Uranus and Neptune: similar altitude

Event Date: October 10th
Time: 9:41(.34) PM


Brief

    Here is a review of Uranus and Neptune's altitudes, in comparison to each other.  I did this yesterday with Saturn and Mercury, showing them close yet not exactly the same.  This evening, with both Neptune and Uranus both very slow moving planets [against the stars], the same altitude value for them only changes by a slight amount each night.  They are 35º 27' apart, and about 40º 10' in altitude.  Since Uranus' declination is more north than Neptune, by about 13º, its change in altitude is faster than Neptune's; I talked about this with Mercury and the Sun yesterday.
Using the gridlines in the image, see how the two are very close to precisely the same altitude.

click on image to enlarge: courtesy of Starry Night Pro Plus, version 6.4.3, by Simulation Curriculum Corp.

Detailed

   As both planets move in either retrograde or prograde, with Neptune going back to prograde first before the year ends, that means that the time of being the same altitude will not always reflect sidereal time, of 3 minutes, 56 seconds.  We also need to take the changes of declination into account, and Uranus is more affected by this than Neptune.  As mentioned earlier this year, Uranus is closer to the celestial meridian, where declination change is faster than where Neptune is.  The celestial meridian, equator and ecliptic are also included in the image.
   Each night, using an altitude/azimuth telescope, try to find a time-pattern for when at the same altitude.  Using a medium-low magnification to center each planet.  By slewing left or right, if you find both in the middle of the field, they are the same altitude.  Remember when doing this, do not change the telescope itself in altitude when slewing, or it will make it harder to keep both centered.