|Ephemeris Interploation and exposure calculation Visual Basic program (EphInterpolator)
This allows positions to be worked out quickly and easily from an
ephemeris. It was originally intended for when orbital elements were not
readily obtainable (e.g. objects still on the NEOCP) so that accurate
telescope pointing and rate of motion could be achieved.
However, it is now used for all ephemeris work at the telescope (and
also when reducing measures with Astrometrica) to interpolate between
the standard ephemeris intervals.
Three or more ephemeris lines are pasted into the large text box in the
centre of the form, together with the object name at top left. The ephemeris can
then be added as a 'tab' at the top of the form. There is no practical
limit to the number of objects and ephemerides that can be added in this
The required date, hour, minute (and optionally second) is then
entered. Pressing the Calculate button works out the RA, Dec, Speed and
PA of motion using a second order interpolation method having added the
three lines used for the interpolation into the boxes in the upper half
of the form. A separate configuration file allows virtually any
ephemeris format to be used very easily.
A separate 'pad' can be undocked from the main form (visible to the
upper right in the screen shot above) which is set to be an 'always on
top' window for ease of use when getting results into other software.
An exposure calculator at the bottom of the form allows the optimal
length of exposure to be determined and the total number of exposures
It also displays how long half of the images will take to expose. This allows the
telescope to be positioned so that the (fast moving) object passes
centrally through the field of view in the middle of the sequence of