Moving from ASCOM to INDI, I just came across the question that which epoch is used in coordinate in both KStars(Ekos) and INDI ? As I could not find any epoch setting.

I just solved an image using astrometry.net on Ekos and on my local machine, which gave me different result:

Local machine: Field center: (RA H:M:S, Dec D:M:S) = (19:30:46.047, +27:57:05.571).

Ekos: Solution coordinates: RA (19h 31m 28s) DEC ( 27° 59' 26")

I am sure that the astrometry.net uses J2000 coordinate ( See here ), from the above test result, I guess both KStars(Ekos) and INDI use something other. Is it JNOW ?


If both KStars(Ekos) and INDI use JNOW, is there any way to switch to J2000?

Yes KStars operates using JNOW because that represents the actual current position of the object for pointing your telescope etc. If you want to know the J2000 coordinates of an object, you can right click the object and get the details dialog about that object. Both JNOW and J2000 positions will be displayed. If you want to type in J2000 coordinates to goto an object that is not in the database, that is possible too. All you need to do is go to the Data menu and click on "Manually Add a deep sky object." Also if you use the observation planner, it will display J2000 coordinates in the object list. Everything else uses JNOW to my knowledge

Thanks,

Rob

Thanks for the reply. I wonder why KStars and INDI use JNOW as default? Since J2000 is more convenient to use, every time I manually enter a coordinate to slew the mount, I have to convert it from J2000 to JNOW first. Is there any setting for choosing default coordinate type?

JNow is where the object currently is and is the most accurate representation of what the mount and software need to use to properly find it. You dont actually want the software to not precess the sky with respect to the current date or the software will get further and further off from the real position. But based on what you said, i think your main issue is in the mount box panel where you enter the coordinates to slew the telescope to (or some control like that one), you just want to be able to enter coordinates to slew your telescope to in J2000, am I correct?

Yes you’re right. I just want to enter a J2000 coordinate from the mount control menu or something similar. As I usually acquire target position from online database such as VizieR, which gives J2000 coordinate. Also it will be nice if there is an option to choose which kind of coordinates to be displayed in INDI (I mean the program still uses JNOW for computation, but provides 2 display options).