A total number of 30 slots of two hour duration each will be available for DI measurements on Monday, Tuesday and Thursday of the meeting. Measurement slots will be be available at the same time as the Observatory tour on Monday (preferentially for observers who know the observatory already), and during the poster and instrument presentations on Tuesday and Thursday. As both instruments and posters will be available throughout the meeting, you won't miss anything during measurements. The measurements will be performed on four piers within the tunnel and two piers in a wooden hut outside the observatory a short walk away. The tunnel temperature is 6°C with close to 100% relative humidity, so be prepared for cold and humid conditions.