Conny Aerts - Asteroseismology

Conny's research covers stellar astrophysics, including stellar structure & evolution and variable stars. She is a pioneer of asteroseismology, which received a major boost thanks to the CoRoT (2006+), Kepler (2009+), and TESS (2018+) space missions. Prior to high-precision space photometry, Conny developed rigorous mathematical methods to detect and identify non-radial stellar oscillations in high-resolution time-series spectroscopy. Her team also designed and applied statistical classification methods in a machine-learning context, discoving numerous gravity-mode pulsators in space photometry. As Chair in Asteroseismology at the Radboud University Nijmegen, Conny introduced herself into the topic of subdwarf stars, their binarity and pulsations, with current focus on development and exploitation of BlackGEM in tandem with gravitational wave studies.

Conny gave a lecture  on thursday evening (11/12/2025) as part of an  Invited theatre lecture performance for Science Cafe De Kempen: “Asteroseismologie: ´ daar zit muziek in!” (in Dutch), Organised in Tabloo, Dessel, Belgium. 

Interstellar Comet 3I/ATLAS

Comet 3I/ATLAS or C/2025 N1 (ATLAS) is the third known object from outside our solar system to be discovered passing through our celestial neighborhood. Astronomers have categorized this object as interstellar because of the hyperbolic shape of its orbital path. (It does not follow a closed orbital path about the Sun.) When the orbit of 3I/ATLAS is traced into the past, the comet clearly originates from outside our solar system.
As of 2025, three interstellar objects have been discovered traveling through the Solar System:
1I/ʻOumuamua in 2017, 2I/Borisov in 2019, and 3I/ATLAS in 2025. The prefix "1I" identifies the object as the first confirmed interstellar interloper, "2I" as the second, and so on.



This morning was the first morning with a clear sky. I used my DSLR Nikon D7500 with a zoom lens to image the comet in constellation Leo. It was not easy with the moon almost 60° illuminated.


Setting: Nikon D7500 with zoomlens.
No Guiding and no cable (as it was broken the night before).
Software: APP, ASTAP, CS4, DeNoise AI, Stellarium, SkySaferi.


Workproces: stacking 7 images with APP each ISO6400 4s. The picture was edited using APP tools light pollution and background calibration. Next, ASTAP was used to extract the green channel and Denoise AI to remove noise. This noise free image was again uploaded in ASTAP and star annotation was set. Unknown star annotation identified the position of the comet. This on the "same" location as found in Stellarium and SkySafari.

Sol'Ex update with 61 sessions and 962 video shoots

 

My Sol'Ex journey started back in August '23 and today I'm looking back ... a steep learning curve, 3 Sol'Ex versions, 2nd Gen Slit, new 678MM camera, improved software, two conferences, a VVS Whatsapp group, contributing to ProAm Paris Meudon (Bass2000), 2 articles in VVS magazine Heelal, 8 lectures but most impressive my 61 Sol'Ex sessions with 962 video shoots. 

Astronomical Challenges 2026

I made some preparation for 2026. Below list are my  Astronomical Challenges 2026 (source Hemel Calender 2026, SkySafari, Stellarium and ChatGPT)

By celestial body/event  (by date see below)

Planetoides

January 5 Eros (433) M33 

January 20 Nysa (44) M44 and 3I/Atlas

February 22 Psych (16) NGC1647

February 26-28 Papagena 471 Urania

April 26 Nysa (44) M44

July 28 Ceres (1) M1 

July 28 10P/ Tempel M30

Comets

February 23 24P/Schamuasse M5

March 6-8 46P/Wirtanen Hyaden Melotte25

March 8-14 10P/Tempel 40P/Vaisala

March 14-20 46P/Wirtanen Pleiades 

April 1 24P/Schamuasse M5

Jun 25: 10P/Tempel M72

June 15-25 C/2025 F2 M53

July 1 10P/Tempel NGC7009

October 23-24 10P/Tempel NGC 7507 7513

Planets

January 10 Opposition Jupiter 

June 3 Sodium tail Mercury

June 8, 12, 13 16 Venus, Jupiter, Saturn, Vesta, Pallas, Mercury, Moon 

July 11 Moon Pleiades Mars Urania

October 4 Opposition Saturn 

October 11 Mars M44

November 26 Sodium tail Mercury

Swingby Juice

28 september

3 december

Occultations

February 17: Felicia 294 UT20h36

Moon

January 27 Pleiades

February 25 Hesiodus Ray

August 28 Eclips

October 19 Hesiodus Ray

October 28 Pleiades

December 21 Pleiades

Variable stars

Februray 27 Algol

October 23 Algol

November 15 Algol

Eclips

August 12 Solar Eclipse

Variables to measure during one night and max +/- 1 or 5 days from new moon, according to ChatGPT 

By date 

January 5 Eros (433) M33 

January 10 Opposition Jupiter 

January 20 Nysa (44) M44 and 3I/Atlas

January 27 Moon Pleiades

February 17: Felicia 294 UT20h36

February 22 Psych (16) NGC1647

February 23 24P/Schamuasse M5

February 25 Moon Hesiodus Ray

February 26-28 Papagena 471 Urania

Februray 27 Algol

March 6-8 46P/Wirtanen Hyaden Melotte25

March 8-14 10P/Tempel 40P/Vaisala

March 14-20 46P/Wirtanen Pleiades 

April 1 24P/Schamuasse M5

April 26 Nysa (44) M44

June 3 Sodium tail Mercury

June 8, 12, 13 16 Venus, Jupiter, Saturn, Vesta, Pallas, Mercury, Moon 

June 15-25 C/2025 F2 M53

Jun 25: 10P/Tempel M72

July 1 10P/Tempel NGC7009

July 11 Moon Pleiades Mars Urania

July 28 Ceres (1) M1 

July 28 10P/ Tempel M30

August 12 Solar Eclipse

August 28 Moon Eclips

September 28 Swingby Juice

October 4 Opposition Saturn 

October 11 Mars M44

October 19 Moon Hesiodus Ray

October 23 Algol

October 23-24 10P/Tempel NGC 7507 7513

October 28 Moon Pleiades

November 15 Algol

November 26 Sodium tail Mercury

December 3 Swingby Juice

December 21 Moon Pleiades

Sun AR4294 4296 4298

Clouds dissapeared for a short time, allowing me to photograph the Sun. Why? Beacuse of a couple of huge sunspots: AR4294, 4296 and 4298. Size are 1280MH, 650MH and 100MH. 

Setting:

TAL200K f/8.5, ASI290MM and Nikon D7500

ND3.8, OIII filter and IR/UV cut filter

Software: SharpCap, AstroSurface, CS4

Saturn November 17

Imaging Saturn on November 17, 2025 with ring tilt of 0,38°.

Editing was done using the newest version of AstroSurface W3.

Setting: TAL200K, ADC, Barlowx2, ASI715MC

Filter: IR/UV Cut

Software: SharpCap, AstroSurface, CS4, DeNoise AI, WinJupos.

Eros (433) with M31 & M110

Image of Asteroid Eros (433) with M31 & M110. 

Setting: TLAPO80/480 f/6 with flattener and ASI2600MC
Filter: Optolong L-Pro
Camera temperature: -20,7°C
Exposure time: 39x 57s,
Software: SharpCap, ASTAP, CS4, APP (Stellarium & Skysafari)

The flattener was used but with wrong distance: 93 instead of 123mm.

Asteroid EROS (433) my first blink!

Asteroid EROS (433) is almost in opposition and thus perfect for observation.  I had a clear sky with a tempurature of -4,2°C .

Setting: TLAPO80/480 f/6 with flattener and ASI2600MC

Filter: Optolong L-Pro

Camera temperature: -20,7°C

Exposure time: 39x 57s, 

Software: SharpCap, ASTAP, CS4, APP (Stellarium & Skysafari)

Difficulties: connection of mount with Sharpcap was not succesful except for moving the scope. But inaccurate use of goto function and platesolving. It even resulted in miscommunication with the mount. As a result I had to set the synscan back into factory setting. After 3h I was able to make my first image but then I figured out the camera hit the tripod. Once this was solved I made 40 images of which one polluted with an airplane. 

Making sure both Eros and M31 was on my picture, I used stellarium without success. This was resolved with Skysafari.

Sun with Sol'Ex November 8th

A clear sky and enough time for adjusting sharpness. Solution was found in getting the spectrum line in the middle of the space; I get sharpest images when both edges are sharp. Once this was done, I make sure the dustlines on the grating are well seen. 

Setting: TLAPO80/480 with Sol'Ex by James R. and ASI678MM

2nd Gen Slit and Herschel Wedge

Software: SharpCap, Inti V7.0.3, CS4, DeNoise AI

Tilt 0,09°; Sx/Sy 1,09

SSM3 with avg < 1,5arcs whole morning

Saturn with new ASI715MC Camera

First time this year capturing Saturn. The tilt of the rings are almost zero with 0,45°, a Saturn with edge on rings is not the Saturn we typically know from the books. But still interesting view.

I used my new camera ASI715MC with small pixels. I forget to keep an eye on the whitebalance on sharpcap. I made image both with and without IR/UC cut filter.

Compared with my ASI224MC

Setting is same as previous year; it was difficult to get blue/red out even when using my ADC.

ASTAP Video Youtube

Some interesting Youtube video on ASTAP (Astrometric Stacking Program).
See this link: https://www.youtube.com/@hank3327/videos

Red Rainbow 4734 likes on Facebook

 

A total of 4734 likes of my red rainbow. Beside this, 244 remarks and 52 times shared with others. Never thought a rainbow would be some much liked.

Comet C/2025 A6 (Lemmon) Nov 2 and ASTAP

November 2nd, 2025, both transparancy and seeing bad. So, no good images of Comet C/2025 A6 (Lemmon). Images stacked using APP and ASTAP. ASTAP was used to identify some object like Messier M10 & M12 aswell as two Asteroids. 

Setting: Nikon D7500 on Skywatchter Star Adventurer 2i

Software : APP, ASTAP, CS4 and DeNoise AI

Comet C/2025 A6 Lemmon

Open sky but a lot of dew resulting in moderate images of Comet C/2025 A6 (Lemmon).

Using ASTAP, area magnitude is 5,4... cool!

ASTAP - Astrometric Stacking Program

I'm working my next challenge: making a light curve of a variable star. I was reading an article in magazine Heelal (November 2025 - Review Dwarf3 by Dmonique Dierckx) which explained the making of a curve using the Dwarf3 and ASTAP. So I went searching for more information on this software.

Downlaoding ASTAP was done via this link https://www.hnsky.org/astap.htm

I also downloading the following databases : D80 and V50

ASTAP, Astrometric Stacking Program, is able to stack images; so far I was only able to do this with Fits files. On top of this, it makes annotations, deepsky, asteroids, comets and variable stars.

There is a section Photometry, which calculates the magnitude and compares those with the database. Using color images, ASTAP can extract the green channel which makes values more accurate. 

When analysing the image with M51, two variable stars showed up. I let the software extract the green channel and measuring the magnitude. This data was copied into excel making the curve. 

Comet C/2025 A6 Lemmon on Halloween evening

Haloween evening, October 31, 2025 during a bright interval I was able to image Comet C/2025 A6 (Lemmon).
This time I used my Star Adventurer 2i together with Nikon D7500, a set up which made it possible to track the comet for 60s.

Setting: Nikon D7500

Mount: Skywatcher Star Adventurer 2i

Exposure : 4x60s ISO800; 2x10s ISO3200; 2x10s ISO6400

Software: APP, CS4 and DeNoise AI

Comet C/2025 A6 (Lemmon) October 27

On the evening of October 27 ... a cloud free sky. So time to observe Comet C/2025 A6 (Lemmon).
I took a wide field using more then 260 images, each 5s.

The other images were taken with a larger focal point but with a time difference of one hour. Due to this time difference, the comet was low above the horizon resulting in fainting out of the tail.

Sun October 26

A small opening in the clouds and windy, but still I took my chance resulting in only one capture of the Sun. Some nice prominences at the east side.

Setting: Sol'Ex by James R, 2nd Gen Slit, ASI678MM, TLAPO80/480

Herschel Wedge

Tilt: -0,7° Sx/Sy 1,12

Software: SharpCap, JSolex, Inti, CS4

Comet C/2025 A6 (Lemmon)

Finally an open sky for about half and hour, which was enough to capture comet C/2025 A6 (Lemmon).

Setting: Nikon D7500 with 112mm f/5.3, ISO6400 and exposure time of 5s

No Guiding

Software: APP 2.0.0. beta29, DeNoise AI, CS4

APP: Normal and MAD regression Avg (8;2)

Discussion:

Brigth core with both dust tail and ion tail. Structure in ion tail with knots aswell with small and wider regions. Tail extends minimum 5° .

Volcano Crater Hrossaborg (Iceland) - Apollo & Oblivion

During our trip through Iceland, we also visited the Hrossaborg Crater.

Hrossaborg Crater is a volcanic crater located in northeast Iceland, near Lake Mývatn. It’s actually an old tuff ring, formed by explosive volcanic activity, est 10.000 years ago, when magma came into contact with groundwater. The crater’s walls rise sharply and form a nearly perfect circle, giving it an otherworldly appearance—especially when seen from above or across the surrounding lava fields.

Because of its dramatic, barren landscape, Hrossaborg has been used as a filming location for several productions that wanted to capture a “moon-like” or alien environment.


Oblivion (2013) – The sci-fi film starring Tom Cruise used Hrossaborg as one of its key shooting locations. In the movie, it served as a backdrop for the scenes involving the base of operations on the desolate Earth. The stark volcanic terrain helped create the illusion of a post-apocalyptic world.

Apollo Connection – While not directly related to the Apollo missions, the resemblance of Iceland’s volcanic landscapes (including Hrossaborg and nearby regions like Askja and the Highlands) to the Moon’s surface led NASA to train Apollo astronauts in Iceland during the 1960s. They practiced geological fieldwork here to prepare for moon exploration.