Falcoln Heavy Launch

On February 6, 2018, SpaceX launched their Falcon Heavy Rocket from pad 39A at the Kennedy Space Center.  Pad 39A is the same launching pad used by the Apollo program to send astronauts to the moon.

Falcon Heavy is the most powerful operational rocket in the world by a factor of two and can lift into orbit nearly 64 metric tons (141,000 lb).  Only the Saturn V moon rocket, last flown in 1973, delivered more payload to orbit.

My nephew who is a rocket engineer at NASA invited us to attend the launch.  Armed with only an IPhone X, we were able to capture some photos and video of the launch and booster landing.  Photos were taken at 10x zoom and video at 6x zoom.

Click the image below to watch the launch video.  There are controls to adjust the size of the video and volume (to hear the crowd’s reaction and the rocket itself).  At the 1:05 minute mark in the video you can begin to hear the sound of the rocket.

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Click the image below to watch the booster rocket landing.  At the beginning of the video, the boosters are falling from the sky on the left hand side of the frame.  You can use the controls to expand the video and see it better.  After the boosters land, you will hear two separate bursts of sounds – like firecrackers.  Each burst corresponds to the sonic booms from each booster as it fell from the sky.

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Supernova 2017 eaw

A new supernova has been discovered in the Fireworks galaxy (NGC 6946).  The Fireworks galaxy is aptly named for the record number of supernovae that have exploded in it over the the last century.   Supernova 2017 eaw was discovered on May 14 and now the number of supernovae recorded in the Fireworks galaxy is ten!

A photo of the Fireworks galaxy  is shown below.  This photo was taken from the observatory in 2013 and supervova 2017 eaw is not yet visible because it didn’t explode until much later in  May of 2017.

NGC 6946 Fireworks Galaxy

A supernova occurs when a star’s core changes, causing a super-massive explosion that is one of the most impression events occurring in the universe.  A Type I supernova occurs when a white dwarf gains too much mass from another star orbiting it.  The white dwarf gains more and more mass until its core collapses from gravitational forces.  A Type II supernova occurs when a massive star (many times the mass of our Sun) runs out of nuclear fuel and collapses.  The star’s core collapses from the gravitational forces and finally explodes.

Both types of supernova are extremely bright for a short time and diminish thereafter.  Supernova 2017 eaw has been determined to be a type II supernova.

On May 24 and 25th 2017, the observatory imaged the Fireworks galaxy again.  The images from May 2017 were compared to those taken in 2013.  The comparison was converted into a video to alternate frames between 2013 and 2017 causing the supernova 2017 eaw to be revealed as a blinking star from frame to frame.  You can play the video below and see the comparison with the location of the supernova in the Fireworks galaxy.



Zodiacal Light

Now is the time of year when the zodiacal light appears in the western sky shortly after twilight.  The zodiacal light is a faint ethereal glow rising in the west in a pyramid shape pointing toward the zenith.  The zodiacal light gets its name from the glow it makes along the line of the ecliptic in the sky.  The ecliptic is the line that the sun, moon and planets follow across the sky.  It is also along this line that the zodiac constellations reside, hence the name, zodiacal light.

Putman Mountain Observatory maintains an All Sky Camera that records video of the heavens every night.  See the link: All Sky Camera. You can see the zodiacal light in the images the All Sky Camera takes each night after twilight in the late winter and spring.  In the All Sky Camera image below, can you see the Milky Way?  Can you see Orion?  Can you see the zodiacal light rising over the dome of the observatory?

Zodiacal Light

The source of the zodiacal light is interplanetary dust left over from the original nebula from which the solar system was formed.  This interplanetary dust lies along the plane of the solar system which is the line of the ecliptic in the sky.  The dust is more easily seen when the ecliptic is at a high angle in the sky so that it is illuminated by the sun but far enough outside the glare from the sun.  In the diagram below, you can see the interplanetary dust lying along the plane of the solar system and why it is visible in the west during twilight.

Zodiacal Light Orientation
Zodiacal Light Orientation

The zodiacal light appears like a pyramid extending up from the horizon and leaning toward the line of the ecliptic since the interplanetary dust is in the same plane as the solar system.     The zodiacal light is brightest near the sun but can never be seen because it’s lost in the glare from the sun.  One of the best times to see the zodiacal light is shortly after twilight in the spring because the Earth blocks the glare from the sun.  In the image below, the zodiacal light is outlined in red to show the location of it’s faint glow.


Zodiacal Light is outlined in red
Zodiacal Light is outlined in red

There are a number of requirements for seeing the zodiacal light.  First you need an extremely dark sky.  The glow from the zodiacal light is much fainter than the Milky Way.  Second, there can be no moon present in the sky.  The light from the moon will overwhelm the zodiacal light and even the Milky Way.  Third, the ecliptic must be high in the sky to make the zodiacal light more visible.  This occurs in the western sky after dusk during late winter and spring and in September and October in the eastern sky before dawn.

The image below shows the Zodiacal Light captured with a simple digital camera pointed toward the west from the observatory.  Take some time after twilight during the spring and go find the zodiacal light.  And remember, turn out the lights!



Enchanted Rock Light Pollution Study

In August of 2015, Bill Wren from McDonald Observatory took measurements from the top of Enchanted Rock to determine sources of light pollution.  He used equipment on loan from the National Park Service to make a panorama photograph of the night sky.  The measurements were processed by the National Park Service to subtract natural light sources like the Milky Way to reveal only man made (anthropogenic) sources of light – in other words light pollution.

In the image above, Bill Wren (McDonald Observatory), Matt Lara (Hill Country Alliance), Scott Whitener (Interpretive Ranger) and Doug Cochran (Park Superintendent) are setting up the National Park Service equipment on the tripod to take panoramic images of the night sky.

In the image above, both natural light sources (Milky Way) and man made light sources (anthropogenic) are shown in the raw data)

In the image above, the natural light sources have been removed to reveal only the anthropogenic light sources.  By comparing the light sources to the azimuth scale on the bottom of the image, the source of the light can be estimated.

The image above shows ERSNA as the center of the compass and the relative direction and “air mile” distance of the anthropogenic light sources from Enchanted Rock.

The image above shows the compass graph above the anthropogenic light sources with the light sources labeled to correspond to their direction and city.  Fredericksburg and San Antonio are in the middle with a heading of 180 degrees or South.  Llano is about 25 degrees or slightly East of North.  Austin is about 100 degrees or slightly South from East.  Mason and Brady are approximately Northwest.

The study will be used as a baseline to monitor future light pollution.

Do your part – Turn out the lights!

All Sky Cam Video

All Sky Cam Video

The All Sky Cam has a new feature – it now records and displays a time lapse video of the sky from the prior night.  By clicking the play button on the video below, you can watch the time lapse video of the sky.  You can see the stars and Milky Way slowly move above the observatory.  Streaks across the night-time sky are meteors, satellites and aircraft passing by overhead.  If you’re lucky, you may be able to see the International Space Station fly over.  During daylight hours, the All Sky Cam is off.

Robotic Mirror Cover


Putman Mountain Observatory’s main instrument is a 16” Ritchey Chretien telescope manufactured by RC Optical Systems. The primary mirror is made from Zerodur which is a zero expansion material to make sure the mirror figure and shape do not change by temperature fluctuations.

The primary mirror is also ion milled to 1/40 wave RMS. The primary would be very difficult and expensive to replace if damaged. Because the telescope is often used robotically, the primary mirror must include a mechanism to cover and protect it when not in use.

Primary Mirror

A robotic cover for the primary is necessary to prevent unwanted dust and pollen build up as well as insects such as wasps that may build nests on the primary and damage it. Finally, the robotic mirror cover must have integrated electronics and software to operate the cover remotely and via computer control for automated image acquisition from night to night.

The observatory’s telescope was delivered with a robotic mirror cover from RCOS, however, the RCOS cover utilized machined metal covers that were too heavy for the actuator motors and accordingly, a redesign was in order.

Right Ascension LLC is a company that specializes in designing and building custom mechanical and electronic parts for RC Optical telescopes, among others. Right Ascension even manufactures and repairs control units for the RC Optical telescopes such as the TCC2 and the newer Telescope Interface Module (TIM).

Robotic Mirror Cover Redesign

Right Ascension was consulted about redesigning the existing robotic mirror covers. It was decided that a complete redesign was warranted to improve operation, reliability and better materials. Computer aided design software and techniques were used to create the initial concept and drawings for all of the necessary parts and to insure proper fit and operation. Telescope measurements were double checked and prototype mounting plates were made and fitted to the telescope to test proper fit before committing the design to actual metal parts.

In addition, substantial work was undertaken by Right Ascension to improve the existing TIM control application with software improvements to expose additional COM objects to allow control of the telescope subsystems with scripting control.

Robotic Mirror Cover Description

Right Ascension christened the mirror covers as the Dust Abatement Cover System or DAC System V1.0. The system utilizes a combined four flap layout with each flap controlled by its own DC gear head motor, sensor PCB assembly and wiring harness. Each flap motor assembly is shielded with a polycarbonate cover.

The mechanical parts are machined aluminum and black anodized. Each flap is actuated by an attached 12 volt dc gear head motor. Each flap assembly has a specialized cam design to hold the flap in place at the minimum and maximum swing points of the armature.

Each flap end position is monitored by a sensor and user adjustable. This design allows the user to adjust the fine points of the open and close positions of each flap. The flaps were designed using black G10 fiber board material for exceptional durability. All fixtures are stainless steel and/or brass.

Each flap has a custom designed circuit board containing an indicator led, two industrial grade hall limit switches that are sealed and protected from environmental elements such as moisture, corrosion and dust.

In the image to the right, the circular disks are user-adjustable to fine tune the open and close position for the flaps and indicate to the hall sensors the designated open and close positions.

The PCB on the top of the assembly incorporates a connector cable that is part of the wiring harness to signal to the TIM unit when the flaps are in the open or closed positions.

The 12 volt dc motor is attached to armatures that are connected to the flaps. The motor is also connected to the wiring harness back to the TIM unit.

Flaps Open No Background_Crop
Robotic cover open
Mirror Cover Sensor
Mirror cover open / close sensor
Open / Close Sensor Indicators
Open / close sensor indicators
DC Motor attached to flap
DC Motor attached to flap


The robotic mirror cover came with a concise and illustrated installation and operation manual.  Each of the four flaps is a separate assembly. The flaps are designed so that two opposing flaps (3 and 4) close first and the other two opposing flaps (1 and 2) close on top of the flaps already closed.

Flaps 3 and 4 have an edge cut into them which allows flaps 1 and 2 to close into the edge resulting in a uniform, even surface when the flaps are closed. When opened, flaps 1 and 2 open first, followed by flaps 3 and 4. The flaps fit very well when closed, providing a very tight seam impervious to insects.

Each flap assembly is attached to the truss plate with two bolts. The wiring harness is then routed around the optical tube assembly to connect to each flap. Each wiring harness connection is numbered to make sure it connects to the correct flap. The end of the wiring harness is attached to the TIM unit through a parallel DB type interface.

After installation, a new version of the TIM control application was installed on the observatory computer. This is version 2.0 of the TIM control application updating from the older version 1.2. Operation of the mirror covers was tested using the TIM control application version 2.0 running on the observatory computer.

Flaps Open and Closed No Background_Crop
Interlocking flaps
Flaps on Truss No Background
Mirror cover installed on truss telescope


Despite its design complexity, the robotic mirror cover is very basic in operation. It opens and closes. Whether it does this well is key.

The DAC System met and exceeded all expectations. First of all, the flaps fit very well together, providing a tight seal against dust and insects. In addition, they also fit with precision around the primary light baffle. The fit and finish of the machined metal parts was executed well. The polycarbonate covers for each flap assembly also fit very well with the button head cap screw fasteners. The entire design was well done making sure the four different flaps lined up perfectly once attached to the telescope truss plate. Careful thought was also put into the design to allow user adjustment of the open and close position for each flap. An indicator LED on each flap signals red when opened and green when closed to assist in adjustments. Upon delivery, no adjustment was needed to the DAC System – the flaps closed tight and opened all the way.

The prior RC Optical mirror covers would exhibit some droop or hang due to backlash in the motor gearing which allowed the flaps to hang open slightly depending on where the telescope was parked. The DAC System flaps exhibited none of this droop or hang. Once closed, the flaps closed tight against each other and remained that way despite the position of the telescope.

The flaps open and close within two to three seconds and are significantly quieter in operation than the previous version by RC Optical. The open and close was tested extensively without any failures or mishaps. Prior to deliver, Right Ascension tested the open and close operation hundreds of times without any failures. Open and close operations were also tested with the telescope in many different positions and during slews to the park position. All operations performed admirably.

Improved Software Interface

The TIM is the essential, central intelligence for the telescope, monitoring and controlling various critical subsystems, such as the secondary focuser, secondary heater, primary fans, rotator, and robotic mirror cover. The TIM is also supported by an integrated, ASCOM compliant software system that runs on Windows computers called the TIM control application. This application allows complete control of the telescope via a software interface running on the computer.

The TIM control application provides for standardized ASCOM control of the focuser and rotator. Moreover, the TIM control application exposes a COM object that can be accessed with the Windows Scripting Host in order to control the telescope’s subsystems.

One of the most significant improvements in the DAC System is version 2.0 of the TIM control application. The robotic mirror covers can now be controlled through a scripting interface even when the TIM control application is running and being used by another application to control the focuser, rotator and other telescope subsystems.

For example, a startup script can be written that will invoke the TIM control application, connect to the application, open the mirror covers, turn the primary fans on automatic and then turn the secondary heater on automatic. More elaborate scripts can also be written to include checking the focuser position, home the focuser and then returning to the focuser position after homing. After an automated imaging run, another script can turn off the secondary heater, turn off the fans and then close the robotic mirror cover.

Along with the upgrade to version 2.0 of the TIM control application, Right Ascension provided example VBS scripts to control all of the telescope subsystems through the TIM unit. Using these examples, startup and shutdown scripts were created and performed flawlessly, opening and closing the mirror covers and turning on and off the fans and secondary heater. A sample startup script can be found here: RCOS_Startup_Script

Use the sample script at your own risk.  The file extension must be renamed to .vbs from .txt in order for it to run under the windows scripting host.

The implications for automated, unattended imaging are significant. For example, automated imaging software like CCDAutopilot will accept and run external scripts at various points in the automated image acquisition process. Using CCDAutopilot and scripts connecting to the new TIM control application v2.0, the telescope can image objects all night unattended. At the end of the imaging session, the telescope will park, the camera will turn off, the primary fans will turn off, the secondary heater will turn off and the robotic mirror covers will close.

Telescope Control Unit (TIM)
Telescope Control Unit (TIM)
TIM Control Application
TIM Control Application
Sample Scripts
Sample Scripts


The diagram below depicts how the telescope subsystems interface with the TIM unit and the TIM control application, and from there, the ASCOM and scripting interfaces.

TIM Interface Diagram
TIM Interface Diagram

The implementation of the DAC System along with the TIM control application version 2.0 has solved a number of issues and problems. Now the observatory operator will no longer worry about damage to the primary mirror caused by dust, pollen and insects and can rest easy at night knowing the primary mirror will be covered automatically at the end of an imaging session.

Asteroid 2004 BL86

On January 26, 2015, the Putman Mountain Observatory telescope was pointed to a near earth object (referred to as an NEO designated 2004 BL86) that passed within 750,000 miles from Earth.  This asteroid was photographed in a timed video sequence of approximately 50 separate images.  Each image in the video sequence is a five second exposure.  The telescope was tracking the background stars, and therefore, the stars appear fixed with the asteroid moving in front of the background stars.

Click on the video below to watch the asteroid video captured by the telescope:



New Website Design

shutterstock_140672914The Putman Mountain Observatory website has been completely redesigned.  A major function of the old website was to dispaly real-time weather information.  The new website improves on the weather information by providing more detail such as forecasts and National Weather Service Alerts for Fredericksburg, Texas.

The new website also displays astrophotography taken by the observatory telescope.  Finally, the website has been divided into different web pages and sections to make information easier to find and to provide for future expansion.

For example, you may need to know about the weather quickly, and therefore,  a streamlined weather page has this information without the additional information related to astronomy.

Below is an explanation of the different sections of  the new website. You can click the headings for each explanation and go to that particular page.

Observatory Design, Construction and Equipment

The sections under the Observatory page provide the details about how the observatory was designed and built.  Pictures of the construction and observatory equipment are also included.  Hopefully this information will help others thinking about designing and building an observatory.

Observatory Automation

Very often you will hear that observatory automation is too difficult to undertake and complete.  While automation is difficult, it can be achieved and special attention should be given to ensuring the automation is robust with many fail-safes.  This section of the new website illustrates how a completely automated observatory can be designed and built.


The Astrophotography page displays the astrophotos taken by the observatory in a gallery format.  Information concerning the celestial object as well as the technical details for each astrophoto are given.


The Weather page shows real time weather information for the Fredericksburg and Llano areas.  The primary source of weather information is the observatory’s Davis Vantage Pro Weather station.  Current weather data is uploaded to this website every ten minutes.  The weather information has been expanded to provide forecast information and weather alerts.  Weather alerts are indicated at the top of the page.  If a weather alert occurs, click on the link and the most recent weather alert from the National Weather Service will be dsplayed.

In addition to weather forecasts, the new Weather page has more almanac information related to rainfall and high / low temperatures.

Astronomical Weather

The Astronomical Weather page has similiar information as the Weather page, but includes additional information concerning astronomical weather, such as  jetstream forecasts, a clear sky chart, sky quality measurements, live images from the all sky camera, and current information from the observatory’s boltwood cloud monitor.  In addition, detailed temperature and wind information is given to assist in telescope operation.

Current Sky

The Current Sky page shows a “live” virtual planetarium that depicts the stars and constellations for the current time.  As time passes, the virtual planetarium is updated to show the movement of the stars and constellations.  Below the virtual planetarium is a “live” view from the all sky camera that shows a real-time image of the sky above the observatory.  The All Sky Camera view shows the actual stars and constellations overhead.  By comparing the All Sky Camera view to the virtual planetarium, you can learn the names and positions of the stars and constellations as they appear in the sky above.

Sky Quality Monitoring

The Sky Quality page explains how our night skies have been affected by man-made light pollution.  The observatory operates a sky quality meter that measures how dark the sky is and provides real-time updates to this web site.  You can see how dark it is at the observatory and how the rising and setting of the milky way and moon affect how dark it is at the observatory.


The Articles page contains a number of articles that explain various celestial events and provide more detailed information about certain equipment used at the observatory.


The Contact page provides a form for contacting the Lead Astronomer at the observatory with any questions or comments.

User File Area

The User File Area provides a login screen for accessing a user file area for uploading and downloading files.  There is a folder that contains files for public access, but you must have a username and password at the observatory to access individual user file folders.

Boltwood Cloud Monitor

The Boltwood cloud sensor is made by Diffraction Limited and measures the amount of cloud cover by comparing the temperature of the sky to the ambient temperature at ground level.  The sensor measure the sky temperature in the 8 to 14 micron infrared radiation band.  A large difference between the ambient temperature at ground level and the sky temperature indicates clear skies.  Conversely, a small temperature difference indicates that the sky is cloudy because the cloud cover appears “warmer” to the sensor than a clear sky.

The cloud sensor is also mounted on the weather telemetry pole and is directly wired to the DarkCloud weather server.  Real time weather information from the cloud sensor is updated to this website every 5 minutes.

The cloud sensor also measures moisture and can detect even a few drops of rain.  When rain is detected, the cloud monitor sends a signal to the Ace Smart Dome control unit to close the dome if it is open.

The sensor also measures wind speed, humidity and daylight.  If any of these values exceeed predetermined maximum levels, the cloud monitior sends a signal to close the dome.  For example, when the sun rises, the cloud monitor will detect daylight and will request the Ace Smart Dome to close the dome.

Finally, the cloud monitor, produces a time lapse chart showing the sky conditions over the last few hours.  The chart to the right is a current real-time time lapse chart showing the changing cloud conditions over the last 12 hours.

The top part of the chart indicates cloud conditions.  White means it is clear, yellow means cloudy and red means very cloudy.  Blue means that rain or moisture is present.

The Astronomical Weather page shows a continual real-time cloud monitor chart.

The DarkCloud weather server post explains how the cloud monitor provides information to the weather server and this web page.

Real-Time Cloud Sensor Chart

All Sky Camera

All Sky Camera
All Sky Camera

The  All Sky Camera is made by Santa Barbara Instruments Group (SBIG).  The camera is an astronomical camera mounted in a weatherproof enclosure with an acrylic dome for the camera lens.  The camera lens is a fish-eye type to give a full view from horizon to horizon.

The camera is permanently mounted on the weather telemetry pole and takes a photo of the sky every minute or two.  Images are downloaded to the DarkCloud Weather server and uploaded to the internet to this web site for viewing.

The All Sky Camera is updated frequently and the images show the night sky including stars, the milky way and consellations.

The All Sky Camera is oriented to correspond with star charts.   This assumes you are looking up at the sky and North is at the top of the image, West is to the right of the image, East is to the left of the image and South is to the bottom of the image.

An example image from the All Sky Camera is shown to the right.  You can see the Milky Way and related constellations.  The observatory dome is on the right side of the picture, or to the west.

This website has a webpage that shows real-time updates from the All Sky Camera and compares the current image to a real-time virtual planetarium illustrating the stars and constellations.  You can see it at this link:

All Sky Camera