Pegasus Astro Uranus Meteo Sensor User manual

Pegasus Astro - Uranus Meteo Sensor Manual
URANUS METEO SENSOR
PRODUCT MANUAL
Version 1.1
2022-Oct-01

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VERSION HISTORY
Version #
Implemented By
Revision Date
Reason
1.0
Evans Souglakos
25/06/2022
Initial Document
1.1
Evans Souglakos
01/10/2022
Add Mechanical Drawings.
Add Emissivity for IR Sensor.
Modify Buttons Operation.

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TABLE OF CONTENTS
1INTRODUCTION.................................................................................................................... 5
1.1 Purpose.................................................................................................................... 5
1.2 Device Care............................................................................................................. 5
2DEVICE DESCRIPTION ....................................................................................................... 6
2.1 Design Overview..................................................................................................... 6
2.2 Battery Operation.................................................................................................... 7
2.3 Battery charging...................................................................................................... 7
2.4 USB Operation........................................................................................................ 8
2.5 Power Consumption and Sleep Mode................................................................. 8
2.6 Device Reset........................................................................................................... 9
2.7 Mounting Holes....................................................................................................... 9
3SENSORS ............................................................................................................................... 10
3.1 Ambient Temperature.......................................................................................... 10
3.2 Relative Humidity.................................................................................................. 10
3.3 Barometric Pressure............................................................................................. 11
3.4 Light / Sky Brightness.......................................................................................... 11
3.5 Cloud Infrared Sensor.......................................................................................... 13
4GPS.......................................................................................................................................... 13
5MEMORY BANKS................................................................................................................ 16
6DEVICE OPERATION......................................................................................................... 17
6.1 First-Time Use....................................................................................................... 17
6.2 Mobile Usage......................................................................................................... 19
6.3 Remote Usage...................................................................................................... 21
7ON SCREEN DISPLAY........................................................................................................ 22
7.1 Organic Led........................................................................................................... 22
7.2 Menus..................................................................................................................... 22
8MEASUREMENT CONSIDERATIONS............................................................................ 32
8.1 Sky Quality............................................................................................................. 32
8.2 Cloud Coverage.................................................................................................... 35
9CONFIGURATION CHANGES.......................................................................................... 36
9.1 Set Units................................................................................................................. 36
9.2 Set Timezone........................................................................................................ 36
9.3 Set Sleep After...................................................................................................... 36
9.4 Set Light Readout Offset..................................................................................... 36
9.5 Set Infrared Sensor Emissivity........................................................................... 36
DIMENSIONS............................................................................................................................. 37
10 TECHNICAL SPECIFICATION......................................................................................... 37

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11 ENVIRONMENT................................................................................................................... 38
12 WARRANTY.......................................................................................................................... 38
13 SUPPORT............................................................................................................................... 38

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1 INTRODUCTION
1.1 PURPOSE
Thank you for purchasing the Uranus Meteo Sensor. This pocket-sized device is an
all-around astronomer, astro-imager companion.Smaller than the size of a cigarette
box, and equipped with a variety of digital sensors, can precisely report the ambient
temperature, humidity, pressure, cloud height, cloud coverage, astronomical dawn,
twilight time, and the night sky brightness.
1.2 DEVICE CARE
The device electronics are housed inside an aluminium anodized blue enclosure.
The enclosure is made from aircraft aluminium alloy 6061 which provides very good
corrosion resistance. The label button on top of the device is water-resistant and the
material was selected to last a long time. However, the device is not waterproof and
it should not be installed outside for long term, exposed to weather conditions e.g.
direct sunlight, rain, snow.
A black silicone case protects the device from drops and scratches. Also it does not
allow contact of aluminium enclosure with your palm. (especially during cold nights
the heat transfer from your hand to the metal can be really disturbing)
We strongly suggest keeping this case, especially if you plan to use the device as a
mobile unit (have it in your pocket etc). In case you need to place the device inside
your observatory, you can remove the silicon case and use the screws at the bottom
of the device to securely attach Uranus on a plate (2xM3 screws) or a tripod ball
head ( 3/8-16 UNC thread).
Please note that the device is not water-sealed and you should not leave it
exposed to weather conditions such as rain or snow. However, the device can
be placed into a roll-off observatory to measure night conditions, for
astronomical observations, when the roof is open.

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2 DEVICE DESCRIPTION
2.1 DESIGN OVERVIEW

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2.2 BATTERY OPERATION
The device includes a rechargeable 3.6Volts - 3xAAA NiMH battery back. The
current capacity of the battery pack is 600mA. The battery can be recharged from
the USB-C socket. A battery management controller inside the device ensures that
the device is properly charged following the NiMH battery charging characteristics.
When the battery is fully charged, the controller cuts the charging current. Battery
levels are shown on the OLED display.
Typically, NiMH batteries can be recharged hundreds of times However, battery
life is limited to up to 5 years. After that, it can be easily replaced with a new
rechargeable battery pack. In order to do that, remove the two screws from the
back of the device and lift the bottom enclosure plate. Locate the battery and
disconnect the two wires. Remove and replace the battery pack. Pay attention to
the battery + and –cable. (black is - , red is +). There is a printed indication close
to the device socket showing how to attach the cables with the correct polarity.
Please note that the device has reverse polarity protection so if you accidentally
reverse the battery polarity, the device will just not start. (It will not get harmed).
2.3 BATTERY CHARGING
When USB-C cable is inserted to the device, the battery automatically enters into
a charging cycle. The internal NiMH change controller decides if battery requires
charging and starts the charge sequence. Also, it stops the sequence when battery
is fully charged.
During charging sequence, the battery pack produces some heat (a normal
condition during any battery charging). Despite the fact that all temperature
sensors are placed into a different compartment of the aluminium enclosure (to

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isolate any heat emission from the electronic board) this will affect them and offset
their temperature readout by 2-3 °C. When charging cycle ends, the battery is
cooled down and temperature sensors readout return to normal values.
To reinitiate a battery charge sequence, USB cable should be re-inserted and
battery should be lower than 90% of its capacity.
This ensures that during remote operation ofthe device the battery will not produce
heat so it won’t enter, periodically, into battery charging cycles. Therefore, the
sensors are not get affected by any abnormal temperature fluctuation.
If you intend to mount permanently the device on your observatory, you can open
the back of the device (remove the two screws and lift the back plate) and easily
remove the whole battery or just disconnect one battery clip.
2.4 USB OPERATION
The device has a USB-C socket on its right side that charges the internal battery
pack, and most important, exchange information with your PC. The USB
communication is USB 2.0. Maximum cable length that ensures a stable
communication between Uranus and your PC is up to 5 meters / 15 feet.
Device prefers the USB power channel (+5V) so when the USB cable is inserted,
the device instantly switches to USB power and battery power consumption falls
to zero. When you remove the USB, device instantly switches back to battery
power consumption, operation (no disruption in device operation happens).
2.5 POWER CONSUMPTION AND SLEEP MODE
Uranus consumes 60mA during its normal battery operation. When the device is
onbattery “mobile”mode (USB cable is not plugged) device enters into sleep mode
after 5 minutes of inactivity (default sleep interval –can be changed from Unity
software). Sleep mode is practically, to the user experience, a full shut down of the
device.

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In sleep mode, the device consumes up to 15μA. This ultra-low power consumption
allows the battery to last for more than a year! The right push-button single click
brings the device back to life, normal operation. Due to this power save feature,
the device does not need a classic switch button to turn on or off.
2.6 DEVICE RESET
A pin-hole on the left side of the enclosure fully resets the microcontroller of the
device. If your Uranus does not turn on for any reason, carefully insert a small
needle and press this button once.
2.7 MOUNTING HOLES
Uranus has two different types mounting holes at the back of its enclosure.
A couple of M3 holes and a 3/8-16 UNC are available according to image below.
The device can be attracted with two different ways:
•On a small tripod by using the 3/8-16 UNC hole, pointing to the zenith of
the sky.
•“Piggiback” on your telescope OTA: In this case, please ensure that the
sensor front area is as close to the front of your telescope. This ensures
that each optical sensor ‘s field of view is not obstructed by an object (such
as the telescope tube itself).

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3 SENSORS
3.1 AMBIENT TEMPERATURE
A digital sensor measures temperature ranges from -40°C to +60 °C. Temperature
readings are taken every 15 seconds, to disallow any heat that might build up if
there were quick time interval readings. After each reading, the sensor enters into
sleep mode in which power consumption is at a minimum. All the above ensure
that the sensor measures precisely the current ambient temperature. Temperature
sensor value is also used for temperature compensation of the pressure and
humidity sensors.
3.2 RELATIVE HUMIDITY
A digital relative humidity sensor ensures accuracy tolerance of ±3 % relative
humidity. The humidity sensor provides a fast response time and high overall
accuracy over a wide temperature range. The integrated temperature sensor has
been optimized for the lowest noise and highest resolution. As the temperature
sensor, each reading is taken every 15 seconds to minimize internal sensor heat-
up and reduce power consumption.
The below image shows the humidity sensor operating range

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The dew point is the temperature the air needs to be cooled to (at constant
pressure) in order to achieve a relative humidity (RH) of 100%. At this point, the
air cannot hold more water in the gas form. Dew Point is automatically calculated
by a math formula that uses readings from temperature and relative humidity
sensors.
3.3 BAROMETRIC PRESSURE
The pressure sensor is an absolute barometric pressure sensor with extremely
high accuracy and resolution and low noise. The sensor provides full accuracy
from 300 to 1100 hPa. Each reading is taken every 15 seconds to minimize internal
sensor heat-up and reduce power consumption.
Uranus firmware is able to calculate and display relative barometric (sea level)
pressure and barometric altitude.
3.4 LIGHT / SKY BRIGHTNESS
The light sensor has a very-high sensitivity light-to-digital converter that transforms
light intensity into a digital signal output. The sensor combines one broadband
photodiode (visible plus infrared) and one infrared-responding photodiode on a
single CMOS integrated circuit. By subtracting infrared from broadband light, the
sensor can precisely calculate visible light. This is the reason why it does not
require an IR-Cut glass. Moreover, sensor comes into a UV-rejection package.
The light sensor has a very high dynamic range of 600M:1 able to measure from
direct sunlight to very dark skies (practically up to 22.0 mag/arcsec2). Its highest
sensitivity is down to 188 μlux.
Light sensor provides data to the microcontroller of Uranus where illuminance
(ambient light level) in lux is derived using an empirical formula to approximate the
human eye response. Lux readings are converted to Magnitudes per square
arcsecond, abbreviated as MPSAS. In addition, Uranus calculates the NELM
(Naked Eye Limit Magnitude) and Bortle Scale.

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Spectral Responsivity: Two channel response allows for tuneable illuminance (lux) calculation
regardless of transmissivity of glass.
White LED Response vs Temp: Effect of temperature on the device response for a broadband
white light source. A temperature compensation algorithm is automatically applied after every
readout.
Each light sensor is factory calibrated with precision close to ±5%. However, if
Uranus is going to be placed inside a 3rd party enclosure, the light sensor will
require an offset adjustment which can be configured via our supplied software.
The light sensor has a 25° FOV opening, covering range, which is appropriate to

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take an average measurement of a whole asterism. (Please note that the purpose
of this sensor is not to measure a narrow part of the deep sky).
The firmware of the Uranus device works in combination with the light sensor and
automatically:
oCompensates dark-current of the sensor based on ambient temperature
from the final reading.
oConfigures sensor analog gain and integration time in order to adapt to the
current light conditions and utilize the full dynamic range of the sensor.
An average reading (10 consecutive measurements) of the light sensor can be
taken by keeping pressed the “Measure” push button or instructed from USB
communication (on-demand).
3.5 CLOUD INFRARED SENSOR
A high-precision non-contact infrared temperature sensor of 60° FOV is used to
measure the sky temperature. By consulting ambient temperature, the firmware
uses a formula to determine the existence of clouds.
The difference between the ambient temperature and the sky temperature is lower
when there is a clear sky compared with a cloudysky. A sky temperature correction
model is applied to account for excessive atmospheric long wave radiation during
summer at different locations. A clear view of the sky is important because any
terrestrial object can cause parasite IR radiation.
Sensor IR temperature measurements and cloud index calculations based on the
temperature correction model are taken every 250 msec.
4 GPS
Uranus incorporates an ultra-low consumption and fast position GPS receiver. The
receiver has 66 acquisition channels, 22 tracking channels and can calculate, and
predict orbits automatically using the ephemeris data (up to 3 days) stored in

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internal RAM memory, so can fix position quickly even at indoor signal levels with
low power consumption. A cold GPS start takes about 30 seconds under open
sky view (can take longer 1-3 minutes if there are obstacles blocking the sky
around the receiver). As the Uranus device enters into sleep mode but never shuts
down, the GPS module battery keeps receiver in “warm”start mode. A warm start
(lock satellites and display precise time and coordinates) happens in less than 5
seconds.
If some or all the GPS data is missing or out-of-date, the GPS receiver needs to
get updated information from the satellites before it can accurately fix a current
position. The types of data that are out-of-date or missing determine how long the
GPS receiver takes to initialize. If the Uranus is, several hundred miles away from
where it was last used, or has been stored for a prolonged period of time,
initialization will take longer.
Uranus communicates with the internal GPS receiver and displays information
about:
•Latitude and Longitude of your location
•Satellite Lock Count
•Local Date and Time (based on your defined time zone)
•Ground Speed
•Bearing in Degrees
•Moon Age and Visibility
•Astronomical Dawn and Dusk Time
GPS receiver updates from Uranus processor for new GPS data every one second
(1Hz). (This can change to higher update rates (up to 10Hz) –will be supported in
future firmware releases)

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Uranus device has an RJ12 port that can (when enabled from supplied software)
output NMEA GPS lines. This port can be used to provide GPS data to other devices
such as telescope mounts that accept NMEA messages.
6P6C GPS NMEA Output Pinout
PIN 1
N/C
PIN 2
RX
PIN 3
N/C
PIN 4
GND
PIN 5
TX
PIN 6
N/C

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5 MEMORY BANKS
The device includes an FRAM memory, capable to store up to 500 records of sensor
data. “Store” (left) push-button press for 2 seconds stores below data into the next
available memory bank number:
•Date & Time (GPS)
•Latitude
•Longitude
•Ambient temperature
•Humidity
•Altitude
•Pressure (absolute)
•Light (MPSAS)
•Cloud Index (%)
Memory banks can be read or fully wiped from (Unity Platform) software. The
technology of this RAM (FRAM) ensures that memory can last for multiple billions
of write or erase cycles.

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6 DEVICE OPERATION
6.1 FIRST-TIME USE
An important step during the first-time use of the device is to initialize the GPS
receiver with the visible satellites of your area.
Locate an open space with unobstructed view of of the sky and place Uranus (with
top label looking up) in a stand-still position for about a minute.
This ensures that the GPS receiver will quickly discover available satellites. GPS
sequence first displays (stratum 0) date & time data.After that,it needs to fix position
(latitude and longitude coordinates) via 4 satellites (at minimum).
It can take anywhere from 30 seconds to 3 minutes for the GPS receiver to gather
enough satellite data to get a position fix for the firsttime. Thisis requiredonlyduring
first usage (GPS cold start). After that, GPS will be fully operational in same
location after 5-6 seconds. (warm start under open sky).
If some or all the data is missing or out-of-date, the GPS receiver needs to get
updated information from the satellites before it can accurately fix a current position.
The types of data that are out-of-date or missing determine how long the GPS
receiver takes to initialize. If the Uranus is several hundred miles away from where
it was last used, or has been stored for a prolonged period of time, initialization will
take longer.
[Please note that internal battery replacement will require a GPS cold start initialization process]
Uranus battery is fully charged, straight out of the factory. However, we recommend
plugging the USB cable and re-charge the battery. (if the device is left for a long
time on the shelf the battery levels will be lower than expected) A full charge time
may take 2.5 hours when the battery is at very low power levels.

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During initial usage (out of the box), one hour of charging time should be sufficient.
Please note that the internal charging circuit automatically cuts battery charging
sequence when the battery comes to a fully charged level so no need to worry about
when to unplug the USB cable).

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6.2 MOBILE USAGE
Press the right [>>] button once, in order to bring Uranus, from sleep mode, back
to normal operation. The device instantly boots and the Pegasus Logo is visible on
the OLED display for about a second. After that, the device is fully operational.
GPS is also operational with satellite data in about 5-6 seconds (GPS warm start).
Please note that if more than 3 days have passed since the last GPS operation,
the GPS receiver might take longer (up to 30 seconds) to locate and track
ephemeris data of available satellites.
Press [>>] button to move forward or press [<<] button to move backward to all
available display pages of the device
[For detailed information please read “On Screen Display Menus” section of this document]
Keep pressing [>>] (Measure) button for 2 seconds to trigger a Sky Quality
measurement. Remember to point the device towards the area of the sky you
would like to acquire a light measurement.
Keep pressing [>>] (Measure) button for 5 seconds to turn off the display. Device
will still enter in sleep mode after the configured time period. Press any button to
turn it on again

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Keep pressing [<<] (Store) button for 2 seconds to store all retrieved sensor data
into the device's next available memory bank.
(By the time you press the store button a sky quality measurement is
automatically taken and included into the memory bank).