Sky Model in SW

[kirkster501]

Hey all, I suppose this is also relevant for observing too but thought I'd post in imaging.

When you guys create your sky model in your software (I use EQmod with NEQ6)  if the clutches are ever loosened is that sky model then defunct  and has to be redone?  I think yes but just checking...

Also, the Sky model with different scopes will be slightly different.  I have done one for my TEC140 and one for my C925  When you swap scopes and load in the Sky model for that scope from a time before, how accurate is this after a scope swap?   I have yet to do this but was thinking about this during a long drive today....!

Thanks!

[steppenwolf]

Quote

if the clutches are ever loosened is that sky model then defunct  and has to be redone?  I think yes but just checking...

In theory, you could easily end up using a different part of the worm gear as your 'start' point so the model would be invalid as any machining errors originally accounted for will now be displaced.

Quote

Also, the Sky model with different scopes will be slightly different.  I have done one for my TEC140 and one for my C925  When you swap scopes and load in the Sky model for that scope from a time before, how accurate is this after a scope swap?  

Any change will invalidate the sky model to some extent, even removing the scope and then re-fitting it as there is no guarantee that the dovetail will seat in exactly the same manner as before.

For imaging purposes where you tend to stick on just one object per session, I find plate-solving at each slew or adjustment to be the best method of guaranteeing accurate positioning. In any event, I re-do my sky model after ANY change just to make sure because a displaced sky model is probably as bad as no sky model at all.

[kirkster501]

Great stuff Steve. You confirmed my thoughts.  It is nice to have them confirmed by one of the experts.  

I've got my MESU ordered.  All the gear and no idea eh?  

[chrisshillito]

EQMOD provides the capability to resync your encoders to a park position and this allows you to get your sky model and mount back in sync. The trick however is to come up with some means to accurately put your mount in that park position (with the NEQ6 you can remove the worm end covers and use the flat on the end as a position indicator that you align to some mark on the housing) . Alternatively you could slip EQMOD into "dialog mode" and sync on a star - this will shift the model to align on the star (you then just put it back to append on sync if you want to further modify the model).

Chris.

 

[steppenwolf]

Quote

I've got my MESU ordered.  All the gear and no idea eh?

It was for that very reason that I dived in as I read elsewhere that you had one on order - although the 'gear' comments don't apply, of course! However, it is interesting that Chris has described a method of re-syncing the EQ6.