Sidereal vs Solar vs Lunar Tracking for planets

[Brutha]

Hi All,

I remember seeing some discussions on various forums about the various tracking options on telescopes, and there was some debate about which mode you should use for solar system objects.

I've been wanting to have a play with Jupyter notebooks and Astropy for a while and this seemed a nice opportunity! So, I set myself a little exercise to find out....

I've assumed that for each tracking option, the telescope only tracks in RA, and for sidereal tracking it just keeps the telescope pointed at the same RA/DEC point. For solar and lunar, I've assumed they just increase RA tracking to move at just under a degree a day, and for lunar at around 13 degrees a day.

Next is to work out how much the planets are moving in RA per day for 2021 and 2022, something you can do easily with Astropy.

Then I work out how many hours it would take in each tracking mode for the object to move to the edge of the field of view - I've used my C8SE and an 8mm eyepiece as the model. Of course, this all assumes perfect alignment and tracking

The results are quite interesting (assuming I've done the calculations right, which is by no means guaranteed!): for Mars, it is mostly solar tracking that wins out over the two years - the green line shows "time in view" for solar, red is normal star tracking. Lunar as expected doesn't do anything:

Again for Venus, solar tracking is better (which makes sense, it being closer to the sun) :

However, once you get to Jupiter and further out, sidereal mode takes over:

Anyway, this only shows max possible with perfect alignment and tracking, so my guess is that things are closer in practice!

If anyone is interested, here's the Jupyter notebook:

Solar system tracking speeds.ipynb

Cheers

Brutha