Comment: not sure what could cause it,

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In reply to comment: thank you for at least looking! (see in situ)

not sure what could cause it,

not sure what could cause it, was hoping someone around here who is knowledgeable on the stereo telescopes would check it out. Visited a few stereohunter chat groups and nobody seems to be talking about it. So maybe it is something normal, like mercury passing in front of one of the telescopes.