You can do this! In the world of macro/closeup photography, there is this ‘optical law’ that states, “any out of focus spot of light in your overall composition will be rendered as an out focus circular shape, and the closer you focus on a given subject, the larger and more diffused the out of focus light will be.” What might look like the ‘moon’ or ‘sun’ behind this dandelion seedhead is actually an out of focus ‘spot’ of light from a nearby streetlight, (see second photo attached to this post). That background and distant streetlight, at dusk, accounts for the out of focus circular shape you see here and is a direct result of positioning a dandelion seed head in the same direction of the street lamp and then focusing on the seed head with a macro lens.
I can’t stress enough that this single idea is NOT limited to street lights, but actually any spot of light including the sun, as it rises or sets on the horizon, Christmas lights, a candle light, even ‘highlights’ on water from the sun overhead. And again, focus on something close, with the highlight(s) in the compositional background, and you will record out of focus, circular shape(s). You keep shooting!
Nikkor Micro 105mm Lens, F/5.6@1/500 sec. 400 ISO