João Calhau
@astrocalhau.bsky.social
The second rock from grandpa. Astronomy from Alentejo🇵🇹 to the World. Lancaster Uni alumnus. Post-doctoral researcher at INAF, Italy. Likes galaxy evolution, AGN,SFR, and Universe in general. Personal account; Opinions my own. astrocalhau.wordpress.com
I may just have started an analysis that takes more than 4 hours to run through the code... No one has ever accused me of being wise.
November 24, 2025 at 9:22 PM
I may just have started an analysis that takes more than 4 hours to run through the code... No one has ever accused me of being wise.
Been having some fun with trying to get a Hubble palette image of the Rosette nebula using my data, Siril, and the tutorials from Deep Space Astro (www.youtube.com/watch?v=fDhO...) - I couldn't find if there was a bluesky account.
My UHC filter isn't exactly dual band but eh - close enough.
My UHC filter isn't exactly dual band but eh - close enough.
November 23, 2025 at 5:38 PM
Been having some fun with trying to get a Hubble palette image of the Rosette nebula using my data, Siril, and the tutorials from Deep Space Astro (www.youtube.com/watch?v=fDhO...) - I couldn't find if there was a bluesky account.
My UHC filter isn't exactly dual band but eh - close enough.
My UHC filter isn't exactly dual band but eh - close enough.
@eggstronomer.bsky.social See, THIS is a proper Pleiades photo!
The Pleiades, M45, a beauty in the dark. Open star cluster only 17.5 LY away in Taurus. Recoginzed since prehistoric times.
5 hours of broadband exposures on 2015-11-14 UT under Bortle 3 skies from Bad Wolf Ranch, Texas. WO RedCat 250/51mm, UV/IR cut filter, ASI2600 MC cam
#astrophotography
#astrophotography
November 23, 2025 at 5:36 PM
@eggstronomer.bsky.social See, THIS is a proper Pleiades photo!
Reposted by João Calhau
A follow up with the Rosette Nebula, NGC2244, this time with correct Darks. Something went wrong with the flats, still haven't figured the flat panel out, but we just crop that zone. Just 1h20min.
November 22, 2025 at 7:09 PM
A follow up with the Rosette Nebula, NGC2244, this time with correct Darks. Something went wrong with the flats, still haven't figured the flat panel out, but we just crop that zone. Just 1h20min.
Two hours of The Seven Sisters, yesterday night, using my cat and the Askar 60F. This is a great little scope. It comes pre-flattened, so no moving parts inducing tilt on the imaging train.
Stars are a bit blown out but I wanted to try and bring out the nebula.
Stars are a bit blown out but I wanted to try and bring out the nebula.
November 22, 2025 at 12:56 PM
Two hours of The Seven Sisters, yesterday night, using my cat and the Askar 60F. This is a great little scope. It comes pre-flattened, so no moving parts inducing tilt on the imaging train.
Stars are a bit blown out but I wanted to try and bring out the nebula.
Stars are a bit blown out but I wanted to try and bring out the nebula.
www.youtube.com/watch?v=Tjjk...
Found this song again after almost ten years. It's changed, I remember the original video including a spinning celtic circle, and the instruments sounded different. Maybe the author remastered it. I honestly preferred the original but it's still a banger.
Found this song again after almost ten years. It's changed, I remember the original video including a spinning celtic circle, and the instruments sounded different. Maybe the author remastered it. I honestly preferred the original but it's still a banger.
From the Fields of Gallia (Epic Celtic Metal)
YouTube video by Antti Martikainen Music
www.youtube.com
November 20, 2025 at 9:26 PM
www.youtube.com/watch?v=Tjjk...
Found this song again after almost ten years. It's changed, I remember the original video including a spinning celtic circle, and the instruments sounded different. Maybe the author remastered it. I honestly preferred the original but it's still a banger.
Found this song again after almost ten years. It's changed, I remember the original video including a spinning celtic circle, and the instruments sounded different. Maybe the author remastered it. I honestly preferred the original but it's still a banger.
Reposted by João Calhau
Remember that lovely aurora last week?
Well...um...this is what Euclid saw... 😱
🧵
Well...um...this is what Euclid saw... 😱
🧵
November 19, 2025 at 11:51 AM
Remember that lovely aurora last week?
Well...um...this is what Euclid saw... 😱
🧵
Well...um...this is what Euclid saw... 😱
🧵
Reposted by João Calhau
Well, here's some very exciting news!
I've been wanting to share this for a few months, but had to wait for the pre-print to drop.
A NEW GLITCH ON A MILLISECOND PULSAR HAS BEEN OBSERVED!
These events are extremely rare - only two others since MSPs discovered.
🔭🧪📡
I've been wanting to share this for a few months, but had to wait for the pre-print to drop.
A NEW GLITCH ON A MILLISECOND PULSAR HAS BEEN OBSERVED!
These events are extremely rare - only two others since MSPs discovered.
🔭🧪📡
For only the third time ever, a glitch event has been observed on a millisecond #pulsar.
@rami.spaceaustralia.com chats with lead author and PhD candidate Bhavnesh Bhat about the significance of this important, yet rare, event.
www.spaceaustralia.com/news/new-gli...
#SpaceAustralia
📸 NASA SVS
@rami.spaceaustralia.com chats with lead author and PhD candidate Bhavnesh Bhat about the significance of this important, yet rare, event.
www.spaceaustralia.com/news/new-gli...
#SpaceAustralia
📸 NASA SVS
November 17, 2025 at 8:05 PM
Well, here's some very exciting news!
I've been wanting to share this for a few months, but had to wait for the pre-print to drop.
A NEW GLITCH ON A MILLISECOND PULSAR HAS BEEN OBSERVED!
These events are extremely rare - only two others since MSPs discovered.
🔭🧪📡
I've been wanting to share this for a few months, but had to wait for the pre-print to drop.
A NEW GLITCH ON A MILLISECOND PULSAR HAS BEEN OBSERVED!
These events are extremely rare - only two others since MSPs discovered.
🔭🧪📡
Reposted by João Calhau
I awoke this morning to find a very generous donation (the highest so far) of CA $400 from the British High Commission in Ottawa(!) The altrusim from near and far is testament to the communicative power of the Internet. Many thanks (Merci beaucoup pour votre gentillesse!)🍁🇬🇧 🇨🇦 🙏 Now < £165 to £2000 !
November 15, 2025 at 10:23 AM
I awoke this morning to find a very generous donation (the highest so far) of CA $400 from the British High Commission in Ottawa(!) The altrusim from near and far is testament to the communicative power of the Internet. Many thanks (Merci beaucoup pour votre gentillesse!)🍁🇬🇧 🇨🇦 🙏 Now < £165 to £2000 !
Reposted by João Calhau
This Black Friday - Every Course Must Go!
✅ 100% reduction of some subjects!
✅ Modules slashed!
Study them before it’s too late!
✅ 100% reduction of some subjects!
✅ Modules slashed!
Study them before it’s too late!
November 14, 2025 at 6:03 PM
This Black Friday - Every Course Must Go!
✅ 100% reduction of some subjects!
✅ Modules slashed!
Study them before it’s too late!
✅ 100% reduction of some subjects!
✅ Modules slashed!
Study them before it’s too late!
The way things are going, it's starting to look like I'll miss M45 and M42 this year...
November 13, 2025 at 9:34 PM
The way things are going, it's starting to look like I'll miss M45 and M42 this year...
Reposted by João Calhau
15+ years old, but still VERY relevent — and if we had acted 15 years ago, the “better world” we’d be creating would be a LOT better & easier to reach. There are real consequences we’re just starting to see to not heeding this cartoon a lot sooner.
Even worse if we don’t heed it now. #ClimateCrisis
Even worse if we don’t heed it now. #ClimateCrisis
November 12, 2025 at 5:04 AM
15+ years old, but still VERY relevent — and if we had acted 15 years ago, the “better world” we’d be creating would be a LOT better & easier to reach. There are real consequences we’re just starting to see to not heeding this cartoon a lot sooner.
Even worse if we don’t heed it now. #ClimateCrisis
Even worse if we don’t heed it now. #ClimateCrisis
Reposted by João Calhau
We're a third of the way through Haiti!! It would be awesome if we could keep the momentum up 🧪
This is a fantastic citizen science project to help with the aid distribution in the Caribbean following Hurricane Melissa!
Very easy to take part and little effort, which translates to a huge help to aid teams on the ground! 🧪
www.iflscience.com/citizen-scie...
Very easy to take part and little effort, which translates to a huge help to aid teams on the ground! 🧪
www.iflscience.com/citizen-scie...
Citizen Scientists Are Helping With Rescue Efforts In Hurricane Melissa's Aftermath – Here's How You Can Too
It is very easy to lend a hand, and you can do it with just your phone.
www.iflscience.com
November 7, 2025 at 5:57 PM
We're a third of the way through Haiti!! It would be awesome if we could keep the momentum up 🧪
Reposted by João Calhau
Mission accomplished! We've hit £1000 in just 12 days. Of course people can always donate more/there is no upper-limit. What next? Well, my sobriety has over 8 months to go, so that's my task. Maybe I can do some other challenge to build on this amount... @braintumourcharity.bsky.social
November 6, 2025 at 6:43 PM
Mission accomplished! We've hit £1000 in just 12 days. Of course people can always donate more/there is no upper-limit. What next? Well, my sobriety has over 8 months to go, so that's my task. Maybe I can do some other challenge to build on this amount... @braintumourcharity.bsky.social
Hell yeah!
Open Sesame!
The ELT doors have moved for the first time. This was no small feat, as each door will weigh 650 tonnes once completed.
The ELT dome & its doors will guard the telescope from the harsh conditions of the Atacama Desert.
https://www.eso.org/public/videos/potw2544a/
🔭 🧪
📹 ESO/ACe
The ELT doors have moved for the first time. This was no small feat, as each door will weigh 650 tonnes once completed.
The ELT dome & its doors will guard the telescope from the harsh conditions of the Atacama Desert.
https://www.eso.org/public/videos/potw2544a/
🔭 🧪
📹 ESO/ACe
November 3, 2025 at 9:51 AM
Hell yeah!
I have a complicated relationship with Weekends. They're technically two days, yet I spend half of the time despairing over the fact that the next day will be Monday and end up only resting for a day...
November 2, 2025 at 9:08 PM
I have a complicated relationship with Weekends. They're technically two days, yet I spend half of the time despairing over the fact that the next day will be Monday and end up only resting for a day...
Reposted by João Calhau
Reposted by João Calhau
–The faint light of the star reflected in the frozen globes of unseeing eyes served as a reminder of reality, because in the end this was all that the ship was: A cold and silent grave, forgotten and left to forever drift through the darkness of space.
[1/4]
#SciFiFri
[1/4]
#SciFiFri
October 31, 2025 at 4:39 PM
–The faint light of the star reflected in the frozen globes of unseeing eyes served as a reminder of reality, because in the end this was all that the ship was: A cold and silent grave, forgotten and left to forever drift through the darkness of space.
[1/4]
#SciFiFri
[1/4]
#SciFiFri
Reposted by João Calhau
Time to spotlight the first paper of my PhD student Gauri Kotiwale that appeared on arXiv last week: Rapid, out of equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy
arxiv.org/abs/2510.19959
arxiv.org/abs/2510.19959
Rapid, out of equilibrium metal enrichment indicated by a flat mass-metallicity relation at z~6 from NIRCam grism spectroscopy
We aim to characterise the mass-metallicity relation (MZR) and the 3D correlation between stellar mass, metallicity and star-formation rate (SFR) known as the fundamental metallicity relation (FMR) fo...
arxiv.org
October 31, 2025 at 10:53 AM
Time to spotlight the first paper of my PhD student Gauri Kotiwale that appeared on arXiv last week: Rapid, out of equilibrium metal enrichment indicated by a flat mass-metallicity relation at z ∼ 6 from NIRCam grism spectroscopy
arxiv.org/abs/2510.19959
arxiv.org/abs/2510.19959
Back home tomorrow. Napoli was a pleasant enough place. Especially the people. And I definitely enjoyed the food. But looking forward to get home.
October 29, 2025 at 5:31 PM
Back home tomorrow. Napoli was a pleasant enough place. Especially the people. And I definitely enjoyed the food. But looking forward to get home.
Reposted by João Calhau
Reposted by João Calhau
1.5°C: what it means and why it matters | United Nations share.google/oEm522fCUaD1...
1.5°C: what it means and why it matters | United Nations
The science is clear: to avert the worst impacts of climate change and preserve a liveable planet, global warming needs to be limited as much as possible and as a matter of urgency. Under the Par...
share.google
October 27, 2025 at 6:38 AM
1.5°C: what it means and why it matters | United Nations share.google/oEm522fCUaD1...
Reposted by João Calhau
Fantastic - now at £600, or 60% of the target (I don't know why it's saying 59%, but whatever.) Many thanks to an anonymous donor who gave £100 🙏👍❤️
October 26, 2025 at 11:32 AM
Fantastic - now at £600, or 60% of the target (I don't know why it's saying 59%, but whatever.) Many thanks to an anonymous donor who gave £100 🙏👍❤️
Reposted by João Calhau
–Captain, the more we talk about it, the less it seems like an accident.
–Oh come on! Don't tell me you've never wondered what the big red button is for. Look at it as a... a scientific experiment! Yeah!
–You could have just read the bloody manual!
–Oh come on! Don't tell me you've never wondered what the big red button is for. Look at it as a... a scientific experiment! Yeah!
–You could have just read the bloody manual!
October 25, 2025 at 3:12 PM
–Captain, the more we talk about it, the less it seems like an accident.
–Oh come on! Don't tell me you've never wondered what the big red button is for. Look at it as a... a scientific experiment! Yeah!
–You could have just read the bloody manual!
–Oh come on! Don't tell me you've never wondered what the big red button is for. Look at it as a... a scientific experiment! Yeah!
–You could have just read the bloody manual!