AAS: solar activity history

[notFritzArgelander]

https://aasnova.org/2019/12/02/featured ... fBxfEmto3o

Shows an image of Hevelius solar observatory set up circa 1600.

[Lady Fraktor]

Thank you for the posting.
I have a digital copy of Selenographia and another atlas by Johannes Hevelius.
Hopefully this minimum does not decide to stretch out like the Maunder Minimum though.

[notFritzArgelander]

Thank you for the posting.
I have a digital copy of Selenographia and another atlas by Johannes Hevelius.
Hopefully this minimum does not decide to stretch out like the Maunder Minimum though.

From a solar observer's POV you are of course quite right. From the different POV of species suicide due to climate change another Maunder Minimum might be just what we need to save our bacon from being fried in our own self heated pan.

[Altocumulus]

Wonderful story. I wonder who was the first person to realise that projecting the image was safer than not

[notFritzArgelander]

Wonderful story. I wonder who was the first person to realise that projecting the image was safer than not

The use of optics for starting fires was known to Archimedes.
https://en.m.wikipedia.org/wiki/Archimedes

Hevelius solar observatory is essentially a camera obscura equipped with a lens instead of a simple pinhole. These were in use ~50 years prior to Hevelius.


https://en.m.wikipedia.org/wiki/Camera_obscura

[yobbo89]

interesting. i had no idea one could get detail from solar astronomy in 1600's with the projection method i always thought solar astronomy was a modern thing.

[notFritzArgelander]

interesting. i had no idea one could get detail from solar astronomy in 1600's with the projection method i always thought solar astronomy was a modern thing.

There have been differently defined ways of counting spots over the 400 year data history. In the 19th century Wolf standardized a method. If you're interested there's a neat history of sunspot observation and data here:

https://arxiv.org/pdf/1407.3231.pdf

Also interesting equipment photos.