1. The Miyun 50m radio telescope and possible upgrading project Jin Chengjin & Zhang Juyong Miyun Radio Astronomy Group, NAOC 2003, 11, 03

2. Contents:  Brief history of the Miyun 50m project  The current status  The possible upgrading plan

3. Brief history: The Miyun Station was founded in 1960s. The MSRT and the Miyun 15m telescope

4. Scientific motives for building a new 50m radio telescope: Long-time monitoring of pulsars Gravitational wave detection IPS observations A VLBI unit

5. The conceptual design in the beginning (~2001,11) : L-band telescope Metal mesh Light weight

6. Some improvement afterwards (~2002,3): Chinese Lunar project S/X band Metal plate + mesh Much stronger

7. The status: The contract was signed in Oct, 2002. The technical design has been finished. In parallel, we have organized several technical reviews for the antenna design. The prospection was completed. The antenna is schedueled to be completed in the first half of 2005.

8. The technical review meetings: Reviewed by domestic experts (2002, 4) Reviewed by experts from Germany, the UK and Australia (2002, 6) Reviewed by structure engineer from NRAO (2003,2) Constructive comments & suggestions

9.  The first pulsar observation was performed with this 15-m telescope. This telescope was built in 1992. The 15-m Radio Telescope

10. The prospecting apparatus(2003, 7):

11. 50m Telescope Design Specifications: Dish diameter ： 50 m Surface ： metal plate + metal mesh Mounting ： Altitude-Azimuth RMS surface accuracy ： 1.0mm (inner 30m) 3mm (outer part) Short wavelength limit ： 2.0cm(15 GHz) (inner 30m) Pointing accuracy ： 19 arcsec Slew rates (elevation) ： 0.5 degree per second Optics ： Prime focus f/D = 0.35 Slew rates (azimuth) ： 1.0 degree per second Metal plate : inner 30m Wire mesh : outer part

12. Possible upgrading plan: The reflecting surface The pointing accuracy The optics Goal: up to 43GHz

13. The reflecting surface Active surface

14. The pointing accuracy: Pointing model & A new servo system

15. The optics: Secondary focus Enough space and weight load

16. The upgrading plan: A doctor student is working on this project.