Field Testing of the Durham/AGI Transmissometer

测量能见度，或者说众所周知的大气透射率，对天文学家来说非常重要。为了在他们位于纳米比亚的望远镜上进行这种测量，杜伦大学高能伽马射线天文小组建造了一种被称为透射仪的仪器。它使用基于LED和ccd的技术来执行测量，这比目前在这类仪器中使用的白炽灯泡和光探测器有优势。特别是，我们的设备比老式仪器更容易校准，需要更少的维护和更少的电力，因此它可以是太阳能供电的，这对远程飞机跑道特别有用。所以，我们申请了这个设计的专利。我们已经对仪器进行了升级，使其能够在白天工作（天文学家只需要夜间测量！），在仪器中安装了一个更便宜的CCD相机，并将其改为软件，以便可以使用Windows来控制它，我们需要进一步改进它，使其能够在机场和军用机场使用，而不是更传统的仪器。这包括使仪器更加坚固，并与我们的合作伙伴公司航空通用仪器有限公司（AGI）目前在美国制造的一个传输表一起进行广泛的现场试验。我们需要做的工作是由为期2年的PIPSS资助的。在PIPSS拨款期的早期，不幸的是，我们对新机场仪器的要求发生了变化；新的透射表不能使用活动部件。这给我们带来了问题，因为最初的设计使用了快门来掩盖LED。因此，我们不得不改变这个系统，包括所有的软件，这比我们最初预期的要花更多的时间，尽管最终我们得到了一个更好的工具。然而，额外的工作意味着我们错过了2008年10月开始的田间试验的窗口期（田间试验必须在冬季进行）。因此，我们要求再提供6个月的资金，使我们能够从2009年10月开始完成现场试验，并给AGI一些时间来了解新仪器，以便他们能够接管制造。

Measuring visibility, or atmospheric transmission as it is known, is important for astronomers. In order to perform this type of measurement at their telescope site in Namibia, the Durham University Very High Energy Gamma Ray Astronomy group built an instrument known as a transmissometer. This uses LED and CCD-based technology to perform the measurements, which has advantages over the incandescent light bulbs and light detectors currently employed in instruments like this. In particular, our equipment is easier to align, requires less maintenance and uses less power than older instruments, so that it can be solar-powered, which is particularly useful for remote airstrips. So, we have patented the design. Having upgraded the instrument so that it will work during the day (astronomers need only night-time measurements!), found a cheaper CCD camera to incorporate in the instrument and changed to software so that it can be controlled using Windows, we needed to improve it further so that it can be used in airports and military airfields instead of more traditional instruments. This involves making the instrument more robust and performing extensive field trials side-by-side with one of the transmissometers currently built by our partner company, Aeronautical & General Instruments Ltd. (AGI) in. The work we needed to do was funded by a 2 year PIPSS grant. Early on in the PIPSS grant period, unfortunately for us the requirements for new airport instrumentation changed; no moving parts can be used in new transmissometers. This caused us problems, as the original design used a shutter to mask the LED. We have therefore had to change the system, including all the software, which has taken more time than we originally anticipated, though has resulted in a better instrument all round. However, the extra work meant that we missed the window for field trails starting in October 2008 (field trials have to be conducted in winter). We are therefore asking for a further 6 months funding to enable us to complete the field trials starting in October 2009 and to give AGI some time to learn about the new instrument so they can take over manufacture.