Rotator

[DaveG64]

Hi guys I’m considering buying a motorised rotator for my rig , I’ve got a starfield gear 80 which has a manual rotator that is attached to the scope does this need to be disconnected to allow the motorised rotator to be added . Sorry if I’m asking really basic questions but I don’t want to make any mistakes especially if it’s going to cost me more money . Anyway clear skies people 

[ollypenrice]

I've no experience of motorized rotators but find myself wondering why you might want one. I only ever shoot with the chip sides parallel with RA and Dec, so that's a choice between landscape and portrait.  Why do I do this?  Because, if I want to go back at some later stage and add more data, I can do so very easily.  I discovered that reproducing an arbitrary angle is a bit of a nightmare. I find that this hardly ever has any consequences for framing and it avoids complications with flats and makes troubleshooting easier. (Guiding, tilt adjustment, etc.)

Olly

[Louis D]

@DaveG64 Are you asking about a field derotator?  They're normally used with alt-az mounted scopes.  If you're using a RA-Dec aligned mount, you shouldn't need one.

The built-in rotator is there for framing purposes.  If you're alt-az mounted, it could still be used for this purpose, with the derotator following it somewhere in the rest of the focuser chain.

[ollypenrice]

1 hour ago, Louis D said:

@DaveG64 Are you asking about a field derotator?  They're normally used with alt-az mounted scopes.  If you're using a RA-Dec aligned mount, you shouldn't need one.

The built-in rotator is there for framing purposes.  If you're alt-az mounted, it could still be used for this purpose, with the derotator following it somewhere in the rest of the focuser chain.

Ah yes, perhaps the OP is talking about a field de-rotator for long exposure alt-az imaging? I would just say 'Don't.' Don't throw money at de-rotators or wedges, just buy a proper equatorial mount. I'm not sure that there is any guiding sytem for alt-az de-rotated mounts, at least for amateurs.

Olly