HERCULES 
(May, June, July, August, September schedule)

     Hercules constellation is spring-summer constellation and it is in best position for evening observing in June and July when it is close to the zenith. We will observe it in May when it is on the eastern sky, in June and July when it is in best position for evening observing and it is close to the zenith, in August when it is high on the western sky and in September when it is on the western sky.

Double and multiple stars

     Kappa Herculis - The combined visual magnitude of this star on the sky is 4.6. The first component has visual magnitude on the sky 5.1 and it is about 400 light years away from the Earth. The second component has visual magnitude on the sky 6.2 and lies about 500 light years away from the Earth. They are separated on the sky by 27 arc seconds. Both stars are giants, they left the main sequence and continued their evolution expanding and becoming giants. Their mass is two or three times larger than the mass of our Sun, and their diameter is more than ten times bigger than that of our Sun. They have surface temperatures of 5,000 K and 4,600 K and should have yellow and orange color in a telescope.
     Alpha Herculis
- Its name is Ras Algethi. The first component is variable star and its visual magnitude changes between 3.0 and 4.0. it is a red giant star with mass about twice the mass of our Sun, but its diameter is about 400 solar diameters. Its temperature is only about 2,800 K and in a telescope should have orange color. Its distance from the Earth is about 400 light years. It is nearing the end of its evolution, losing big amount of its mass through stellar winds, its outer envelopes of gas will split from the core and will finish as white dwarf.
     The second component has visual magnitude on the sky 5.4. The separation between the first and second component is 5 arc seconds. It is yellow giant with surface temperature same as our Sun. Its orbital period is several thousand years.   
     Delta Herculis
- Its name is Sarin. The combined visual magnitude of this star on the sky is 3.1 and it is about 90 light years away from the Earth. The main component in fact consists of two main sequence dwarfs which are very close and only spectrometer can resolve them. Both are larger and with more mass than our Sun, and with higher temperature. It is about 350 million years old.
     The companion has visual magnitude on the sky 8.3. The separation between the main component and the companion on the sky is 11 arc seconds. The main component and the companion are not physically related and are only visual double star.   
     Rho Herculis
- It is a binary star system. Its combined apparent visual magnitude on the sky is 4.1 and the system is about 400 light years away from the Earth. The first component have visual magnitude on the sky 4.5 and it is hot, massive giant star with mass and diameter several times bigger than our Sun.
     The second component has apparent visual magnitude on the sky 5.4. It is main sequence star, larger, more massive and hotter than our Sun. The separation of the components on the sky is 4 arc seconds. The orbital period of this binary star system is several thousand years.
     95 Herculis
- The combined apparent visual magnitude of this star is 4.3. The first component apparent visual magnitude on the sky is 4.9 and that of the second is 5.2. This binary star system is about 400 light years away from the Earth. The separation between the components is 6 arc seconds. The first component is rare white giant star and the second component is yellow giant star. The first star is hotter than our Sun, with three times the mass of our Sun and seven times the diameter of our Sun. The second star is cooler than our Sun, with more than three times the mass of our Sun and twenty times the diameter of our Sun. The orbital period of this binary star system is over ten thousand years.  
     100 Herculis
- Both components of this double star have apparent visual magnitude on the sky 5.8. They are also identical by their spectral class - both are A spectral class and main sequence stars. That means they have almost the same mass, the same diameter and the same temperature. They are bigger, more massive and hotter than our Sun. They are separated by 14 arc seconds on the sky. Not exactly known if the components form true binary star system or they are only visual double on the sky. Their distance from the Earth is about 200 light years. 

Deep sky objects
(will be observed only from dark location outside of the city)

     M46 - It