Pascal Hilkens Astro Home Page
Saturday, December 23, 2017
Friday, December 22, 2017
Astronomical Highlights 2017
My Astronomical Highlights of 2017 is, of course, the Great American Eclipse. Beside this wonderful and beautiful moment also other moments are worthwhile to share :
Solar Eclips in Rexburg Idaho Aug 21, 2017
The Milky Way or a Meteor as seen in National Park Arches (Utah)
The Sun this year with a perfect 360° Halo and with Sunspots (even when the Sun is getting into a minimum period) :
The Planets this Year with Saturnus and Jupiter :
Deepsky Objects M42 en M51 :
And My Solargraph using a 72cl can :
Solar Eclips in Rexburg Idaho Aug 21, 2017
The Milky Way or a Meteor as seen in National Park Arches (Utah)
The Sun this year with a perfect 360° Halo and with Sunspots (even when the Sun is getting into a minimum period) :
The Planets this Year with Saturnus and Jupiter :
Deepsky Objects M42 en M51 :
And My Solargraph using a 72cl can :
Thursday, December 21, 2017
Ms Hisako Koyama - Observing Sunspot for more then 40 Years
![]() |
Hisako Koyama +40Years Observation of Sunspots |
Via the website of the University of Colorado Boulder I found an article on "Hidden Figure" Hisako Koyama. She is a Japanese Solar Observer and observing +40 years of sunspot and making +10000 drawings.
To better understand the solar cycle, an international group of scientists reconstructed the number of sunspots seen each year since scientists first observed them by telescope in 1610. A researchers team searched through original sunspot observations for the past 400 years and discovered Koyama’s work in Japan. They combined her collection of drawings with those of Galileo Galilei, Pierre Gassendi, Johann Caspar Staudacher, Heinrich Schwabe and Rudolf Wolf to establish a continuous sunspot count for the past four centuries.
Those five names are the giants of sunspot records. Koyama’s more than 40 years of drawings proved invaluable to the scientists because few solar observations have been collected by the same person, using the same telescope and using the same observation method for such a long time.
Her drawings are digitized and available via the Japanese National Museum of Nature and Science.
Interesting to note is that she is one of few people who ever witnessed a white-light flare with the naked eye. She recorded this on November 15, 1960.
If you want to search into the archieves for digitized sunspot drawings, use this link.
Winter Solstice
The Astronomical Winter will start Today at 17h28 local time (UT 16h28) and it is the Day with the least Sunlight.
Wednesday, December 20, 2017
Solargraphs Results
Magnificent Solargraph from the period July-Dec 2017 using a 72cl can with Ilford MGRC Multigrade RC Cooltone photopaper.
Six months ago, I installed two pinhole camera's with the intention to track the sun's orbit at the sky. This was my sixt consecutive year doing these experiments. This is what I learned this year :
![]() |
Solargraph made with 72cl can |
1) One of my pinhole camera's had a rather large pinhole. This can result in an overexposure, so keep the pinhole as small as possible;
2) I used a 72cl can and the results is much better when comparing with a 50cl can;
![]() |
Second Solargraph : 50cl can with rather big pinhole resulting in an overexposed Solargraph |
Friday, December 15, 2017
Pinhole Camera Ready
Star Wars VIII
Subscribe to:
Posts (Atom)