Starship Asterisk*

Hello all, I took this image, the 1500mm focal length can easily be explained by me pressing the 0 one too many times. It's 150mm focal length. If anyone wants to see where it was taken from, it was the south side of the A303 south and slightly west of Stonehenge. Thanks for that clarification on t...

"Magnification" is a meaningless concept photographically. Hmm. Is that because you can blow up a photograph after taking it to simulate any magnification you want? Magnification is essentially an angular measurement, one that involves telescopic optics- that is, an optical system with bo...

Another impressive comet pic, but, as usual, one that belies what you can see with your own eyes. The image details reveal: Camera: @Canonuk EOS Ra Lens: @SigmaPhoto 150-600mm f/5-6.3 DG HSM Focal length: 1500mm Aperture: f/5 Iso: 1600 Shutter speed: 30s for sky; 15s for foreground . That lens is a...

https://apod.nasa.gov/apod/calendar/S_200714.jpg Comet NEOWISE over Stonehenge Explanation: Have you ever seen a comet? Tonight -- and likely the next few nights -- should be a good chance . Go outside just at sunset and look to your northwest. The lower your horizon, the better. Binoculars may hel...

This comet is pretty spectacular I suppose, but I have to say I'm getting a little worried. Anyone here good at cometomancy? Does NEOWISE portend a quick end to the COVID-19 pandemic, or instead, prolonged misery for humanity? Comets portend disaster. This one is clearly running a good four years l...

This comet is pretty spectacular I suppose, but I have to say I'm getting a little worried. Anyone here good at cometomancy? Does NEOWISE portend a quick end to the COVID-19 pandemic, or instead, prolonged misery for humanity? The COVID-19 pandemic can't be left to cometomancy pseudo-science :!: Su...

https://apod.nasa.gov/apod/calendar/S_200713.jpg Comet NEOWISE Rising over the Adriatic Sea Explanation: This sight was worth getting out of bed early. Comet C/2020 F3 (NEOWISE) has been rising before dawn during the past week to the delight of northern sky enthusiasts awake that early. Up before s...

Do the jets impart a net thrust on the nucleus sufficient to change its trajectory or rate or axis of rotation over time? Has data been obtained on jet locations, composition and velocity sufficient to calculate mass flow rates and resulting thrust vectors? There seems to be some similarity to spac...

As for why we don't see a green coma with NEOWISE, I'm not sure. Really bright comets (that is, naked eye) don't usually have obvious green comas, because the bright reflected sunlight from dust overwhelms the much dimmer green glow. All those pretty comets with their green comas are more gassy tha...

Neat. I've been looking for a comet with a green ion tail - because why couldn't there be one? - but I haven't found any. Maybe there's a reason? As for why we don't see a green coma with NEOWISE, I'm not sure. Maybe it needs to be closer to the sun? But having things line up so that sunlight hitti...

🌞☄️ Ann Thanks - cool site! (and very appropriate emojis) And now I have to ask the obvious follow-up: is it always primarily carbon monoxide ions (and why would that be, unless all comets are made up of the same stuff, which I find hard to believe), or have there been other comets with different c...

https://apod.nasa.gov/apod/calendar/S_200711.jpg The Tails of Comet NEOWISE Explanation: Comet NEOWISE (C/2020 F3) is now sweeping through northern skies . Its developing tails stretch some six degrees across this telescopic field of view , recorded from Brno, Czech Republic before daybreak on July...

https://apod.nasa.gov/apod/calendar/S_200711.jpg The Tails of Comet NEOWISE Explanation: Comet NEOWISE (C/2020 F3) is now sweeping through northern skies . Its developing tails stretch some six degrees across this telescopic field of view , recorded from Brno, Czech Republic before daybreak on July...

If that comet is just visible to the unaided eye than then how would anybody even know those noctilucent clouds were even there with the unaided eye? Noctilucent clouds with dark clouds like letters July 5 2020.jpg Noctilucent clouds can be really bright, and they are often very extended. I took th...

Every body in the Solar System has a tail, because every body is losing atoms to the surrounding space, and there are directional fields and forces present everywhere. But in most cases, these tails are extremely rarefied. Every body? Even small rocky satellites of the outer planets, or asteroids i...

Every body in the Solar System has a tail, because every body is losing atoms to the surrounding space, and there are directional fields and forces present everywhere. But in most cases, these tails are extremely rarefied. I'm pretty sure my "body" doesn't have a tail (visible, anyway), a...

Unlike Mars & Mercury, Earth has both a high escape velocity and a protective magnetic field. <...much snipped...> Despite all that good info, I'm still not clear on whether earth has a tail or not. It is "losing" both hydrogen and helium at fairly low rates, and that these come to ma...

Surely Earth should have a tail, too? Unlike Mars & Mercury, Earth has both a high escape velocity and a protective magnetic field. <...much snipped...> Despite all that good info, I'm still not clear on whether earth has a tail or not. It is "losing" both hydrogen and helium at fairl...

If anyone did not know Saturn's strange hexagon recreated in the lab. ... Saturn's Hexagon Recreated in the Laboratory Emily Lakdawalla | Planetary Society | 2010 May 04 A Laboratory Model of Saturn’s North Polar Hexagon ~ Ana C. Barbosa Aguiar et al Icarus 206(2):755 (Apr 2010) DOI: 10.1016/j.icar...

Two great videos to watch here: https://www.youtube.com/watch?v=sQH6Oo4hn94 https://www.youtube.com/watch?v=tGPQ5kzJ9Tg The first video (from NASA) focuses on blue jets, yay! The other one, made by amateurs, explains a lot about red sprites (mostly) and some of the blue phenomena involved. I find b...

I found the nice picture at left of LDN 1251 and friends! :D Note the PGC and LEDA galaxies. The picture is not as deep as the APOD, so we don't see any Herbig-Haro objects or small stars with jets. Note the HD numbers of some of the stars, and the Dobashi designations of some of the extra-dark clo...

APOD Robot wrote: Distant background galaxies also lurk on the scene, buried behind the dusty expanse. 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?...

Hi, Sp0ck! 🖖 You're right, there are a pair of interesting streaks there. The longer, fainter streak looks like some kind of imagery flaw or mistake to me, and the shorter, brighter streak baffles me. Well, maybe it's a satellite. That short streak looks especially strange because it seems to pass ...

Some of the composite photos offered on your website are a little squiffy in their verisimilitude, but this one demonstrates truly lazy and/or sloppy image fiddling. Whoof! And why is this photo particularly bad in your view? (I'm honestly asking in the name of science, not trying to start a fight ...

orin stepanek wrote: ↑Thu Jul 02, 2020 11:40 am APOD: The Galaxy, the Planet, Apple Tree, Water, and Moon Reflection!

Moon reflection? Don't you mean Jupiter?