How to find Boötes constellation

Constellation Boötes

Fig. 1. Constellation Boötes (Boo), scheme

The Boötes constellation at the latitude of Moscow can be seen completely every night, the main thing is that the meteorological conditions allow it to be seen.
Historically, it is not customary to search for the constellation Boötes in modern starry sky guides. Actually, you don’t need to look for him either - the handle of the Big Dipper points directly to Boötes. But now the brightest star of Akturus is taught to search for everything, and in one manner, they offer a scheme similar to that shown in Figure 2, and at the same time they repeat the strange words:
"And we are leading an arc here ... and then an arc there ...
And then you will find Spica and Arcturus! "
(almost a Song about the Hares)
and no one indicates where the center of the circle is for this arc.

Fig. 2. How to find How to find Arcturus using the stars of Ursa Major?

I don’t manage to draw arcs in the starry sky, so I first mentally draw a ray through Mizar and Alkaid (light blue arrow in Fig. 2).
If the visibility of the starry sky is good, then this ray definitely falls into the second brightest star of Boötes - Izar. At equal distances from Izar will be: to the left of the beam - the brightest Arcturus; to the right is the dull Princeps.
In that case, if it was not possible to make out along the Isar beam (haze or urban sky flare), you need to draw a line to Arcturus a little to the left of the beam, gradually taking it to the left (the red arrows in Fig. 2 are the four lengths of the Big Dipper handle) , this is best work out the technique when all the stars of the constellation are visible, with it you will find Arcturus always unmistakably!

In violation of all traditions, we will nevertheless try to tell how to find the Boötes constellation and draw for ourselves in heaven a favorite schematic image. Take a look at Figure 3. The brightest stars of Ursa Major provide 4 accurate hits in the stars of Boötes.

Fig. 3. How to find the constellation Boötes from Ursa Major?
  - It is necessary to mentally draw a line through Mizar and Alkaid - in this way we will find the star Izar . The Merak-Phecda line will lead first to Hemelein Prima, and then to Izar. The Megrez-Alkaid line will lead to the star Princeps . If all these stars are clearly visible, then it is possible to build any of the constellation schemes proposed here, problems can arise, except with a spear-staff, its stars are too dim.

Now it remains only to correctly determine the angular dimensions of the Boötes constellation. In Figure 4, the constellation is presented in an upright position, so it can be seen overhead in the spring evening, turning to the north or northeast.

Fig. 4. Evaluation of the angular size of the Boötes constellation using an outstretched arm.

The largest angular distance between the brightest stars of Boötes is the distance from Izar to Moufrid , which is slightly more than 16°. The angular distance between the thumb and index finger of the outstretched arm of a person of normal physique is 16-18° (regardless of gender and age from 7 years), thus the Stars of Boötes against the background of an outstretched arm will look approximately as shown in Figure 4.

Sergey Ov (Seosnews9): Созвездие Волопас