How can I get prevent ghost sun images when shooting with a solar filter?

Question

I am getting ready to shoot the upcoming solar eclipse. During my practice runs, I am getting either single or multiple reflections of the sun. Using Star Adventurer tracking mount, Canon 500D with an adapted Olympus fixed 400mm F5.6 (old, from the 70's), solar filter and UV filter on lens.

What can I do to get rid of this without doing it in post processing. I want them to be clean straight off the card. I really hoping for big corona pics that will not need much processing. (shooting both RAW & jpg)

I think it's the lens & I need a reason to get another anyway. Looking a either buying a 70-80mm APO prime telescope or some new lens (maybe a Canon L type zoom?).

Answer 1

Don't use the UV filter.

Not only is it completely useless while using an actual solar filter, it is actively hurting your image by creating reflections. Even if it is the highest-quality UV filter with multi-coating, the strong and contrasty image of the sun will bounce off the lens (usually the front element), to the filter's flat surface, and back to the lens, perhaps multiple times before the reflections are too dim to be seen.

Also, your image looks overexposed. The center of the sun is clearly clipped, meaning it's exposed too brightly. Bring down the exposure a stop or two, and you'll see the ghost images reduced substantially as well.

Answer 2

Dump the UV filter!

It is contributing to the reflections. It is probably the primary cause of them.

For more regarding how this happens, please see:
is it normal to get significant lens flare with a 50mm f/1.8 prime lens?
Does high reflectiveness of digital sensor lead to poor lens performance?
What is the blue circle in this moon image?

Expose Properly

Your image is overexposed. Details on the surface of the sun are washed out. Your camera is trying to balance exposure between the incredibly bright sun and the blackness that surrounds it. Left to themselves, cameras don't like to leave large parts of the frames black and will try to raise exposure so that everything averages out to a mid-tone grey. You need to take control and set exposure manually so that the details of the sun, such as sunspots, are visible in the image.

For visual examples of how different exposure levels of the exact same scene can contribute to flare and reflections, especially when shooting astronomical scenes with celestial objects of varying brightness, please see this answer to Can you photograph the milky way with a full moon out?