Temperhum calibration

for those who’s Temperhum does work, but show wrong readings, it would be nice to have an option to calibrate it. For instance, when my ambient temp is around 24C, SGP reports 60C. So I could adjust readings by -36 to show the right temps. Same for Humidity. BYE does have that option and it works wonderful.

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SGPro has strange readings with my TEMPerHum device, witch by the way was calibrated before. .

So, calibration is an must!

Hi Sabin,
Would you mind sharing where you obtained your TemperHum from? Mine appears to work fine under its software, but generates no data in SGPro.

It was bought from ebay, a few yers ago, I belive.
I will put some pics with it later.

LE: this is it

Thanks, I’ll see if I can find that version.

I think the latest one has a silver case. I had two that looked the same but behaved differently. I eventually gave up on them and converted my focusing system to one that had an external temp sensor. Ken and Jared have looked at these before: The dilemma is they are cheap- but numerous forum posts suggest undocumented inconsistencies. (In an attempt to unravel this, I emailed their support three times but received no reply).
I think a calibration was on the cards for V2.4 bit it is like asking SGP to improve the autofocus for a child’s Fisher Price telescope.

All of these devices seem to come with some sort of software that’s more or less compatible with it, something that allows it to display the temperature and humidity on a PC.

Could that be used to collect the data without using the device API?

I can’t help thinking that this would be better in an ASCOM Switch device, thus making the collection of the data for a specific device someone else’s problem. SGP shouldn’t be expected to have to worry about the details of every device that people want to use.

People wanting to implement a sensible device could use the same interface of course.


The one I have is silver and, as mentioned, produces no data within SGPro.

I suspect my MicroTouch focuser system from Starzona does not accurately report the ambient conditions due to heat from surrounding electronics.
In fairness to MicroTouch, I do not know this for a fact. But I have turned the temperature compensation off and am seeing better focus results. I’ve recently begun plotting the reported temps through the night for review, but It would be helpful to have an independent source (i.e. Temperhum) to compare to.

EDIT: just saw your post Chris (ascom). Not sure i can do it, but I will see if the Temperhum’s native software can provide the temp info to compare with MicroTouch’s.

I’ve heard that using temperature to compensate for focus change is difficult. Some people have reported that rate of change in temperature may be better. This makes sense, different parts of the system will respond to temperature changes at different rates.


My focus controller that has the temp sensor is in a box with other electronics at the bottom of my mount. It’s likely not accurate or precise but it does change at about the same rate as the ambient temperature which is all that you need for a focus trigger.

Are you noticing focus drift when using the temp from the microtouch? If not I wouldn’t worry about it.


Chris - your approach is logical. Unfortunately, I found the supplied software continually crashed on startup. I tried different versions of the software on three PC’s, with no luck.

@niteman1946 From the data I have seen, temperature compensation is tricky - you cannot really do it in real time, as any focuser image shift will degrade an exposure and for that reason it has to be in-between exposures. The rate of cooling affects the focus position. You would think, with a refractor, that the aluminum housing would shrink as it gets colder, requiring the focuser to move out to compensate. I found the opposite. That suggests the focal length is changing too. I found better results by noting a temperature drop and autofocusing for a 0.5 to 1C change, depending on the scope.

The original Microtouch module has a built in sensor that pokes out, it tracks fairly well. The Microtouch module does generate some heat, and since I had mine housed with other electronics it did not react as quickly. The latest Microtouch systems have external sensors in their new clutched motors.

I decided to switch from Microtouch to Lakeside motors and modules, so that I could have a common system with all my scopes. Their motors have an external temp sensor, which solves the problem with SGP.

I have some spares if anyone wants them. I’m re-branding them TEMPperMENTAL.

To all that have the TemperHum device, and to solve all calibration issues with SGP.

There is an TemperHum Ascom driver (see this forum link)

The driver can be downloaded from a shared folder

My TemperHum was also showing wrong values and with the ASCOM driver solved the issue.


This is awesome. For anyone that was not following this drama or is not sure what TemperHum is… it is a simple USB based device that reports temperature, humidity, and, by virtue of this, the dew point. We attempted to include TemperHum support in SGPro years ago, but they turned out to be too difficult yo work with. New versions would come out and need completely different support… while this is not all that uncommon, these new devices were completely indistinguishable from others. Over time, we found that we were spending more time on TemerHum than almost anything else in SGPro.

If somebody is now maintaining a driver specifically designed to broker this complexity, TemperHum may yet make an outstanding addition to your rig. Most can be had fro about $20.