lnspired by [Jupiters moons tracked over 17 days by Chiron]......
l decided to challenge again to seek the light speed by Roemer,s way.
l guess that Roemer maybe used very crude instrument such as 2" or 3" refractor(Gallillean ?).
For this purpose l must follow,track lo's position for some months(like Roemer or unless, its interval ( this case for easy) ...it need physical health...moreover the Jupiter,s position(low) is not good .
lf failed, must wait untill Jupiter rises high.
.....# Using sketch data of lo's move this night l could seek lo's velocity as 12.4km/sec ( 17km/sec on paper...... as l used only my ordinary eyepieces without micrometer etc. )....also lf possible lt'll be desirable to seek myself lo's rotation period even at years or decades interval to find its possibility of change of period.