13 replies to this topic

[aleixandrus]

Hi! A quick question about NINA, PegasusAstro Powerbox Advance and ZWO EAF focuser:

 

Is there a way to configure NINA to use the autofocus routine trigger using the temperature sensor of the Powerbox instead of the temperature sensor of the EAF?

 

I couldn't find any info about this... Also, I don't have the temperature probe of the EAF (although I read it is not very accurate). The Powerbox temperature is displayed in the weather tab and works fine.

 

Thanks a lot!

[Arie]

You may wonder how accurate the Upb temp sensor is . . . . 
Their humidity sensor usually is frozen at 99%

[dghent]

NINA does not support using a non-focuser temperature source for determining focus changes. The entire point of an on-focuser temperature probe is to measure the temperature of the drawtube and the material it is made out of, not the temperature of the air. The drawtube can change temperature at a rate that is different from that of the surrounding air, thus taking measurements of the air is not reliable when determining how much to move the focuser due to the drawtube's (and other aluminum components of the imaging train) thermal expansion and contraction.

[Jeff Morgan]

The Pegasus temperature seems best for managing dew controllers.

 

On my ZWO focuser, I do not use the temperature focuser.

 

On my Optec temperature compensating focuser, they provide a sticky foam insulation pad specifically to isolate the probe from the structure. That would indicate to me their method is to use air temperature.

 

Either way, for AF I use the Percentage Change HFR trigger in NINA.

 

In the final analysis, isn't best HFR what we are directly after?

[imtl]

You may wonder how accurate the Upb temp sensor is . . . . 
Their humidity sensor usually is frozen at 99%

If you are getting 99% humidity then might as well fold up and go to sleep

[Arie]

I have three other sensors telling me it’s about 75%

This happens all the time.

Supported by more users. 

[dghent]

I have a PPBv2 and a PPA Gen2 and one came with a bad temp/humidity sensor. It also constantly read 99%. I got a replacement sensor and it was consistent with my other humidity sensors, within 2%. You probably just have a bad sensor that needs to be replaced.

[Arie]

This is the second one. 
When I take it in the house, it indicates alright.

Back in my dome it starts ok but after some time it increases again to 99%

The other sensors stick to the 75%

I think it doesn’t like temperatures below 10C

[WadeH237]

You may wonder how accurate the Upb temp sensor is . . . . 
Their humidity sensor usually is frozen at 99%

I have to wonder if your unit is working properly.

 

I use a UPBv2, and I can't remember it ever showing me 99% humidity.  It usually says something completely reasonable.

 

For example, I have my imaging package off the mount and inside my home office at the moment.  I also have the imaging computer indoors, connected and running.  I just started NINA and connected to my weather provider (the UPBv2), and it says the humidity is at 21%.

[Arie]

Thanks Wade,

I have a few friends here in the Netherlands. They have the same experience as I have.

I guess it is a climate thing.

As I said, when I take it in the house it indicates correctly.

BTW. Right now at 4°C the UPB says 95% whereas the others are 72% and 77% 

[AaronH]

My PPBA humidity sensor often ramps up to 99% soon after going outside, then stays there. But being in hot, humid Australia, that may not be far off the truth. My gear is often dripping.

 

Meanwhile, the temperature sensor on the PPBA is always 2-3 degrees off the ZWO EAF temperature probe, but it tracks pretty consistently with it. Neither matches the reported temperature for my location exactly, but they follow the trend. So I ditched the EAF temperature probe and just use the PPBA one. For focusing it's the temperature deltas that matter, and by using the PPBA sensor it's one less wire to worry about. However, I use KStars/Ekos/Indi rather than NINA.

[aleixandrus]

Thank you so much for your responses. As you said, it may be better to rely HFR values than temperature but, as I have a temperature sensor, I say to myself: "hey, why not adding an additional focus trigger?". In fact, I'm autofocusing every 'x' minutes/shots and on filter change. And as I try to intercalate S2, Ha and O3 frames to get a full color image each night (weather just sucks here), maybe I'm just focusing too much. However, I'll explore the possibility to acquire the EAF probe if an opportunity arises.

 

Regarding to  humidity, I was aware about some people complains about the PegasusAstro sensor but I don't have too much experience with the Powerbox yet. What I saw in the last 3 nights is that humidity was ramping from 60% to 97-99%... BUT weather was awful and it seems right. I'll check in the future who it behaves.

 

So, as conclusion, NINA doesn't allow to use the weather temperature to trigger the autofocus routine (at least at this moment).

[AaronH]

Either way, for AF I use the Percentage Change HFR trigger in NINA.

 

In the final analysis, isn't best HFR what we are directly after?

I've experimented with using HFR for re-focus in Ekos, and am a bit suspicious about it. Ekos refocuses when HFR degrades by a user-defined percentage, and there seems too much risk of the following happening:

• You achieve good focus.
• You happily image for a while.
• You hit a patch of poor seeing.
• Due to the poor seeing, refocus is triggered, and it can't nail perfect focus because seeing is shifting constantly.
• The refocus routine ends up suboptimal.
• Seeing clears up, and despite being off critical focus, it's still better than it was during the focus routine, so refocus isn't triggered.
• You now image for an extended period with sub-optimal focus.

But perhaps NINA handles this better?

 

In the end, I just set my rig to refocus every 30 minutes or after a one degree temperature change. It's almost always the former that triggers the refocus.

[Schlansk]

When NINA refocuses, It requires that the new focus point actually provides an HFR improvment, otherwise it reverts to the prior focus position unitl you refocus again.