Polaris Distance from Celestial Pole

If you've taken star trails photos facing north, or used Polaris to calculate latitude, you're probably aware that the North Star doesn't sit directly over the north celestial pole. But how far off is it?

My trails are a little wonky because my tripod was on a wooden balcony, 300mm zoom lens, field of view in this image is about 3.5°

In the above photo, Polaris is the brightest line in the center of the image. You'll notice that there are quite a few stars in between Polaris and the true celestial pole. However, none of these stars are bright enough to be reliably visible, and aren't used for naked eye navigation or basic polar alignment.

Polaris lies 0° 40' 37" from the celestial pole

Polaris' position in the sky is moving toward the pole, making it a better pole star by the day! In the year 2000, Polaris was located at 89° 15' 50.8", and is now (according to Stellarium) located at 89° 19' 23".

I thought it would be a relatively simple question to answer "how far is Polaris from the celestial pole" but now I've been looking up terms and reading about things like parallax, precession, nutation, aberration, and proper motion. Wow! So much to learn still.

So in the year 2000 at exactly noon (terrestrial time) on January 1st, the position of stars was calculated as the new standard for the next 50 years. This is called J2000.0 denoting Julian date 2451545.0 TT. I still can't find a good description of the difference between equinox and epoch, but nevertheless right ascension and declination are constantly changing, so the epoch servers as a standard starting point for calculations.

This is getting a bit heavy, so I'll wrap up by saying that since the reported "to date" position of Polaris is 89° 19' 23" all we need to do is subtract from the celestial pole 90° 00' 00", which (be sure to borrow units of 60) comes out to 0° 40' 37" (or 40 and 37/60 arc minutes = 40.6166 arc minutes).

Don't take my word for it, kids! I never took a class on this, I'm just sort of thinking out loud trying to figure all this stuff out.

Surprise University of Hawaii Institute of Astronomy Swag

I came home from work on Monday to find an inconspicuous brown paper bag stamped FIRST CLASS MAIL with a return address from Hawaii. My friend Mike sent me a surprise gift with a hand written note.

It's a shirt from the University of Hawaii Institute for Astronomy! Mike visited during an open house, and got to tour around the facilities. His favorite part was learning about Dr. Gary Greenberg's microphotography (sandgrains.com).

I waited to post about this until I gave my thank you card a chance to get back to Hawaii. Thanks Dhoe, you rule! I'm wearing the shirt right now, it's a great fit!

Venus Approaching The Teapot in Sagittarius

I've been wanting to get a nice close up photo of The Teapot asterism in Sagittarius, and I'm glad I got a chance before this section of the sky sets for the season. Even in this single frame, you can easily make out some fuzzy blobs to the side. This asterism lies directly over the main swatch of Milky Way, which means there are plenty of interesting things to see in the neighborhood. 

At first, I used my 75-300mm lens on 75mm, and had a calculated field of view of 16° 50' 20" horizontal. I only needed 15 degrees to fit Venus in frame with The Teapot, but I decided to scale back to my 18-55mm lens at 55mm, which gave me a little elbow room on either side (about 22° horizontal FOV).

Single frame at ISO 1600, f/5.6, 55mm, 3.2 sec, color adjusted in Photoshop

Single frame at ISO 1600, f/5.6, 55mm, 3.2 sec, contrast adjusted in Photoshop

November 2013 Indiana Astronomical Society Novice/Urban Observing List

Phil Dimpelfeld from the Indiana Astronomical Society creates a Novice/Urban Observing List each month for newbies like myself with not-so-dark skies and not-so-powerful equipment. The October 2013 list had some very close double stars, but I was still able to observe and document 6 of the 11 objects, including the challenge object!

November looks like a lot of fun, but doesn't include the typical two lunar items. Considering my equipment limitations, Phil suggested Mare Humboldtianum and Riccioli (crater) as optional additional lunar targets. Comet ISON (C/2012 S1) is also on the list! Oooh baby here it comes!

Venus, planet in south-western sky after sunset, mag = -4.2, size = 23”. What is the phase of Venus?

Uranus, planet currently in Pisces, 00h 36m, +03° 03’, mag = 5.7, size = 4”

M32, satellite galaxy to M31, 00h 42.7m, +40° 52', mag = 9.0, size = 8’ x 6’

M31, the “Andromeda Galaxy”, 00h 42.7m, +41° 16', mag = 4.4, size = 180' x 63'

Eta Cassiopeiae, double star in Cassiopeia, 00h 49.1m, +57° 49', mag = 3.4, 7.5, sep = 12”

Psi 1 Piscium, double star in Pisces, 01h 05.6m, +21° 28', mag = 5.6, 5.8, sep = 30"

NGC 457, the “E.T.” Cluster, open cluster in Cassiopeia, 01h 19.1m, +58° 20', mag = 6.4, size = 13.0'

NGC 663, open cluster in Cassiopeia, 01h 46.0m, +61° 15', mag = 7.1, size = 16.0'

Gamma Arietis (”Mesartim”), double star in Aries, 01h 53.5m, +19° 18', mag = 4.8, 4.8, sep = 7.8”

NGC 752, open cluster in Andromeda, 01h 57.8m, +37° 41', mag = 5.7, size = 50.0'

Challenge Object #1:
M110, satellite galaxy to M31, 00h 40.4m, +41° 41’, mag = 10.0, size = 17' X 10'

Note that the surface brightness of M110 is much fainter than M32, although theses two satellite galaxies have the same magnitude. Tip: study the photographs of M31 to locate M32 and M110 relative to the core of M31. It will be easier to find M110 if you know the general area to look in. Moving the scope makes it easier for your eye to pick up this faint object.

Challenge Object #2:
Comet ISON, eastern sky before dawn, check star charts for position (in Leo for October)

Saturn Mercury Close Conjunction in November (Less than 1° Apart)

In late November, Saturn and Mercury will make a very close conjunction, coming within 1 degree of each other from our perspective. The pair will be low in the SE sky an hour before sunrise.

November 23, 2013 Mercury is about 6° above the horizon to the SE about an hour before sunrise. Screenshot from Stellarium.

Comet ISON (C/2012 S1) is predicted to pass Spica on November 18 as it dives toward the horizon, passing the Mercury Saturn conjunction around November 22-23.

November 25, 2013 Mercury and Saturn will be within 1 degree separation low in the SE to the left of the double star Alpha Librae (α Lib). Mercury will only be about 5 degrees above the horizon an hour before sunrise. Screenshot from Stellarium.

November 26, 2013 Mercury and Saturn switch places, with Saturn now on top and still within 1 degree separation. Saturn will only be about 5 degrees above the horizon an hour before sunrise. Screenshot from Stellarium.

Saturn joins the party on December 1, 2013 - this screenshot from Stellarium shows 7:00am ET from Indiana