Observatories that I have visited:
Stockholm's old Observatory, Sweden

Content:

1. Stockholm's Observatory, part 1
2. Stockholm's Observatory, part 2

Stockholm's (old) Observatory, part 1.

This is the closest observatory from where I live, I just take the subway for 30 minutes to the center of Stockholm at Odenplan and there it is. These photos I took when I was close to the observatory on an evening walk.

When they built the new observatory 1931 at Saltsjöbaden they called it Stockholm's Observatory, then this observatory had too change its name to Stockholm's old Observatory.

The observatory is placed on top of the hill at Odenplan. After I have come into the park I can see the silhouette of the old observatory.

An early photo of the observatory up on the hill, view from the street from the bridge Sveabron (crossing todays Sveavägen). The bridge is buried under the street Sveavägen since long time ago. Just thought about it, this photo is 116 years old, but already in that time the observatory was 153 years old.

Alternative link to the photo with higher resolution: Archive-Sveabron.

When I was a member of STAR amateur astronomy club I came in contact with Nils-Erik Olsson, all people call him Nippe. At that time he was the chair holder of the club and we talk a lot and email each other. Even now when I'm not a member anymore of that club we still have contact. When Nippe saw my report of Stockholm old Observatory which most contain photos of the buildings he mentioned that he had written an article about the observatory and he sent me the article. I found this article very interesting with a lot of information that I wasn't aware of. I asked Nippe if he want to have that text on this page, he gave me permission to use that article. I have translated it to English to let the world outside Sweden read this exiting article, if you understand the Swedish language there is a downloadable PDF file of the original article in Swedish at the end.

How could Nippe know all this history of the Observatory ? I can guess, he had earlier hold guided tours at the observatory museum during many years.

The House on the Observatory hill

Text (in slanted format) by Nils-Erik (Nippe) Olsson, translation and photos with complementary text by Lars Karlsson.

In 1739 the Royal Swedish Academy of Sciences was formed in borrowed rooms and stores in the Knight-house. That they did not have their own stores was a big problem for theirs collections were stored in many different places. On in some places everything was taken care of as it should be, others did worse. Among others Linnaeus natural history collections became so badly handled that some parts must be discarded. So something must be done. In the late 1740s when the astronomer Pehr Wilhelm Wargentin was secretary it was decided that the academy would build its own house with space for everything. Astronomy was already an important science within the academy so the house must accommodate one observatory, which placed great demands on the site and that the house was stable. It was common that existing observatories were built at the top of houses and often on poor land, which resulted in vibrations that made astronomical measurements more difficult. Vibrations in the house were the cause to the fact that Tycho Brahe built as early as the 16th century its second observatory Stjärneborg to some extent under ground. Uranienborg Castle Observatory was not stable enough.

From 1998 to 2013, I worked as an astronomy guide at the Observatory Museum. In addition to viewing the starry sky through a telescope, I chose to talk about the astronomical science of the house. And to make a story of the show, I also told about historical scientists in astronomy and their significance for today's astronomy. Therefore, I chose to learn a little more than just what was seen through the telescope. Nils-Erik (Nippe) Olsson

Carl Hårleman, who was a member of the academy and also a relatively new castle architect after Nicodeus Tessin the Younger in the reconstruction of Stockholm Castle, he was elected as an architect. Because it would be an observatory it was chosen to the highest place, the hill just north of the city with a clear view to above all the southern latitudes. Today's Observatory Hill 44 meters above sea level on Drottninggatan was chosen. The location was well chosen given the observation conditions. It was outside the city and was not disturbed by so much noise. The surroundings to the Observatory hill  was just country side with cows and windmill as nearest neighbors. The most famous of the mills that remained the longest is the one that is now at Skansen were it was moved.

If you came to the observatory from the Southwest you will have a look of the observatory hill like this. text by Lars.

Carl Hårleman immediately started studying and thoughts on how the house should be designed to meet all the requirements of the academy. Among other things, he learned from the observatories in Lund and Uppsala, which was placed at the top of its houses, they shacked and gave vibrations. The observation hall would therefore be located on the entrance level so it got direct support from the ground and so vibrations were avoided. Hårleman also thought over the design of the observation room. Then he remembered that the church rooms he had previously designed were shaped round around the altar. At the request of astronomers the house was oriented with the observation hall to the south and the entrance in the north. The observation hall itself became round large windows to the southeast, south and southwest. The one who have been inside the observatory has seen that it's similar to a church hall with its round shape and its large windows.

This observatory was founded already in the 18th century. In the side buildings they did meridian observations. An accurate calendar was important to have and they where based on these observations. Text by Lars.

Now only a small problem remained to be solved. The Royal Academy of Sciences didn't have enough money. 1747 had the Academy of Sciences admittedly received the almanac privilege as the sole publisher of almanacs in Sweden. But that money was not enough to a big house like this. Traders Claes Grill who since 1740 was a member of the Academy of Sciences apparently had plenty of that them (money). He gave The Swedish Academy of Sciences an interest-free loan that was enough to the entire construction.

Now all major practical problems are solved so it was just to 1748 put the shovel in the ground and start building. It was probably difficult to get building materials at a sufficient rate or by someone else cause. Stockholm Castle, which was rebuilt at the same time after the fire had to assist with some of the material. Now it was probably not so much for that was enough with material so both the Castle and the Observatory were completed. Something I often thought about is how they succeeded get all the material up to the top of the hill. That horse and wagon was used, we may well agree. But the road up to the top was hardly as smooth as it is today. Rather, it was probably the case that the road was paved with stone and gravel and very slippery. Construction work took place almost all year round. Only the coldest season it stood still.

A drawing by the artist Aleander of the old observatory, created about 1790-1850. Nippe who know this observatory very well give a comment, Nippe: "The original information must be wrong, it's a view from South".

At the beginning of the summer of 1753 the house was finished and ready for inauguration. However, the inauguration was postponed to September of the same year. One reason may be that architect Carl Hårleman died just before it planned the inauguration in June. The inauguration in September became, however, very solemn with the king Adolph Fredric as a guest.

Permanent Secretary Pehr Wilhelm Wargentin had already moved into the house with his family. The instrument maker Daniel Ekström also got a home and an instrument workshop. A janitor was needed and he got a place with his family in an apartment. Carl von Linné finally got a permanent place for large parts of their natural history collections. The rest of the rooms were offices and meeting rooms.

At that time, astronomers were mostly busy to determine the position of the planets, stars and their movements. The astronomers had to their help east of the observation hall a meridian room with a meridian instrument. It is permanently mounted straight in south and can be moved only up and down. When the star passed the telescope the height and time were measured. You already had the sideways direction. Sweden the national meridian, 18 degrees east of Greenwich, went through the room. Eventually it was discovered that it was 18 meters wrong and was therefore moved to the west side of the observation room. A new meridian room was built at the new correct place with two slightly different meridian instruments which are still there today. If you go south of the house you see the two steel lines in the ground that mark the old and new meridian.

The observatory building is very beautiful placed in the park. In the 18th century there where no other buildings that blocked the view. It was the countryside, now inner city of Stockholm. Text by Lars.

Measurements of the Earth's magnetic field were important to do. The observatory was no good because there was too much magnetic material. Therefore, one new house of its own was built that was completely free from anything that was magnetic and the measurements could be made without any disturbances. In 1838, the Magnet House was completed and it is where the STAR amateur astronomy club is today.

In this tower in one of the wings an amateur astronomy club has its office, the name of the club is STAR. In early 2000s I was member of this club and enjoyed it a lot, here is more information about STAR: Text by Lars.

• https://www.starastro.org/
  (Star - Stockholms amatörastronomer)

In the middle of the 19th century, the observatory became too crowded so a great expansion to the north was made. It is the rectangular building facing the courtyard. The old entrance thus ended up inside the hall and the new entrance ended up on the east side. In the same time it was determined that the telescope would be replaced and get a new place in the house because of the air pollution started disturbing the observations. The lantern on the roof above the observation room was demolished and replaced of the round room that is still there today. Many who worked at the observatory lived in the house and needed to wash clothes and other things. Associated with the large expansion, a new laundry room was built and it is in that house as Café Himlavalvet is placed today. In the 1870s, the new extension stood finished.

One of the wings to the observatory building, today there is a cafe in one of these wings. Text by Lars.

An important event for Stockholm Observatory were the passages of Venus in 1761 and 1769. All over Europe was planned for the passages that were important to determine the distance between the Earth and the Sun. If you knew that distance, you could with Kepler's laws calculate the distance to all other planets. Wargentin who was a well known and talented astronomer was given responsibility for observations in Sweden and Finland. Except in Stockholm it was made observations near Torneå, where Anders Planman was sent 1761. When Planman compiled all data it were sent to Paris where observations from all over the world gathered.

Another thing that made Stockholm Observatory known worldwide is that Wargentin 1756 began with observations of the weather. Three times during the day he read the temperature on the thermometer outside his window on the second floor and wrote down all the data. Weather observations have since it started been done three times every day but it's nowadays managed by SMHI (Swedish Meteorological and Hydrological Institute). Their measuring station is located at the northeast corner of the house. The measurement series may be the longest in the whole world made from the same place without the instruments moved longer distances.

Erik Nordenskiöld's polar voyage with the ship Vega was planned at the observatory where the Polar Institute had its seat. On the south side of the house is the ship Vega on a pillar as a memory.

During all the years the observatory has existed, of course lots of things happened. The writer August Strindberg was often guest there. He had opinions on observations and theories, which is documented in letters. The former Prime Minister Hjalmar Branting lived at the Observatory. After several years of study in Uppsala he moved to the observatory. It is said of him that he had a mistress in an apartment that was visible from the observatory. To let them meet each other when no one saw them, she lit a lamp in the window. When Branting got to see the light on, it was free to visit her.

Other fun events are the comet Donatis appeared on the sky in the mid-19th century. A janitor, Sven Roos, used to show it for a fee the public in a telescope. But comets disappear, so also this one and his extra income were threatened. That is why it is said that he managed to draw the comet a blackened glass attached to the telescope and he could for a fee continue to show the comet until his fraud was discovered.

Sweden's first balloon rise took place at the observatory the year after the world's first in France. It happened in 1784 and the hill was full of visitors. The balloon was filled with hydrogen and in the basket below the balloon was placed a cat. The rope that held the balloon was anchored on the ground, it was cut by the queen and the balloon headed east. Later they found the balloon with the basket on Värmdö but the poor cat was not left in the basket.

The original article in Swedish language to download as a PDF file:

• Observatoriemuseet PDF
  (Stella 3 Observatorie museet, Nils-Erik (Nippe) Olsson)

You download at your own risk !