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SPIE Poster for PCS WP2
by haffert＠strw.leidenuniv.nl 24 Jun '26

24 Jun '26

Hi all, I have adjusted the Spirit of Lyot poster a little bit by adding some recent results. I mostly kept the layout the same. Let me know if you have any comments. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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Meetings in June
by Axel Potier 12 Jun '26

12 Jun '26

Dear team, Friendly reminder for this month’s PCS WP2 meetings: - Tomorrow Friday June 4th from 10am to 11am: WP2.3 meeting. Agenda: - Presentation by Aya Harkat (« Predictive LQG control for the compensation of NCPAs measured with SPHERE/ZELDA » ) - Discussion on pupil stabilization. - Discussion on deformable mirrors: how many DMs? Distance from the pupil? Technology? - Writing of WP2 proceedings . - Friday June 12th from 11am to 12pm: WP2 general meeting. Agenda: - update on budget allocation and meeting with WP3+WP6 - update on the sub-work packages and their progress - update on SPIE proceedings See you there! Best, Axel

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Postdoc position on metasurface coronagraphs for HWO and PCS
by haffert＠strw.leidenuniv.nl 14 May '26

14 May '26

Hi all, I wanted to reach out about this postdoc position that I have available in Leiden since I have not advertised it that widely. It’s focused on the development of optical metasurfaces for coronagraphs for HWO and PCS https://jobs.strw.leidenuniv.nl/2026/HaffertPD/ . I would really appreciate it if you forwarded it to anyone that you know that would be interested in it. And sorry for everyone that already got this through other channels. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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IMPORTANT update about the PCS-CEP
by haffert＠strw.leidenuniv.nl 11 May '26

11 May '26

Hi all, I just finished migrating all the code to a new github repo to remove any traces of the original pupil generation script. This was a bit cumbersome. To keep the same name of pcs-cep, I migrated the repo to pcs-cep-old. That repo contains the pipeline as developed until now. Then I made a new repo pcs-aperture which contains purely the aperture generating functions. People within the consortium and that are part of the elt-pcs organization on github should be able to access that repo and install it. The new PCS-CEP code is in pcs-cep. This new repo tries to import the pcs-aperture library to create the aperture and if it is not found it will default to using the supplied fits files. This now works seamlessly and transparently. From the user perspective there is no difference. Your task: delete the old PCS-CEP repo if you have it on your computer and install the new one. This is necessary to completely purge all possibilities of accidentally adding the pupil generation script back into the code. Thanks for staying patient with me while I fixed this issue. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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Re: Next general meeting
by haffert＠strw.leidenuniv.nl 08 May '26

08 May '26

Hi everyone, I forgot to share a meeting link for today. Here is one: https://universiteitleiden.zoom.us/j/7267353069?pwd=JQ4pnKb14HkPby0v9XJqmcg… Sebastiaan From: haffert(a)strw.leidenuniv.nl <haffert(a)strw.leidenuniv.nl> Sent: Wednesday, 22 April 2026 17:50 To: pcs-wp2(a)strw.leidenuniv.nl Subject: Next general meeting Hi all, I propose we should have our next general WP2 meeting on Friday May 8th at 10:00. Agenda: * Coordination of removing the pupil generating function for external collaborators. * Sebastiaan will present the first draft of the opto-mechanical volume envelope. * Current state of the coronagraph design call. * Current state of the wavefront sensing sub-group. * Set goals for SPIE and what we will put on the poster. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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Re: WP2 PCS overleaf link
by haffert＠strw.leidenuniv.nl 24 Apr '26

24 Apr '26

Okay that went wrong. I accidently sent the email before finishing it. Here is the overleaf link: https://www.overleaf.com/4661613744fbwcjjhfjgwn#91e901 The sub-WP leads will have the responsibility for their sections. I added some basic bullet points for each section. We can discuss these of course. Best, Sebastiaan From: haffert(a)strw.leidenuniv.nl <haffert(a)strw.leidenuniv.nl> Sent: Friday, 24 April 2026 13:26 To: 'pcs-wp2(a)strw.leidenuniv.nl' <pcs-wp2(a)strw.leidenuniv.nl> Subject: WP2 PCS overleaf link Hi all, We decided today during the WP2.3 discussion that we will aim to have the SPIE proceeding done by June 17th. I prepared an overleaf document for all of us to work together. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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WP2 PCS overleaf link
by haffert＠strw.leidenuniv.nl 24 Apr '26

24 Apr '26

Hi all, We decided today during the WP2.3 discussion that we will aim to have the SPIE proceeding done by June 17th. I prepared an overleaf document for all of us to work together. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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Re: WP2.3 literature review and next meeting
by Axel Potier 23 Apr '26

23 Apr '26

Dear all, Friendly reminder for our PCS WP2.3 meeting that will take place tomorrow from 10am to 11am (see zoom link below). Here is a tentative meeting plan: - Presentation from Jalo about fast & furious concept associated to RL. - Open discussion about best criteria to downselect the WS&C architectures we have discussed so far. - Discussion regarding the next steps toward the common WP2 SPIE proceedings, and beyond. See you there, Best, Axel Axel POTIER vous invite à une réunion Zoom programmée. Sujet: WP2.3 zoom meeting Heure: 24 avr. 2026 10:00 AM Paris Participer à la réunion Zoom https://u-paris.zoom.us/j/81928907331?pwd=MebhBUKg6y9z6jHQramlzCb3aJ14qD.1 ID de réunion: 819 2890 7331 Code secret: 860862 --- Une seule pression sur l’appareil mobile +33186995831,,81928907331#,,,,*860862# France +33170372246,,81928907331#,,,,*860862# France --- Participez à l’aide d’un protocole SIP • 81928907331(a)zoomcrc.com Code secret: 860862 Instructions pour participer https://u-paris.zoom.us/meetings/81928907331/invitations?signature=AZkMRhXH… > Le 2 avr. 2026 à 18:10, Axel Potier <axel.potier(a)obspm.fr> a écrit : > > Dear PCS WP2 member, > > I propose you to postpone our next meeting WP2.3 (wavefront sensing and control) that was originally planned tomorrow. > Here is the new time slot: April 24th from 10am to 11am. I will ask some of you to present their current projects, followed by a discussion on the next steps. > > Meanwhile, you can find attached the literature review we have discussed the past few months. This is still a draft and I know I still miss a few information some of you already provided. So please reach out to me for any update or correction on the current draft :-) . > > Have a great end of the week, > Best, > Axel > > <PCS_WP23_WFSConcepts_Draft.pdf>

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Next general meeting
by haffert＠strw.leidenuniv.nl 23 Apr '26

23 Apr '26

Hi all, I propose we should have our next general WP2 meeting on Friday May 8th at 10:00. Agenda: * Coordination of removing the pupil generating function for external collaborators. * Sebastiaan will present the first draft of the opto-mechanical volume envelope. * Current state of the coronagraph design call. * Current state of the wavefront sensing sub-group. * Set goals for SPIE and what we will put on the poster. Met vriendelijke groet / With kind regards, Dr. Sebastiaan Haffert Assistant professor Leiden Observatory, Leiden University Einsteinweg 55, 2333 CC, Leiden, The Netherlands

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Re: WP2.3 literature review and next meeting
by Absil Olivier 03 Apr '26

03 Apr '26

Hi Axel, Thanks for sharing the slides! A new variation around the sequential phase diversity / fast&furious concept, now using reinforcement learning, should be added to your list: https://arxiv.org/abs/2604.00993 I guess Jalo will be talking about that during our next meeting. The accepted paper only presents wavefront flattening, but FYI Jalo has already been able to dig dark holes with the same framework, by ‘just’ changing the reward. Regarding the asymmetric pupil WFS, you may want to add a ref to the Asymmetric Lyot Wavefront sensor (Orban de Xivry+2024), which shows that the concept can be extended to focal-plane phase mask coronagraphs. Cheers, Olivier On 2 Apr 2026, at 18:10, Axel Potier <axel.potier(a)obspm.fr> wrote: Dear PCS WP2 member, I propose you to postpone our next meeting WP2.3 (wavefront sensing and control) that was originally planned tomorrow. Here is the new time slot: April 24th from 10am to 11am. I will ask some of you to present their current projects, followed by a discussion on the next steps. Meanwhile, you can find attached the literature review we have discussed the past few months. This is still a draft and I know I still miss a few information some of you already provided. So please reach out to me for any update or correction on the current draft :-) . Have a great end of the week, Best, Axel <PCS_WP23_WFSConcepts_Draft.pdf> --------------------------------------------------------------------- Dr. Olivier ABSIL F.R.S.-FNRS Research Director & Professor Space sciences, Technologies & Astrophysics Research (STAR) Institute Université de Liège (ULiège) 19c allée du Six Août, bât B5c, 4000 Liège, Belgium Tel: +32-(0)4-366.97.24 Email: olivier.absil (at) uliege.be Homepage: https://www.psilab.uliege.be/ ---------------------------------------------------------------------

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