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Goddard Space Flight
													      Center Sonoma State University
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GORT Observatory Information GORT
Location Hume Observatory, east of Windsor, CA
Longitude 122o 41' 13.8'' W
Latitude 38o 33' 55'' N
Elevation 335 m = 1099 ft
MPC Observatory Code U54
Exposure Calculator

Not sure what exposure time to use for your observations? Use the link below to launch our exposure calculator applet to help you decide. Our exposure calculator suggests exposure times based on V magnitudes. For I filter observations decrease the suggested value by 25%. For B filter observations increase by 100%. The returned values are suggestions only. Sky conditions and the type of object will both influence exposure times. When imaging faint objects (V mag > 10) use exposures no longer than 120s, as our telescope does not have a guider. The suggested exposure time is designed to return an ADU count around 45,000 (that is a lot!) for the entered magnitude. Our chip saturates around 65K ADU.

Launch Exposure Calculator

Sky Conditions

GORT Weather Station

The GORT Weather Pages show current data from the GORT weather station and are updated every 15 minutes. The Pepperwood Weather and Skycam Page shows data from the Pepperwood Preserve weather station, located about a kilometer away from the observatory. That station includes a skycam looking off toward the southwest, the direction from which fog and other clouds often approach.

Satellite Imagery (Click heading to view image)

expand sectionVisible


expand sectionIR


expand sectionNorthern Hemisphere Enhanced IR

Northern Hemisphere Enhanced IR

expand sectionWater Vapor

Water Vapor

expand section12 Hour US Weather Forecast

12 Hour Map

expand section24 Hour US Weather Forecast

24 Hour Map
Phase of the Moon
EThe moon NOW!W
Predicted Observing Conditions

This link to the Clear Sky Clock for Hume Observatory will provide predictions for observing conditions for the next three nights. Predicted conditions include cloud cover, transparency, and seeing. (Times are also shown for daylight, twilight, and darkness.) These predictions are based on atmospheric models for the north-eastern Pacific Ocean and the North American content.

Clear Sky Clock for Hume

Getting Your Data

Once your data has been collected by GORT you can retrieve if using the File Transfer Protocol (FTP). To learn about FTP please visit University College Cork Computer Centre FTP Info page. To retrieve your data FTP to using the username and password supplied by the observatory engineer. Here you will be able to download your data. If your not sure when your data was taken you can search for it online at Please note that if your data was taken using an ACP Plan you may search for the object name. If your data was taken manually through a MaxIm sequence then you can search by coordinates.

If you have a question about the GTN, please contact one of the "Responsible SSU Personnel" below.

This page was last modified on Friday 01st September 2017 @ 09:15am

Science Mission Directorate Universe Division

Responsible SSU Personnel:

Dr. Kevin McLin (mclin at universe dot sonoma dot edu)

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