1. When will Eclipses occur ?
Working it out for yourself …

2. Using Published Predictions
You could use the predictions on the BAA VSS web pages
These are very useful if you want to know which stars will be in eclipse tonight
The SAC elements, rather than the GCVS elements, have been used for these predictions because the SAC elements are more up to date

3. Predictions on BAA VSS web pages

4. Working it out yourself …
Sometimes, however, you will want a list of predictions for an individual star
For TV Cas, the SAC elements are :
Epoch = (24)
Period = days
Enter these in a spreadsheet and convert them to a date and time

5. C4 = MOD(A4+0.5,1) B4 = A4+0.5-C

6. Setting the date & time format
However this results in a day count (since 1/1/1900) and a decimal fraction of a day
Click on each cell in turn and select Cells from the Format drop down menu and convert them to the required format
e.g. for the Date cell ….

7. Display the date as dd/mm/yyyy

8. Predicting later eclipses
Predictions for later dates are calculated by adding multiples of the period
1980 was many orbits ago, so this first calculation adds 1000 orbital periods

9. A5 = A

10. Exploiting Excel to repeat calculations
Later predictions can be generated by selecting cell A5, clicking on its bottom right hand corner and dragging the mouse down column A …

11. Repeat the calculation for A6-A9

12. … and for columns B and C …

13. Add smaller multiples of the period after you reach the current date …

14. Avoiding Bias
In practice, its best not to know the predicted time of mid eclipse to the nearest minute
This can be aided by leaving column C as a decimal fraction
Then multiplying this by 24 and using Format/Cells/Number to give the time to the nearest hour in column D….

15. D4 = C4*24