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  • Custom objects using J2000.0 coordinates

jNow and j2000 are not the same coordinate format?

I've been using j2000 coords for manually inputting comets that aren't in the S50 comet database.

    sthscan the format is the same but the values will be slightly different due to the precession of the Earth’s poles. The change in coordinate values from 25 years ago (J2000) to now (J2025) for custom objects may make enough of a difference that your object won’t be centered in your image. I use SkySafari to find Jnow coordinates (currently showing as J2025) for inputting my custom object coordinates but it would be so much simpler to use J2000 as you’ve been doing since that’s the usual epoch you’ll see in most catalogs or online sources of coordinates for things like comets. Hoping ZWO implements my suggestion so you can pick which epoch your coordinates are tied to. Hope that helps!

        sthscan Like the names imply, they are two different things. Jnow are RA/Dec coordinates based on the current position of the Earth's axis, J2000 coordinates are based on where the North Pole was 25 years ago. Both are useful, Jnow for precisely pointing to a target right now, J2000 as a common reference for images of the same object taken at different times. There is a difference of about 8 arc minutes between the two right now.

          I have no problem with entering coordinates into Custom. But for some entries I fat fingered the RA and DEC and cannot see how to delete or edit them. Is it possible to edit or delete Custom entered objects?

            You cannot edit an entry, that would be too useful. You have to delete it (swipe it left, which is not obvious) and re-enter it.

            Chiefland go to "My favorires" "customize" swipe from right to left to get the delete symbol.

              7 days later

              LA3QMA THANK YOU! I would have never found this and greatly appreciate you providing me with the answer I was hoping to find.

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