Re: Pier crash while #APPM paused -


Sébastien Doré
 

That's good information indeed.

In my case I really don't think it has something to do with my computer performance as when I use ASTAP directly I am able to solve almost anything in less than 2 seconds.

Also since I use an SCT at more than 2000mm FL and a 300mm FL refractor, I have been using all available database (V17, G17, H17 an H18) from the start, so I don't think it's related to that either. Unless I should remove the oldest V17 and G17 and only use the H1x ? I always have the H18 selected in ASTAP but sometimes it seem to choose H17 first anyway and fall back to H18 if it doesn't find a solution.

Han has written an extensive section in the ASTAP documentation if one really wants to get into the details around which database is most appropriate. You can find it here: http://www.hnsky.org/astap.htm#database_usability

Thanks for the link, I think I already went through it rapidly at some point. Will try to get to the finest details to see if I can find something interesting that could help.

 In NINA, we'll extract any WARNING or ERROR keyword from the .wcs file and bubble it up to the user as a notification.
That's definitely going to be useful to help troubleshoot such issues.

Anyway, thanks for the good tips guys! I guess I'll wait for the real stars to get unclouded and see how it goes in real conditions to really assess what the issue might be / or if it still exists, as Linwood experienced.

Sébastien



De : main@ap-gto.groups.io <main@ap-gto.groups.io> de la part de Dale Ghent <daleg@...>
Envoyé : 23 août 2021 10:05
À : main@ap-gto.groups.io <main@ap-gto.groups.io>
Objet : Re: [ap-gto] Pier crash while #APPM paused -
 

Which database you need to use when operating in a realm that can overlap the H17 and H18 ones is a big "it depends". FOVs that are larger than 1 degree will /likely/ be ok with V17 or H17.

It will not only depend on your fov, but also your exposure time, which is related to your focal ratio, and there are other influences such as if one bins their plate solve exposures (which is not a bad universal suggestion.) This is why my advice is to use H18 if your focal length is > 1m. I prefer to make this simple rule instead of playing games with 5 different parameters to answer what is a very simple question. The only casualty is 500MB extra disk space.

Han has written an extensive section in the ASTAP documentation if one really wants to get into the details around which database is most appropriate. You can find it here: http://www.hnsky.org/astap.htm#database_usability



> On Aug 23, 2021, at 08:58, Andrea Lucchetti <andlucchett@...> wrote:
>
> Thank you Dale, I am going to try Nina soon and this is good info.
> One thing I don’t get, I wonder what could be the difference using plate solve images that are 4 seconds and binning 2x2. If the difference between H17 and H18 is the magnitude it shouldn’t make much difference.
> By the way my fov will be bigger than 1 deg and will install the H18 as suggested.
> Thank you,
> Andrea
> Il giorno lun 23 ago 2021 alle 14:46 Dale Ghent <daleg@...> ha scritto:
>
>
> Coming from supporting ASTAP with NINA users, the #1 pitfall we see is that the wrong (or inappropriate, to use another word) star database is used.
>
> Han supplies a bunch of different star databases that ASTAP can use, the two main ones being the H17 and H18 databases. The number refers to the limiting magnitude of the stars present in the database. This of course means that the H17 database is a subset of the H18 one. We always recommend that the H18 database be used when the focal length is > 1m, as that starts getting into a constricted-enough FOV where the H17 database might not define enough stars for ASTAP to find a solution with.
>
> The difference between the two databases is size - the H18 db is 1GB and H17 is half that size, so one can roll with the H18 database even if they don't really /need/ those extra stars if they don't mind burning the 500MB extra drive space for it.
>
> ASTAP will insert any warnings or errors it encountered into the .wcs file it generates for each solve attempt. It'll do this with a "WARNING" or "ERROR" FITS keyword, with the fault message being a string. If ASTAP complains about finding an insufficient number of stars and you have the H17 db installed, then it's quite likely that the user will need the H18 db instead. In NINA, we'll extract any WARNING or ERROR keyword from the .wcs file and bubble it up to the user as a notification.


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