Astronomical seeing forecast assessment with in focus Airy disk at different Pickering’s values
Channel: Bartolomeo Montrucchio
Date: 2020-04-12

In order to produce good images, a good telescope needs to fulfil four conditions: collimation, thermal equilibrium, no atmospheric dispersion and good seeing. In the video, weather forecast specific for astronomical seeing is compared from an experimental point of view with images in the field. Two telescopes are used, Vixen VMC 110L and Celestron C11, both with artificial star and in different seeing conditions using non tracked Polaris (45 degrees above horizon). Full HD video vision is suggested to better understand details.

Here are three suggested books, the first for star testing and the other two for better understanding the behaviour of your scope and your eyepieces. For example in [3 p.91] you can find the behaviour of a SCT (like C11) in close focusing, in [2 p.290] you can find Klevtsov-Cassegrain scheme (Vixen VMC) and compare it with Celestron Edge (p.259) and Meade ACF (p.252). In [1] you can find a truly excellent description of all you need to know about star testing, a must have.
[1] ”Star Testing Astronomical Telescopes”, H.R. Suiter, Willmann-Bell
[2] ”Telescopes Eyepieces Astrographs”, Hallock Smith, Ceragioli, Berry, Willmann-Bell
[3] “Telescope Optics”, Rutten and van Venrooij, Willmann-Bell
Suggested websites:
http://www.damianpeach.com/images/articles/JBAA%20dispersion%20Peach.pdf
http://www.damianpeach.com/pickering.htm
http://www.damianpeach.com/forecast.htm
https://www.meteoblue.com/en/weather/outdoorsports/seeing/turin_italy_3165524

(00:00) Astronomical seeing forecast assessment with in focus Airy disk at different Pickering’s values
(00:20) 4 conditions
(01:45) Risley prisms
(03:30) Meteoblue.com
(04:15) experimental setup (two Barlow lenses)
(05:15) artificial star (Vixen VMC 110L and C11) and bad seeing images  
              (Vixen VMC 110L only), with forecast for bad seeing (07:27)
(07:52) intermediate and excellent seeing with both 
              Vixen VMC 110 L and C11
(09:00) atmospheric dispersion effect on C11 images
(10:55) forecast for intermediate and excellent seeing