How do you receive data from scripts/direct in the RemoteControl API?

[DrRichardDaystrom]

Greetings, again! I would like to call core.getJD() using scripts/direct in the RemoteControl API but I don't understand how to receive the resulting output.

In Python, this looks like ...

import requests

params_direct = {'code': 'core.getJD()'}
response = requests.post(url_stellarium + 'scripts/direct', data = params_direct)

Where does the output get returned? I can't find it anywhere in the response structure (e.g., response.content, response.text, response.raw, etc.). The status_code is 200 so the request appears to be successful.

Am I not calling core.getJD() correctly? I've tried 'return core.getJD()' as the code for scripts/direct but that doesn't seem to work either.

Any insight would be appreciated. I would like to use the functions in the Calendars plugin but I am stuck on how to receive their output.

[10110111]

I don't think you can get back the return values from the code executed this way. To get current JD you can query api/main/status, taking jday item from time section in the output.

[DrRichardDaystrom]

Unfortunately, what I really want to do is use Calendars.getJD() to convert a (known) Gregorian date to its corresponding (unknown) Julian day so that I can POST that to api/main/time/. However, to do so, I need to be able to receive the output from the first to pass as input to the second.

I was hoping to use Stellarium for this, since it seems to have all the required functionality (esp. for more esoteric calendars), rather than having to use separate packages like juliandate.

I appreciate your help - on this and my previous issue. If anyone else knows how to do this, I am all ears.

[10110111]

Why not just pass the value you got to core.setJDay() directly in the same JS code?

[DrRichardDaystrom]

Good idea. That works. As a proof of concept, here is a snippet that gets the JDay and then increments the JDay by one ...

params_direct = {'code': 'JD = core.getJDay(); core.setJDay(JD+1);'}
response = requests.post(url_stellarium + 'scripts/direct', data = params_direct)

I am trying to do as much as possible in Python since I am working on some Jupyter notebooks for students and I want them to be able to inspect all the variables in that environment. However, your initial suggestion of using api/main/status to retrieve the JDay after it has been set in this fashion will work for my purposes.

I'm still working on understanding the calling syntax for Calendars.getJD() but now I can poke at it to see if I can figure it out.

I also have question about how api/main/time interprets the JDay when the timezone is set to LTST but I will bang my head on that a little more before opening up a new question.

Thanks again for all your help. I am very much enjoying playing with the program. Keep up the good work.

[10110111]

how api/main/time interprets the JDay when the timezone is set to LTST

Julian day is timezone-agnostic, see its definition.

[DrRichardDaystrom]

Yes, understood. I guess my issue is that I have to account for the time offset due to longitude when calling api/main/time.

When I call api/main/time with a round JD, like 2110695, it is only solar noon when the longitude is zero.

If I want it to be solar noon at my observation location, I have to add (or subtract) the offset due to the local longitude.

It makes sense that it works that way - there's no such thing as a "local" JD. I'm working on accounting for this right now.

[DrRichardDaystrom]

Ugh, it is harder than that. Round JDs correspond to 12:00:00 UTC - not local solar noon at the prime meridian.

Therefore, if I want to set the time to local solar noon (at the prime meridian or elsewhere), I first need to figure out the UTC time of local solar noon and use that to modify the JD passed to api/main/time (as well as accounting for the time offset due to longitude).

I presume I can use the equation of time to figure this out but I was hoping that I could just use LTST to handle this (and do the longitude correction myself). I know see why that was naive.

If there is an easy way to do this, please let me know.