Map of the Sun, Tokyo Astronomical Observatory

11 10 2017

Tokyo Astronomical Observatory Map of the Sun, March 21, 1959. Image: Kodaikanal Observatory Library / JR

I found a whole book of these maps of the Sun made for the International Geophysical Year (July 1, 2957 to December 31, 29158) in the library at Kodaikanal Observatory. It took me awhile to track down their origin, but I finally found the entire collection online at the Solar Science Observatory of the National Astronomical Observatory, Japan. (Scroll down to the section of the table that says “Map of the Sun in the IGY period),

According to the Historical Sunspot Drawing Resource Page:

  • The Toykyo Astronomical Observatory moved to Mitaka (near Tokyo) in 1924 (construction began 1904)
  • Sunspot observations made from January 1929 to March 1999
  • 203-mm f/18 Zeiss refractor
  • Observation method: Eyepiece projection method, 24-cm image
  • Solar projection unit at NOAJ: Cloudy Nights
  • Drawings archived at Solar Activity World Data Center, Tokyo
  • An extensive database of drawings and observations is available online

According to the National Observatory of Astronomy Japan (NOAJ), the dome housing the 20-cm refractor built in 1921 by Mr. Chodayu Nishiura. The refractor, set on an equatorial mount with clock drive, was used to map sunspots from 1938 to 1999.



The dome for the 203-mm f/18 Zeiss refractor at the NOAJ Mitaka campus.
Image: おむこさん志望 / Wikimedia Commons / CC BY-SA 3.0

Venus-Mars Conjunction

6 10 2017

Venus and Mars with Sigma Leonis, October 5, 2017. Image: JR

To say that I got up early to view yesterdays’ close conjunction of Venus and Mars would be stretching the truth. My alarm went off the same time it does every weekday morning, so viewing it took no special effort on my part. And If I’m telling the 100% truth, I’m saying that I can see Venus from an upstairs window, so technically, I didn’t even have to go outside for a decent naked-eye or binocular view of the event. (Remember, I’m the person who once did an entire day of solar observing with a 130-mm reflector from inside the house.)

Mars and Venus were about 1/4° apart yesterday  morning (October 5th) as viewed from Metrowest. Sigma Leonis was something like 19 arcminutes from Venus. Through binos, the difference between 15 and 19 arcminutes is obvious.

Mars and Venus had moved on this morning. Detectably orange Mars stood about 1/2° upper right of Venus (1 o’clock on the dial), with Sigma  about 1-1/4° directly above Venus.