This may be me not understanding how SharpCap displays coordinates, but when I set a sequence to go to the Pleiades (using its internal lookup), the coordinates it comes up with don't agree with other sources. The manual pretty much says that everything Sharpcap does is in J2000, but does that section actually display JNow, maybe? Or is there an error in the library?
SharpCap is coming up with RA=03:46:60.0,Dec=+24:07:12, while the other sources I can find all say 03:47:24.00, +24:06:59.9 (or 24:07:00) for the J2000 coords. If the Sharpcap displayed coords are in JNow, is that what it sends to the mount, or does it send J2000?
Target coordinates don't agree with other sources
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Re: Target coordinates don't agree with other sources
Hi,
the display on the right hand side will use the same co-ordinate system that your mount uses in it's ASCOM driver (or at least the one it claims to use - there have been cases where particular drivers claim to be J2000 when they are actually JNOW, for instance). Most mount ASCOM drivers actually work in JNOW, so the co-ordinates shown on the right will be JNOW.
All the catalog information that SharpCap uses for object positions is J2000 (as is standard for catalogs). Co-ordinates that are entered manually by the user are also taken to come from a catalog and be J2000.
SharpCap tracks the co-ordinate system for each set of co-ordinates and also the system that is needed for a particular operation, so if you select a target from the catalog, that produces a set of J2000 co-ordinates. If you then ask SharpCap to GOTO that target with a mount that works in JNOW, SharpCap will convert the co-ordinates to JNOW before sending them to the mount.
Hope this helps,
Robin
PS. EQMOD is one of the problems for the co-ordinate system error in an ASCOM driver - by default it works in JNOW (maybe unless you have built a custom pointing model), but there is a dropdown letting you 'choose' the co-ordinate system in the driver. This dropdown *only* changes what is reported to applications like SharpCap - it doesn't actually change the behaviour of the movement of the telescope, so if this is set to J2000 in the EQMOD setup, things go wrong
the display on the right hand side will use the same co-ordinate system that your mount uses in it's ASCOM driver (or at least the one it claims to use - there have been cases where particular drivers claim to be J2000 when they are actually JNOW, for instance). Most mount ASCOM drivers actually work in JNOW, so the co-ordinates shown on the right will be JNOW.
All the catalog information that SharpCap uses for object positions is J2000 (as is standard for catalogs). Co-ordinates that are entered manually by the user are also taken to come from a catalog and be J2000.
SharpCap tracks the co-ordinate system for each set of co-ordinates and also the system that is needed for a particular operation, so if you select a target from the catalog, that produces a set of J2000 co-ordinates. If you then ask SharpCap to GOTO that target with a mount that works in JNOW, SharpCap will convert the co-ordinates to JNOW before sending them to the mount.
Hope this helps,
Robin
PS. EQMOD is one of the problems for the co-ordinate system error in an ASCOM driver - by default it works in JNOW (maybe unless you have built a custom pointing model), but there is a dropdown letting you 'choose' the co-ordinate system in the driver. This dropdown *only* changes what is reported to applications like SharpCap - it doesn't actually change the behaviour of the movement of the telescope, so if this is set to J2000 in the EQMOD setup, things go wrong