Need help with an astronomy experiment

[Slimchandi]

I am at the moment in the middle of the classic "determining the mass of Jupiter by the motion of the moons" experiment. I have, however ground to a halt at a certain point, and am unsure as how to proceed.

I have a series of photographs of the moons. We have a beautiful 14" in our University obs, but this gives too small a view, so we use a 500mm camera lens on the mount. Seems like a waste to me..

So as you can imagine, Jupiter appears pretty small on these images. The next difficulty comes with measuring the distances moved by the moons. Some pictures appear to have different scales. They were not all taken by myself, they were taken by lots of other people over a period of about a month. This means I have no way of relating the distance traveled in one picture to that of a different scale in another.

The only almost suitable method is to compare the distance of the moon to the diameter of Jupiter. But the small size of the pictures means that if I use a picture viewer, I can never measure to the middle of the moon, only to the edge of a pixel either side.

We've been given a spreadsheet with a SOLVER routine to output more accurate measures of a and P which would be needed for the graph which gives the mass, but until all the images are at the same scale, this is pretty useless. Also, the routine calculates assuming you used millimetres in the measurement, which is pretty silly!

I have about five or six data points for each moon. If anyone could impart any words of wisdom to help me with this, it would calm me down an awful lot, It's due in in three days!

 

[M98Ranger]

First of all, don't panic! Astronomy experiments can be tricky and it's not uncommon to run into roadblocks along the way. It's great that you have access to a 14" telescope and a 500mm camera lens, but I understand your frustration with the small size of the images. One suggestion would be to try using a higher magnification eyepiece on the telescope to get a closer view of Jupiter and the moons. This may help with your measurements.

As for the issue with different scales in the photographs, it's important to have a consistent scale in order to accurately measure the distances moved by the moons. One solution could be to reach out to the individuals who took the photos and ask for their camera settings or the distance from the telescope to the camera. This may help you to calibrate the images and have a consistent scale for your measurements.

Another option could be to use a computer program or software designed for astronomical measurements. These programs often have tools that allow you to calibrate images and measure distances accurately. It may be worth looking into and seeing if your university has any resources or software available for this purpose.

In regards to the spreadsheet with the SOLVER routine, it's unfortunate that it assumes millimeters for the measurements. One solution could be to convert your measurements to millimeters before inputting them into the spreadsheet. Alternatively, you could use a different spreadsheet or program that allows for different units of measurement.

Lastly, don't be afraid to reach out to your professor or classmates for help. They may have some tips or suggestions that could help you with your experiment. And remember, even if your results are not perfect, the process and effort you put into the experiment is still valuable and a learning experience.

Good luck with your experiment and don't stress too much! You got this.