I have a picture of comet Hale-Bopp taken on April 4, 1997. In the picture, the comet is (almost) on the line between Almach and M34.
This does not fit in SN where it was on the line on April 3. Not at all on April 4.
Could it be because SN now uses current orbital data for the comet, which I then "rewind" 28 years backwards? Where can I find orbital data published in the spring of 1997?
Best regards,
Niels