The spot diagram size of compensating test for primary mirror is 0.02 mm. The spot diagram size of the system is 0.02 mm,RMS is 0.18 λ and PV is 1.2 λ measured by WYKO laser interferometer.

The paper introduces the ways of increasing the investment ecomonic efficiency and the evaluation for the ecomonic results of the projects relating to geological disasters control in the area of three gorges . The author provides the evaluation models and standards for the economic results.

Based on the third-order aberration theory the initial configuration parameters of the mirror compensator in testing the conicoid are solved in theory,making spherical aberration coefficient ∑S_1=0,and the relations between the compensating mirror and the tested mirror are given,with the surface of compensator chosen as sphere or ellipsoid.

Based on third-order aberration theory, a null testing system using compensator for an off-axis convex hyperboloid mirror is designed, it avoids that the aperture of auxiliary lens is overmuch larger when the Hindle test is applied.

Based on third-order aberration theory, a method of null test using compensation that include three compensating lens and a field lens is put forward for paraboloid mirror with super relative aperture, and describes detailed the design process of compensation system. The testing system is designed successfully for a paraboloid mirror that relative aperture is F0.6 and aperture is φ290 mm. The result of design show that aberration of testing system is well corrected and the system reached to diffraction limit.

In this paper, the concept of compensa Hon to null tests using compensators in astronomical optics is advanced. As for Fig. 1, formula (1) and formula (2), if the parameters of the compensator A have been so selected as to yield b1-a1, only, we define it as the first order compensator. If to yield b1=a1 and b2=a2 simultaneously, we define it as the second order compensation, etc.And we suggest three following principle points about the design of null test systems: 1. Because the selected focal ratio of the primary...

In this paper, the concept of compensa Hon to null tests using compensators in astronomical optics is advanced. As for Fig. 1, formula (1) and formula (2), if the parameters of the compensator A have been so selected as to yield b1-a1, only, we define it as the first order compensator. If to yield b1=a1 and b2=a2 simultaneously, we define it as the second order compensation, etc.And we suggest three following principle points about the design of null test systems: 1. Because the selected focal ratio of the primary of modern reflecting telescope diminishes steadily, and more and mose higher order aspheric systems of excellent image quality have been designed, we should lay emphases on the second order, or higher order compensators in later design and research work. 2. The compensators should consist of small size optical elements. 3. Fig. 3, Fig, 4 and Fig. 5 are the principle configurations for testing concave surfaces, convex surfaces and aspheric plates. In any above arrangement, B is a spherical mirror to converge the beam and A is a small size optical system providing the compensation of the requested order.It is put forward in this paper, that the applicable range of a compensator can be enlarged, by shifting optical elements and changing object distance. Let's take the Of-fner compensator of Chinese 2.16-meter primary as an example. Its structure data are given in Table 1. When the refractive index changes from 1.5163 to 1.5313, it is only needed to change S1 to -580.85785, d2 to 505.45925 and d4 to 12998.533. When e2 of the primary changes from 1.0951347 to 1, it is only needed to change S1 to-678.56510, d2 to 504.25088 and d4 to 12961.746. When the radius of curvature changes from -12960 to -13960, it is only needed to change & to -607.29751, d2 to 522.64348 and d4 to 13990.144. In above cases, almost the same good effects of compensation are obtained. Even if the refractive index and the parameters of a primary change far more, very good results can be still obtained by changing S1, d2 and d4 correspondingly. On the other hand, if the changes of refractive index and the parameters of primary are small, it is already good enough by changing S1, and d4 only.In addition, it is also mentioned that the better method is to compromise by defining a reasonable merit function for optimization during the later stage of the design process of null tests using compensators. The special programme we developed for null tests is also introduced briefly. All results in this paper are obtained by the programme.

In this paper,compensating test systems for high-order aspherical plates are proposed.The fifth order spherical aberration is applied to solving the initial structure of the compensator.The initial structure of the compensator agrees with the optimal result very well.There are two compensating test systems for the 1 5 m correcting plate of an achromatic Schmidt telescope with a field of view of 2 W =6°.All compensating test systems reach high accuracy,the residual...

In this paper,compensating test systems for high-order aspherical plates are proposed.The fifth order spherical aberration is applied to solving the initial structure of the compensator.The initial structure of the compensator agrees with the optimal result very well.There are two compensating test systems for the 1 5 m correcting plate of an achromatic Schmidt telescope with a field of view of 2 W =6°.All compensating test systems reach high accuracy,the residual of each tested surface is less than λ/100(λ=0 5893 μm).Finally,we discuss the test system errors in detail when the system is misaligned, and put forward an effective method of reducing the test system errors. This method is also applicable to other compensating test systems.

In this paper an approaching method is adopted in marking the Offner compensatory for testing a φ800mm parabolic mirror.According to the actual situation, we fix the parameters, which had already been accurately measured and then optimize the whole system by adjusting the residual parameters to meet practical precision. Thus critical requirement in manufacturing can be alleviated and the processing time can be saved as well.