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Sunday, August 02, 2015

 

Charon Surface Texture for Celestia

Charon simulated in Celestia with the Charon Global Map used to generate the Charon texture. Click to embiggen

The Charon Global Map has just been released to complement the Pluto Global Map, so I resized it (1024x512) and converted it to a 72 DPI png to use as a texture for  Celestia.

You need to copy the texture file  Charon.png  to the textures/medres folder in the Celestia directory, then edit the solarsys.ssc file in the data folder (make a backup copy first) to replace the texture name in the Pluto definition section with that of the new texture, save it and you are good to go (just as you did for Pluto).


"Charon:Pluto I:134340 Pluto I:1978 P 1" "Sol/Pluto"
{
    Texture "Charon.*"
    SpecularTexture "charon-lok-spec.*"
    SpecularColor            [ 0.135 0.12 0.08 ]
    SpecularPower             9.5

Now I have to learn how to do XYZ or SPICE orbits to add in the New Horizons flyby. And also fix the north polar alignments.

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Southern Skywatch August 2015 edition is now out!

North-western evening sky at 6:15 pm as seen from Adelaide on August 7, Mercury and Jupiter are less than a half a finger-width apart.

The August edition of Southern Skywatch is now up.

This month starts with some excellent planetary action  with Jupiter meeting Mercury and Mercury the Moon.

Jupiter is in the early evening twilight sky in the first half of the month before it disappears into the twilight. It meets swift Mercury on the 7th.

Mars is visible low in the morning twilight.

Venus is readily visible in the evening twilight early in the early part of the month.  It is visible in even small telescope of good bioculars as a thing crescent. It is lost to sight around the 10th-13th as it comes close to the Su. It re-emerges in the morning sky in late August.

Saturn is in Libra. Saturn is close to the waxing Moon on the 22nd.

Mercury enters the evening sky it is close to Jupiter on the 7th, and the Moon on the 16th.

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Friday, July 31, 2015

 

Aurora Watch (31 July-1 August) and Blue Moon

An Aurora watch and a geomagnetic alert has been issued by the Australian  IPS for 31 July to 1 August due to  a coronal hole solar wind stream. This could translate into aurora at any time during the night time of the 17th to early morning 18th.  Aurora, if they flare up, are likely to be seen only in Tasmania (possibly Victoria).

Aurora can occur at any time after nightfall (although around midnight or just after seems to be common). Dark sky sites have the best chance of seeing anything, and always allow around 5 minutes for your eyes to become dark adapted.
As always look to the south for shifting red/green glows, beams have been reported consistently over the last few aurora and a large green "blob" has been seen.

Unfortunately, the light from the Full "Blue Moon" of 31 July will make seeing aurora hard.

The all sky aurora camera in Southern Tasmania at Cressy may be helpful.
<http://www.ips.gov.au/Geophysical/4/2>

SUBJ: IPS GEOMAGNETIC DISTURBANCE WARNING 15/30
ISSUED AT 0132UT/30 JULY 2015
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

A high speed solar wind from a recurring coronal hole is expected
to raise the geomagnetic activity levels to minor storms on 31
July and 1 August.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED
DUE TO CORONAL HOLE HIGH SPEED WIND STREAM
FROM 31 JULY 2015 TO 01 AUGUST 2015
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
31 Jul:  Quiet to minor storm
01 Aug:  Minor storm declining to unsettled.

SUBJ: IPS AURORA WATCH
ISSUED AT 0139 UT ON 30 Jul 2015 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE

A high speed solar wind stream from a coronal hole is expected to
impact the Earth from 31 July. There is some possibility of seeing
auroras on high latitudes on 31 July and 1 August during local night
time hours. Aurora alerts will follow should favourable space weather
activity eventuate.


Further monitoring at
http://www.ips.gov.au

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Wednesday, July 29, 2015

 

Comet C/2014 Q1 from Australia (30 July - 6 August 2015)

The evening sky at 700 pm ACST looking west as seen from Adelaide from 30 July to 6 August.  The circles show successive positions of Comet C/2014 Q1 PanSTARRS every two days. Similar views will be seen elsewhere in Australia at equivalent local times. (click on image to embiggen).

Comet C/2014 Q1 PanSTARRS is climbing higher in the sky, and is now visible after Astronomical twilight.

Unfortunately it is fading (current estimates are around magnitude 7) and the Moonlight is increasing as the Moon heads towards a blue Moon on the 31st.  After this the sky will be darker, but the comet will only be accessible in telescopes.

Printable black and white map suitable for use with binoculars, the  circle is the field of view of 10x50 binoculars. The time is 19:00 ACST, similar views will be seen at equivalent local times elsewhere in Australia. Click to embiggen and print.

If you try looking an hour and a half after sunset you will see it low above the horizon. After last weeks effort the skies have been covered in cloud, so I have no sightings to report.

The comet is only visible in high power binoculars or a telescope, it is currently around magnitude 7 as a fuzzy ball of light (with a short tail in small telescopes).

On the 30th sweeping right of Lambda hydra (one of the three bright stars in Hydra, just below the distinctive contellation of Crater the cup) by about two binocular fields should bring you to the comet (there are no other bright fuzzy blobs about).

Animation of Comet C/2014 Q1 PanSTARRS at 7:00 pm from  30 July to 6 August. Click to embiggen

As the week progresses, the comet continues to climb higher in the sky but remains near Hydra.

On the 6th the comet is within a binocular field of  nu Hydra and alpha Crater (right and below) will bring you to the comet. At this time it should be around magnitude 10.

 

Pluto Surface Texture for Celestia

Pluto simulated in Celestia with the Pluto Global Map used to generate the Pluto texture. Click to embiggen

The Pluto Global Map has just been released, so I resized it (1024x512) and conveyed it to a 71 DPI png to use as a texture for  Celestia.

You need to copy the texture file  pluto_surface1.png  to the textures/medres folder in the Celestia directory, then edit the solarsys.ssc file in the data folder (make a backup copy first) to replace the texture name in the Pluto definition section with that of the new texture, save it and you are good to go.

"Pluto:134340 Pluto" "Sol"
{
    Class "dwarfplanet"
    Texture "pluto_surface1.*"
    SpecularTexture "pluto-lok-spec.*"
    SpecularColor            [ 0.135 0.12 0.08 ]
    SpecularPower             9.5

Now waiting for the Charon map. Then I have to learn how to do XYZ or SPICE orbits to add in the New Horizons flyby.

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Tuesday, July 28, 2015

 

The Sky This Week - Thursday July 30 to Thursday August 6

The Full Moon is Friday July 31. This is a Blue Moon. Venus is brilliant low in the twilight evening sky with bright Jupiter below it. Comet C/2014 Q1 PanSTARRS is visible in binoculars above Venus. Mercury Joins Venus and Jupiter late in the week. Saturn is in the head of the Scorpion and is easily visible in the evening.

The Full Moon is Friday July 31. This is a Blue Moon, the second full Moon in a month (the previous was July 2). The Moon is at perigee (closest to Earth) on August 2.

Early evening sky on Wednesday August 5 looking north-west as seen from Adelaide at 18:15 ACST showing Venus, the star Regulus,  Jupiter and Mercury forming a triangle. Comet C/2012 Q1 PanSTARRS is visible in binoculars above. The inset shows the telescope view of Venus and Jupiter  at this time.

Similar views will be seen elsewhere in Australia at the equivalent local time. (click to embiggen).


Mercury climbs from the twilight into the evening sky, heading for Jupiter. Early next week the pair and Regulus will be less than a finger-width apart. However, you will need a fairly level, unobstructed horizon to see them.

Mars  is lost in the twilight but will return to the morning skies in the coming weeks.

Venus is becoming harder to see above the western horizon in the twilight as it rapidly falls towards the horizon. At nautical twilight, an hour after sunset, it is around a hand-spans above the horizon, although still visible at civil twilight, half an hour after sunset. Venus is a distinct thin crescent shape in  small telescopes and even strong binoculars.

Venus and the bright star Regulus are drawing apart, with Jupiter below making a triangle in the sky. At the end of the week they are joined by Mercury.

The evening sky at 7:00 pm ACST looking west as seen from Adelaide from 30 July to 6 August.  The circles show successive positions of Comet C/2014 Q1 PanSTARRS every two days. Similar views will be seen elsewhere in Australia at equivalent local times. (click on image to embiggen).

Comet C/2014 Q1 PanSTARRS is now visible in the evening high in the twilight. Although much faded it is still sporting a nice double tail http://apod.nasa.gov/apod/ap150721.html.

 If you try looking an hour and a half after sunset you will see it low above the horizon. It is only visible in good binoculars or a telescope. It is now around magnitude 7 and  looks like a faint fuzzy ball of light in binoculars. At the beginning of the week sweeping up from Venus by about three binocular fields should bring you to the comet (there are no other  fuzzy blobs about).

As the week progresses, the comet rides higher in the sky so you will need to sweep further up from Venus (see diagram above), but the comet also dims and increasing Moonlight will make it harder to find.

More details and a printable black and white map are here.

Jupiter  is also becoming harder to see in the early evening twilight sky below Venus in the north-western sky. It is also near the bright star Regulus in Leo. Jupiter and Venus  move further apart as the week goes on while Jupiter moves closer to Regulus.

Jupiter is no longer high enough for telescopic observation once twilight is over. Jupiter's Moons are still putting on a good display in  binoculars.

Evening sky on Saturday August 1 looking at the zenith while facing west as seen from Adelaide at 22:00 ACST.  Saturn is  easily visible high above the western horizon near the zenith near the head of the Scorpion. The inset shows the telescopic view of Saturn at this time. Similar views will be seen elsewhere in Australia at the equivalent local time. (click to embiggen).

Saturn is now easily visible from twilight near the head of the constellation of the Scorpion not far from the bright red star Antares. The sight of the distinctive constellation of the Scorpion curled across the zenith, with bright Saturn close to its head, is very nice indeed.

While Saturn is  readily visible from the end of twilight, it is best for telescope observation from around 20:00 into the early morning hours. At 20:00 it is at it's highest above the northern horizon near the zenith (with Saturn facing west). By 22:00 Saturn is high above the western horizon. This is also a good time to scan Scorpius and Sagittarius with binoculars to reveal the clusters in and around the Scorpions tail.

There are lots of interesting things in the sky to view with a telescope. Especially with Jupiter, Venus and Saturn in the sky. If you don't have a telescope, now is a good time to visit one of your local astronomical societies open nights or the local planetariums.

Printable PDF maps of the Eastern sky at 10 pm AEST, Western sky at 10 pm AEDST. For further details and more information on what's up in the sky, see Southern Skywatch.

Cloud cover predictions can be found at SkippySky

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Monday, July 27, 2015

 

The ISS and Venus and Jupiter (July 27-29, 2015)

The ISS passes between Venus and Jupiter, as seen from Melbourne on the evening of Wednesday July 29 at 18:17 AEST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes above Venus and Jupiter, as seen from Adelaide on the evening of Tuesday July 28 at 18:39 ACST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.The ISS passes passes above Venus and Jupiter, as seen from Sydney on the evening of Monday July 27 at 18:29 AEST. Simulated in Stellarium (the ISS will actually be a bright dot), click to embiggen.
All sky chart showing local times from Heavens Above for Wednesday July 29 for Melbourne.All sky chart showing local  times from Heavens Above for Tuesday July 28 for Adelaide.All sky chart showing local times from Heavens Above for Monday July 27 for Sydney.

Starting  tomorrow night until the 29th there are a series of  evening passes of the International Space Station that take them close to the paring of Jupiter an Venus, or even between them.

When and what you will see is VERY location dependent, so you need to use either Heavens Above or CalSky to get site specific predictions for your location (I'm using Melbourne, Adelaide and Sydney as examples, for example, the view from Melbourne is radically different from that of Adelaide and Sydney on the night of the 29th). Even the difference between the city centre and the suburbs can mean the difference between seeing the ISS go through Venus and Jupiter or just above it.
 
Start looking several minutes before the pass is going to start to get yourself oriented and your eyes dark adapted. Be patient, on the night there may be slight differences in the time of the ISS appearing due to orbit changes not picked up by the predictions. The ISS will be moving reasonably fast when it passes near Venus and Jupiter, so be alert.

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Sunday, July 26, 2015

 

Celestia Files for Kepler 452b (the "so called" Earth 2.0)

Kepler-452b and Kepler-452 simulated in Celestia (click to embiggen).

Friday's announcement from the Kepler mission of the discovery of Kepler 452b had the media galvanised, with some calling it "Earth 2.0".

Kepler 452b is earth-like, and in a habitable zone, but that doesn't meant that it is Earth's twin. Similarly, not being Earth's twin does not make it disappointing.  

Kepler-452b is in the habitable zone of it's star, with a radius 1.6 times that of Earth (technically making it a super Earth). While there is a lot of to-do about habitable zones, it simply means the zone where liquid water can exists on a planets  surface. Other factors may be involved in habitability too. Mars is in our habitable zone, but was too small to hold on to a substantial atmosphere, and is now a freezing desert. 

 As of this discovery there are 13 earth-like worlds orbiting stars in their habitable zomes, and Kepler-186f is one that is closer in size to Earth than Kepler 452b. However, all but Kepler-452b orbit smaller, cooler stars and most are tidally locked to their sun (Kepler-186f orbits roughly where Mercury would be in our solar system, but because its sun is a cool red dwarf, it is not baking hot).

Kepler-452b orbits a sun-like G2 star, and has a year of 385 days, failry similar to our 365 days (all the others are much shorter, as they are closer in).

We don't know if Kepler-452b is a rocky world like our own, or a water world, however, it is the first time we have found an earth-like world around a sun that is the near twin of our own. Technically, it is quite difficult for find these kinds of planets (finding planets that have short years around dim cool stars is much easier) and gives us hope that we can find more of them in the near future.

Once again I've made Celestia files for the system. One for the star (which isn't in the default files) and one for the planet.

As usual, copy the data here to plain text files (Kepler452.stc and Kepler452b.ssc), copy both of the files to the Celestia extras folder. The star is around 1400 lightyears away in Cygnus, so in the Celestia star browser, you will have to show around 500 stars to see Kepler-452 in the list. You can find the paper from which I took the data here.


===============Kepler452.stc===============================
#Kepler survey DISCOVERY AND VALIDATION OF Kepler-452b
# The Astronomical Journal 150 (2): 56. doi:10.1088/0004-6256/150/2/56

"Kepler-452:2MASS 19440088+4416392:2KOI-7016.01:KIC 8311864"
{
RA  296.0042
Dec 44.2775556
Distance 1400 # light years from published data
SpectralType "G2"
AppMag 13.4
Radius  772005    # in km, 1.11 Sun radii
}
========================================================
===============Kepler452b.ssc=========================================
"b" "Kepler-452"

# earth like, possibly water world

{
    Texture "exo-class4.*"
    NightTexture "exo-class4night.*"


Mass 5 # M.sin(i) = 5 Earth, from paper
Radius 10400 # 1.63 Earth radi, from paper

#InfoURL "http://en.wikipedia.org/wiki/Kepler-452b"
# The Astronomical Journal 150 (2): 56. doi:10.1088/0004-6256/150/2/56

EllipticalOrbit {
Period 1.054364
SemiMajorAxis 1.046
Eccentricity 0.02
ArgOfPericenter 267 #guess
Inclination 89.806
#MeanAnomaly 271
}


}

AltSurface "limit of knowledge" "Kepler-452/b"
{
Texture "venussurface.*"
OverlayTexture "ganymede-lok-mask.png"
}
================================================================

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Thursday, July 23, 2015

 

New Ceres and Vesta textures for Celestia

Ceres simulated in Celestia with a surface map taken from the Dawn spacecraft (click to embiggen)Vesta simulated in Celestia with a surface map taken from the Dawn spacecraft (click to embiggen)

Celestia is an amazing 3Dspace simulation program. It is expandable, you can add comets, asteroids, exoplanets and more (see some examples here). I use a simulation of the STEREO  spacecraft to helpd identify comets in the STEREO images.

Celestia also has a wonderful online community building a variety of different worlds. They have taken the latest surface maps from the Dawn orbiter of Ceres and Vesta and made them into textures for the respective asteroids simulated in Celestia. The Vesta and Ceres packs are here (scroll down the lists of asteroids till you come to them).

There are actually quite comprehensive and use advanced techniques. Being simple minded I just copied the texture files into the /texture/medres folder, then edited the asteroids.ssc file (after making a backup first).


"1 Ceres:Ceres:A899 OF" "Sol" 
{ 
 Class "dwarfplanet" 
 Texture "ceres.0center1.png" 
 
 Color [ 0.800 0.745 0.681 ]

As an example this is the edited bit of the Ceres entery in asteroids.ssc

Anyway, download the asteroid packs, add the textures, and you can zoom to the realistic versions of Vesta andd Ceres now.

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Aurora Happening NOW (23 July 2015)

Aurora are Happening NOW. Unaided eye Aurora and beams have been reported in Tasmania, from a wide variety of locations.

An Aurora Alert and a geomagnetic alert has been issued by the Australian  IPS for the 23th due to an anticipated impact from a coronal mass ejection.
Currently, the Kindex is 4.

 Dark sky sites have the best chance of seeing anything, and always allow around 5 minutes for your eyes to become dark adapted.
As always look to the south for shifting red/green glows, beams have been reported consistently over the last few aurora and a large green "blob" has been seen.

The all sky aurora camera in Southern Tasmania at Cressy may be helpful.
<http://www.ips.gov.au/Geophysical/4/2>

SUBJ: IPS GEOMAGNETIC DISTURBANCE WARNING 15/29
ISSUED AT 0749UT/23 JULY 2015
BY THE AUSTRALIAN SPACE FORECAST CENTRE.

A sustained period of southward IMF is resulting in mildly elevated
levels of geomagnetic activity, particularly at high latitude
regions. Further mildly elevated levels of geomagnetic activity
are possible during the remainder of 23 July.

INCREASED GEOMAGNETIC ACTIVITY EXPECTED
DUE TO CORONAL MASS EJECTION
FOR 23 JULY 2015
_____________________________________________________________

GEOMAGNETIC ACTIVITY FORECAST
23 Jul:  Unsettled to active with possible minor storm periods at high
latitudes.


SUBJ: IPS AURORA ALERT HIGH LATITUDES
ISSUED AT 0720 UT ON 23 Jul 2015 BY IPS RADIO AND SPACE SERVICES
FROM THE AUSTRALIAN SPACE FORECAST CENTRE
       

GEOMAGNETIC STORM IN PROGRESS. AURORA MAY BE OBSERVED
DURING LOCAL NIGHT TIME HOURS IN GOOD OBSERVING CONDITIONS
AT HIGH LATITUDES.

Follow the progress of this event on the IPS web site
by following the links to the Space Weather Status Panel,
Home > Space Weather


Further monitoring at
http://www.ips.gov.au

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