Lat Long Question

[ultramol]

I have my home position for my mount  bang on in latitude and longtitude. My question is this , how far could I move my mount before I need to recalc my settings ?. The reason I ask is my son lives about a mile and a half from me and I am thinking of taking my scope there sometimes as it has a better view. I have C de C which I use for goto in finding my targets and just wondered if anyone knew a safe distance before having to change things....Thanks in advance....Geoff

[JG777]

Not sure what you are using but Celestron seem to quote Lat/Long being good for up to 50 miles. certainly for visual although imaging might need a recalculation.

[jambouk]

You'll be fine with a few miles. You'd be fine with one hundred miles

 

James

 

[ultramol]

Thanks Guys, That is very helpful, much appreciated

[perfrej]

I'd say the need to recalc for a move depends on your expected precision. You have a mount that can perform pretty well with EQMOD, so I would definitely recalc just to be sure. I use 10Micron mounts, and they have rediculous precision; precision that is somewhat wasted if you're not spot on with your location (and altitude).

 

/p

[Ruud]

One degree is about 111 km.

1.5 miles is about 2.4 km.

You'd be about 0.02 degrees off if you used your home settings. That's not much.

EDIT: sorry about your binoculars being stolen.

[jambouk]

The issue is what would be off by 0.02 degrees?

If using just the handset, the longitude is used in conjunction with the date/time (and latitude) bu the "mount" to just make suggestions of where it thinks stars should be in the sky to help with the star alignment process. It is the star alignment process itself which marries the actual positions of the stars in the sky with the map in the mounts memory; inputting totally wrong latitude and longitude data makes no difference to how accurate the subsequent GOTO accuracy is. Tracking is mostly down to polar alignment.

James

 

[Ruud]

6 minutes ago, jambouk said:

The issue is what would be off by 0.02 degrees?

If using just the handset, the longitude is used in conjunction with the date/time (and latitude) bu the "mount" to just make suggestions of where it thinks stars should be in the sky to help with the star alignment process. It is the star alignment process itself which marries the actual positions of the stars in the sky with the map in the mounts memory; inputting totally wrong latitude and longitude data makes no difference to how accurate the subsequent GOTO accuracy is. Tracking is mostly down to polar alignment.

James

 

The vertical would be off by that amount. 0.2 degrees seems negligible to me. I have no idea what would happen if it were 20 degrees off though.

[ultramol]

Thanks for the very interesting and comprehensive answers to my question. They are very much appreciated....Geoff

[astrofox]

Not far enough to worry about.