Thomas Karlsson

@thomaskarlsson.bsky.social

Swedish amateur astronomer and Ukraine supporter.

AM Dra is one of the brightest mira among the SAAF's collection of 50 forgotten miras. The brightness of our observations varies between magnitude 9.3 and 16.6 and with a period of 329.1 days. The star was discovered in 1955 by Edward H. Geyer at the Bamberg Observatory.

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Berkeley Earth global temperature to June 2026 + trend forward, compared to 1850-1900. Current temperature: 1.47 (June 1.49) Rate of increase: 1970-2026: 0.21 deg/decade 1970-2009: 0.19 2010-2026: 0.36 2015-2026: 0.30 With current trend, 1.5 degrees will be reached in 2028, 2.0 in 2044.

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MetOffice HadCRUT5 global temperature to May 2026 + trend forward, compared to 1850-1900. Current temperature: 1.42 (May 1.37) Rate of increase: 1970-2026: 0.20 deg/decade 1970-2009: 0.19 2010-2026: 0.32 2015-2026: 0.26 With current trend, 1.5 degrees will be reached in 2029, 2.0 in 2047.

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R Ari is a short-period mira discovered by Friedrich Wilhelm Argelander in 1857. Here is a phase diagram with SAAF/V observations since 1990, with my observations in yellow. Based on our data, its period is calculated to be 186.45 days.

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Berkeley Earth global temperature to May 2026 + trend forward compared to 1850-1900. Current temperature: 1.41 (May 1.35) Rate of increase: 1970-2026: 0.21 deg/decade 1970-2010: 0.19 2010-2026: 0.36 2015-2026: 0.29 With current trend, 1.5 degrees will be reached in 2029, 2.0 in 2046.

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WZ Del is another star among the SAAF's 50 forgotten miras. It was discovered in 1930 by Cuno Hoffmeister. Not much observational history exists for the star before SAAF began observing it in 2012. Its period, currently 259.1 days, is quite short and appears to be stable.

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R Tri is a short-period and bright mira. It was discovered in 1890 by the English amateur astronomer THEC Espin and independently by Williamina Flemming at Harvard. The phase diagram shows 569 observations made by SAAF/V from 1990 onwards. From these observations the average period is 265.16 days.

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Berkeley Earth global temperature to April 2026 + current trend forward. Current temperature: 1.41 Rate of increase: 1970-2026: 0.21 deg/10 years 1970-2010: 0.19 2010-2026: 0.36 2015-2026: 0.30 With current trend, 1.5 degrees will be reached in 2030, 2.0 in 2047.

Red line: One year moving average. Blue Line: 21 year moving average + confidence interval and current trend forward.

WX Del is one of the SAAF's 50 Forgotten Miras. It was discovered by Cuno Hoffmeister in 1930. WX Del is the longest-period mira of the 50 on the SAAF's list. The current period is 528.8 days, close to the average period since 1897 of 528.3 days. The diagram shows SAAF observations 2012-2026.

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R Boo is a bright and fairly short-period mira. Here is a phase diagram with observations made within SAAF/V 1990-2025. Most are visual (black) but also some photometric with V-filter (green). The star's period is quite stable with a variation between 222 and 226 days during the observed time.

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V2330 Cyg is a mira among the SAAF's 50 forgotten miras. Discovered by Mike Collins, UK, in 2000 and independently by Lennart Dahlmark, Sweden, in 2001. The average period since 1899 is 382.5 days. Its current period is similar, 383.6 days.

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Alpha Ori or Betelgeuse, the orange-red supergiant in Orion that could go supernova any day in the next 100,000 years. In 2020, the star had a sharp dip in brightness. Below are SAAF's visual observations of Betelgeuse since 2018.

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V2331 Cyg is an deep eclipsing binary that was misclassified as an irregular variable. In 2012, members of SAAF/V discovered its true nature. After a few months of observations, the correct period could be determined. We also wrote a short article in JAAVSO about the star.

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Here is a graph showing Swedish solar observations since 2020. Gray crosses are individual observations, the blue line shows the mean value per month and the red line is a moving average over 12 months. Maximum solar activity was reached in October 2024.

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V2072 Cyg is another mira among SAAF's 50 Forgotten Miras. The variable was discovered by the Swedish amateur astronomer Lennart Dahlmark in 1982 with the designation LD 55. The period has been fairly stable since 1895 with a mean value of 318.6 days. Since 2012 it is 316.8 days.

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I have used data from Berkeley's new climate model with 0.25 deg resolution and made a new temperature forecast. The temp in this model is slightly lower than in their previous 1 deg model. The global temp now reaches +1.5 deg in 2028, +2 in 2044, if the temp increase continues at the same rate.

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V742 Lyr is an R Coronae Borealis, or RCB, variable. A rather unusual type characterized by irregular, sudden and very deep drops from the star's normal brightness. V742 has been observed within SAAF since 2012 and is now recovering from its most recent decline.

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V750 Cyg is one of the SAAF's 50 Forgotten Miras. Discovered 1938 by the Russian astronomer Pavel Parenago. The average period is 428.4, but the current period is more like 421 days. This makes the phase diagram quite fluffy and the maximum point shifted. It also has a hump on the ascending branch.

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Berkeley has just released temperature data for 2025. From their data, my own calculation of the Earth's average temperature with a 21-year moving average and a forecast to 2050. +1.5 degrees is now predicted to occur in 2027, one year later than the forecast showed last year.

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TT Aur is an eclipsing binary of subtype EB. The star was discovered in 1907 by Henrietta Leavitt at Harvard. The phase diagram shows my observations from 2009-2018 from images I took with my DSLR camera of epsilon Aurigae during its eclipse.

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V673 Cyg is a mira among the SAAF's 50 Forgotten miras. It was discovered in 1943 by Cuno Hoffmeister at Sonneberg. Since SAAF began observing it in 2012, its period has been 327.0 days. Since 1890, the average period has been almost the same, 326.4 days.

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