Re: APPM data meaning


Ray Gralak
 

Hi Sam,

However it would be interesting to know what should be expected for a mount like AP1100 class. For
instance, Is an RMS of 8 sec with a range 20 sec a good result for such a mount ?
Besides polar alignment, it's not the mount contributing to the pointing terms, but the telescope that your mount is carrying. So, you can't really state an expected RMS number for the mount alone, as two different telescopes can produce completely different pointing terms.

However, in general, refractors with solid connections and no dangling cables to get caught will produce the best results. Telescopes with mirrors that can randomly tilt/move, like SCTs, will usually have the worst performance.

-Ray

-----Original Message-----
From: main@ap-gto.groups.io [mailto:main@ap-gto.groups.io] On Behalf Of Sam
Sent: Saturday, January 22, 2022 5:58 AM
To: main@ap-gto.groups.io
Subject: Re: [ap-gto] APPM data meaning

Hi

Someone pointed out that the APCC help files have some descriptions on the meaning of certain APPM
model variables (see below).
However it would be interesting to know what should be expected for a mount like AP1100 class. For
instance, Is an RMS of 8 sec with a range 20 sec a good result for such a mount ?

I believe that these questions would come to mind after someone performs a pointing model - so it would be
appreciated if anyone can share their experience. As well, It would also be valuable if anyone knows of any
further explanations or documents on this topic.

Thanks
Sam


In the upper left section is the Model Properties Group Box. These are are the most important model
terms. You can check/uncheck them to see how well the model fits the data by looking at how the
average and maximum errors (and graph points) change. Usually you will want all terms selected.
NOTE: in the terms the Index Dec Error, Non-perp (Dec. OTA), and Flex Cantilever Axis usually have
inverted signs between the axes. Also, the quality of the Polar alignment numbers can be judged by
how well they match in each of the dual models. If they are close you can be confident that the
numbers are modeled well (the Azimuth is most important).
The last large section in the upper right, the table, simple shows the raw data points collected for the model.
You can uncheck specific data points if they seem to be bad data points.

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