2025-07-13, 05:49 PM
Hello,
If you only use the Current bright minor planets download as a source for the minor planets in your database, these are biased. They are selected as the ones that are at opposition that month. This is because the main belt asteroids are at their brightest when they are opposite the sun (opposition). So each month this list makes a very good selection of minor planets to view, because they are at their brightest and higher in the sky at midnight. Because they are all near opposition to the sun, they are naturally in a range of RA in that direction. Right now, Sagittarius is too close to the sun to be highlighted for observation. But as each month passes you will get a set of minor planets in a different direction (RA range).
So lets talk about minor planets. There are far too many of them, so if we were to download all of them automatically, your charts and other functions would slow to a crawl. That, and they need to have their orbits refreshed every 6 months at the most (if you want accurate positions then it should refreshed every every 90 days or so). Given that most people aren't interested in all of those minor planets anyhow, it makes more sense to allow the people who are interested to download a subset of minor planets that meet their interests. For example, Phil downloads near earth asteroids. I tend to get the ones far out in the solar system.
So the first step in your search for minor planets is to download more of them to complete your database. After that, you will be able to use the search function more reliably. To download minor planets, select Minor Planets from the top level Data menu. Click the Download/Import button. There are a variety of ways to limit the number of minor planets that you download, so you should come up with a plan which meets your needs without downloading all of them. Keep in mind that selecting by limiting by magnitude is tricky because the magnitudes change with time.
Let me know if you have more questions.
If you only use the Current bright minor planets download as a source for the minor planets in your database, these are biased. They are selected as the ones that are at opposition that month. This is because the main belt asteroids are at their brightest when they are opposite the sun (opposition). So each month this list makes a very good selection of minor planets to view, because they are at their brightest and higher in the sky at midnight. Because they are all near opposition to the sun, they are naturally in a range of RA in that direction. Right now, Sagittarius is too close to the sun to be highlighted for observation. But as each month passes you will get a set of minor planets in a different direction (RA range).
So lets talk about minor planets. There are far too many of them, so if we were to download all of them automatically, your charts and other functions would slow to a crawl. That, and they need to have their orbits refreshed every 6 months at the most (if you want accurate positions then it should refreshed every every 90 days or so). Given that most people aren't interested in all of those minor planets anyhow, it makes more sense to allow the people who are interested to download a subset of minor planets that meet their interests. For example, Phil downloads near earth asteroids. I tend to get the ones far out in the solar system.
So the first step in your search for minor planets is to download more of them to complete your database. After that, you will be able to use the search function more reliably. To download minor planets, select Minor Planets from the top level Data menu. Click the Download/Import button. There are a variety of ways to limit the number of minor planets that you download, so you should come up with a plan which meets your needs without downloading all of them. Keep in mind that selecting by limiting by magnitude is tricky because the magnitudes change with time.
Let me know if you have more questions.
Clear skies,
Greg
Head Dude at Skyhound
Greg
Head Dude at Skyhound