Archive for Fine Guidance Sensor

Euclid Update

Posted in Euclid, The Universe and Stuff with tags , , , , on October 7, 2023 by telescoper

Having settled in to my new apartment on the Gran Via I’ve got time for a another quick update on the European Space Agency’s Euclid mission. For full details about what follows you can see here. Everything I mention here is already in the public domain, so I am not disclosing any secrets!

The last update I posted contained some frustrating and potentially worrisome news: the Performance Verification (PV) phase of the mission had to be put on hold in order to troubleshoot an intermittent problem with the Fine Guidance Sensor (FGS), which is supposed to help to maintain correct pointing of the telescope. This wasn’t working correctly as demonstrated vividly by the following image:

Obviously the survey couldn’t proceed without accurate control of the pointing of the telescope so it was urgently necessary to find out what was going wrong and fix it. It turns out that the software was getting confused by the flashes caused by cosmic ray protons hitting the detectors, think they were the gude stars it was supposed to be steering by. After identifying the problem, new software was written and uploaded to the spacecraft.

I wasn’t sure how this had gone until I saw via an internal communication that the PV phase had restarted. That announcement would not have been made had the upgrade not worked and sure enough it has now been made public that all is well. Congratulations to the instrumentation and software teams for this success. They’ve been working phenomenally hard on this.

There was an additional problem with stray light in the telescope that I have also mentioned before. That was only an issue for specific orientations of the telescope and has been dealt with by simply redesigning the survey a little to minimize the occurrence of the effect.

So the gremlins have been dispelled, and we go on into the PV phase after a delay of about a month. The survey is due to last 6 year so this hiccup is not a big deal really. We can in fact anticipate some early science results from this phase in a month or so, although they will not be part of the full survey which will start after the PV phase is complete, after a few months.

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Euclid Update

Posted in Euclid, The Universe and Stuff with tags , , , , on August 27, 2023 by telescoper

Time for a quick update on the European Space Agency’s Euclid mission. For full details about what follows you can see here. Everything I mention here is already in the public domain, so I am not disclosing any secrets!

The last update I posted mentioned that Euclid had moved into what is called the Performance Verification phase of its mission. That has now been put on hold in order to troubleshoot an intermittent problem with the Fine Guidance Sensor (FGS) which helps to maintain correct pointing of the telescope. This issue can probably be fixed by software updates, but these will have to be tested, hence the pause. This is rather irksome, but the instrument teams are confident they can find a solution soon.

Anyway, while we’re waiting, here is a video from Launch Pad Astronomy explaining about the mission. It was actually released about six days ago but I didn’t have time to post it until now. About 15 minutes long, it’s a big longer than previous official Euclid videos I’ve posted, but I think it’s very informative:

Oh, I almost forgot to mention that I’ll be talking a little bit about Euclid among other things at this event on 6th September.

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