Inauguro il thread sul mission log di Euclid con la comunicazione di qualche giorno fa che tra il 15 e il 18 luglio gli strumenti VIS e NISP, rispettivamente operanti nel visibile e nell’infrarosso, sono stati attivati.
https://twitter.com/ESA_Euclid/status/1681628251519582209?s=20
Qui il link del blog di ESA sul primo mese di commissioning di Euclid (citato nel tweet)
Posto qui un articolo che parla del segmento di terra (ho visto in un altro thread che si parlava di traffico dati e occupazione delle stazioni di terra)
Euclid arrivato a destinazione.
https://twitter.com/ESA_Euclid/status/1684914011224076288?s=20
https://twitter.com/esascience/status/1684914162688786432?s=20
Prime immagini
L’immagine in tonalità di grigio è stata prodotta da VIS mentre quella rossastra da NISP (il colore rosso sta ad indicare che è un’immagine nell’infrarosso). La qualità delle immagini ingegneristiche ottenute rivela che il telescopio è in ottima salute, ma le immagini scientifiche saranno ancora migliori di queste.
E’ stata pubblicata anche un’immagine (anch’essa prodotta da NISP) piena di righe verticali ognuna delle quali è lo spettro di un oggetto (stella o galassia). Questa immagine permette di calcolare il redshift spettroscopico con il quale si può misurare la distanza molto più accuratamente rispetto a ciò che si può fare con il redshift fotometrico.
Dall’integrazione delle informazioni ottenute dalle prime immagine (in particolare studiandone il Weak gravitational lensing) e dal calcolo della distanza tramite redshift si dedurrà la struttura della materia luminosa ed oscura dell’universo nell’arco di 10 miliardi di anni di evoluzione. Ne sapremo di più sulla materia e sull’energia oscura e testeremo la validità della relatività generale.
Qui un ottimo articolo in italiano con il link di un’eccelsa spiegazione di Andrea Cimatti:
https://www.media.inaf.it/2023/07/31/euclid-prima-luce/
Non so se avete notato che Euclid sta avendo problemi con il fine guidance sensor.
Dal già citato blog (25 agosto): https://www.esa.int/Science_Exploration/Space_Science/Euclid/Follow_Euclid_s_first_months_in_space
Last week, Euclid was operated in science-like conditions by executing the first activities of the performance verification (PV) phase. Although most systems are performing well, these brought to light cases in which the guidance system failed to deliver and maintain correct pointing. The problem is intermittent, but with a frequency that requires attention. The team found that under certain circumstances the FGS did not provide reliable guiding information, which was problematic for the software on the spacecraft to handle.
Poco dopo si parla di una possibile soluzione.
To address this situation in the most effective way, the decision has been taken to halt the PV phase and to return to operating the spacecraft in commissioning mode. In the coming days, the team will be developing and testing new software updates, and the schedule for the PV phase will be adjusted.
Non ho chiaro però se questo problema sia di tipo software e, a prescindere, se sia completamente risolvibile via update o se invece ci saranno ripercussioni sulla missione.
Aggiornamento dal blog di ESA già linkato sopra
(tl;dr: sempre “lavori in corso”):
The effort to resolve the issues affecting the guiding of the Euclid telescope continues steadfastly (see blog updates 14 and 25 August).
Industry experts are working on an update for the flight software of the Fine Guidance Sensor (FGS), which will be thoroughly tested on-ground before it is installed on the spacecraft. Once the new software is uploaded, the operation team will carry out a week-long series of tests to confirm the update has the desired effect and the telescope can be reliably pointed to cosmic sources again to create sharp images. After this, the performance verification phase will be resumed.
Meanwhile, the Euclid team will progress with performance verification activities that are not sensitive to the reliability of the spacecraft pointing.
Aggiornamento non ufficiale: una persona che è in contatto con il gruppo che si sta occupando dell’update mi ha confermato che si tratta di un problema esclusivamente software.
In un’intervista su Media Inaf la coordinatrice delle attività italiane per Euclid, Anna Maria Di Giorgio dell’Istituto nazionale di astrofisica, ci tranquillizza un po’:
Aggiornamento.
tl;dr: FGS: progressi, i primi test della patch sembrano positivi; stray light: ancora problematica; solar flares (mi pare che il problema sia una novità di questo aggiornamento): al momento si rischia di perdere il 3% dei dati raccolti; i tecnici sono al lavoro per trovare una soluzione.
Fine Guidance Sensor (FGS)
[Euclid Operations Director Andreas Rudolph] “I’m relieved to say that initial tests are looking good. We’re finding many more stars in all our tests, and while it’s too early to celebrate and more observations are needed, the signs are very encouraging.”
The updated software has already passed with flying colours on a spacecraft simulator and ‘test bench’ (Euclid replica) at mission control, then performed perfectly in orbit and will next be tested under the control of the Science Operations Centre at ESA’s ESAC Astronomy Centre in Spain.
“Obviously, this is where we will have the real test of truth, as only the science images can provide us with absolute certainty that Euclid’s pointing is performing well,” cautions Euclid Project Manager, Giuseppe Racca.“However, all evidence so far makes us very optimistic. We will continue to keep our fingers tightly crossed, but the restart of the performance verification phase gets nearer every day.”
Stray Light
The majority of VIS’s observations showed no significant stray light interference, but at particular angles, about 10% of observations were affected. Science, engineering and industrial teams spent weeks deciphering which angles let too much of this unwanted light in and have re-designed and optimised Euclid’s survey to constrain each pointing’s orientation in the sky.
While this will not affect Euclid’s ability to take the precise images required, it could impact the efficiency of the survey – something that is still under investigation.
Solar flares
Euclid’s detectors are being shielded from low-energy protons that could do them damage. However, it appears that at particular angles, X-rays emitted by the Sun during solar flares can occasionally reach the detectors, spoiling a portion of the images taken at that moment.
Analysis currently predicts that, depending on solar activity, Euclid could lose about 3% of its data if this problem were left untackled. However, now that the issue has been discovered teams are able to identify affected pixels and discount them in later analysis and are working on plans to repeat observations to eventually make up for any gaps in Euclid’s cosmological survey.
Problemi al FGS risolti! 
Euclid has found its ‘lost’ guide stars as a software patch has solved its navigation woes and the next six years of observation schedules have been redesigned to avoid stray sunlight: it’s the end of an interesting commissioning phase and Euclid will now undergo its final testing in full ‘science mode’.
La fase di verifica proseguirà comunque fino a Novembre.
(bella la foto di Euclid “ubriaco”) 
The most ‘loopy’ show an extreme case of Euclid failing to lock into place while observing a star field, resulting in an image of swirling star trails and ‘lassos’ as the spacecraft tried to home in on its target. Clearly, to reveal hard-to-see, subtle patterns in distant galaxies and star clusters, this won’t do. Teams got to work to come up with a fix.
The software patch was tested first on Earth with an electric model of Euclid and a simulator, then for ten days in orbit. The signs were positive, as more and more stars revealed themselves.
… Giuseppe Racca, Euclid Project Manager adds; “The performance verification phase that was interrupted in August has now fully restarted and all the observations are carried out correctly. This phase will last until late November, but we are confident that the mission performance will prove to be outstanding and the regular scientific survey observations can start thereafter.”
Nuovo articolo di Luca Frigerio pubblicato su AstronautiNEWS.it.
Il 7 ci sarà la live durante la quale verranno mostrate le prime immagini.
Never before has a telescope been able to create such razor-sharp astronomical images across such a large patch of the sky. Five images show that the telescope is ready for its mission to create the most extensive 3D map of the Universe yet and uncover some of its hidden secrets.
Link YouTube della diretta:
Il 9 ci sarà invece un AMA .
Thursday, 9 November, you can interact with the Euclid team during a Reddit AskScience AMA (Ask Me Anything) session. The AMA link will be published on 9 November at 12:00 CET here: https://www.reddit.com/r/askscience/ and the team will start answering questions at 15:00 CET.
Pubblicate le prime immagini di Euclid.
Today, ESA’s Euclid space mission reveals its first full-colour images of the cosmos. Never before has a telescope been able to create such razor-sharp astronomical images across such a large patch of the sky, and looking so far into the distant Universe. These five images illustrate Euclid’s full potential; they show that the telescope is ready to create the most extensive 3D map of the Universe yet, to uncover some of its hidden secrets.
Il trailer di ESA.
AMA: We’re scientists and engineers behind ESA’s Euclid space mission, which has just delivered its first five dazzling images. Ask us anything!
https://www.reddit.com/r/askscience/comments/17rahok/askscience_ama_series_were_scientists_and/
Da cui riporto il passaggio che riassume i tre problemi principali incontrati:
a) straylight on the focal plane: this was solved by constraining the allowed domain the telescope to look at. In this way the structure that was reflecting indirectly onto (and into) the focal plane will always be “hidden” behind the solar panel.
b) x-ray imprinted on the instrument detectors: here nothing can be done. That means ~3% percent of the observations will be affected. They would need to be repeated and/or part of the images are still ok after processing
c) Guidance lost by one of the main attitude control sensors, the so-called Fine Guidance Sensor. This required an on-boards software update and caused a delay of the Euclid program in the order of 5 to 6 weeks. But the on-board software update fixed the issue.
Un video molto interessante dell’Euclid Consortium che riassume quanto fatto fino a ora con approfondimenti sui problemi incontrati, data processing e dati tecnici sugli strumenti.
Il commento su Nature.
https://www.nature.com/articles/d41586-023-03498-1
Il commento di Chris Pattison (Portsmouth Cosmology)
Edit. 17.11
Video che mostra la differenza di risoluzione e campo visivo tra Euclid e Hubble.
Commento e spiegazioni varie di Becky Smethurst, junior research fellow a Oxford.
07:46 Euclid’s first science images!!
11:54 Euclid diffraction spike shape explained
12:57 Euclid rainbow diffraction spike colours explained
14:45 Euclid purple spoltches explained (ghost image)
Edit. 19.12
Altro ottimo video - pubblicato solo ieri - sulle difficoltà incontrate da Euclid e sulle prime immagini scientifiche.
Nuovo articolo di Matteo Deguidi pubblicato su AstronautiNEWS.it.
Intervista in inglese ad uno degli astronomi dietro alla pubblicazione delle prime immagini.
Novità da Euclid. Se non ho capito male, si è conclusa la lunga fase di commissioning e si passa da progetto a missione. Non ho trovato il comunicato ufficiale, immagino uscirà a breve. Rimando a due post dal blog In the Dark curato da Peter Coles, Editor-in-chief Open Journal of Astrophysics.
Il secondo è ricco di informazioni.
Over the past few months, there has been a huge amount of activity relating to commissioning the instruments, verifying their performance, and measuring parameters of the optical system that will be needed for analysis of the huge amount of data due to come from Euclid. All this effort fed into the Mission Commissioning Results Review (MCRR) which concluded yesterday that all was well.
This is an important milestone for Euclid because, in ESA parlance, it marks the change from a project to a mission. Until commissioning, there is a project manager who works with ESA and the industrial contractors to ensure everything functions properly; when nominal operations start the project team is disbanded and the mission team takes over; and so it came to pass that the Project Manager (Giuseppe Racca) handed over the reins to the Mission Manager (Pierre Ferruit).
Approfitto per segnalare anche un video pubblicato ieri dall’Euclid Consortium - purtroppo di qualità amatoriale - con alcuni contenuti interessanti.
Edit.
Uscito il comunicato ufficiale. Primi dati l’anno prossimo.
Today, Euclid officially started its survey. The telescope is currently scheduled to observe a patch of 130 square degrees – more than 500 times the area of the full Moon – over the course of the next 14 days. This patch is in the direction of the constellations of Caelum and Pictor in the Southern Hemisphere.
In the coming year, Euclid will cover around 15% of its survey. This first year of cosmology data will be released to the community in summer 2026. A smaller data release of deep field observations is foreseen for spring 2025.
Il gemello di Euclid è arrivato all’ESOC.
“The Euclid flight control team now has direct access to a fully functional replica of the inner workings of the satellite,” says spacecraft operations manager Micha Schmidt.
“The avionics model has already proven very important to the mission. It was used extensively during Euclid’s demanding commissioning phase to validate the safety and effectiveness of critical updates to the Fine Guidance Sensor and other on-board software on the ground before we uploaded them to the spacecraft.”
Euclid ha gli occhiali appannati:
Per fare evaporare il ghiaccio formatosi, basta riscaldare la superficie. Fino a -3°C…
