Data: Stellar Quadrant Observations – 4/22/22

With the moon phase nearly third quarter and clear skies, I finally got a chance to do some observing this year.

Since it’s been almost five months since I’ve been out, and because I didn’t have an assistant, last night I headed to the more nearby Broemmelsiek Astronomy Park to set up. Turns out, so were nearly 200 Cub Scouts. So I was barely able to do any actual observing due to frequently stopping to answer questions.

However the real challenge for the observations was the wind. Gusts were $15-20$ mph which is evidently enough to push the quadrant around quite a bit. I nearly fell off the ladder at one point because I was bracing the quadrant against a gust that stopped suddenly! In several other cases, I had to retake measurements because the wind pushed the quadrant and changed the azimuth reading before I was able to read it.

As a result of these two things, I only took $11$ measurements. I certainly could have gone longer, but at the end, I finally figured out why something had felt wrong the whole night: I’d put the azimuth pointer on wrong. In the picture above, you can see it’s pointed to the right when looking at the front of the quadrant. It should be pointing left!

This result isn’t catastrophic. It just means I was looking down the wrong side of the quadrant arm to aim at objects and all the altitude reading I took needed to be subtracted from $90º$.

Observations were two bright stars in Orion and then a few stars in Gemini which is well under-sampled in my data so far. Only a few of the stars in that constellation have I observed more than once or twice now and there’s still several notable stars I’m missing all together!

In processing the data, things looked reasonably good. However, I quickly noticed that all of the azimuth readings were high by $\approx 1.5º$, likely due to the wind pushing things while I was trying to get aligned on north. As such, I had to make this minor correction to the azimuth as well. But once done, the data looked quite good.

As always, the data can be found in the Google Sheet.