axis of camera pointing vertically downward
Vertical photographs are used for most accurate maps
All the above
A nautical mile is
One minute arc of the great circle passing through two points
One minute arc of the longitude
1855.109 m
All the above
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 point on the photograph where bisector between the vertical line through optical centre of the camera lens and the plate perpendicular meets, is known as
Principal point
Isocenter
Plumb point
Perspective centre
The prime vertical passes through
The east point of the horizon
The west point of the horizon
The zenith point of the observer
All the above
The position of the sun when its north declination is maximum is known as
Vernal equinox
Autumnal equinox
Summer solstice
Winter solstice
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°
Triangulation surveys are carried out for locating
Control points for surveys of large areas
Control points for photogrammetric surveys
Engineering works, i.e. terminal points of long tunnels, bridge abutments, etc.
All the above
α and β are the angles subtended by a point of elevation h at their air station with respective plumb points. Photo scale and focal length of the lens being S and f respectively. Parallax displacement of the point due to relief, is
h tan α/S
h tan β/S
h (tan α + tan β)/S
h (tan α - tan β)/S
Sidereal day
Is the period of time taken by the earth in making a complete rotation with reference to stars
Is slightly shorter than an ordinary solar day
Is divided into the conventional hours, minutes and seconds
All the above
If α is the observed altitude, the refraction correction in seconds, is
58 cot α
58 tan α
58 sin α
58 cos α
The angle between the observer's meridian and declination circle of a heavenly body, is known as
Hour angle
Azimuth
Right ascension
Declination
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
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
Circumpolar stars
Rotate round the North Pole
Rotate round the celestial pole
Remain always above the horizon
Are seldom seen near the pole star
The scale of the photography taken from a height of 300 m, with a camera of focal length 15 cm, is
1 : 10,000
1 : 15,000
1 : 20,000
1 : 30,000
Invar tapes used for measuring base lines, is made of nickel-iron alloy containing nickel
24 %
36 %
40 %
60 %
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
A star may culminate at zenith if its declination is
Greater than the longitude of the place
Less than the latitude of the place
Equal to the latitude of the place
None of these
Accidental errors
Do not follow any definite mathematical law
Cannot be removed by applying corrections to the observed values
Are generally small
All the above
The solar tidal force divided by lunar tidal force is
1/3
1/2
3/4
5/4