Starship Asterisk*

So, are there more than two background galaxies in this image? Here are at least two clear ones: galactic cirrus and background galaxies.jpg Ahh, IC 4633 and IC 4635. Those are among the few nearby galaxies partly seen through thicker lanes of Milky Way dust, allowing study parallel to the way one ...

Question: Why aren't there any light spikes -- that one usually sees in these kinds of photos -- around any of the local stars that are located within our Milky Way galaxy? Surprisingly, the stars in this view are perfect spheres of different sizes, and it is a pleasure to view them this way. All t...

The strange OIII cloud right next to Andromeda is slightly similar to the (admittedly quite differently shaped and also starforming) feature known as Hanny's Voorwerp near galaxy IC 2497. Hanny's Voorwerp may have formed as a tidal tail was drawn out of IC 2497 by a passing galaxy, and the tidal ta...

Both the orientation of the lunar disk and the layout of telescopes show that the viewpoint was west (maybe a bit northwest) of Kitt Peak, almost opposite the direction of Tucson. That's about right for pulling off on the shoulder of Arizona highway 86 as it rounds the mountain (it's 11 road miles f...

The longer the photographic exposure, the more the dimmer star stuff starts appearing at the outer edges of any galaxy, thereby increasing its apparent size. I think we need a definition of diameter something like: the minimal extent within which 95% (say) of the mass is concentrated. A recently po...

Well, 658 nm is the wavelength of ionized sulfur. It's seems relatively straightforward that sulfur should be ionized and made to emit photons in the relative presence of an extremely hot white dwarf. Similarly, 501 nm is the wavelength of doubly ionized oxygen. Doubly ionized oxygen represents a h...

Sites with visible-light AO systems use human plane spotters to avoid accidentally flashing a pilot's vision, with some work in progress on automated systems to first augment, and eventually replace, the spotters. (I am told that UV lasers such as the Robo-AO setup do not need this step). And at lea...

The spacecraft with the crane..after it gets out of the way..is it landing or crashing? It crashes. The "spacecraft" at this point is now just the rover, and by "crashing", I take you to mean the it simply falls after being released by the sky crane, as opposed to being further ...

AO always feels like a case of "extracting information from noise" to me, but obviously it works. Here's a twitter thread from the author of the picture - Juan Carlos Muñoz - explaining in more detail how AO works: https://twitter.com/astro_jcm/status/1248640837086560257. It'a still quite...

Well, I found a possible background galaxy, which looks pretty much like a fine face-on spiral galaxy to me. (Or else it's just another patch of illuminated nebulosity.) Have you found any others? As an aficionado of seeing galaxies though other galaxies' dust, I know that one! It's UGC 12160, whic...

Yes. This is a most regular looking irregular galaxy. Indeed, in the Sculptor Galaxy Group link http://www.atlasoftheuniverse.com/galgrps/scl.html in the explanation it isn't even classified as an irregular. That reference lists it as "SBm", which makes it a barred spiral. I don't know wh...

I wonder, was there ever any early confusion, with some observers thinking there was a mysterious lunar corona? Apparently it was ambiguous until 1724, when Giacomo Maraldi noted that the Moon moves during totality with respect to the inner features in the corona, so it must belong to the Sun. (Bes...

Thanks for featuring my image as APOD! I think I figured out where Proxima Centauri is in the field: https://i.postimg.cc/gkthMh07/Prorxima-Centauri.jpg Am I right?? I agree on the ID. Here is a 2014 image I did with a remote telescope (field about 10 arcminutes), where the ID was confirmed by the ...

The APOD blurb doesn't say why there are two expanding reflection rings. Did Supernova 1987A explode twice? For each value of the time delay (time since we served the direct light of the explosion), there is a locus of possible light echos which is an ellipse with the observer and the supernova at ...

I recalled scanning this paper Experimental Simulation of Meteorite Ablation during Earth Entry using a Plasma Wind Tunnel , from which I learned: (1) The spectra of meteors combine glowing (sometimes ionized) atmospheric gases, which happen to dominate in the red part the spectrum, and vaporized me...

According to the ESA science summary , the standard Gaia scanning mode works for stars of (green) magnitude 3 and fainter, with a special mode available for brighter stars (not clear to me whether they have actually been done by now). I suspect an equally large issue with the all-sky visualization i...

Elon Musk launched a useless, worn out car and a dummy, when surely he could have offered the launch for a scientific package? I didn't feel so bad about it when word came in from a science writer at the launch that SpaceX had at least informally offered to include payloads from NASA and the USAF, ...

Is there enough known about barred galaxy development to determine if this is a stable form or if the bars represent a transitional state on its way to a more stable shape? There's been lots of work with increasingly elaborate simulations of galaxy history. Bars can originate as one of the instabil...

I'm obviously confused. If the ISS transited the sun (angular diameter of one half degree) in one second, wouldn't it cover 360 degrees in 720 seconds, and orbit the earth in 12 minutes, rather than 90? I'm willing to be proved stupid to increase my understanding. What's missing there is that the o...

Eta Carinae, show us how to explode while I am still around. I dare you ...... By the way, do astrophotographers plan to stitch together upcoming two minute total eclipse movies and result in a three hour total eclipse movie ? That's one of the goals of the Eclipse Megamovie . As long as gaps cause...

And, is the red spot stationary over a point on the planet, or are the 'clouds' moving faster/slower than the planet is rotating ? Jupiter's rotation rate, like the Sun's. has multiple values depending on which part of the non-solid planet is referenced. Whichever one uses for Jupiter (low-latitude...

Permit me the capacity to compare the concept of magnetic and electrical flux to IFN. No, I mean integrating flux from zero to infinity . Just kidding but it does make you curious how the name was derived. :facepalm: There is actual integration involved. This nomenclature seems to originate from a ...

It's really just a catchall designation for any galaxy that has lost much of its symmetry. In some ways, morphological classification of galaxies is a scientific fossil (not unlike the morphological classification of species in biology). Generally of more interest these days is the physical evoluti...

NGC 3628: not suitable for vegetarians and vegans! :D :lol2: Also this is called the Sandwich Galaxy. I think it has a ionized Ha outflow, which isn't visible with amateur equipment? That it does. This old processed image (so old it was scanned from a 35mm slide shot off a monitor...) is a pseudoco...

Hi. As you work at an observatory, could I as what "p" is, please? Top left side, I'm guessing that "N" is north but I can't decide between many possibilities for the orthogonal "P" direction. "Positive"? "Prograde"? "Pandas-this-way"? P=p...