Variable stars observer DPV

Pavol A. Dubovský

News

Madeira 2023

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Another full family trip after 3 years long gap. Besides the wellness for the rest of the family, my main goal was to make first steps in the telescope hosting project. Indeed the meetings with president of Ponta do Sol and Calheta municipalities took place. The next steps are to prepare the project of the planned facility and to get the permission of the Secretaria do Ambiente e Agricultura.

In the free time I made 567 visual estimates of variable stars. Included is the visually covered eclipse of the dwarf nova GY Cnc during the outburst. During this time no one observation was made in Kolonica observatory in Slovakia due to the bad weather. Also several events took place on the top of the island in Paul da Serra. In the following photo-gallery one can see that the sky was not optimal. Humid, hot air from the south was always present. So instead of beautiful images, the gallery demonstrates the influence of the light pollution. Pictures especially focused on the lamps of Ponta do Sol are included. The effect of new LED lamps is visible. These lamps are well shielded, so the lamps are not visible from above. But the scattered blue light strongly affects the sky.

https://rajce.net/dpv44/album/madeira-2023-astro

Look and relax. Following are several daytime and nighttime timelapses.

Variable stars in 2022

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Thanks to a fortunate time-space configuration, signals about several interesting phenomena in our Galaxy reached Earth during 2022. In this post I will summarize the basic information about some of them.

First of all, novae that exploded in the period of 2020, 2021 were still active. Of them, I will mention two completely opposite objects. V1405 Cas is a very slow nova with multiple maxima and brightness variations. By the end of 2022, it was already in the nebular stage, but still brighter than 12 mag. And short-period variations with a characteristic time similar to the orbital period also appeared. However, there is no stable signal corresponding to the orbital period. In the world of cataclysmic variable stars, such behavior is usually called quasi-periodic oscillations. It will require a detailed periodic analysis. Fig. 1 shows the last few light curves.

Fig. 1. V1405 Cas – light curves in the V filter obtained by fast photometry at the 60 cm Csere telescope in Hlohovec and the 35 cm Celestron in Kolonica. From left to right 22.9.2022, 20.10.2022, 28.11.2022 and 1.12.2022.
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Greatest hits 2021

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Unprecedented rate of novae for northern observers. Final count is six in one year included the recurrent symbiotic nova RS Oph as the most important event. The photometric an spectroscopic coverage made at the Kolonica observatory is also unprecedented. The first results were presented at the Bezovec conference and will be published in the proceedings. In this article let me demonstrate the variety of light curves of these objects and how dense was our coverage. For more details see the presentation.

Besides the novae few words should be dedicated to SS Cyg. The prototype of regular dwarf novae systems. After more than century of periodic outbursts it presented typical Z Cam type behavior = standstill.

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Final report of the first season of Stars Above Ponta do Sol

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The pandemy of the new coronavirus gave me the possibility to extend the season from planned two months to more than half year period.

Many astronomical activities were performed between 11/01/2020 and 31/07/2020 on Madeira island. In the following I summarize activities with my personal participation as a representative of the Observatory and Planetarium M.R. Stefanik in Hlohovec, Slovakia and a member of Associação de Astronomia da Madeira. Step by step history of this stay can be found on https://www.facebook.com/stars.above.pontadosol.

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May 2020 – still in Madeira

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The winter stay became the spring one. However after many clear nights in April only one in May until now. We had spectacular green flash on 1st of May (see astro-gallery ), then practically nothing special.

In the meantime new section appeared in this web. In Photogrammetry – you can find several 3D reconstructions of objects typical for madeirian architecture.

On 30 of April the project proposal MADASTRA was submitted to FCT. Now waiting for the approval. If successful can be a big milestone in the development of observational astronomy in Madeira. The plan is to put in operation two small optical telescopes. The existing one 12″ Meade telescope on the terrace of the University to perform spectroscopic observations. The new 14″ will be installed on Achada do Teixeira (1590 m asl) and used for photometric observations.

YY Her

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Nice example of co-operation of visual and electronic observations. YY Her is symbiotic variable showing periodic variations connected with the orbital motion. Porb = 589.5 d. Sometimes the outbursts occurs. See the long term light curve below:

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