Cassiopeia Observatory

Moon-Jupiter Conjunction

Posted: 22 January 2013

The sky was cloudy on Sunday, 20 January 2013, but mostly clear on Monday, 21 January. At 1713 MST, about 35 minutes before sunset, I photographed the Moon-Jupiter conjunction with the D7000 DSLR, 300mm lens, handheld. Jupiter was visible in the camera viewfinder. Jupiter was also visible to the naked eye, using the moon to locate it. This is a cropped, f/5.6, 1/200sec, ISO 100, image:

The observatory was opened at 1806 MST, 68°F. At 1813 MST, viewed Jupiter, 77X. Three moons were visible, with a fourth very near the planet's limb. Then I viewed the moon, 77X. Added a focal reducer and switched to a visual back for later imaging of the Moon-Jupiter conjunction. Using a 1.25" 26mm eyepiece, both Jupiter and the moon were in the same field-of-view (FOV) but not all of the moon could be seen. Switched to a 1.25" 40mm eyepiece; better, but still not all of the moon in the FOV. Closest approach for the conjunction was still about 90 minutes away. Viewed Jupiter and the moon using 7x50 binoculars. Lovely view.

I mounted the D7000 DSLR on a photographic tripod and took this photo (cropped to the same scale as the image above) at 1836 MST, f/8, 1/250sec, ISO 100, 300mm:

This photo (cropped the same), was taken at 1929 MST, f/8, 1/160sec, ISO 100, 300mm:

The three photos above show the progression of the conjunction in a period of over two hours as the moon moved eastward.

This next photo was taken at 1931 MST, f/5.6, 1 second, ISO 1600, 70mm, showing the moon (overexposed), Jupiter just to its left, and the Pleiades (top):

I then mounted the D7000 DSLR on the 8" LX200-ACF at prime focus + focal reducer + visual back. This image (full-frame) was captured at 2002 MST (approximately closest approach), using the "Hat Trick" method, ISO 100:

I ended imaging at 2004 MST. Viewed the conjunction with the 40mm eyepiece + focal reducer + visual back. The moon was fully in the FOV with Jupiter. Switched from the visual back to the diagonal for easier viewing since the moon was nearly straight up by now. Both objects were fully in the FOV with the 26mm eyepiece + focal reducer. Removed the focal reducer and tried 2" 30mm and 2" 50mm eyepieces; neither allowed both objects to be fully in the FOV.

At 2019 MST, switched to the 2" 9mm 100° eyepiece (222X) and did some lunar observing. Seeing was good and the views along the terminator were fascinating.

I have added an Astronomy Mementos photo album page. It includes caps, shirts, pins, patches, etc., that I have collected over the years. Have a look.

Comments are welcome; use the Comments section below, or you can Email Me. Thanks.