Good Old Days
I'd brought my work home with me. I couldn't help that the stars and moon called to me—it was my cutie mark, my destiny. And I loved it. Measuring the intensity of various stars, using that combined with the color data to interpret not only how far they were away, but how bright they actually are, was my specialty.
My darling wife, Twilight Velvet, was away for a few days—Cadance called her for a parenting emergency. Apparently the Crystal Empire was due to collapse unless Cadance and Shiny both dropped everything and stopped it. Everything included Flurry Heart—my granddaughter.
I didn't exactly expect to hear a knock on the front door, but when it came I wasn't surprised. There were plenty of ponies that could be knocking on the front door of our house at—an hour after sundown. Or maybe I'd just spent too long engrossed in my work and forgot how time moved.
"Coming!" I said.
Setting my charts down, I slid my reading glasses off and got to my hooves. As a unicorn, I could have just opened the door from where I sat, but I was a bit old-fashioned in the ways of chivalry. Walking to the door, I had no compunction in using magic to open it once I was there. Pulling it open, I beheld somepony who could be called even more old-fashioned than myself—though never to her face.
"Princess Luna," I said. "Please, come in."
Luna looked like she was ready to use the Royal Canterlot Voice with enough power behind it to actually destroy Canterlot. I quickly gestured to the couch.
"Th-Thank you, Night Light. Is Mistr—Is your wife h-home?" Luna asked.
The full effect of the tremble and pain in the princess' voice was impossible to convey without using the word terror. Princess Luna was terrified of something, and my Velvet wasn't here for her.
"She's in the Crystal Empire, foalsitting Flurry Heart. Please sit down, princess, and let me fetch you some tea," I said.
It must be said that was—according to Princess Celestia—the second best teabrewer in Canterlot. My darling wife was the best by a comfortable margin. I'd attained this skill only because the sight of Twilight's face, when she tasted anything but a perfect cup of tea, broke my heart.
"When will she be back?"
Using magic, I forced the water to boil faster, simply raising its temperature with my magic. Making tea might be a delicate process, but it only became delicate once the water was hot enough.
"I don't know. Would you like to talk?" I asked.
Carrying the tray to the living room, I saw the Princess of the Night almost chewing her hooves with worry. She held back any words, and actually jumped a little when I came into view. Setting the tray down, I presented two cups.
"It's just like last time. Another summer sun celebration, another year of ponies waiting on my sister's every word," Luna said. "I'm not mad at her. She doesn't have it easy—I know that after what Starlight Glimmer did for us—but I work as hard as she, and get none of the suitors or praise."
Nightmare Moon had happened the last time Princess Luna had lost herself in jealous anger at her sister. My wife, Twilight Velvet, did what she could to keep both reigning princesses at ease, but she was not here tonight. I poured Luna tea, after waiting for the tea to steep, and then poured my own.
I had to say something. I hope I have the right words for this.
"When did you start to feel this?" I asked.
Luna needed the tea more than my advice, or so it seemed. She lifted the cup up and took a long sip of the almost-scalding liquid. She waited a few moments, sipped again, then opened her mouth to speak.
"When we were still students under Star Swirl," Luna said, a little smile pulling at her lip. "We had no responsibility but to learn. Tia took to social sciences first, and magic second—I was the opposite. There was one exception to my love for learning magic—"
"The moon," I said.
Nodding, Luna's smile grew. She took another sip of her tea.
"We didn't have our cutie marks yet—late bloomers—but I already felt the moon pulling at me, always urging my eyes up to it at night. I wish…"
We sat in silence, sipping tea and relaxed. Well, I was relaxed. Princess Luna was trying to relax. Despite the chance of it saving Equestria (and dooming the royal bladder), the tea would not last forever. Luna looked calmer, but I could feel tension growing again.
What would Twilight do? Cuddle with Luna all night and pick apart her problems with expert precision and insight. There was no way I could manage that. But could I do like my wife with Celestia, and play a part?
"Are you done with that?" I asked.
My tone wasn't harsh, but it was sharp.
Luna's head shot up, and I could see surprise on her face. She quickly put the cup down on the table and looked at me with trepidation.
"Good," I said. "Now we can get back to your lesson."
I hadn't often had the privilege to see an alicorn completely flummoxed (usually there was a minor cataclysm in progress, so the chance to enjoy the sight was even rarer), but the look of surprise on Princess Luna's face was priceless.
"Well? Come on, Miss Luna."
I stood up and returned to the kitchen table. I had nearly five seconds of panic to wonder if I'd gone too far, or if my voice hadn't been the right tone. I'd spent some time early in my career teaching students at Princess Celestia's school, so while I might be rusty, my voice should have conveyed what I wanted.
"Y-Yes Mister Light."
Settling back in my seat at the table, I quickly (and magically) exchanged my working notes for blank paper. The sound of heavy hooves—alicorn hooves—walking into the kitchen was a relief. I glanced once toward her, and tsked.
"Enough of the theatrics, Miss Luna. Please make yourself small again," I said.
When Luna and my wife spent time together, Luna often used a similar spell to her sister. But this time, when a flash of cobalt light flickered, Luna was less than half her normal size. She was smaller than me—though she had her cutie mark still—she looked like a mid-teen filly.
"Sorry, sir."
I couldn't believe I was doing this, or that she was letting it go on. It was mad, it was silly, but when I looked into Luna's eyes, I saw that she didn't consider it either of those things. She pulled out a chair and climbed up into it.
"I'm not sure your regular teachers would have taught you this, but I think it's essential to know," I said, and pulled a particular star-chart across. "This is a magically generated photograph, and this,"—I used a pencil to gesture at one white dot—"is a supernova."
Princess Luna, now looking like a filly, sat in attentive attention to my description of how to measure the distance of stars. She didn't seem fazed by my talk of red-shifting, nor did she blink at the complex mathematics I wrote down.
"Now you try it for this one," I said.
The star I pointed to wasn't one I'd calculated yet. Luna's magic took up a pencil and a piece of paper, and she began writing out the formula I'd given her. She looked focused, intent, and completely into the problem. I remembered back to my teaching days, and meeting many young unicorns who wore that same expression as numbers became their world.
With each star I gave her, Luna would have to cross-reference it to a data-sheet measuring its luminosity and color profile, then she would need to perform the complex mathematics to turn the numbers into a single, final figure.
I knew the math, knew it well, and by watching her working out I could see if she was getting them right or not. It took her fifth one before she made a mistake.
"Your arithmetic is fine, but took the wrong red shift value," I said. "Use this one here and try again."
"Sorry, Mister Light," Luna said, before she attacked the problem anew.
The problems continued long into the night—there was a lot of stars in the sky after all. About midnight I decided it was time for a break.
"Last one, then we have recess," I said.
Prince—Luna's head nodded, though with her tongue poking out the corner of her mouth it was hard to take her seriously—but I had to. She finished the calculations and pushed the sheet toward me.
I didn't need to check if they were correct since I'd been checking as she went. But I made sure to take out the red ink and dipped my quill in it. Normally, quill-writing was reserved for important things—though my daughter considered every bit of writing important—but there was something special about a teacher using red ink. It was how things were done.
"Very good, Miss Luna. Except for the one value-lookup-mistake, you have a perfect mark."
Standing up, I gave her two little pats on the head and headed to the refrigerator. Some bread, avocado, tomato, and lettuce later and I had two sandwiches made. I was proud of my sandwiches. Two further generations of our family had enjoyed my sandwiches—though Flurry's enjoyment consisted of using Shiny's to paint a wall.
"Here you go," I said, passing the sandwich to Luna.
"Thank you, Mister Light."
There was a lightness to Luna's features, a weight that was missing from her that had nothing to do with her physical stature. She chewed on the sandwich, but kept glancing back at the table. She gulped down one mouthful and cleared her throat.
"How did you get all this information on the stars?" Luna asked.
I chuckled—I couldn't help it.
"You don't know I work for the observatory? Stars and the moon are my passion."
Okay, so I'd gotten to see a startled princess twice in one day now. Luna barely managed to pick her jaw up from the floor.
"You study the stars and my—and the moon?" Luna asked.
My own mouth was full of sandwich, and despite having my legendary sandwiches every day, I was loathe to waste so much as a mouthful of one. Finishing my mastication, I swallowed.
"I do."
"Then all those—what I just worked out—you already knew all that?"
"No, Miss Luna. I was in the process of working on it when your class started," I said.
Luna was very quiet for the remainder of her meal. She chewed little bites, and chewed them well before swallowing. Meanwhile, I racked my brain to think of what to study next. By the time she was done with her sandwich, I had the answer.
"All done?" I asked.
It was small talk. Luna was finished eating the sandwich and I could see her eyes straying back to the table.
"Mmhmm! More stars?"
Excitement and raw enthusiasm was writ large on her face. I wouldn't be the patriot of Equestria I am if it didn't make my heart warm.
"No. Stars were a warm-up. Follow me, Miss Luna."
I took the stairs slowly, making the moment of anticipation draw out for Luna—this was all for her, after all. All the way to the end of the hall, and I opened my conservatory.
"In here," I said.
The moment Luna looked inside was obvious by her gasp of excitement. I walked up to my pride and joy. Ranked fourth, so far, out of my greatest loves, the telescope was already prepared and ready.
"It's a Neightonian-reflector telescope of my own design. I got my cutie mark when I first made this," I said. "Would you like to see the moon, Miss Luna?"
I'm not sure that she teleported, but Luna broke at least one natural law reaching my side. I adjusted the angle on the 3-pony-length tube, and looked through the targeting eyepiece. Precise adjustments were the order of the day when working with my telescope, and there was nothing better for the task than unicorn magic.
"Here. Look. Tell me what you see," I said and stepped back.
Stepping up to the side of the telescope, Luna leaned in and peered through the telescope—then gasped.
"The moon. This is—These are the Brumby Craters. I can see right down the ridges and—This is amazing," Luna said.
"Tell me what you see different about the left-most one, and the one beside it?" I asked.
Luna's magic seemed hesitant, like its owner, but I didn't fight her for control of the eyepiece. The raw emotions on Luna's face would have been worth ten telescopes.
"There's an impact on the left crater's upper-right rim. A smaller crater. When did this happen?" Luna asked.
"Four days ago. Now, given that we know the crater is two-hundred-pony-lengths wide, how big would you judge that new crater?"
My wife looked ragged. She'd caught the late train from the Crystal Empire, and arrived in the middle of the evening. She hadn't knocked, instead she stumbled in the front door and dropped her bags beside her.
"Three," I said. "Two… One…"
"Princess Luna?" Twilight Velvet asked. "D-Do you need help with something?"
I cleared my throat, getting my wife's attention.
"Twilight, dear, this is Miss Luna. I'm tutoring her on astronomy," I said. "I hope you don't mind, but we really should get back to this."
Luna blushed in the face of my wife's initial confusion, but when Twilight Velvet smiled, Luna did too.
"Perfectly understandable, Night. Don't stay up too late," Twilight Velvet said.