Last night was the much hyped Great Conjunction of Jupiter and Saturn. I was asked if this had any meaning for my project. It really doesn’t have any special astronomical meaning, but it was fun to look at through a telescope. However, I decided that this would be an interesting stress test for the quadrant. After all, Jupiter and Saturn were only $6$ minutes of arc apart. This is a single division on the quadrant’s scale. So could I actually tell them apart?<\/p>\n
To find out, I took the quadrant out to Broemmelsiek. Knowing that it was going to be crowded, I decided to go in full garb, and indeed, it prompted several people to stop by and ask questions. So if you’re one of the people I handed a card out to, welcome!<\/p>\n
Unfortunately, I forgot to bring the azimuth ring with me, so I’ll have to look up the azimuth in Stellarium which is cheating, but the best I can do since by the time I got home to grab it, the event would have been nearly over, even if I didn’t come back out.<\/p>\n
However, this does mean that I essentially eliminated the azimuth as a variable so any error must be the result of errors in the altitude or the sidereal time. With sidereal time, I take this number off an app on my phone so it’s highly reliable. However, because I don’t suspect that period clocks could be accurate to the second, I round down to the nearest minute since it takes me a bit to clamp the quadrant arm and climb down the ladder. However, even $30$ seconds here can be a notable difference in the right ascension: about $0.15\u00ba$. So really, I think this potential error entirely swamps the potential for determining if the quadrant can read down to $0.10\u00ba$ ($6$ arcminutes) if it could.<\/p>\n
That being said, I was able to take $4$ measurements of both Jupiter and Saturn before they were too low to point the quadrant at and the overall error for both was right about $0.33\u00ba$ which is clearly larger than any potential error due to the sidereal time. So clearly, from a few measurements, the quadrant is not that precise. At least, from a few measurements. As we’ve seen from the larger averages, it gets closer.<\/p>\n
I think there’s definitely some improvements to be made with the sights which would help, so that’s going to be on my project list for the coming year!<\/p>\n
If you’re looking for some historical information on the great conjunction, the Renaissance Mathematics blog has a great post<\/a>.<\/p>\n","protected":false},"excerpt":{"rendered":" Last night was the much hyped Great Conjunction of Jupiter and Saturn. I was asked if this had any meaning for my project. It really doesn’t have any special astronomical meaning, but it was fun to look at through a telescope. However, I decided that this would be an interesting stress test for the quadrant. … <\/p>\n