Sol'Ex Presentation at VVS Capellla Hoegaarden

At the request from astronomyclub VVS Capella Hoegaarden my collegue Walter and myself (collegue Johan was excused) gave a lecture on our project Sol'Ex. The title of the lecture was "DIY The Solar Explorer".

We arrived quite early, so early in fact that we were the first. Plenty of time to settle in and explore the place. A little later Joost, chairman of the club, arrived and treated us to a drink. The room slowly filled up and Henk ensured that online streaming could take place. The lecture could begin, a bit awkward at first, but after the first of the many questions were asked it went much more smoothly. Walter supplemented well and provided additional explanation where necessary. Ultimately, the lecture lasted an hour and a half and the feedback from those present was good. The conversations at the bar continued with satisfaction.

The online recording is available and can be viewed via this youtube link.

The presentation (PDF version) itself is available via Google Drive  via this link. 

Sol'Ex Presentation @ VVS Capella Hoegaarden

 

Together with my collegue Walter, I wll be talking our Sol'Ex project next thursday December 21, 2023 @ VVS Capella in Hoegaarden. 

Latest Solar Maps and images on the internet

The latest Solar images and maps with all kind of information can be found on the internet. But where?

I made an overview of some interesting websites (but without being complete).

Spaceweather 

Spaceweatherlive   

NOAA Spaceweather Prediction Center

Solar Influences Data Analysis Center SIDC

Solarmonitor

Helioviewer - create your own images or movies with all available images 

Student Helioviewer

Facebook Struve Solar Society

NSO Gong H-alpha Network 

My blogpost number 2000! Celebrating with a Halo

Yes, this is my 2000nd blogpost since I started back in december 2011! And I'm celebrating with a halo around the Sun. 

Spectral Lines of Hydrogen, Calcium II H&K and Helium I (D3)

In astronomy ionization of atoms are noted different then in chemistry

Neutral Hydrogen : H I
Neutral Helium : He I
Neutral Calcium : Ca I
Ionized Calcium : Ca II or Ca+ (noted in chemistry)

Clarification of spectral lines of Hydrogen (H I)

 

Spectral lines can be explained due to electron transitions between energy levels.

For neutral Hydrogen or H I :  

Lyman series : transition to groundlevel
Balmer series : transition to energy level 2; all transitions are within visible wavelenght
Paschen series : transition to energy level 3
Brackett series : transition to energy level 4
Pfund series : transition to energy level 5
Humphreys series : transition to energy level 6
Hansen-Strong series : transition to energy level 7

The H-alpha line is due to an electron making a transition between energy level 3 to energy level 2.

Clarification of  Helium I (D3) lines

He I (D3) line - 587,572nm via Ortho Helium 1s3d to 1s2p but more in detail :

587,5545nm 1s3d 3D1 – 1s2p 3P2

587,5561nm 1s3d 3D2 – 1s2p 3P2

587,5562nm 1s3d 3D3 – 1s2p 3P2

587,5571nm 1s3d 3D1 – 1s2p 3P1

587,5588nm 1s3d 3D2 – 1s2p 3P1

587,5913nm 1s3d 3D1 – 1s2p 3P0

Clarification of  Ca II H and K line

Calcium electron configuration : 1s2 2s2 2p6 3s2 3p6 4s1

Ca II H line :  396.847nm

Ca II K line :  393.366nm

Comet 12P/Pons-Brooks

It's been a while since I set up my telescope for DSO. This evening I took my chance and made some images of Comet 12P/Pons-Brooks. Comet 12P/Pons-Brooks is a Halley-type periodic comet that was first discovered by Jean-Louis Pons on July 12, 1812 and then independently rediscovered by William Robert Brooks in 1883. It's period is about 71.3 years. Maximum brightness is foreseen during the month of April with the potential to see the comet during the solar eclips of April 8th 2024.

Setting: 

TLAPO80/480 f/6 with ASI2600MC

Filter Optolong L-Pro

Exposure: 5x60s & 2x180s

Software : SharpCap4, APP, CS4, Denoise AI

Cardinal Librarian de Zelada @ Vatican Museum - Time the Sun takes to pass across the Sundial

Pair of shutters in Vatican Museum (Pascal Hilkens)

This pair of painted shutters pertaining to the original windows of the "Sundial Gabinet" show a list of days, months,sun diameter and the time the sun takes to pass across the sundial in seconds and minutes.

This of course took my interest and I started to make my own calculations in order to compare with the data on the shutters. The easiest formula I found :

Time (seconds)  to pass across the meridan line = 128 / cos(delta)
    delta = declination of the sun at a specific day = cos ((360/365)*(N+10))*-23.7333
    N = day of the year starting at january 1

The results of both my calculation as of the shutters are shown in the graph below and are quit comparable.

The below marble sundial with bronze inlays was originally embedded in the pavement of the Vatican "Sundial Gabinet" which was the apartment of Cardinal Librarian Francesco Saverio de Zelada (1717-1801) who live here from 1780 till 1798. Only this piece did survive.

Marble Sundial Vatican Museum (Pascal Hilkens)

Cardinal de Zelada by Anton Raphael Mengs (source wikipedia)