Vern’s Weblog

Highlights Dec 30 to Jan 5

• 8P/Tuttle very close to Messier 33 (if not within) early Sunday evening
• Dark sky weekend coming up
• Bright ISS passes early in the morning this week (see below for Denver times)
• Earth at perihelion (closest to the Sun) on Thursday, Jan 4 at 4 pm MST distance 0.983 a.u. (91.4 million miles)

International Space Station

Some good passes this week, but you’ll have to get up before sunrise to see them.
On Sunday Dec 30 the ISS appears at 06:59:47 am in the SSW and disappears at 07:05:00 am in the ENE (magnitude -0.4)
On Monday Jan 1 the ISS appears at 06:06:16 am in the SSW and disappears at 06:11:19 in the ENE (magnitude -0.4)
On Thursday Jan 3 the ISS appears at 06:47:31 in the West and disappears in the NNE at 06:52:28 am (magnitude -1.3)
On Friday Jan 4 the ISS appears at 05:36:15 halfway up in the sky in the NE and disappears at 05:38:20 in the NE (magnitude -1.5)
On Saturday Jan 5 the ISS appears in the North at 05:56:36 and disappears in the NE at 05:58:38 am (magnitude -1.1)

Sun

No regions are currently visible as of today. Solar activity is expected to remain at very low levels this week.

Moon

The moon is in last quarter early Monday morning, Dec 31 at 0:51 am MST. It will be “new” a week from Tuesday.

Planets

Mercury appears very low in the southwest a half hour after sunset late in the week. It will be in better position next week.

Venus is very bright at magnitude -3.95 and 14.2 arc sec across. It moves from constellation Libra into constellation Scorpio on New Years day.

Mars dims a bit this week from -1.6 to -1.4 magnitude in brightness. Our view of the martian disk shrinks from 15.55 arc sec Sunday to 15.1 arc sec next Saturday. However it is still a good time to view Mars. Seeing It is detail visually through an eyepiece is difficult unless seeing conditions are very good. Use as much magnification as conditions permit and experiment with red and green filters to reduce the glare. To get the best view, replace the eyepiece with a webcam and view it on your laptop. Later process the video with Registax and you should be able to identify some features.

Saturn is in constellation Leo. It rises just after 9 pm by Saturday and is +0.9 magnitude in brightness. The disk is 19 arc sec across.

Dark Sky

Dark sky weekend is here once again! The truly dedicated can get 11 hours and 21 minutes of astronomical darkness Saturday evening.

Take a look directly south around 10 pm about half way up in the sky and locate “Orion, the Hunter”. Look for three bright, second magnitude stars in straight line from the southeast to the northwest. These stars form Orions Belt. To the upper left is the reddish 0.5 magnitude star Betelegeuse. Toward the upper right is the 1.6 magnitude bluish star Bellatrix. Below are two other bright stars, 2nd magnitude “Saiph” on the left and magnitude 0, “Rigel” on the right.

Use binoculars and center on the middle belt star called “Alnilam”. Surrounding it is a magnificent sprinkling of about a hundred stars from 5th to 10th magnitude in a 3 degree field called “Collinder 70″.

Drop southward from the middle star and locate Orion’s sword. This region is the location of one one of the night skys most splendid show pieces, the Great Orion Nebula. This is one of everyone’s favorite objects to view in a telescope of about any size. In the center of the region are four bright stars forming a diamond shaped asterism called the “trapezium”. In steady skies a couple additional 10th magnitude stars may be seen. Just above M42 is another diffuse nebula, “Messier 43″ which surrounds an irregular variable star “NU Orionis”. If you are fortunate have dark skies, continue exploring another 30′ north and view some of the faint nebulous swirls of NGC 1973-1975-1977. This region is a continuation of the same large cloud of dust surrounding the Orion nebula. If conditions are really good, point your scope toward the left most star in Orion’s belt, “Alnitak”. Move north and east until Alnitak is just out of field and view the NGC 2024, the “burning bush” or “flame nebula”. If you center on Alnitak and then slew straight south, you may be able to see the elusive “horse head” nebula, IC434 or Bernard 33, use UHC or OIII filter.

Comets

Comet 17P/Homes is in constellation Perseus, above and west of star Algol. It is around magnitude 5 in brightness and 70 or so arc minutes across.

Comet 8P/Tuttle is projected to be around magnitude +5.7. As soon as its dark on Sunday night, Dec 30 it should very close if not within Messier 33 in constellation Triangulum. It moves to southern Pisces on Saturday (just above Alrisha or Alpha Pisces).

See http://cometchasing.skyhound.com for charts and more information regarding comets.

Merry Christmas and Happy Holidays everyone!

Highlights this week

• Bright ISS pass tonight, Dec 23rd, at 5:16 pm
• Mars opposition on Monday Dec 24
• Checkout Comet 17P Holmes and 8P/Tuttle with binoculars before moonrise

International Space Station

Only one good pass this week, tonight at 5:16:23 pm. Appears in the WNW and disappears in the SSE at 5:21:40 (magnitude -0.6).

Sun

No regions are currently visible as of today. Solar activity is expected to remain at very low levels this week.

Moon

The moon is full tonight, Dec 23 at 6:16 pm MST. Take a look for rays and bright albedo features.

Planets

Venus is visible before dawn in constellation Libra. It is very bright at magnitude -4.0. It shrinks in angular size this week from 15.3 to 14.7 arc sec across.

Mars is at opposition on Christmas in constellation Gemini. It is -1.6 magnitude in brightness. Our view of the martian disk shrinks from 15.85 arc sec tonight to 15.56 arc sec on Saturday.

Saturn is in constellation Leo. It rises at 9:39 pm by Saturday and is +0.9 magnitude in brightness. The disk is 19 arc sec across.
Dark Sky
Starting Wednesday, we’ll get some dark sky before moonrise in the early evening. On Saturday, the moonrises at 11:11 pm.

Comets

Comet 17P/Homes is in northern Perseus, around magnitude 5 in brightness and 70 or so arc minutes across.

Comet 8P/Tuttle is brightest this week at magnitude +6.4.Tonight it is in constellation Casseopia but will move rapidly south for several weeks. It be in constellation Andromeda on Christmas day. Coma is about 5.2 arc-min.

See http://cometchasing.skyhound.com for charts and more information regarding comets.

Image below of Mars from last night around 11pm, MST.  Clear, transparent sky, 22°F , 2-3 mph wind,  but turbulence not good, maybe 4/10 — too much movement to even check collimation. Image came out far better than I expected.  Celestron Nexstar11 telescope at cassegrain focus, Phillips Toucam 840K, 20 fps, 3/4 gain, 100% brightness,  and 1/500 sec shutter. Approx 4000 frames aligned, stacked, histogram adjusted, and wavelet filtered with Registax4. Resized 150%.  North is approximately up, east to the left in the image.  The central meridian should be around 19 degrees, so that is Mare Acidium near the top, Mare Erythreum is the dark feature extending from 9 o’clock on the left. Sinus Sabeus extends from about middisk to the 5 o’clock position.

 Some things to see in the sky, this week Dec 16 to Dec 22, 2007.

Highlights

• Bright ISS passes on Thurs at 5:48 pm and Sat at 4:55 pm
• Mars is closest to Earth on Dec 18 around 5 pm (0.589 AU, 54.94 million miles, or 88.42 million km), apparent diameter of Mars is 15.87 arc sec
• Comet Holmes is still a great object to view in binoculars
• Winter solistice Friday, Dec 21 at 11:08 pm 

International Space Station

There are some very good ISS passes in the early evening this week.  The best ones are:

Sun

The Sun rises at 7:17 to 7:20 am and sets 4:40 to 4:42 pm this week.  A fair size region 10978 is near the western limb and will rotate from view on Tuesday.  Solar activity is predicted to be at very low levels according to the Space Weather Prediction Center.

Moon

The Moon is at first quarter on Monday, Dec 17 at 03:18 am . Its a great week for lunar observing.

PlanetsVenus rises around 4 am in constellation Libra and is very, very bright magnitude at -4.

Mars rises before dark and increases in brightness to magnitude -1.64 and to 15.9 arc sec across. It is in good position for viewing around 8 pm.

Saturn rises 10:11 pm by the end of the week in constellation Leo. It is magnitude +0.93  in brightness.

Dark Sky

Not this weekend, moon interfers all night.

Comets

Comet 17P Holmes is getting larger and dimmer (around magnitude 5)  in constellation Perseus. It is over a degree across and easy to spot in binoculars even in light polluted skies. 

Comet 8P Tuttle is now about magnitude +8.2 in constellation Cassiopea.

Comet 46P Wirtanen is magnitude  +11 in constellation Aquarius. Look for it early in the evening around 6pm.

(See SkyHound.com  or Seiichi Yoshida’s Comet pages for charts and additional information).

Comet 46P/Wirtanen is a short period (5.4 year) comet discovered in January 1948 by Carl Wirtanen at the Lick Observatory. According to the JPL Horizons Ephemeris it is currently magnitude 13.1, several other sites have it at magnitude 11.5 and 11.6. 

Image taken from light polluted Louisville, CO with Celestron Nexstar11 telescope, F3.3 focal reducer, and Astrovid Stellacam II video camera (9/14 gain, 128 integration (4 sec), 0 gamma), 30 frames taken at 6:29 to 6:31 pm and 6:40 to 6:42 pm. Images flat field corrected, dark subtracted, aligned, stacked, and histogram adjusted with Registax4.  Two resulting images were then aligned, text added, brightness adjusted, cropped, and animated with Photoshop Elements2. Sky was mostly clear, temperature 29°F, no wind, high humidity, transparency very good, and poor turbulence, maybe 4/10.