Re: Alternatives to Drift Alignment?

On Mon, 1 Dec 2003 17:15:09 +0000 (UTC), [EMAIL PROTECTED] (Brian Tung) wrote:

>Chris L Peterson wrote:
>> > And I don't think that 5'
>> > accuracy is enough for any decent image scale and exposure length.
>> 
>> The majority of imagers seem to work with around 3 arcsecond seeing
>> (which is more an issue than the actual pixel scale) and take
>> subexposures of 10-30 minutes. I don't see a problem with a 5 arcsecond
>> alignment error...
>
>Do you mean 5 arcsecond or 5 arcminute?  You wrote 5', which is 5
>arcminute.  Getting it within 5 arcseconds does seem pretty good to me.

Sorry, I meant 5 arcminute- just confused myself using "arcsecond" earlier in
the same sentence <g>. Field rotation will be negligible for typical exposure
times if the polar alignment error is only 5 arcminutes (Andrea used the symbol,
and it is her assertion I am disagreeing with).

_________________________________________________

Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com