The sky this week April 16 to April 22 (Colorado Front Range)
International Space Station
Starting Wednesday night the ISS makes a brief 1-2 minute pass each night between 8:30 and 10pm. None of them are outstanding. See http://www.heavens-above.com for details.
Sun
The sun rises at 6:23 am on Monday and 6:15 am on Saturday. Sunset is 7:41 pm to 7:47 pm. The sun remains exceptionally quiet, even for solar minimum. There are no active regions visible. See http://spaceweather.noaa.gov for more info.
Moon
There is a chance on Tuesday evening of spotting a very thin crescent moon. The moon will be just 14 hrs and 5 minutes past new at sunset at 7:41 pm. Moonset (assuming a clear western horizon) is 8:24 pm. The world record for seeing the youngest crescent moon without optical aid is 15 hrs 32 minutes which is held by Sky & Telescope editor Stephen O’Meara. If you can spot it before moonset, you’ll break his record by at least 44 minutes. Spotting a young crescent moon even with a telescope or binoculars is extremely difficult, however. The contrast between bright twilight and the crescent is very low. Probably only a small patch (the central quarter) of the crescent will be visible because of the bright background. See http://skytonight.com/observing/objects/projects/3308686.html for more info.
If you also observe the crescent at dawn Monday morning (which should be easy) you could break the naked eye crescent bracket interval (time between waning crescent to waxing crescent) which is also held by O’Meara (35 hrs 42 min). On Monday moonrise is 5:41 and sunrise is 06:23. The binocular crescent bracket interval record of 35 hrs and 14 min held by Don Pearce could be broken as well.
Planets
Venus is in constellation Taurus and shines at a brilliant -4.1 magnitude. In a scope Venus appear as a crescent disk a couple days past first quarter.
Saturn is between constellations Leo and Cancer. It is still in good position for early evening viewing.
Jupiter rises before midnight this week in constellation Ophiucus around 11:57 to 11:32 pm late in the week. Several of the cloud features on Jupiter have been changing lately. Additional white spots are showing up in Jupiter’s northern tropical zone. The GRS is reported to be a bit more prominent than usual.
The great red spot (GRS) crosses the center at the following times this week:
Tues Apr 17 05:04 am
Wed Apr 18 00:55 am
Fri Apr 20 02:33 am
Sun Apr 22 04:11 am
The GRS is visible about an hour before and after the central meridian crossing.
Mars rises in the constellation Aquarius around 4:30 am and is very low in the SSE. Disk is only 5 arc sec across so little detail can be seen. We’ll have to wait until late fall for a better view.
Mercury, Uranus and Neptune are too close to the sun for viewing.
Comets
It should be possible to view a number of comets this month such as 2P/Encke in constellation Aries. It is said to be about mag 3.8 and has 4.4 arc-min wide coma. Best time to view is 7:50pm.
C2007 E2 (Lovejoy) is in constellation Sagittarius at mag 7.8 and has a 7.1 arc min coma. Best time to view is 04:40 am (high in southern sky) .
185P/Petriew is in constellation Aries at mag 11.9 and has a 1.9 arc-min coma. Best time to view is 8:10pm (low in the western sky). I tried for this one, verified the star field, but still couldn’t locate it.
96P Machholz is in the constellation Pegasus . It should be about magnitude 9.
4P Faye is in constellation Orion at mag 12.8 and has a 1.2 arc-min wide coma fairly. Best time is 8:20 pm.
29P Swassmann-Wachmann is in constellation Taurus at mag 12.6 with 1.1 arc min coma. Best time is 8:20pm (Fairly high in west)
C2006 XA1 Linear is in constellation Perseus at mag 13.4 and has a 1.2 arc-min wide coma. Best time is at 7:20pm (Fairly high in western sky)
See http://www.skyhound.com/sh/comets.html for charts and details.
Dark Sky
The Lyrid meteor shower peaks on April 22nd. About 10-20 meteors per hour should be visible. Best time should be after moonset at 2:07 am.
If you have a large aperature scope and dark sky, check out Copeland’s Septet in constellation Leo . Contained in a 5 arc-minute area are seven galaxies ranging in brightness from mag 13 to 15. Image below taken with Stellacam2, F3.3 focal reducer, and Nexstar11.
