Starship Asterisk*

Sh2-82
https://www.astrobin.com/d7qbqc/
Copyright: Boris Chausov

IC 1613
http://www.karelteuwen.be/photo_page.ph ... 5&album=14
Copyright: Karel Teuwen

Duo in the Dark
ESO Picture of the Week | 2020 Oct 19

Image Credit: Yuri Beletsky (LCO)/ESO

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Winter nights on the Chajnantor Plateau can seem incredibly isolating — but the wonder of some of the driest, darkest skies in the world is definitely something to be shared.

This image shows two of the 66 antennas that comprise the Atacama Large Millimeter/submillimeter Array (ALMA), in which ESO is a partner, as they work together to observe the skies in millimetre and submillimetre wavelengths. These wavelengths are notoriously difficult to observe, as water vapour in the atmosphere absorbs this kind of light and prevents it from reaching the ground. To catch sight of it, telescopes must be placed at very high altitudes where the air is drier and less absorbent. For ALMA, that means an elevation of 5000 metres.

Hanging above the pair of telescopes is the constellation of Orion (The Hunter), identifiable by his distinctive star-studded belt. His shoulder is marked by the red supergiant Betelgeuse, on the right of the photo, located just under 650 light-years away from us. Betelgeuse is a prime target for observations in millimetre and submillimetre wavelengths, as is the neighbouring Orion Nebula.

Galactic Waterspout
ESA Hubble Picture of the Week | 2020 Oct 19

Credit: ESA/Hubble & NASA, SDSS, J. Dalcanton; Acknowledgement: Judy Schmidt (geckzilla)

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In this spectacular image captured by the NASA/ESA Hubble Space Telescope, the galaxy NGC 2799 (on the left) is seemingly being pulled into the centre of the galaxy NGC 2798 (on the right).

Interacting galaxies, such as these, are so named because of the influence they have on each other, which may eventually result in a merger or a unique formation. Already, these two galaxies have seemingly formed a sideways waterspout, with stars from NGC 2799 appearing to fall into NGC 2798 almost like drops of water.

Galactic mergers can take place over several hundred million to over a billion years. While one might think the merger of two galaxies would be catastrophic for the stellar systems within, the sheer amount of space between stars means that stellar collisions are unlikely and stars typically drift past each other.

PN G352.2-04.3
http://members.pcug.org.au/~stevec/PNG352_04.3.htm
Copyright: Steve Crouch

Sh2-64 region
http://www.astrosurf.com/ilizaso/orriak ... Q_U16m.htm
Copyright: Iñaki Lizaso

bystander wrote: ↑Mon Oct 19, 2020 2:03 pm Galactic Waterspout
ESA Hubble Picture of the Week | 2020 Oct 19

Credit: ESA/Hubble & NASA, SDSS, J. Dalcanton; Acknowledgement: Judy Schmidt (geckzilla)

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In this spectacular image captured by the NASA/ESA Hubble Space Telescope, the galaxy NGC 2799 (on the left) is seemingly being pulled into the centre of the galaxy NGC 2798 (on the right).

Interacting galaxies, such as these, are so named because of the influence they have on each other, which may eventually result in a merger or a unique formation. Already, these two galaxies have seemingly formed a sideways waterspout, with stars from NGC 2799 appearing to fall into NGC 2798 almost like drops of water.

Galactic mergers can take place over several hundred million to over a billion years. While one might think the merger of two galaxies would be catastrophic for the stellar systems within, the sheer amount of space between stars means that stellar collisions are unlikely and stars typically drift past each other.

I find the yellowish galaxy in the ESA/Hubble/NASA and SDSS (and Geck) picture in bystander's post, NGC 2798, very interesting. It reminds me of the nearby starburst galaxy, M82. Like NGC 2798, M82 has a "bland" yellowish disk with little or no star formation, but it displays a furious starburst in its center.

NGC 2798 looks just like that to me. The "water spout" of gas and stars from NGC 2799 appears to hit NGC 2798 right in its "solar plexus", causing a "splash" of dust and (mostly) old stars to fly up from its center. At the same time, all that fresh gas pouring into the center of NGC 2798 is apparently triggering a starburst there. We can clearly make out a large and bright blue star cluster below the dusty ring surrounding the inner bulge, and there are almost certainly massive bright young clusters much closer to the nucleus, too.

It is interesting to compare the color indexes of M82 and NGC 2798:

M82, U-B: +0.310. B-V: +0.890.

NGC 2798. U-B: -0.010. B-V: +0.720.

So in fact, NGC 2798 is a much bluer galaxy than M82, at least as seen from our vantage point. But of course, M82 contains massive amounts of dust, so that it is considerably dust-reddened, and its center is mostly hidden from our view by dust. NGC 2798 looks a lot less dusty, and we can see its center clearly.

It is interesting to consider the possibility that the "water spout" sending gas directly into the center of NGC 2798 is a relatively recent phenomenon, so that NGC 2798 has not had time to produce all the dust that is so characteristic of M82's moderately old starburst.

Ann

Galactic Center Mosaic
http://www.pampaskies.com/gallery3/Wide ... aic_lowres
Copyright: Ignacio Diaz Bobillo
Full size here (10.58 MB).

Ann

NGC 7793
http://www.azstarman.net/CDK/NGC7793.htm
Copyright: Bernard Miller

Leo Triplet
https://www.flickr.com/photos/manueljas ... 618641432/
Copyright: Manuel Jimenez

B174 region
http://galaxyphoto.de/de/b174-de/
Copyright: Michael Deger

IC 1396
https://www.flickr.com/photos/146686921 ... 289666347/
Copyright: Franz Klauser In the full resolution image, a planetary nebula can be found somewhere!

IC 4870
https://www.spacetelescope.org/images/potw1823a/
Copyright: ESA/Hubble & NASA

LDN 664
http://www.atacama-photographic-observa ... php?id=181
Copyright: Thierry Demange, Richard Galli and Thomas Petit

M92
https://www.cxielo.photography/m92
Copyright: Martin Rusterholz

Bright Planets Imaged as La Silla Restarts Observations
ESO Picture of the Week | 2020 Oct 26

Credit: ESO/NTT/EFOSC2

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ESO’s New Technology Telescope (NTT) has captured the familiar sight of three of our planetary neighbours as limited science operations restart at La Silla Observatory, located in the Chilean Atacama desert. Images of the three brightest planets visible in the sky that night: Jupiter, Mars and Saturn were taken as the operations team tested the NTT’s versatile EFOSC2 instrument. The subtle orange, yellow and reddish hues of the three planets are seen by combining images captured by the instrument using five different filters.

This Picture of the Week shows a montage of the images taken of the three planets. The relative sizes seen in this montage are proportional to the angular size of the planets in the sky. Mars appears rather large and bright because it was in opposition when the image was taken, that is, the Earth was positioned between Mars and the Sun.

Following these successful tests, very limited science operations restarted with this instrument last week after the pandemic-induced pause. These limited operations are being conducted under strict health and safety measures by a very small team, who use special tools to interact with the astronomers observing remotely.

Beauty From Chaos
ESA Hubble Picture of the Week | 2020 Oct 26

Image Credit: ESA/Hubble & NASA, A. Adamo et al

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Appearing within the boundless darkness of space, the NASA/ESA Hubble Space Telescope’s snapshot of NGC 34 looks more like an otherworldly, bioluminescent creature from the deep oceans than a galaxy. Lying in the constellation Cetus (The Sea Monster), the galaxy’s outer region appears almost translucent, pinpricked with stars and strange wispy tendrils.

The main cause for this galaxy’s odd appearance lies in its past. If we were able to reverse time by a few million years, we would see two beautiful spiral galaxies on a direct collision course. When these galaxies collided into one another, their intricate patterns and spiral arms were permanently disturbed. This image shows the galaxy's bright centre, a result of this merging event that has created a burst of new star formation and lit up the surrounding gas. As the galaxies continue to intertwine and become one, NGC 34’s shape will become more like that of an peculiar galaxy, devoid of any distinct shape.

In the vastness of space, collisions between galaxies are quite rare events, but they can be numerous in mega-clusters containing hundreds or even thousands of galaxies.

A FAR SATURN

More details
https://www.astrobin.com/full/jcai5o/0/?nc=user

Equipment
MEADE LX200 10 "UHTC
ZWO Optical ASI 462 MC
Filter: Planetary Baader L 1.25 "
Accessory: TeleVue Powermate 2.0x
Mount: Ioptron Cem60
Polar alignment: Sharcap
Capture: SharpCap V3.0
Processing: Photoshop CS6, AutoStakkert AutoStackert !, Registax 6, Winjupos

10/12/20
22: 40UT
São Paulo-SP-BRAZIL

Copyright: Fernando Oliveira de Menezes
Email: Barretosmed@hotmail.com

starsurfer wrote: ↑Sat Oct 24, 2020 1:35 pm IC 4870
https://www.spacetelescope.org/images/potw1823a/
Copyright: ESA/Hubble & NASA

Click to view full size image

Wow, this appears to be an incredibly blue galaxy!!!

According to Principal Galaxy Catalog, the B-V index of this galaxy is +0.03! Incredible! I've never come across such a blue galaxy!

It's like an entire galaxy that is pretty much as blue as Sirius!

I guess it is possible for this galaxy to be so blue because it is obviously quite small. So the light from this galaxy is overwhelmingly dominated by the light from big and bright young star clusters.

Ann

Ann wrote: ↑Tue Oct 27, 2020 6:31 am

starsurfer wrote: ↑Sat Oct 24, 2020 1:35 pm IC 4870
https://www.spacetelescope.org/images/potw1823a/
Copyright: ESA/Hubble & NASA

Click to view full size image

Artist's impression of Sirius A and B. NASA, ESA and G. Bacon (STScI).

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Wow, this appears to be an incredibly blue galaxy!!!

According to Principal Galaxy Catalog, the B-V index of this galaxy is +0.03! Incredible! I've never come across such a blue galaxy!

It's like an entire galaxy that is pretty much as blue as Sirius!

I guess it is possible for this galaxy to be so blue because it is obviously quite small. So the light from this galaxy is overwhelmingly dominated by the light from big and bright young star clusters.

Ann

I think some parts near the centre are HII region, which seem to have unusual colours depending on what filters are used.

Veil Nebula
https://www.astrobin.com/ksxd4l/
Copyright: Jonas Illner

IC 348 and NGC 1333
https://www.astrobin.com/338969/
Copyright: Byoungjun Jeong

LDN 1551
https://www.astrobin.com/nc9i9t/0/
Copyright: Tim Gillespie

NGC 1999
https://www.astrobin.com/m7bbgc/
Copyright: Eric Coles and Mel Helm

starsurfer wrote: ↑Tue Oct 27, 2020 1:05 pm
I think some parts near the centre are HII region, which seem to have unusual colours depending on what filters are used.

I absolutely agree, but I don't base my assessment of the colors of this galaxy on the appearance of IC 4870 in the Hubble image. Like you said, the filters used for the image were not intended to bring out the "true" RGB colors of that galaxy.

I base my assessment of the colors of IC 4870 on the B-V index as listed by Principal Galaxy Catalog.

Ann