As you might have guessed, I’m writing about our latest visitor, comet NEOWISE. Once again, I’ll start off by defending my title from any more pedantic readers.
1: The death ROCK from beyond the stars.
Some of the more scientific-minded will argue that NEOWISE, like other comets, is made up of dirt and ice(correction, ices: not only frozen water, but also frozen nitrogen, ammonia, etc), not rock. My rebuttal? Stop being so Geocentric! Ice is a rock on many planets and moons; On Titan, water ice it is a solid object and a major part of the surface, and Pluto? Don’t get me started on Pluto. (OKAY! fine, If you insist, I’ll get started on Pluto. My opinion: Pluto should not be a dwarf planet, but big science is once again suppressing the information we need to make an objective choice. I’m not afraid of them, however: I am clearly stating for the record that Pluto is obviously a star. Pluto and the Sun are made up of the same objects: electrons and two types of quarks. Therefore, they are the same. That also means that the coffee I’m drinking is a star, and the coffee and the sun are both very hot, so my theory holds true).
Back to my point. Just because ice is a rock with a low melting point, and we live on a warm planet, doesn’t mean it isn’t a rock. Besides, look at Basalt. Big Science agrees that it is a rock, but it still exists in liquid underground. A very glowy, painful, liquid, but a liquid. The ice isn’t always solid in the comet, either. The tail of the comet is the part that is heated by the sun, and evaporates, while the small core is the still-frozen part(the core of the asteroid is only about 5 km across, and I’ve really angered the pedants now by calling it ‘core’ instead of ‘nucleus’ and ‘asteroid’ instead of ‘comet’).
2: The death rock from BEYOND THE STARS.
Comet NEOWISE orbits the sun about once every 6800 years. Earth also orbits the sun. In an amazing mathematical coincidence, we orbit once every one year. Therefore, the comet must often be on the opposite side of the sun from us about half of the time (always assuming that you are reading this on the earth… if not, please send me a postcard). As the sun is a star, the comet is literally from beyond a star. I did say stars, plural, but that’s because I decided to round up. NEOWISE reaches a maximum distance of about 630 Astronomical units(630 times the distance of the sun to the earth). Maybe I’m wrong about Pluto(I’m not, but lets just pretend I am), and there wasn’t any other star that passed between it and us(I think I would have heard about it if one did come that close). That would mean NEOWISE is beyond exactly one star. However, I’ll still add the miscellaneous hydrogen the comet passed to the total, as Hydrogen is a main component of a star.
I’ll also add the helium, as that is also a major factor in stars. I’ll also add the other elements, as most of them are leftovers from star fusion; the heavy ones are even from dead stars. Therefore, NEOWISE is beyond one star, plus various star component, plus various star debris. As it one star plus a small fraction of star fuel and pieces, I can round up to two stars.
3: The DEATH rock from beyond the stars.
The last time NEOWISE passed by earth, they didn’t write much about it. Perhaps they were too busy learning how to write(and farm, and build shelter, but I have it on good authority that a lot of people succumbed to their injuries while the comet was overhead. Many more died from illness and starvation, and a few unlucky souls even DIED OF OLD AGE!
Admittedly, the death toll directly attributable to the comet this time is… about zero… but you have me to thank for that: my supplications and virgin sacrifices have worked! It did come while we are in the middle of another plague, so I might need to update my sacrifice game before next time.
Anyways, I defended my title, so lets talk about Comet NEOWISE.
… I think I covered all the relevant comet facts already.
After all, NEOWISE is only it’s stage name; the real name is C/2020 F3. However, it was discovered by the Near-Earth Object Wide-Field Infrared Survey Explorer, an orbital telescope system. I’m not going to get into asking if the observatory is compensating for something; I’m sure it is a complete coincidence that the the observatory’s name shortens to the word ‘wise’ and a synonym for ‘New’. I’ll just say that the comet chose to take its name once they found one another, and the explorer seems happy to be the centre of attention for a little while.
I took these photos on the evening of the 19th, because that was literally the only night when the skies were clear at the same time the comet was out. It’s been a wet, cloudy non-summer. Being so far north, the comet wasn’t close to the horizon, but it was still bright at 11:00 PM(the sun set at 9:30 PM, for the record), and the horizon was still bluish after midnight.
I still couldn’t see the comet even at 11:00 PM, but a few planets and stars were out, and I knew about where in the sky it was(it could be found by drawing a line from two stars in the Big Dipper.
With no clear view, I relied on my backup plan: Take a bunch of photos in about the right direction and hope one of them shows something interesting. I’m not just talking about the comet. This is my backup plan for every situation, so I’m fairly good at it by now.
Sure enough, on my ninth photo, I saw this:
The comet still wasn’t visible to the naked eye. By about 11:30, as I knew exactly where it was, I could follow the line from the Big Dipper and just barely see it as a brighter smear; by the time I left at about 12:30, I could faintly make it out just by scanning the sky. It was never stood out in the sky, but I could see it a little bit. Long exposures were the way to go. I’m a little disappointed that I couldn’t get any photo of the comet with the horizon in shot, as I couldn’t zoom out far enough. I had only brought two lenses with me: my Canon 75-300 mm telephoto lens, and my Canon 50mm prime lens. The above photo was taken with the 50mm one.
Each lens has a specific advantage for this situation: the 75mm-300 mm one has zoom, obviously; If I want a closeup of the comet, I’ll need it.
The 50 mm has a large aperture(1.8) , so a lot more light can pass into the camera sensor. That’s a big issue at nighttime, when I need long exposure. As the stars move relative to the sky(and now I’m being geocentric too… sorry!), a long exposure will see the stars turn from pinpoints to lines. I could use a star tracker to move the camera with the stars, but I don’t have one. The 50mm lens lets in 10 times more light than the 75-330 mm one(which has a f-stop of 5.6 when fully extended), so I can take an equivalent photo more about 10 times faster…
Except, it gets more complicated. I don’t have a regular camera, I have a full spectrum one. That means that I don’t just photograph visible light, but also near-infrared(and ultraviolet, but that really isn’t a factor here for reason I’ll get into). In my experience, the 75-300 mm lens is better at blocking IR light than the 50mm lens. In some situations, that might be an advantage, but not when I want full spectrum photos. Without filters, the real difference between the two cameras seems to be closer to 15 times. This is all anecdotal, from my personal experience, as I’ve never found any reputable site to compare them. I should do that sometime myself, but there’s a lot of things I should do, but won’t.
And of course I’m going to take full spectrum photos; that’s my hobby and the purpose of my blog. In fact, I decided to take photos in four spectrum ranges for the following reasons:
1: Visible Spectrum(Schott BG40 filter), because it is the equivalent to what you could see in real life. Actually, as I mentioned, the comet is a faint smudge in the sky at best, but long exposures are a great advantage for making the comet look better.
2: Full Spectrum(no filter). Letting the maximum amount of light into the camera will mean that I can take photos with a shorter exposure, and less blur. It might also show some additional infrared features.
3: Near infrared(Zomei 680 nm filter only). Infrared light might reduce the atmospheric pollution and haze; I was taking these photo well outside of the city, but still… as well, maybe something will pop up in the near infrared range. 680 nm is the closest to the visible range, so the exposure will be the shortest out of all my infrared filters.
4: Dual-band infrared & ultraviolet (Schott UG11 filter), because… I dunno, why not? I don’t really have a reason. I do have a dual band filter, so why not try it?
I’m leaving out ultraviolet(It is too dark for my camera to take any UV photos without a star tracker) and thermal infrared(my thermal camera is too low resolution to see anything in space smaller than the moon, and even that is only couple pixels wide).
One last thing: I usually have my white balance for my photos set ahead of time(matching them to a white piece of paper in sunlight): It allows me to compare the pictures more accurately. That is all out of the window here; I altered the RAW photos to get what I thought was the best image, regardless of the colour.
Here’s the comet in the visible spectrum, once I dialed back the exposure and focused the lens better.
Fairly good- I did an exposure time of 1.3 seconds here.
Much nicer, and a shorter shutter speed too(1 second).
It looks clear, and the comet stands out, but the exposure was much longer, a whopping 15 seconds! Going any deeper into infrared would require me to take longer exposures over 30 seconds, which is the most my camera will do automatically. I could do longer, but then, as I mentioned, the objects in the sky will start to blur.
I KNOW, OKAY?! I knew ahead of time, don’t blame me! It’s not going to look good; There’s just not enough light getting into the camera. I needed 30 second exposure, AND I had to bump the ISO from a nice 200 to a noisy 6400, and the comet is still fainter than in the other spectra.
In all, only the visible and full spectrum pictures have any chance of making a good photo with my telephoto lens; the 680 nm filter needs too long of an exposure, and the UG11 exposure would have to be well over two minutes, and the sky would still move.
As I’m not going for a telephoto lens photo with my infrared filter, here is another photo of the comet from the 50mm lens, zoomed in to better see the detail in infrared.
It’s a little grainy at this zoom, but I really can’t do much better. The comet tail is clearly visible, and maybe the ion tail leaving the comet at an angle to the right is barely visible too?
With my maximum zoom on my telephoto lens, the comet looks like this in the visible range:
That’s pretty good; maybe a little faint, but the tail is clear, and the comet stretches across the sky. That photo’s one that I’ll be sharing.
But the best is last: Maximum zoom, low ISO, Full Spectrum! GO!
The infrared does add a lot of texture to the comet, especially when added to the visible spectrum instead of standing on its own. There’s a diagonal line to the right; a satellite photobombed me while I was taking the exposure.
And that’s about it for my comet viewing. If you want to see it now for yourself, and don’t want to wait for the next pass, there’s not much time left; it is already getting dimmer, and might already be too dim to see in the city even with a telescope. Bring binoculars, and look up where it will be in the sky beforehand! Next time it passes I’ll have to try some UV photos. Maybe by then, I could afford a star tracker for them.
How about one more pic for the road?
The above photos were taken with a modified Canon T3i Rebel camera.