A real light source, or an artifact? I was taking shots of the 2017 eclipse using my D7200 camera with a 1000 ND filter. As I was going through the pictures after downloading them to a pc, I noticed that there's what appears to be a tiny light source present off to the side of the sun. I have circled it in the picture below. It is also present in the pictures during totality, which I took without the ND filter. 

It doesn't seem like a camera or a lens artifact, since it showed up pretty consistently in different shot configurations, but I did not know that a 300 mm zoom with an 1000 ND filter could capture a light source besides the sun and the moon in full day light. If it is not an artifact, what could be the source of this light?
I agree with the comment by StephenG. This is a stuck pixel. As the link suggests, they are a very common flaw in digital cameras, and not an astronomical feature. 

I think this because it appears, on zooming in, to be a single pixel defect, most light sources even with the best focus, cover more than 1 pixel. The filter you are using is very powerful removing nearly all light. An object would have to be exceptionally bright to be seen through such a filter. If it was real then it would be so bright that when you removed the filter, that one spot would have totally overexposed your image. Since stuck pixels are pretty common, and you might not have noticed them in a picture taken at day, or of a star-field, it is a safe bet that that is the problem.