Starship Asterisk*

I caught it tonight, through thin clouds. Huge tail easily seen with direct vision. Kind of neat, you can see the globular cluster M5 up in its tail! Excellent! M5 is clearly visible as well. I see a few "double" stars in the area of the comet's head- are these artifacts due to separate e...

Chris Peterson wrote: ↑Sun Oct 13, 2024 10:11 pm How about a full ten hours, dusk to dawn, in two minutes? The aurora never completely stopped.

Nicely done!

Steve

What I find interesting about this image is that we can see large-scale structures in the shape of long twisted "tubes", and then there is a lot of small-scale turbulence inside those tubes. What keeps the small-scale turbulence contained inside those long tubes? Ann It's important to dis...

The Wright Flyer of 1903 was NOT "the first aircraft to achieve powered, controlled flight" on Earth! In 1884 the airship La France made a 23-minute, 5-mile round trip flight, returning to her starting point against the wind. Other less-successful craft made powered flights even before th...

Ann wrote: ↑Sun Dec 10, 2023 6:21 am Although in this picture its shape seems slightly squashed.

Ann

This is a beautiful image. This effect is typical of barrel distortion when using a wide angle lens.

The two images are too far apart. I can't bring them together. :( If you are on Windows, simply click CTRL - or CTRL + to adjust the spacing until you can cross your eyes and merge the two images together (I'm sure there's an equivalent way to do this on a Mac). It's a very nice effect. Steve Steve...

I think I would appreciate this "hidden galaxy" a lot more, and also appreciate the efforts behind revealing its appearance, if I could also be shown what it looks like when it is hidden --that is what it looks like before filtering and manipulating noise and signal. Lasse, sorry for the ...

I have nothing against this galaxy, but I would like to see just how it is "hidden". Each time the caption claims it is only glimpsed through the veil of stars, gas and dust clouds in our galaxy. The photos do not really show this veil of gas and dust---to me it comes forth as quite visib...

I've never been fan of such artificial mixture of different compositions with different settings and processing.. What's the purpose ? Why make something appear so incorrect from physics and reality perspective.. it's not like we are here at APOD to watch a Sci-fi movie with CGI effects.. It's imag...

There’s a lot of information in the “Frontier Fields” site mentioned. The picture subtends approximately 1 square arcminute; a grain of sand held at arm’s length. How many square arcminutes make up the whole sky globe? I don’t know how to figure this out. Roy, you would need to figure out the radiu...

Steve, it would still be interesting to know what you estimate. Here is what I obtained- From my first post: Radius(rigel)/Radius(sun) = [sqrt(LUM rigel)/Temp^2 rigel] / [sqrt(LUM sun)/Temp^2 sun] Values for the above variables obtained from Wikipedia: LUM(rigel) = 1.2x10^5 * LUM(sun) Temp rigel (p...

How is it determined (or estimated I suppose) that Rigel is 74 times the radius of the Sun? By using the Stefan-Boltzmann Law, which states that a star's luminosity L is proportional to its radius^2 and temperature^4. It's been a (long) while since I crunched these numbers myself, but you can deter...

The subject of this APOD is not dark matter, it is a specific galaxy. A galaxy that has a particular significance because of its role in the use of galaxy rotation curves as evidence for dark matter. And that work was Rubin's, not Zwicky's. Chris, I understand your point. However, the main subject ...

Every man and his dog is fully aware that Fritz Zwicky was the first to demonstrate the presence of dark matter by the studying the Coma cluster of galaxies (using the virial theorem just as Rubin did). I was also very surprised that there was no mention of Fritz Zwicky in the APOD text. Since a lo...

https://apod.nasa.gov/apod/calendar/S_230130.jpg Globular Star Cluster NGC 6355 from Hubble ...Globular cluster stars are concentrated toward the image center and highlighted by bright blue stars. ... Who can explain to me why there should be so many blue stars in a 13.2 million old globular star c...

Please! The link, the featured photo , took us to a Facebook page, and since I don't have Facebook, I was unable to find any information at all about the image. Surely the links to information about the APOD in question should go to pages that are open to all? I second that. No links for APODs to s...

Ann, your explanation should have been part of the APOD caption in my opinion- a missed educational opportunity for the APOD viewership. The ram pressure that smooths out the leading edge of M88 (the long, continuous white line on the right side of your annotated image) has been recognized for over ...

A cool red star emits red light of many wavelengths, and the specific Hα wavelength of 656.46 nm does not stand out among them. The Hα wavelength only stands out where hydrogen has been ionized. So, in short: Ionized hydrogen emits red Hα light because it has been ionized either by hot stars or by ...

The phrase "with 15 times more light-collecting area" as currently written in the caption can be misinterpreted. It refers to field of view, which is a function of the scope's focal length and the camera's sensor size. It is true that JWST has a field of view (how much sky it can capture i...

From what I understand, JWST's main goal in taking these images was not to image Jupiter per se, but to show that the telescope can resolve faint structures like the ring system, which would suggest that it could also reveal equally faint structures like plumes of water extending from moons like Eur...

This is a pretty image, expertly processed. However, the red, visible light signal from Hubble (and other visible light sources) is now conflated with the IR signal(s) of JWST- that would be fine if they represented similar spatial and intensity distributions of light, but this isn't necessarily the...

This is certainly not the first time women have space walked, and I'm proud to see that this is continuing. Too many men have risked (and lost) their lives in the name of their country in general and in space exploration in particular. I would like to see more women contribute equally to this effort.

Thanks for the interesting discussion regarding my image. I would point out that the faint pink ribbon in the center of NGC 7129 doesn't seem to emit much in the way of pure Ha signal. In fact, I initially took about 4 hours worth of Ha in this field and didn't use it at all in this image (it's pure...

Wolf, the age of the universe is estimated to be around 13.8 billion years based upon the latest assessment of the Hubble "constant". It is tempting to interpret this as meaning that the observable universe should be 13.8 billion light years in radius, but that would not be correct, becaus...

Hello Anthony, Nice write up and photo. I imaged this object over 2 years ago at an image scale of 3.5"/pixel using the STL11K and the FSQ-106N: http://www.starrywonders.com/ctb1cropped.jpg More details can be found here: http://www.starrywonders.com/ctb1.html It's an interesting object that be...