Re: Interesting Behavior with APCC Pro and Pegasus Astro UPBv2

Ray Gralak

Hi Wade,

You might want to check the PNT file to see if the temperatures were recorded in degrees C instead of degrees F. There will be no obvious sign of the wrong scale except that the values might look unreasonable for that night.

If they were recorded in F, then you would need to convert them to C, or do another APPM run.


-----Original Message-----
From: [] On Behalf Of W Hilmo
Sent: Wednesday, April 21, 2021 1:12 PM
Subject: Re: [ap-gto] Interesting Behavior with APCC Pro and Pegasus Astro UPBv2

I wanted to revisit this topic with an update.

I reached out to Pegasus Astro, and they are aware of the issue with unit in the temperature value. At this
time, they can’t fix it because SGP apparently has a dependency on the current behavior. They are reaching
out to the SGP folks to see if they can coordinate a proper fix.

Regarding my unguided imaging results, I switched the units back to metric in the Pegasus Astro software, and
that fixed the incorrect temperature in APCC Pro. I ran unguided again last night, and it was a slight
improvement over the previous unguided session, but still wasn’t satisfactory. I forgot to note yesterday that I
have my camera oriented so that declination in up/down in the frame. The elongation is diagonal, and flips 90
degrees after the meridian flip. That means that the components of drift are not isolated to either axis in

So I went back to take a closer look at the model in APCC. I played with setting and clearing different terms to
see the effect on the model. When I was doing this, I noticed that the “Correct for Refraction” checkbox was
cleared. When I checked that box, the east and west scatter plots dropped from 53.35 and 50.20 arc seconds,
respectively, to 9.42 and 6.32 arc seconds.

In my head, I assume that drift due to refraction will be aligned perpendicular to the horizon, instead of being
aligned with one of the axes. If that’s true, then my elongation might be up/down, relative to the horizon. I’m
going to give it another run tonight and see if I get better results with refraction correction enabled.



From: <> On Behalf Of W Hilmo
Sent: Tuesday, April 20, 2021 7:10 AM
Subject: Re: [ap-gto] Interesting Behavior with APCC Pro and Pegasus Astro UPBv2

Thanks for the response.

I’m using the latest version of the Pegasus Astro software for the UPBv2, so it sounds like I need to contact
them regarding the temperature reporting issue. I’ve not yet confirmed that after switching back to Celcius, that
it restores the unguided accuracy. I should be able to give that a try tonight.

As for the Advanced Sequencer, I saw it for the first time yesterday. I was expecting a UI similar to the original
sequencer, which it’s not – but I think that it’s better. I really like to flexibility. I’m already thinking ahead to
when Astro-Physics updates APCC to support the new few-stars tracking model that they introduced with the
Mach2. It would be really cool to write a script to sample and plate solve 6 or 8 points along the target’s
declination for unguided imaging, and then have NINA invoke the script at the start of an imaging session.


From: <> On Behalf Of Dale Ghent
Sent: Tuesday, April 20, 2021 4:34 AM
Subject: Re: [ap-gto] Interesting Behavior with APCC Pro and Pegasus Astro UPBv2

Hi Wade,

You may need to update your Pegasus software to fix this issue.

Older versions of the Pegasus UPBv2 console app and ObservingConditions driver will relay the Fahrenheit
temperature to downstream consumers such as NINA or APCC when the console app is set to display units in

The ASCOM ObservingConditions interface specification specifies that the values for its various meteorological
properties must be in SI units (ie, Celsius when it comes to temperature), so that is what APCC is expecting.
Pegasus issued a fix for this last year so you might just need an update unless they’ve reintroduced the bug in
a recent version.

This issue was even more obvious to those who have NINA set to convert the SI units too imperial for display.
This caused NINA to convert the Fahrenheit temperature to Fahrenheit again, resulting in some outlandish
temperature values being reported.

Aside from that, your description is quite an interesting depiction of how much temperature can alter the
tracking of the mount under a model, though. Glad you were able to work out the cause. Hope you like the
Advanced Sequencer, too. It is of course a work in progress but it’s maturing nicely.

On Apr 20, 2021, at 00:35, W Hilmo <> wrote:

I've been doing some unguided imaging with my AP1600 w/Absolute Encoders and APCC Pro and have
seen some interesting behavior with unguided imaging.

The first few nights that I run unguided after building a model of about 180 points, everything was great.
I was blown away by how well it worked. The last few nights, not so much. I am seeing elongated stars and
some image drift over the course of the night.

I do not believe that this is flexure. I'm imaging with my AP130GTX, and I've double checked all
connections. I've double checked to make sure that the pointing model is enabled. I verified that the polar
alignment is still spot on. It's a bit difficult to troubleshoot because, without guiding, there aren't any log files to
examine. All I have are the subs that I can inspect.

Since we're getting into more moonlight, I've done some software updates (switched to the daily builds
for NINA so that I can use the advanced scheduler). I've also set up for doing tonight's run with the guider
enabled so that I can get some logs. As I was watching the session get started, I noticed something odd.
Specifically, I noticed that APCC reported the temperature at over 40 degrees C, which is very wrong. I am
using the Pegasus Astro Ultimate PowerBox v2 as the weather sensor.

It occurred to me that I made a change to the Pegasus software a few days ago to change from reporting
the temperature in C, to reporting the temperature in F. It looks like both APCC and NINA are reporting the
Fahrenheit value as Celcius. I am wondering if the significantly incorrect temperature interpretation has
effected the model such that it's lost accuracy. I have reverted the Pegasus software back to reporting in C,
and after tonight's run, I'm going back to unguided operation to see if I get that great result back that I was
getting the first couple of nights.


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