Hello to the list,
I'm using 20 minutes exposure poses with my setup (RC16/ME/STL11K/AOL); how should I set the Meridian AM stop offset to optimize (reduce) the "wait for méridian crossing" time?.
I have sometime cases where CCDAP3 waits at least for 17 or even 19 minutes before fliping the mount (due to my 20 min exposure), and so I'm loosing time and good taget position in the sky.
If I set AM stop offset to 15 minutes, doest it mean that the waiting time will be reduce around 5 minutes ? it's a bit confusing for me...
Regards
Eric

Hi Eric,

I would leave the AM stop offset at zero since you have a Paramount. I have my flip delay set to 2 min. and try to pay close attention to when I start a run and how many exposures can be taken before a flip. I will wait longer to get started and sacrifice lower altitude data to make sure I get as much around the meridian as possible. CCD Navigator is a good tool for determining a structured approach to the meridian. Knowing how many focus runs you will need and the time it takes, how long to get the guidstar within its set limits, download times, etc. will all need to be factored in to get you close. I normally don't lose more than 5-10 min around the meridian flip with good planning. Regardless of how much time you set the flip delay to, you can still benefit from a good imaging plan based on your particular parameters. HTH .....

Hi Frank,
Thanks for your message, but this solution is not so good in my case, the weather here change very fast and most of the time I have to lauch CCDAP3 on the fly, I'm never sure to have a clear sky all night long, so loosing time at the begining or at the méridian flip time is a problem when I have only 2 or 3 hours to image.
Eric

The ME can continue to track at least 10 minutes past the méridian, so it could be nice if CCDAP3 adjust the Flip according to the sub exposure time (20 min in my case) and the available timing for fliping the mount.
I don't know how and if it's possible to do it with CCDAP3
This is certainly not a big problem with 5 min sub exposure but it is with long sub exposure, I plane to have 30 min sub exposure in my future location observatory ( sky very dark)
Eric

I believe you can set the offset to negative values to counter this effect. If you're using 20 minute exposures, setting it to -20 will essentially cause CCAP3 to check for flips at the start of exposures rather than the end.

But it means that the mount must be able to track 20 minutes beyond the meridian so be careful not to damage anything.

Thanks Steve, maybe 10 minutes will be safe !
I will try it next time .
Eric

Eric,

I have an idea on how to address this and improve the overall efficiency of meridian usage. I agree it is precious and should not be wasted.

Stay tuned...

Thanks John !!!
Eric