Re: Adjust CP4 Clock Frequency
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Craig, where are you observing that seeing allows you to keep a 1 arcsecond accuracy on a single pixel for several hours?
Here on Mauna Kea we frequently get sub-arcsecond seeing but we can't even keep the mighty Kecks to that standard of precision for hours at a time. The seeing, even at the summit of Mauna Kea, just simply doesn't allow it.
I frequently (with my personal AP mounts) do photometric and millisecond GPS-timing measurements of stellar occultations and using nearby stars for photometric calibration of each FITS frame. My AP mounts don't have abs encoders and I don't even bother to autoguide.
What kind of OTA are you using for your measurements? I see lots of gravitational sag in my cheaper APO refractors and compound OTA's. Especially in a 20" RCOS truss OTA that I use. At least the sag is predictable and is directly correlated to the OTA's orientation to gravity.
Waikoloa, HI 96738
On Wed, May 6, 2020, 11:32 AM Craig Young <craig.young.m8@...> wrote:
The ATrack design is very similar to DONUTS, introduced in 2013: https://www.jstor.org/stable/10.1086/670940?seq=1#metadata_info_tab_contents