“Tracking works through pattern recognition, right?” his wife asked.
“Exactly. But where it’s stuck, nothing has changed. It shouldn’t get stuck.”
“What do you mean, nothing has changed?”
“Nothing has been added. I was hoping that I might have found a new comet by chance. I’d even thought of a name.”
“Too bad. I would have been happy if a new comet had my name on it. Preferably a great comet that predicted lots of disaster for people. Later it would have been called ‘2026, the year Franziska announced death to humanity’, or something.”
“I guess that’s not going to work out.”
“Someday you’ll find a comet. I know you will. But the fact that nothing has been added is one thing. Pattern recognition might also fail if something is missing that should be there—or is that a stupid idea?”
Peter straightened up despite the pain in his back. “Of course, that would be a possibility! Thank you, Franziska. I’ll check right away to see if anything is missing from the telescope images.”
“Later. Now, we’ll have breakfast. The rolls are still warm.”
They usually went for a long walk following their Sunday breakfast. After three or four hours, they would stop for lunch at a pleasant inn. But Franziska had given him an idea that he would like to check out right away. He chewed on the rest of his roll but didn’t dare tell her.
“What do you say we meet at Rixinger’s at one o’clock?” asked Franziska suddenly.
The Rixinger was an inn with traditional German cuisine. In the summer, you could enjoy sitting outside under old chestnut trees. It was located in a neighboring village, about 20 kilometers as the crow flies.
“I, yes, that’s a great idea,” he replied.
“Then you can take your time trying to figure out why the tracking isn’t working.”
“Exactly. And you’re not mad?”
“No. I’m going for a ride on my bike. You can join me there by car. And for the tradeoff, I get the car for the way back.”
Peter smiled. On the way back, it was uphill almost all the way. That was why Franziska didn’t really like biking home from the Rixinger.
“Agreed. But what about the snow?” he asked.
“Just look at it. It’s not staying around. The sun is supposed to come out later, too, my weather app said.”
“See you!” called Franziska from the hallway.
“Have a good trip!”
“And don’t forget, you have to leave at twenty minutes before one. The Rixinger closes its kitchen at half past one!”
Yes, that was typical for these village inns, and his mouth was watering for a schnitzel. Peter winced when the door slammed shut, but it meant he was alone. He rolled his office chair closer to the desk, pushed the pile of classwork aside, and flipped open the notebook.
What was the best way for him to verify the tracking algorithm? He brought up the last image he had taken with his telescope, which should show the area where the algorithm failed. At first glance, there was nothing special to notice. So he needed comparison material.
Peter moved his chair a little closer to the desk. Franziska would scold him for sitting too close to the screen, but he didn’t need glasses this way. He started a program that could retrieve star charts from all available databases. He always enjoyed his program icon, a stylized sun with many rays, displayed when he switched through the running programs.
He switched to the image server of ESO, the European Southern Observatory. The program asked him for the galactic coordinates and the size of the desired image section, data which he had to look up in the telescope’s tracking app. He entered the data and clicked on ‘Download,’ and shortly thereafter, an orange image full of stars appeared in the program window. To be able to compare better, he switched to a grayscale display.
Good. Now he had the photo from his telescope on the screen on the left, and on the right he could see what the expensive instrument of the European Southern Observatory had observed in the sky in the same region at some other time. The area contained thousands of stars. When Peter squinted, he could see at least ten times as many stars on the right as on the left. He let the program lay a coordinate grid over it and immediately noticed the first problem, that the image coming out of his telescope was oriented differently. He rotated it by about 30 degrees, and it matched better.
But there were still far too many stars in the ESO photo. In the image viewer, he switched from the preset logarithmic to a linear scale. The faintest stars, which his hobby telescope could not see, faded into the background. Much better! Now he only needed to systematically search through both images. He arranged them side by side on the screen. His eyes wandered from left to right, left to right, again and again, but this soon became exhausting. His head ached after barely five minutes. Surely there had to be a better way?
As Peter moved a little away from his desk, his gaze fell on the class assignments. Sometimes he evaluated them with the help of a stencil. What if he made himself a star stencil? First he adjusted the scale of the two pictures more precisely. Then he increased the contrast in the photo from his telescope. The stars became even brighter, while the background turned black.
He got a foil from his office cabinet, put it in the printer, and printed the picture on the foil. The stencil was translucent wherever there was a bright star in the image. He put it over the screen but couldn’t see anything. Sure, if a black spot shines through, he couldn’t see it. He changed the color representation of the ESO data to redscale. Much better.
But again, nothing stood out. He slapped his forehead with the palm of his hand. Of course! He’d done it the wrong way around. He had to
