
What Is Mercury Venus Transit Maestro?
Mercury Venus Transit Maestro is an automated Mercury or Venus transit photography freeware. Commercial distribution is strictly forbidden. To help you enjoy the event, you can use it to control up to four USB or Firewire connected cameras (Nikon and Canon DSLRs or MILCs, plus Nikon Coolpix line and now a few Panasonic, Sony, Fuji and Olympus) during an eclipse so that you can be free to concentrate on observing the event visually. Up to four USB or Ethernet connected SBIG CCD cameras with filter wheels are supported as well. You must preprogram all exposure information according to a script. Observer position (latitude and longitude coordinates, altitude) is used to calculate local circumstances so that camera actions can be referenced to specific transit events. All features are optional, so the application can be used for as little or as much as desired.
First developed for the 2006 November 8th Mercury transit, it has been successfully tested in Los Angeles.
Solar Eclipse Maestro is a similar application meant for solar eclipses.

Hardware and Software Requirements
- There are two versions of the software: the first one is a Universal Binary, meaning it runs on both Mac Intel and PPC, that runs under MacOS X 10.4.x (a.k.a. Tiger) to MacOS X 10.14.x (Mojave) and the second Intel only runs under 10.6.x (Snow Leopard) to MacOS X 10.14.x (Mojave). The first does support Canon’s legacy cameras (EOS 350D/Rebel XT/Kiss N, 20D/20Da and 5D), but not the models released after the 60D; this remains true until Yosemite, with El Capitan or newer this version can not control DSLRs or MILCs anymore. The Intel version doesn’t support Canon’s legacy cameras, but supports all the latest models. A screen with a minimum 1024x768 resolution is recommended, although it will work with smaller screens.
- To use a SBIG CCD camera you need to install the SBIG driver that is available with the installer. This feature is only supported for Leopard and newer.
- One or more USB or Firewire ports for DSLRs or MILCs and optional GPS device or USB shutter control cable (DSUSB from Shoestring Astronomy) are required.
Overview
- This application uses materials from Nikon, Canon, SBIG, Panasonic and Ricoh. However no specific driver is required to control the supported digital cameras.
- Scripted control of up to four DSLRs or MILCs (see supported camera list below) over USB or Firewire connection, with full control of shutter, aperture and ISO. For higher frame rate and reliability, images are stored to the camera’s memory card, not the computer.
- High speed shooting on USB or Firewire connected cameras is available but limited by the camera (typically up to 3-10 frames per second).
- Scripted control of up to four SBIG CCD cameras over USB or Ethernet connection, with full control of the exposure time and filter wheel. Exposures are automatically recorded on the computer.
- Scripted playback of self-recorded WAVE sound files for reminders. Please be considerate of others when using this feature.
- Garmin USB GPS support for position and time information, all serial NMEA 0183 GPS units through either USB or Bluetooth. Highly stable timing via 1 pulse per second signal when specially cabled Garmin GPS18-LVC used. For utmost timing accuracy, the observing site latitude/longitude/altitude should be known to within ≈200 meters, and the Mac clock should be set to within ≈0.5 second, which requires a GPS measurement on transit day. All Garmin USB GPS units using the proprietary Garmin PVT protocol (untested with serial devices using a serial to USB converter) are supported and most NMEA 0183 compliant units either through USB, serial or Bluetooth.
- Calculation and display of transit local circumstances, with capability to reference camera script items to transit events ("5 seconds after second umbral contact", at maximum transit, etc.) or use absolute UTC date/times.
- Refraction and ΔT correction supported. UTC event times for subsecond accuracy.
- Manual override of computed contact times.
- Easy adjustment of computer clock: a static offset correction can be entered if no GPS is connected.
- Simulated time support (fudges clock without affecting the Mac’s system time) to allow easy rehearsal.
- Sun-Planet diagram and large event countdown display.
- Transit map with mouse-over geographic cursor coordinates and transit type info. A maximum transit diagram at the mouse-over location can also be displayed.
- Solar terminator animation on the transit map.
- Sky chart at the time of maximum transit.
- Camera’s date and time synchronization available when supported by camera.
- Manual (M), Bulb (B) and Program (P) modes supported.
- Multiple cameras can be fired simultaneously.
- Upcoming script item display.
- ⌘1-⌘4 keys fire camera shutters.
- Live View (Lv) mode support to allow easier focussing.
- Generation of Google Earth and GPS files of the transit visibility areas and geometry.
- Night vision mode for preserving your dark adaptation.
- Multiple locations of the observer can be saved and later reloaded.
Limitations
- Bulb (B) mode not supported.
- Camera scripts are plain text files in CSV format (comma-separated values) and must be edited in a plain text editor like TextEdit or TextWrangler. Opening a CSV script file in Microsoft Excel will corrupt times.
- Works only with Nikon, Canon, Panasonic, Sony, Fuji and Olympus DSLRs and MILCs plus Ricoh Theta cameras at the moment, but depending on number of requests received other makers’ DSLRs or MILCs could be added in the future.
Supported cameras
Nikon
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Canon
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Santa Barbara Instrument Group (SBIG)
Sony
Panasonic
Fuji
Olympus
Ricoh
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(*) Works only with the Intel release of the application |