Already in September 2019, me and my wife decided that we would go on holiday to northern France in May 2020. Life is relaxed there, there is peace, a beautiful landscape and beautiful nature. And we can take all our four dogs with us. And when the sky is clear, we are in a region with a sky that (measured in 2018) can reach at least SQM 21.60 and lm 6.6. Unfortunately, due to the corona pandemic we had to cancel this holiday in early May.
Fortunately, it turned out that a holiday in the Netherlands still was possible, and luckily, I was able to book at an address where we have often been guests with our dogs. This was in Midden Eierland (south of the little village of De Cocksdorp) on the island of Texel. Since 2012 we have been several times to Middle Eierland. Unfortunately, the weather was not so cooperative at the time, but when sky got clear you are immediately in a prime location. As mentioned, little could be observed during those previous visits, only in 2013 two nights permitted visual observing [2].
The village of Midden Eierland is actually not more than a crossing of two roads and 10-15 houses around it. On Texel people are very busy with dark sky and light pollution. A few years ago, the public lighting on the entire island was adapted to dimmed LED lampposts. At some roundabouts, all lighting has even been removed and replaced by LEDs built into the road. The light pollution maps (https://www.lightpollutionmap.info/) show that the area north of the villages of Den Burg and De Koog in particular is very dark to Dutch standards.
Figure 1. Light pollution map of Texel 2019. My observation location is marked with a black star.
Observations in 2020
This year we were guests on Texel between May 20 and 29. Given the short preparation time, I decided not to bring any equipment, just a digital voicerecorder, a sleeping bag, DCF-77 clock and observation forms. We arrived on Texel on Wednesday 20 May, but visited astrophotographer Marco Verstraaten in Twisk on the way, to discuss the new all-sky housing that he will made for me. We were warmly welcomed and shown around his impressive back yard observatory and studio. Then we headed quickly to Texel.
The weather forecast was good for the Netherlands with lots of sun (and clear nights). However, during the weekend temporarily some rain and clouds were expected. The first night was clear but with some cirrus clouds. After the clouds on Friday and Saturday it got better on Sunday with blue almost Provencal skies during the day. Unfortunately, in the evening on the North Sea, middle high clouds and cirrus formed and moved over the island. Fortunately, the next night (Monday / Tuesday) had a clear sky so I could do some observations.
Figure 2. View from the garden towards the north. The lighthouse is left outside of the picture behind a row of trees.
Figure 3. View to the south. The tall tree gives some obstruction.
May 25/26, 2020
The lampposts on the south side of our house were also adapted to (low!) full cut off luminaires with LED lighting. However, from the 2nd evening these were no longer turned on. Well I didn’t think that was a disaster of course. The observations were done far back in the backyard. There is a small meadow with unobstructed views up to the northern horizon. De Cocksdorp lighthouse is 5 km away and hardly disturbs. There are also trees that way so you do not see direct light from the tower. Only the wall of a building a little further lit up weakly when the beam of light came by. To the south there is a little bit of obstruction of small trees and the houses.
I started at 21:53 UT when the SQM is 20.18. A small crescent moon was low in the west and set after one hour. In 2013 I did not have an SQM meter so I was curious about what it would eventually be. However, I kept in mind we were now at the beginning of the gray nights season and here and there also was some sharply defined small tufts of cirrus… I was still surprised when I read the SQM measurements during the night, around 23:30 UT I even measured 21.53. The limit magnitude was then 6.5!
Soon after the start of the meteor observations I saw the ISS, it always remains impressive when it passes. Unfortunately, a group of Starlink satellites also passed by around 22:26 and 00:00 UT. They were not as bright as in April [3], usually they were about magnitude +4 or +5.
I was observing meteors between 21:53 and 00:50 UT. The first hour was pretty tame with only 8 meteors, most of which were weak. The second hour was much better with 15 meteors, but during the last 50 minutes things started to settle down a bit with 8 meteors. So, a total of 31 meteors in 2.92 hours effective of which 6 ANT. Three of them in the second hour. The most beautiful meteors were at 23:39 UT (a short +1 orange ANT near the star alpha Libra), at 00:03 UT a beautiful fast bluish-colored -1 sporadic meteor in Lyra and Cygnus with a persistent 4-second train and later an orange +2 Antihelion. At 23:01 UT I was startled by a flash of light from the north. Turns out to be a very bright satellite that gave flashes up to magnitude -6.
All in all a nice session! The combination of the beautiful clear starry sky with the planets Jupiter and Saturn from 0 UT, with the rest (barely car traffic), the sounds of the birds and frogs remains great!
The next night, there was an alternation of clearings and fields of medium and high clouds. Fortunately, it cleared up very nicely later in the day and a bright and clear night awaited!
May 27/28, 2020
Unfortunately, the Moon would disturb much longer his night. The Moon would set at 00:06 UT, when twilight was beginning. Indeed, this was clearly visible in the SQM measurements. After an increase to a maximum of 21.40 around 00:00 UT it slowly started to decline again. Still, an SQM measurement of 21.20 at 23:00 UT is quite impressive if you take into account the Moon and the gray nights. The maximum limiting magnitude reached 6.4.
Also this night, again 31 meteors were counted in 2.73 hours effective. Of those, 4 were Antihelions. Also, this time a ISS passage and later a Starlink train. Slightly less bright meteors, a nice magnitude – 1 moved through Hercules with a wide wake. A bright meteor that was recorded at 00:43 UT with the all sky camera at Twisk (Marco Verstraaten) was not seen, it appeared behind my back. All-in all this visual session was very successful.
28/29 May 2020
Although the Moon would disturb all night, I did another observational session. This time from the small garden on the street side. You could look over there over the meadows. There was a small light dome in the south, this will be probably Den Helder. The Den Helder lighthouse was also visible as a small rotating light beam up to 10 degrees in the south. The advantage of this location tonight was that the Moon stays hidden behind the house of the owners. The street lighting was also off, otherwise the story would have been different. I was surprised again when I read the SQM measurements, it still reached 21.15 around 00:12 UT.
I was able to observe between 23:35 and 01:03 UT. During 1.45 hours I counted 9 meteors, 1 ANT. Two +2 sporadic meteors were the brightest.
Figure 4. Evening twilight Midden-Eierland. The street lighting was off….
Three successful observations under very dark skies this time was a great score! On the way back we paid a visit to Jos and Karin Nijland, who showed us their new impressive house. Thanks for the hospitality Jos and Karin!
References
[1] Miskotte K., Midsummer nights 2018. Meteor observations at Any Martin Rieux, Northern France, Meteornews 2019, vol. 4, p. 241-243.
[2] Miskotte K., Meteoren en satellieten vanuit Texel, eRadiant 2013-2 p. 55-56.
[3] Miskotte K., Lyrids 2020: another great campaign!, Meteornews
