The Observatory and COVID-19
We are working to develop a protocol to ensure the maximum protection against the transmission of COVID-19 during observing sessions in the observatory. The factors we are considering are:
1. Although the observatory is open to the sky, it is still enclosed by 4 walls, so it is a semi-open space. Virus transmission in open spaces is considered to be less likely than in enclosed spaces. We are in-between the two situations.
2. The observatory has a limited space available for distancing.
3. We are assuming that a group of visitors to the observatory are in the same social group, so that visitors do not need to maintain distancing measures between themselves, and nor do we. So the distancing only needs to apply between 2 sets of people: the visitors and us. With this assumption we can manage within the observatory.
4. During the observing time in the observatory it is very dark, and the position of the eyepiece often needs the use of a small step-ladder, so there is an obvious impulse to hold onto either the ladder or some part of the telescope for support.
5. Observing with the telescope means that one must put ones eye up against the eyepiece, and it is known that transmission can occur via the eyes.
6. In order to use the telescope it is necessary that one of us slews the telescope to the object, and then centers it and then adjusts or verifies focus, having in some cases changed the eyepiece.
The protocol we have developed so far includes the following steps:
1. To avoid virus transmission via droplets, particularly onto parts of the telescope near the eyepiece, everybody shall wear a surgical mask (we will provide these if necessary).
2. To avoid virus transmission via hands and surfaces being touched in the dark, everybody shall wear gloves (we will provide these if necessary); obviously for this to be effective everybody needs to resist the urge to touch their face with the glove.
3. To maintain distance, the visitor group shall stay closely together, while we will keep a distance of at least 1m. This will require some choreography while adjusting the telescope.
4. To minimise transmission risk via the eyes at the eyepiece, we will wear secure eye-protection while using the telescope. This will not be necessary for our visitors as we assume they are in the same group.
5. Between visits we will clean the eyepieces which have been used, and the nearby telescope surfaces, with a suitable disinfectant.
6. To assist any eventual contact tracing, will request that visitors enter at least one contact in a guest-book. This is not mandatory but is for everybody’s benefit.
Our remaining problem with this protocol is with item 4. Suitable eye protection needs to ensure isolation of the eyes from the eyepiece and surroundings, yet also meet the optical demands. These are firstly that the optical view is of high quality, to ensure accurate focusing, and also without too much loss of light, to enable faint objects to be properly seen. Secondly, the eye protection needs to allow our eyes to get sufficiently close to the eyepiece that we can actually see something!
In this context, eyepieces have a characteristic called “eye relief”, which measures the distance away from the optic that the eye can be. Larger values are good for spectacle wearers (or those wearing eye protection), but can be tricky for beginners to find the right place for the eye.
We have a range of eyepieces with different amounts of eye relief, and some have a mechanical adjustment to make it easy for everybody to use them.
We have ordered several different types of eye protection, selected by protection level, optical quality and transparency, and will be assessing them in the near future.