Saturn @opposition August 27, 2023

There were a few moments with no clouds which I used to iamge Saturn. Saturn was in opposition and thus ideal circumstances; Unfortunately both seeing and transparancy was fair. and even poor.

Polarallignment was done using SharpCap4 with ASI290MM on guiding scope 50x240. Imaging with TAL200K @f/22 with ADC, Barlow x2 and ASI224MC camera with UV/IR blocker. 

Software: SharpCap4, AstroSurface U4 and CS4

Lights:  34.8ms and 28.36 fps, total of 3000 frames

White Balans : B85, R55

Saturn August 22, 2023

 

Another image from Saturn on August 22, 2023. Stacking was done using Astrosurface U4, keeping 12,5% of the 3000 frames. Further editing was done with Astrosurface and CS4.
The white balanced is changed to get out more colours. 

Details below and above the rings are clearly visible. 

Exposure time was 22,6 ms or 44 fps with a total of 3000 frames.

Effective focal length and best sampling factor

My Helios collegue, Walter, asked me about the effective focal length of my set up when imaging Saturn (august 22, 2023).

So here it is:

I uploaded my picture of  Saturn in WinJupos. Using the measurement - adjustment tab it's possible to obtain the diameter of the planetary disk in pixels (Di). The apparent diameter of the planet in arc seconds  (Dp) is provided by ephemerides tab. 

Sampling S = Dp/Di = 19/128.8 = 0.1475 arc seconds per pixel

The image sampling is equal to :

S = 206 P / F  (P = pixelsize of the camera and F = effective focal length in mm)

So F = 206 P / S = 206 3.75 / 0.1475 = 5237 or F/D = 5237/200 = 26.18 

Conclusion :

My set up with barlow x2, ADC and ASI224MC (3.75 micron) on TAL200K f/8.5 has an effective focal length of f/26.18. This means that my magnification is 26.18/8.5 = 3.05

Based on this f/26.18 and a Dawes resolution power (RP=1.02 wavelenght/diameter telescope) of 0.5838 it possible to measure the sampling factor k (k = RP / S).

k = RP / S = 0.5838 / 0.1475 = 3.95. 

Conclusion :

The Nyquist-Shannon theorem requires a k>2 but in practice a sampling factor of  3 to 3.5 is recommended according to Christian Viladrich - Solar Astronomy page 300 - Planetary Astronomy page 80). Increasing the sampling factor k beyond this would not bring a significant gain. Wirh my set up of 3.95 I will investigate how to reduce this to a value of 3 to 3.5. 

For information: the formule on page 81 of Planetary Astronomy should read F =206 Tp Di/Dp and not using factor 260.

Saturn reworked picture adjusting white balans

My previous reworked pictures of Saturn had some issues with colour setting. Again I reworked my pictures using AstroSurface U4 for stacking and sharpening and CS4 for adjusting white balans (RGB adjustment).

The result is more bright and the image has more colours. 

Saturn reworked

My picture of August 22 is reworked using Astrosurface U4. Below the picture I added all related information.

Software used: SharpCap 4, Astrosurface U4 and CS4

Saturn 5 days before opposition

Capturing Saturn 5 days befores opposition.

Setting: TAL200K f/8.5, ASI224MC, ADC, Barlow x2

Filters: IR/UV blocker

Software: SharpCap 4, Autostakkert3!, CS4, DeNoise AI

Seeing: Good 

Transparency : Good

Sun un H-alpha and AS3! setting

SolarMaxIII 70/400 f/5.7 DS BF15 with ASI290MM and reducer x0,5
Lights: 82fps 3000 frames (via SSD Samsung T7), flats 

Software: SharpCap 4, AS3! (10%), CS4

Setting in AS3!

Some nasty circles around the sundisk appeared when min brightness was set on "0". After adjusting to 15 the circles dissapeared.

Actual Frames per Second (FPS)

SSD Samsung T7 (2Tb)

I'm using a regular Hard Disk of my PC to capture my astro images. For the Sun and Planets my camera's typicaly goes up and beyond 80fps. But after capturing for a few seconds, the frames per second drop. I always thought the rate would keep up in the back but  I found out that this was not realy true. 

This morning I did a test when capturing the Sun with ASI290MM:

When using an external SSD (Samsung SSD T7) the actual frame rate = 82,1097 fps

When using my existing Hard Disk on my PC, I start with 82 fps but my actual rate drops to 27.0601fps.

Conclusion: be aware that capturing time is depending on your set up eg. type of hard disk, connection (eg. USB2, 3), ....

Sun in H-Alpha

Some images of the Sun in H-alpha from this morning.

Imaging was done with an external SSD resulting in an avg frames per second of 81.

Setting: 

SolarMaxIII 70/400 f/6 DS BF15 ASI290MM x0,5 reducer

Software : SharpCap 4, AstroSurface U4, CS4

Na D1, D2 and He D3 line in solar spectrum

Using ASI224MC on Sol'Ex, I'm able to mark the Na D1 and D2 line but also the He D3 or d line. Capture done using SharpCap 4.

Sol'Ex Spectrum with ASI2600MC

This afternoon I connected my ASI2600MC to the Sol'Ex and TSAPO60/360 f/6. Using SharpCap 4 I made a couple of images of the solarspectrum.

Based on known line I calculated some more difficult lines :

    - He D3 or d line, 

    - H delta or h-line and 

    - Fe I G-Line. 

Sol'Ex - Exploded view

Building my Sol'Ex ... Exploded view. The slit has an angle of 15°. The grating has 2400 grooves/mm. Shortly I will be discussing the theory. 

Sol'Ex with ASI2600MC

 

Some further experimentation with my Sol'Ex. This time I'm using my ASI2600MC color camera. This camera has an APS/C sensor which results in a capturing a bigger spectrum. Getting a larger spectrum was easier to find the absorption lines: eg. CaK &H line, H beta, Mg triple, Na double and H-alpha. I was also able to find the slit, and thus the zero order. 

Saturn: First picture of 2023

My first picture of Saturn this year 2023. It's 17 days before opposition and after a long time a cloudfree night. Seeing was poor and good transparency. The image shows some destinction of the clouds. 

Setting: 

TAL200K f/8.5 ASI224MC

ASI224MC setting

    - WB setting: R55, B85

    - Exposure 65ms

    - RAW16 488x488 PNG files (no SER)

Barlow x2, ADC, UV/IR cut filter

Software: SharpCap 4, AS3! (5% Best of), AstroSurface U4, CS4, WinJupos

First light with Sol'EX

My first light with Sol'EX with TS APO60/360 f/6 and ASI224MC. Capturing was done using SharpCap4 and editing with CS4. Still some learning to do but so far... real cool! I'm to trace back the Ca K&H line, hydrogen Beta and the triple magnesium. In the red spectrum I'm not sure what the elements are.

Website J Giesen Physics and Astronomy - Use of Applets via Chrome

Sometimes I surprise myself about the functioning of a website and I underestimate the value and power of a website. I'm talking about J.Giesen's website (http://www.jgiesen.de/welcomeEnglish.htm) which provides a huge information about the Physics and Astronomy and more specific on everything related to the sun and it's calculations.

The website is referring to different Java applets. I knew this but only now I figured out how to run them. So what did I do?

- I add CheerpJ Applet Runner (free of charge) to my Chrome browser (edge is also possible)

- Next, I go to a webpage of J.Giesen's website with a specific applet and click on "extentions" and o double click on CheerpJ Applet Runner. What happens now is that the applet will be opened. Real cool.

These applets are a real help in understand calculations of spherical astronomy and solar calculations. A real cool applet is the one of the Meridian of Santa Maria degli Angeli e dei Martiri in Rome which gives you a details. 

SAVE THE DATE : 9 and 10 September 2023 – Open Doors at the Humain Radio Astronomy Station

Source: website: https://www.astro.oma.be.

Mark your calendars: the weekend of the 9th and 10th of September 2023! Join us at the Radio Astronomy Station of Humain, in Wallonia, to celebrate Belgium’s rich and diverse heritage.

This station was founded in 1953 by the Royal Observatory of Belgium to house the very first Belgian radio telescopes dedicated to observing the Sun. In the 1960s, a solar interferometer of 44 radio telescopes was constructed and operated up until 2001. Today, the station continues to host radio and optical experiments to observe the sky, the Sun, the Earth’s space environment and its atmosphere.

This is the first time this station will open its doors to the public, where you will be able to stroll along the two north-south and east-west axes of the old interferometer, see the old control laboratory of the interferometer, discover the history, of the site and its observations and know everything about the current scientific activities.

There are also activities for children. Bring your family, friends, and neighbours, to embark on a captivating cosmic adventure!

Dates: 9th-10th September 2023 during the Heritage days
Time: 10h -18h
Location: Rue de l’Observatoire, 6900 Marche en Famenne.
Foodtrucks will be present on site.