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
Correct Answer :
A. sin α = sin φ cosec δ
Related Questions
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 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
The correction for parallax, is
- 8.8 cos α
+ .8 sin α
+ 8.8 cos α
- 8.8 cos α
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
The zenith is the point on the celestial sphere
East of observer
West of observer
North of observer
South of observer
If δ is the declination of the Polaris and λ is the latitude of the place, the azimuth of the Polaris, is
cos δ/cos λ
cos (90° - δ)/cos (90° - λ)
sin (90° - δ)/sin (90° - λ)
tan (90° + δ)/tan (90° + λ)
The coverage is least if photography is
High oblique
Low oblique
Vertical
None of these
The point at which sun's declination changes from north to south, is known as
First point of Aeries
First point of Libra
Vernal Equinox
Both (b) and (d) of 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
At eastern elongation, the pole star moves
Eastward
Westward
Northward
Southward
If θ and δ be the latitude of an observer and declination of a heavenly body respectively, the upper culmination of the body will be south of zenith if its zenith distance, is
δ - θ
θ - δ
θ + δ
½ (θ - δ)
The length of a parallel of λ latitude between two meridians is equal to difference in longitudes multiplied by
sin λ
cos λ
tan λ
cot λ
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
If δ is the declination of the star and φ is the latitude of the observer then the hour angle of the star at elongation is given by
sin H = tan φ . cot δ
cos H = tan φ . cot δ
tan H = tan φ . cot δ
None of these
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 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
Pick up the correct statement from the following:
Sidereal time at any instant is equal to the hour angle of the first point of Aries
Local sidereal time of any place is equal to the right ascension of its meridian
Sidereal time is equal to the right ascension of a star at its upper transit
All the above
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
For any star to be a circumpolar star, its
Declination must be 0°
Declination must be 90°
Distance from the pole must be less than the latitude of the observer
Hour angle must be 180°
The First Point of Aeries
Is the point in the celestial sphere where zero meridian crosses the celestial equator
Is usually denoted by the Greek letter γ
Is located near the very conspicuous rectangle of stars in the constellations of Pegasus and Andromeda
All the above
Rotation of the camera at exposure about horizontal axis normal to the line of flight, is known as
Swing
Tilt
Tip
None of these
The normal longitudinal overlap is generally kept
50 %
60 %
70 %
75 %
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
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
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 most convenient co-ordinate system for specifying the relative positions of heavenly bodies on the celestial sphere, is
Altitude and azimuth system
Declination and hour angle system
Declination and right ascension system
Declination and altitude system
If α is the observed altitude, the refraction correction in seconds, is
58 cot α
58 tan α
58 sin α
58 cos α
Stellar astronomy deals with
Plane surveying
Geodetic surveying
Star observations
Planet observations
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 scale of a tilted photograph of focal length f, taken from an altitude H, along the plate parallel through plumb point, is
f/H sec θ
f sec θ/H
f/H
f/H cos ½θ