Grazing Lunar Occultation of Mars

This Lunar occultation of Mars was captued from just east of Egin, Texas on 2022-12-09 between 02:40 and 03:21 UT during a break in the clouds in central Texas. Thanks to the Astrospheric app's Ensemble Cloud forecast I was able to identify the location most likely to be clear during the occultation. A forecast is no guarantee, but it can put the odds in your favor.

I used a Questar 1280/89 mm with a Sony A7 iii camera. I timed the images to take advantage of the best transparancy and avoid the occasiona thin clouds. Images exposed 1/160 sec at ISO 100 and f/15. A time lapse composite, mages aligned with Autostakkert! 3, lunar surface from the best 9 images, final time lapse composite and exposure adjustment in Photoshop. The uncropped image is below:

Below is my equipment setup at my scenic location in an empty parking lot along US 290 east of Elgin. The clouds are just starting to break up.

The Astrospheric Ensemble Cloud forecast that I used to identify the location of a break in the clouds at occultation time is below. The ebsenble shows the RDPS model (Canadian Regional Deterministic Prediction System, 10km grid) in blue, NAM (US NOAA NCEP North American Mesoscale, 12km) in green, and GFS (US NOAA NCEP Global Forecast System, 28km) in red. Areas where all forecasts agree will be cloudy appear white, and areas that all models agree will be cloud free are colorless.

Astrospheric can also display on the map the NBS hourly forecast (US NOAA NWS National Blend of Models) and a summary of 8 to 10 days of extended cloud forecasts. All together the best and most useable astronomical forecast tool that I've found. It's avaialble in a web version and Apple iPhone app. Free, but some products like the ensemble forecast require a small subscription fee.

Content created: 2022-12-09




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