The Yerkes refracting telescope has a 1 m diameter objective lens of focal lengt

Question

The Yerkes refracting telescope has a 1 m diameter objective lens of focal length 20.0m. Assume it is used with an eyepiece of focal length 2.5cm. Determine the magnification of the image of Mars obtained. Are the Martian polar caps right side up or inverted? Assume the intensity of sunlight is 1.00kW/m2 at a particular location. A highly reflecting concave mirror is to be pointed towards the Sun to produce a power of at least 350 watts at the image, i) find the required radius R of the surface area of the circular mirror, ii) The Sun subtends an angle of 0.53 degrees at the Earth. If the radius of curvature of the mirror is 2m estimate the light intensity at the focus.

Explanation / Answer

a)The angular size of the craters when viewed at the closest approach of Mars to the Earth would be:

= crater diameter/ distance from Earth= 3x104 m / 5.60x1010 m = 5.36x10-7 radian

Magnification m required is such that m x must at least =the minimum resolution of the eye.

Take this to be o = 2x10-4 m x = o

Magnification required = / = 2x10-4 /5.36x10-7 = 360

The Yerkes refracting telescope has:

fo = 2000 cm

fe = 2.5 cm

Therefore the angular magnification m is :

m = fo/fe = 2000/2.5 = 800

The 30 km craters would be seen with the Yerkes telescope.

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.