Matthias Rauls
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dobsonaut.bsky.social
Matthias Rauls
@dobsonaut.bsky.social
180 followers 200 following 190 posts
Hobby astronomer who loves to share his inspiration
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dobsonaut.bsky.social
Matthias Rauls @dobsonaut.bsky.social · Aug 27
The star that expanded the universe was discovered by Edwin Hubble in 1923 with a 2.5m telescope. The Cepheid star V1 gave first prove that Andromeda is a galaxy outside our milkyway. Today, this #Astrophotography with my little #CelestronOrigin clearly shows this star in the gorgeous spiral of M31.
The contrasting spiral arms of a galaxy, with old stars in yellow, young and hot groups of stars in blue and some tiny specs of magenta for glowing hydrogen gas.
dobsonaut.bsky.social
Thanks - but my brain starts spinning ... (or is it expanding?)
February 7, 2026 at 12:23 PM
dobsonaut.bsky.social
Wouldn't the "galaxies move through space" argument quickly 'collide' with the speed limits of relativity?
February 7, 2026 at 12:02 PM
dobsonaut.bsky.social
This maps neglects the long history of making excellent wines in many European regions before 1960, German Riesling being only one among many.
January 10, 2026 at 4:40 PM
dobsonaut.bsky.social
This illustration is not appropriate. No question about it. Without wishing to defend the authors, I could imagine that the extremely rapid rotation of the asteroid gave rise to the idea of it having a more solid structure and less being of the rubble heap type.
January 10, 2026 at 11:47 AM
Reposted by Matthias Rauls
coreyspowell.bsky.social
The universe is still full of surprises! This is Cloud-9, a starless blob held together by dark matter--a "failed galaxy."

Astronomers have long speculated that such hidden objects formed the building blocks of bright galaxies like our own. Now we've found one. 🧪🔭

esahubble.org/news/heic2601/
This image shows the location of Cloud-9, which is 14 million light-years from Earth. The diffuse magenta is radio data from the ground-based Very Large Array (VLA) showing the presence of the cloud. The dashed circle marks the peak of radio emission,which is where researchers focused their search for stars. Follow-up observations by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys found no stars within the cloud. The few objects that appear within its boundaries are background galaxies. Before the Hubble observations, scientists could argue that Cloud-9 is a faint dwarf galaxy whose stars could not be seen with ground-based telescopes due to the lack of sensitivity. Hubble’s Advanced Camera for Surveys shows that, in reality, the failed galaxy contains no stars.
January 5, 2026 at 11:25 PM
dobsonaut.bsky.social
Lovely!
January 6, 2026 at 8:43 AM
dobsonaut.bsky.social
I enjoyed reading your summary on the physics of skating. I remembered, however, that 40y ago I was told in Chemical Physics, that transient pressure on ice can not suffice to melt it. May I bring to your attention this recent MD study on an interesting alternative? journals.aps.org/prl/abstract...
Cold Self-Lubrication of Sliding Ice
The low kinetic friction between ice and numerous counterbodies is commonly attributed to an interfacial water layer, which is believed to originate from preexisting surface water or from melt water i...
journals.aps.org
December 30, 2025 at 9:52 AM
dobsonaut.bsky.social
Thanks!
December 14, 2025 at 8:16 AM
dobsonaut.bsky.social
M31 is our neighbor in the ocean of the universe. I recently showed that my telescope can detect individual stars 2.5Mio LY away. Imaging the entire galaxy with the same telescope is more difficult. This #astrophotography with my #CelestonOrigin is a mosaic from 6 images, each 1h of exposure time.
A yellowish shining spiral galaxy with dark brownish dust bands and blueish groups of young hot stars.
December 13, 2025 at 5:43 PM
dobsonaut.bsky.social
What a beautiful, instructive visualization (and it is still even if people dispute the one or the other color shade by 10.000y).
December 1, 2025 at 8:40 AM
dobsonaut.bsky.social
Is there a higher resolution version of this map available?
October 26, 2025 at 8:59 AM
dobsonaut.bsky.social
There seems to be a bad link attached!? But gorgeous image!!
October 25, 2025 at 8:40 AM
dobsonaut.bsky.social
Great visualization!
October 23, 2025 at 7:23 AM
dobsonaut.bsky.social
Have you yet seen two lava fountains close to each other? Check this live cam from Kilauea:
www.youtube.com/live/BqmpkUd...
[V3cam] Kīlauea volcano, Hawaii (south Halemaʻumaʻu crater)
YouTube video by USGS
www.youtube.com
October 18, 2025 at 8:12 AM
dobsonaut.bsky.social
Today, that star marked with "Var!" can be imaged with a 6 inch telescope: bsky.app/profile/dobs...
dobsonaut.bsky.social Matthias Rauls @dobsonaut.bsky.social · Aug 27
The star that expanded the universe was discovered by Edwin Hubble in 1923 with a 2.5m telescope. The Cepheid star V1 gave first prove that Andromeda is a galaxy outside our milkyway. Today, this #Astrophotography with my little #CelestronOrigin clearly shows this star in the gorgeous spiral of M31.
The contrasting spiral arms of a galaxy, with old stars in yellow, young and hot groups of stars in blue and some tiny specs of magenta for glowing hydrogen gas.
October 6, 2025 at 7:04 AM
dobsonaut.bsky.social
But the point you are making is interesting, though!
October 5, 2025 at 11:43 AM
dobsonaut.bsky.social
I am sure that you are using the word lie as a rethoric hyperbole here. To me, it's just our eyes (and monitors) that are incapable of displaying and recognizing exponential brightness profiles.
October 5, 2025 at 11:42 AM
Reposted by Matthias Rauls
mcnees.bsky.social
Happy 120th birthday, special relativity!

Albert Einstein introduced special relativity in the paper "On The Electrodynamics Of Moving Bodies," published in Annalen der Physik #OTD in 1905. 🧪 ⚛️ 🔭

Manuscript: onlinelibrary.wiley.com/doi/abs/10.1...
English: www.fourmilab.ch/etexts/einst...
A black and white photo of Albert Einstein, around age 25, sitting at a desk. He is a wearing a flannel suit and resting his right arm on the desk. Einstein is looking to the left of the photographer in this posed photo. The first paragraph of the paper, in German. Translated to English is reads: It is known that Maxwell's electrodynamics—as usually understood at the present time—when applied to moving bodies, leads to asymmetries which do not appear to be inherent in the phenomena. Take, for example, the reciprocal electrodynamic action of a magnet and a conductor. The observable phenomenon here depends only on the relative motion of the conductor and the magnet, whereas the customary view draws a sharp distinction between the two cases in which either the one or the other of these bodies is in motion. For if the magnet is in motion and the conductor at rest, there arises in the neighbourhood of the magnet an electric field with a certain definite energy, producing a current at the places where parts of the conductor are situated. But if the magnet is stationary and the conductor in motion, no electric field arises in the neighbourhood of the magnet...
September 26, 2025 at 6:17 PM
dobsonaut.bsky.social
Interesting! The word "kwaksalver" also is equivalent to the old German word for the element mercury, whick is "Quecksilber". So this could be someone who prepares mercury containing ointments which must have been quite common then.
September 27, 2025 at 7:34 AM
dobsonaut.bsky.social
Constellation Cygnus hides a marvel of galactic nebulae. The Eastern Veil Nebula is part of a much larger remnant of a supernova that exploded around 8,000 years ago. This #astrophotography was created as a mosaic of two images taken with my #CelestronOrigin, each with an exposure time of one hour.
Blue-white wisps of a galactic nebula against the backdrop of countless stars in the summer Milky Way. A close-up of the blue-white wisps of the Eastern Veil nebula against the backdrop of countless stars in the summer Milky Way.
September 20, 2025 at 8:44 AM
dobsonaut.bsky.social
That person in the '70s is exactly me!
September 16, 2025 at 9:12 AM
dobsonaut.bsky.social
"The star that changed the size of the universe" was discovered in 1923 by Hubble on a plate taken with the 2.5m Hooker telescope. This variable Cepheid star proved that Andromeda is a far away galaxy like our own. Today, #astrophotography with my little #CelestronOrigin can show this star clearly.
The yellowish tone of old stars in the center of the Andromeda galaxy contrasts with the blue from groups of hot young stars, dark dust lanes and a few small magenta blobs from ionized hydrogen clouds. The image was exposed for around 2 hours with a 6 inch Celestron Origin telescope. In the midst of a featureless star cloud in the Andromeda galaxy, a single star is highlghted. This variable "Cepheid" star was discovered in 1923 by Edwin Hubble on photographic plates with the 2.5m Hooker telescope on Mt. Wilson. Today, a 6 inch Celestron Origin Intelligent Home observatory can image that star quite easily.
September 16, 2025 at 8:18 AM
dobsonaut.bsky.social
Congratulations on that phantastic journey!
September 15, 2025 at 3:40 PM
dobsonaut.bsky.social
Sehr interessante Seite, danke! Vor allem, da ich mich da altersgemäß (und damit vorteilhaft!) einordnen kann.
September 11, 2025 at 7:52 AM
Reposted by Matthias Rauls
astropicdaily.bsky.social
Galaxies, Stars, and Dust

#astronomy#astrophotography#apod
This well-composed telescopic field of view covers over a Full Moon on the sky toward the high-flying constellation Pegasus. Of course the brighter stars show diffraction spikes, the commonly seen effect of internal supports in reflecting telescopes, and lie well within our own Milky Way galaxy. The faint but pervasive clouds of interstellar dust ride above the galactic plane and dimly reflect the Milky Way's starlight. Known as galactic cirrus or integrated flux nebulae they are associated with the Milky Way's molecular clouds. In fact, the diffuse cloud cataloged as MBM 54, less than a thousand light-years distant, fills the scene. The galaxy seemingly tangled in the dusty cloud is the striking spiral galaxy NGC 7497. It's some 60 million light-years away, though. Seen almost edge-on near the center of the field, NGC 7497's own spiral arms and dust lanes echo the colors of stars and dust in our own Milky Way.
August 28, 2025 at 5:31 AM