Barriers gestures to participate in On the Moon Again


This is about mobilizing amateur astronomers in the search for barrier gestures that we should adopt in our practice. As you know, the eyes and their mucous membranes are entry and exit points for contamination by the SARS-CoV-2 virus. They are connected to the nasal passages by the nasolacrimal duct via the lacrimal sac. Therefore, putting your eye to the eyepiece, or to your researcher, or observing with a pair of binoculars, or aiming with your SLR camera and then offering the observation to another person are risky gestures potentially contributing to the circulation of the virus. Of course in groups and for everyone, wearing a mask, hand hygiene (washing hands with soap or using hydro-alcoholic gel) and respecting the gestures of physical distancing are essential, including during the evenings of observation with the manipulation of astronomical instruments.


A good hygiene of the hands and eyes, gloves, your glasses and eyepieces or sights being able to come into contact with the eyes and the fabrics in direct proximity is thus essential between each observer. If you wear glasses, it is recommended to keep them to have a first barrier, even for the hypermetropes and the myopes who could compensate their vision by correcting the focus of the eyepiece. It is not recommended to wear contact lenses because of the consequences of the virus that can generate conjunctivitis or keratoconjunctivitis. These symptoms are described by the learned societies of ophthalmology as being one of the first possible symptoms of a Covid-19 infection ( For non-glasses wearers with good vision, it is recommended to wear a visor or, better yet, protective eyewear of optical quality in order to have a barrier to protect one's eyes or to avoid transmitting the virus through one's ocular secretions.

For eyepieces, it is preferable to choose models with a large eye relief (distance between the eye lens and the eye circle), which are better suited to wearing glasses and do not attract the eye to the eyepiece. Long focal length eyepieces with Orthoscopic or Plössl combinations are preferable from this point of view and it may be possible to fold down or remove the rubber cap from the eyepiece to avoid contact.

The following products and procedures are recommended:


  • for the eyes, at this stage, no virucidal eye drops against Covid-19 are known, so the simple hygiene gesture of washing the skin near the eyes is recommended with soap and water, of course the hydroalcoholic gel is not appropriate because it is too irritating


  • to disinfect glasses, use for example wipes soaked in a dilution of Ethanol and Chlorhexidine Digluconate, such as Anios wipes, or wash them with water at room temperature (to avoid thermal shock which would degrade the thin anti-reflective layers) with soap


  • for the eyepieces, the previous product can be used or a dilution of Ethanol or better Isopropanol which have a disinfecting and degreasing power. Distilled water with a neutral surfactant or washing-up liquid can be used as usual.


  • Finally, don't forget to clean and disinfect the buttons of the frames, the focusing wheels, the rackets, the tactile tiles, the keyboards and the mice which are traps in the transmission of the virus, if you are several to handle them successively.


  • Of course, digital cameras, CCD cameras and CMOS cameras replacing our eyes at the focus of telescopes and glasses, by being associated with display screens by a means of transmission in real time are solutions to be preferred. It is also possible to realize this sharing of the display with the smart-phones either directly, or possibly by passing by the applications of video-conferences. All this is a source of ideas to realize animations and share in group the discovery of the sky in security.


Martine and Thierry Midavaine - French Astronomical Society (SAF)