Jupiter in the daytime

Jupiter is bright and easy to find in the early morning sky.  I really wanted to see for myself that Jupiter, which usually has two darker cloud bands, now has only one.  But sunrise is sooooooo early in summer, I really couldn’t get up before dawn this morning, but I had to see the ‘single-banded’ Jupiter in the telescope for myself.

So I decided to try to find Jupiter in the daytime.  With the bright sunshine overwhelming the fainter stars and planets, how to find it?  My palm pilot (Andreas Hofer Planetarium) told me that after 9am, Jupiter was in the open sky over my house between the trees, but Jupiter isn’t easy find in the daytime and I don’t have one of those fancy pointing computers on my telescope. So how to  point my telescope, with its tiny field of view, to  find Jupiter, a tiny needle in a large haystack of the sky?

To do this, I needed to find a spot out of direct sunlight and know which direction to point and how high Jupiter is above the horizon.  Our large tree shaded me from the sun, and I used a Wixey Digital Angle Gauge I attached to my 8″ dob to find the correct elevation above the horizon, which I found from my palm planetarium.  I tilted the scope until the angle gauge read Jupiter’s altitude (40 degrees), then rotated the scope to the approximate azimuth from the palm pilot.  Then, using my 7×50 finder telescope attached to the dobsonian (which sees more sky then the telescope itself, I scanned right and left a bit and found Jupiter -a small, non star-like round dot..

Then I observed through the dobsonian with a 6mm (200x) eyepiece.  Jupiter looked soft around the edges, no moons, no color, but the one band of darker shading, offset from the center of the planet, was easy to see, even against the bright sky.  While I had glimpses of  detail, nothing consistent.  The polar regions were slightly darker.  Polarizing sunglasses worked best to help increase the contrast.  A yellow filter helped the view a bit.
It doesn’t seem like there’s enough detail to do any serious work, but it was clear that Jupiter had only one prominent band, and that was worth it.  And thanks to my $35 angle gauge and a bubble level to set the gauge to horizontal, I’ve found Venus and Jupiter in the daytime.
Attached is a photo I took with the Rebel through the eyepiece.  I just held the camera right next to the eyepiece and used Live View to wait until Jupiter moved through the center of the view.  The I took the photos – using the settings I already had set to take a photo of my scope.  The technical settings are: 55mm zoom at the P setting minus 2/3 step, ISO 800 which resulted in 1/30 sec F5.6.  Playing with the brightness and the levels in my photo software brings out the band a bit more.  In the photo, Jupiter is the white disc in the upper part of the blue area.  Since I used the zoom on the camera, Jupiter is larger than it looked to me though the eyepiece, but the view (and the band) was clearer than seen in the photo.

Jupiter through the eyepiece at 200x of my 8inch dobsonian

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s