Temperature Compensation for The 'Pegasus FocusCube2' Will Not Stay ON

[Jim Waters]

Release 1.10 Build 075.

Windows 7 Pro x64 w/ all patches and updates.

Description

NINA Temperature Compensation turns OFF after connecting to the Pegasus FocusCube2 and cannot be turned back ON. The temperature probe functions as expected running the Pegasus SW (Pegasus Focus Controller Rel 3.14.0). The Pegasus FocusCube2 Temperature Compensation looks like it functions correctly running SGPro 3.1.0.457. The focuser temperature is being displayed in the SGPro Focus Control applet.

Steps to Reproduce

1. Turn ON the NINA Temperature Compensation.
2. Select the Pegasus FocusCube2.
3. Connect to the Pegasus FocusCube2.

At this point it turns OFF. It also cannot be turned ON if you skip step 1 above.

Expected Behavior

To be able to turn ON the NINA Temperature Compensation and have it remain on.

Actual Behavior

The NINA Temperature Compensation turns OFF after you connect to the Pegasus FocusCube2 and cannot be turned back ON.

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[Dale Ghent]

When you mean “NINA Temperature Compensation”, which option are you referring to, specifically? Are you referring to the option in a sequence to trigger an autofocus if the temperature changes X degrees from the previous focus run?

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[Stefan B]

NINA does not have any temp comp. The toggle in the focuser is just straight from the ASCOM interface, so it is up to the driver.

[Jim Waters]

On the Focuser Panel.

Equipment => Focuser. The Temperature Compensation slider. If you turn (slide) it ON it turns OFF after you connect to the FocusCube2.

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[Jim Waters]

Dale - Yes.

[Dale Ghent]

Ok, you’re interpreting these things as the same, when they’re actually different. Here’s why:

Focuser-based temperature compensation is its own thing, and NINA’s own temperature compensation is another. The two systems are exclusive to each other.

Focuser-based temperature compensation is driven solely by the focuser driver and hardware, independent of the application. The only knob that is made available to the application to control such compensation is an on/off switch, which is what you see on the focuser control screens. Focuser-base temperature compensation take a temperature coefficient that you program into the driver directly and it will move the focuser in or out in response to temperature changes, the amount of change governed by that coefficient. NINA doesn’t actually know when these changes are happening - they are driven independently by the focuser driver and hardware, and this means even during the course of an exposure.

Separately, in NINA’s sequences, there is the option to trigger an autofocus run if the temperature changes however many degrees since the previous autofocus run. This is different, and would conflict with focuser-based temperature compensation if it were on, which is why turning on one will disable the other. In this case, NINA will use the temperature probe on the focuser and monitor the temperature after every exposure. If the temperature changed by the specified amount since the previous autofocus operation, a new autofocus run will be initiated before the next exposure commences.

So, you pick one OR the other, you cannot have - or would want - both running at the same time. If you have a temperature coefficient calculated for your equipment programmed into the the focuser driver, you would want to use focuser-based temperature compensation and would have no need for NINA’s feature. However if you do not, you would want to use NINA’s ability to monitor the temperature and trigger autofocus as needed. I think this is what most people do, because deriving a temperature coefficient for your gear is time consuming and no really easy.

[Jim Waters]

I understand the distinction between the two approaches. Focuser based compensation is too difficult to setup and its generally expensive. I prefer the NINA’s approach. If the temperature changes X degrees NINA forces a refocus. I have this enabled along with other trigger points – Elapsed Time, Temperature Change, HFR Increase.

The wording on the Equipment => Focuser Panel can be confusing. I understand why it turns OFF now. Thanks… To avoid confusion maybe a wording change such as ‘Third Party Temperature Compensation’ -OR- ‘Focuser Based Temperature Compensation’.

Thanks Dale.

[Jim Waters]

I downgraded this to a Proposal Change.

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