coordinates. J2000 or JNOW for sequence planner ?

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TimHaymes
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Joined: Sun May 28, 2017 8:11 am

coordinates. J2000 or JNOW for sequence planner ?

#1

Post by TimHaymes »

Hi,
I have my system as JNOW for pointing. As i understand, the plate solve uses J2000 and this is converted to JNOW - im fine with this.
Which coordinate system is expected by the sequence planner and advance editor, where the coordinates can be entered [Move mount to] ?

For example, i have a list of topocentric J2000 coordinates for a NEA. If i put these coords into a sequence to move the scope to the target, should i expect this to work ? My plan is to goto a star nearby, solve and sync, then use the script to move to the asteroid's position.

Cheers Tim
(near Abingdon)
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Re: coordinates. J2000 or JNOW for sequence planner ?

#2

Post by admin »

Hi Tim,

J2000 is what you want to use - SharpCap co-ordinates supplied to the sequence planner and tools like the 'Goto Target/Co-ordinates' tool to be in J2000 form. Conversions are done automatically when required - for instance when sending the GOTO co-ordinates to the mount, SharpCap will realise that it needs to convert to JNOW from J2000.

If your field of view is reasonable, then just tell SharpCap to goto the co-ordinates of the asteroid, then solve+sync - that should put the asteroid co-ordinates in the center of the frame as long as there are enough background stars for the plate solving.

Looking at the local weather forecast, you might have a chance to test on Friday night (which may be the only one for a week or so). Typically, that's the night that I'll be away staying in Kettering in prep for the Practical Astronomy Show on Saturday. I think the hotel will be full of astronomers bemoaning the loss of the one clear night this week!

cheers,

Robin
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