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
Correct Answer :
A. At culmination
Related Questions
Pick up the correct statement from the following:
Refraction correction is zero when the celestial body is in the zenith
Refraction correction is 33' when the celestial body is on the horizon
Refraction correction of celestial bodies depends upon their altitudes
All the above
The parallax of a point on the photograph is due to
Ground elevation
Flying height
Length of air base
All the above
The altitudes of a circumpolar star at culminations are 70° and 10°, both culminations being north of zenith. The declination of the star, is
80°
70°
60°
50°
The correction applied to the measured base of length L is
Tension = (P - Ps)L/AE
Sag = L3w²/24P² where w is the weight of tape/m
Slope = (h²/2L) + (h4/8L3) where h is height difference of end supports
All the above
If E is the spherical excess and R the radius of the earth, the surface area of the triangle, is
πR²E/90°
πR²E/180°
πR²E/270°
πR²E/360°
Pick up the incorrect statement from the following. High oblique photographs
May have tilt up to 30°
May include the image of the horizon
May not include the image of the horizon
None of these
Parallax bar measures
Parallax
Height
Parallax difference
Height difference
The station which is selected close to the main triangulation station, to avoid intervening obstruction, is not known as
Satellite station
Eccentric station
False station
Pivot station
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
In field astronomy, the quantities observed are entirely
Lengths
Angles
Heights
All of these
Perspective centre relates to
Parallel projection
Orthogonal projection
Central projection
None of these
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
The moon rotates round the earth once in every
29 days
29.35 days
29.53 days
30 days
Pick up the incorrect statement from the following. In a spherical triangle
Every angle is less than two right angles
Sum of the three angles is equal to two right angles
Sum of the three angles less than six right angles and greater than two right angles
Sum of any two sides is greater than the third
The true and mean suns occupy the same meridian at the same time on
April 15
June 14
September 1
All the above
The difference of parallax for a given difference in elevation is independent of
Focal length of the camera
Overall size of the photo graphs
Percentage of overlap
All the above
Pick up the correct statement from the following:
The plane passing through the perspective centre of a stereo pair and a ground point, is known as basal plane
Each pair of image points on stereo pair have their own basal plane
Relative orientation means reconstructing the basal plane
All the above
In a tropical year, the numbers of sidereal days are
365
365.2224
365.2422
366.2422
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
Spring tides are caused when
Sun and moon are in line with earth
Solar tidal force acts opposite to lunar tidal force
Solar tidal force and lunar tidal force both coincide
None of these
The principal plane contains
Nadir point
Iso centre
Principal point
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
Pick up the correct statement from the following:
The measured stereoscopic base of photographs is obtained by dividing the air base in metres by the mean scale of the photograph
The difference between the absolute parallax of two points depends upon the difference in their elevations
The line joining the principal point of a photograph and the transferred principal point of the adjoining photograph, is called stereoscopic base
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
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
Places having same latitude
Lie on the parallel of the latitude
Are equidistant from the nearer pole
Are equidistant from both the poles
All the above
The point where vertical line passing through the perspective centre intersects the plane of the photograph, is known as
Photo plumb point
Plumb point
Nadir point
Isocenter
The distance between the projection centre and the photograph, is called
Principal distance
Principal line
Isocentric distance
Focal length
The latitude of a place was obtained by subtracting the zenith distance of a star from its declination, the observed star was between
Horizon and equator
Equator and zenith
Zenith and pole
Pole and horizon
The product of the distances of plumb point and horizon point of a vertical photograph from its principal point, is
f2
2f2
3f2
½f