Dome Seeing and Proposal for Enclosures of Telescopes at Gaomeigu

Seeing is very important for an observatory.The seeing includes atmospheric seeing outside of the enclosure and man-made seeing coming from inside the dome and the telescope itself. Mixing air masses with different temperatures around and inside the dome does deteriorate the seeing. At best sites,the seeing is not dominated by the turbulence created within the dome or its immediate surrounding. Some examples of pragmatic solutions not to depreciate the capabilities of the site are reviewed. Operating a telescope in the open air(no-dome)is not a common solution and may be available only in very clean sites. Since the wind-induced moment on telescopes in the open are an order of magnitude higher than those for sheltered telescopes. Another problem is stray light, especially when the moon is up. Finally, the air can easily transports dust inside the telescope chamber and get onto the optics. The requirements and proposals of the enclosure for 2-meter telescope at Gaomeigu are given in detail hereafter: Protection against adverse weather and environmental conditions. The height of the center of telescope should be higher than 15m. The diameter of the enclosure is 8-10m with observing slit and several side doorThe half open dome is discussed. The dome rotation speed is up to 2°/s. The enclosure for 1 m telescope is also described.