Portable Multi-Channel Intensity Interferometer

在不断努力获得宇宙中物体的更好图像的过程中，重点通常集中在轨道天文台或更大的地面设施上，这些设施具有激光校正大气湍流的能力。这两种方法都是昂贵的，而且有物理限制。一种完全不同的方法，强度干涉测量法，在射电天文学中有着重要的历史，但最后一次被认真用于光学体制是在20世纪70年代，使用当时可用的简单探测器。南康涅狄格州立大学（SCSU）的E. Horch博士已经认识到，如今非常灵敏、速度极快的固态探测器促使人们重新审视这项技术，因为它将提供一种可能性，即使用小型廉价、中等大小的望远镜和商用仪器，就可以获得轨道双星、恒星直径的分离，甚至是完整的恒星图像。事实上，SCSU项目正被推广为一项非常适合学生参与的小型本科大学活动。天文学的强度干涉测量利用玻色子（因此光子）的玻色-爱因斯坦相关来提供有关辐射源角尺寸的信息。霍希博士预测，对于分布在SCSU校园内的口径略小于1米的望远镜，0.1毫弧秒的角分辨率可以达到~3.5的视星等，可以详细检查大约200颗恒星。相比之下，太阳移动到这个视亮度的距离，其角直径为2毫角秒。此外，利用量子效率接近0.5、时间响应约0.1纳秒的单光子雪崩二极管（SPAD）阵列，以及利用GPS技术记录的数据，可以在多个波段同时监测这种效应。美国国家科学基金会天文科学部通过其参与的主要研究仪器项目，为光学强度干涉仪阵列的现代双望远镜原型的开发提供了资金。

In the continual effort to obtain better images of objects in the universe, the emphasis has generally been centered on orbiting observatories or ever-larger ground-based facilities with laser correction of atmospheric turbulence. Both are expensive endeavors with physical limitations. A quite different approach, intensity interferometry, has a significant history in radio astronomy, but was last seriously used for the optical regime in the 1970's using the simple detectors available at the time. Dr. E. Horch of Southern Connecticut State University (SCSU) has recognized that today's very sensitive, extremely fast solid-state detectors motivates that the technique be re-examined, as it would offer the possibility of obtaining separations of orbiting binary stars, stellar diameters, and even complete stellar images using a small array of inexpensive, modest-sized telescopes and commercially available instrumentation. Indeed, the SCSU project is being promoted as an activity well-suited to student involvement at a small undergraduate university.Intensity interferometry for astronomy utilizes the Bose-Einstein correlation of bosons (and therefore photons) to provide information on the angular size of the radiating source. For telescopes with somewhat less than 1-m aperture distributed over the SCSU campus, Dr. Horch predicts that an angular resolution of 0.1 milliarcseconds can be achieved down to a visual magnitude of ~3.5, allowing detailed inspection of about 200 stars. For comparison, the Sun moved to a distance that yields this apparent magnitude would have an angular diameter of 2 milliarcseconds. Moreover, the effect can be monitored in several wavebands simultaneously through the use of Single Photon Avalanche Diode (SPAD) arrays that have quantum efficiencies near 0.5 and time response of ~0.1 nanoseconds, and the data recorded using GPS technology.Funding for the development of a modern two-telescope prototype of an intensity interferometer array for the optical is being provided by NSF's Division of Astronomical Sciences through its participation in the Major Research Instrumentation program.