Photometric observation of asteroids is one of the most interesting activities for amateurs. To analyse the rotation of an asteroid it is necessary to follow it across the sky all night long, making continuous measurements, and to repeat this for several nights, depending on its rotation period. This is a resource-intensive activity for professional observatories, which cannot devote themselves exclusively to one stellar object, so amateurs have an opportunity to contribute to science and collaborate with professionals.
An asteroid observing session can last many hours, as long as the asteroid is at a suitable altitude (e.g. >30°), and our camera will record what is happening in the star field through which the asteroid is moving as we track it.
Amateur astronomers are increasingly using the Tycho software developed by Daniel Parrott (https://www.tycho-tracker.com/) to analyse asteroid trajectories and perform quality photometry. Of course it is not the only software, and the classic software for this kind of measurements is Fotodif developed by Julio Castellano (http://astrosurf.com/orodeno/fotodif/index.htm).
The Tycho software allows you to locate asteroids other than the one you are tracking, and shows you the traces with their name. When I do the analysis of the data captured one night, I like to analyse other asteroids in the field, see their magnitude and sometimes, if they have the right brightness, also get their light curve.
In this case the asteroid observed was (6100) Kunitomoikkansai with a magnitude around 16, more or less at the limit of amateur telescopes. But I was surprised to see in the field other asteriods of magnitude up to 20 that were possible to see moving during the night.