sync to catalog target hazard

[PeterAB]

Hi,

I have been using 4.2.15098.0 mostly without issues.

One issue is with the "sync to catalog target" new feature. The issue arises from clumsy mouse work at night on my part. For example, my GEM mount is set up pointing west. I intended to use "goto catalog target" to flip the mount and slew point east. Instead I missed clicked and did a "sync to target". It appears to me like this caused my mount (Celestron AVX) to lose track of which side of the tripod it was on. Going back and doing the intended "goto catalog target" to the same east object led to a tripod crash.

I'm not sure that I understand "sync to catalog target" completely. I have not found documentation. It appears that a sync is done to the targets coordinates unconditionally without sanity checks. At any rate, I'm thinking sync's need to be done with caution because some mounts will become confused about which side of the tripod they are on.

Please advise if I am misunderstanding the "sync to catalog target" feature. In the meantime I will be careful not to use this feature by mistake.

Thanks, Peter

[admin]

Hi Peter,

thanks for reporting - the aim of the 'Sync to target' tool is to tell the mount "you are pointing at <X> right now" - this is most useful for some types of mount that don't remember their position on power on, meaning that the mount is initially 'lost' until you tell it what it is pointing at.

If you inadvertently use this tool when you meant to use the equivalent 'Goto' tool, the mount should think it is already pointing at the target, so in some circumstances a subsequent GOTO would do nothing. However, if the sync causes the mount to be confused about the side of pier, it could end up deciding it needs to flip to hit the target, and then all sorts of strange things could happen as the mount is confused about where it actually is...

I will add a safety check based on the distance between the current and target positions to this tool - probably 5 degrees. If the offset is bigger than that then it will prompt you to confirm, which then means that the opportunity for serious problems is largely removed.

cheers,

Robin

[PeterAB]

Hi Robin,

Thanks, that would have caught my error. Now that I know that "sync to target" is in the menu and what it does, I can take care not to use it by mistake.

The sanity check will also catch the case where "sync to target" is intended, but, a wrong catalog number is entered. At any rate, there are many ways to confuse an EQ mount to be aware of. I don't think software can catch them all in the absence of encoders above the clutches.

Peter