WT5L Blog

After much work and much learning, all my amateur radio contacts dating from the very first one recorded in July 2000 are now online.  The complete set of 11,333 contacts (current count) have been uploaded to my website’s server and placed into a MySQL database.  I’ve also written and posted a php web page (click here) to access, search, and display the database contents.  In addition to having the ability to search for individual callsigns, it is also possible to search and display any callsigns matching particular patterns (i.e. ‘ve%’ searches for all callsigns beginning with the letters, VE; ‘%5% searches for all area ‘5′ callsigns).  The database can also be filtered by band, mode, or date-time range.  Finally, a custom query string allows anyone familiar with SQL statements to enter custom search statements.   (Some possible search statements are given as examples).  Keeping the online database up-to-date is simplified using the export feature of DXKeeper, the desktop database manager where I record all my amateur radio contacts.

I finally decided to sit down and really learn some Javascript programming.  The end result is two apps that I put together and is available here.

The first app reads the user’s computer time and displays the local time, local date, GMT, time zone offset from GMT, Julian date, and local sidereal time with continuous updates every second.  The only input required is the user’s longitude and this is only used for the local sidereal time calculation.  Through the use of a cookie, once the user enters the longitude the first time, this value will be remembered the next time the app is invoked.  Being a Javascript application, this is a “client side” program that runs only on the user’s local machine (as opposed to a “server side” program that runs on the server hosting the called website.)

The second application is useful for astro-imagers.  This app, also written in Javascript, takes the user’s input of the pixel size of a CCD imaging device and the scope’s focal length to calculate the image scale for the given scope/camera combination.  Additionally, it will then take this calculated image scale and, using the user’s input of the number of rows and columns of pixels of the same CCD imaging device, calculate the field of view in arcminutes and in degrees.  Error checking is provided to make sure the user enters valid numbers for the calculations.

More Javascript apps are in the works and will be added as they become available.

To follow up on the previous two posts, I was slightly puzzled by the different motions of Mars and Uranus.  As shown in the composite image above, Mars is seen drifting toward the southeast and Uranus is seen drifting toward the southwest.  (All images that make up the composite were shot at the same scale and same camera orientation.)  After a little research, I found that all the planets, in general, drift toward the east.  However, as the Earth, in it’s faster orbit around the Sun, catches up to the outer planets, these outer planets appear to stop their eastward drift and reverse to a westward drift.  Later as the Earth passes, this westward movement stops, before the planet resumes a normal eastward drift.  When I shot these images of Uranus on Nov. 13 and 14, I just happened to catch it while drifting westward (retrograde).  Simulating this in The Sky planetarium program, I found that Uranus ceased its westward drift around Nov. 30 before resuming its normal eastward motion (prograde).  The inner planets also exhibit direct and retrograde motion for similar reasons.  A more detailed description of “apparent retrograde motion” is available here.

As detailed in the article linked to above, it isn’t very hard to catch Uranus in retrograde since the more distant planets are more frequently in retrograde.  It turns out that Uranus is in retrograde for 151 days out of every 12.15 months.  In contrast, Mars is in retrograde for only 72 days out of every 25.6 months.

Click here to view a larger version of the image above.

Like the Mars image previously posted, the image above is an attempt to illustrate the movement of the planet Uranus against the background stars over a period of time.  During my November trip to the Chiefland Astronomy Village, I was able to photograph Uranus on two consecutive nights.  On the first night, Nov. 13th at about 7:15 pm local time (Nov. 14 0015 UT), Uranus was in the upper-left position in the image.  On the second night, Nov. 14th at about 7:10 pm local time (Nov. 15 0010 UT), Uranus was in the lower-right position.  I was able to determine from the images that Uranus moved approximately 31 pixels for this 24-hour period.  Given that the image scale for my setup is 1.76 arcseconds per pixel, this 31-pixel movement represents about 55 arcseconds movement (slightly less than one arcminute) per night.

Click the following link for a small version of this image:

http://astro.wt5l.com/Astro_Images_Content/Uranus-nov2009-small.jpg

Click the following link for a large version of this image:

http://astro.wt5l.com/Astro_Images_Content/Uranus-nov2009-large.jpg

The image above is an attempt to illustrate the movement of the planet Mars against the background stars over a period of time.  During my November trip to the Chiefland Astronomy Village, I was able to photograph Mars on three consecutive nights.  On the first night, Nov. 13th at about 3 am local time (0800 UT), Mars was in the upper right position in the image.  On the second night, Nov. 14th at about 2:30 am local time (0730 UT), Mars was in the middle position and on the third night, Nov. 15th at about 2:45 am local time (0745 UT), Mars was in the lower left position.  I was able to determine from the images that Mars moved approximately 729 pixels each 24-hour period.  Given that the image scale for my setup is 1.76 arcseconds per pixel, this 729-pixel movement represents about 21.4 arcminutes movement per night, about 2/3 the width of a full-Moon.

Click the following link for a small version of this image:

http://astro.wt5l.com/Astro_Images_Content/Mars-nov2009-small.jpg

Click the following link for a large version of this image:

http://astro.wt5l.com/Astro_Images_Content/Mars-nov2009-large.jpg