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  1. Earlier
  2. Having had a series of G1 and G2 alerts on Monday/Tuesday I can't quite determine if the major storm arrived earlier than expected or if the initial figures for Mon/Tues were just significantly stronger than forecast. The joys of space weather! only time will tell.
  3. Welcome to the site. If you are still in the learning phase, please take a look at our topic below, which you may find useful
  4. GOES magnetometer, is the next important thing and we're doing some studies as to how the effect on GOES becomes indicative of BEAMS or the potential to see beams. There used to be a choice of magnetometers, but NOAA’s Geostationary Operational Environmental Satellites (GOES) are currently limited to 1, and that is number 16, which is positioned somewhat inconveniently on the Eastern seaboard of the US at 75.2° West. On a GOES plot, GOES has a natural curve in its graph, based on the rotation of the Earth and the position of the satellite in relation to the sun ( i.e. day or night).
  5. Why do we see those stunning lights in the northern- and southernmost portions of the night sky? The Aurora Borealis and Aurora Australis occur when high-energy particles are flung from the Sun's corona toward the Earth and mingle with the neutral atoms in our atmosphere -- ultimately emitting extraordinary light and colour. Michael Molina explains every step of this dazzling phenomenon. https://www.youtube.com/watch?v=czMh3BnHFHQ
  6. The north-south direction of the interplanetary magnetic field (Bz) is the most important ingredient for auroral activity. When the north-south direction (Bz) of the the interplanetary magnetic field is orientated southward, it will connect with Earth's magnetosphere which points northward. Think of the ordinary bar magnets that you have at home. Two opposite poles attract each other! With a southward Bz, solar wind particles have a much easier time entering our magnetosphere. From there they are guided into our atmosphere by Earth's magnetic field lines where they collide with the oxygen and
  7. Aurora On : Aurora Off In my experience, the Interplanetary Magnetic Field, or Bz is fundamentally the aurora on and off switch. Although there are exceptions, they are few and far between and this is applicable for all but the most hardened scientific aurora hunter. So if Bz is reading +'ve or northerly, you are unlikely to see an aurora at all. The stronger the northerly reading the less likely you are to see anything. I've been in Kp 9 conditions with a northerly Bz and not seen anything at all. However, if Bz is reading -'ve or south then you are likely to see one - if other
  8. Very excited about the next few days, if the weather clears. Only just started learning a few years ago and excited to visit the observatory soon as have now moved to Christchurch
  9. What are these G numbers you speak of? Geomagnetic storms are labelled G1 to G5. It is a period when there is strong to very strong geomagnetic activity due to a lot of build up in Earth’s magnetotail. Here is a table which converts the G into Kp. G1 = Kp5 G2 = Kp6 G3 = Kp7 G4 = Kp8 G5 = Kp9 It's for this reason you hear a lot of people say they wouldn't get out of bed for anything less than KP5. They like their aurora potential to be strong, just like their coffee. If you waited for a KP5 event every time before going aurora hunting you'd rule out 60% of your opportunitie
  10. Usually the first sign of any potential aurora activity chatter, comes from the Kp indices forecast, such as the one below. These values indicate the expected geomagnetic activity for any given 3-hour period for the next three days. This is the fastest way to quickly find out what kind of geomagnetic conditions are to be expected over the next 3 days. The times are in UTC, which is a time standard used across the globe. For NZ daylight savings we're 12 hours ahead, so 21:00 on the 28th UTC, would be 09:00 on the 29th NZST. The Kp number system is a scale of planetary geomagnetic acti
  11. What's producing this aurora activity? The current activity seems to be from 2 solar phenomena, which may be why the alerts are coming through stronger than the associated forecast models. The dark area spreading from the northern hemisphere is a Coronal Hole. This was detected as being Earth facing on Saturday. "A transequatorial coronal hole was detected in an earth-facing position on Saturday, 26 September 2020". This means solar winds are flowing towards us, and they in turn can produce Aurora activity. A large hole has potential to do this over several days. Behind the CH is a glo
  12. Looking at the current aurora forecast for this week, sees some potential viewing opportunities. Here is the predicted Kp indices chart On this chart the times are in UTC. This isn't a time zone, but a time standard. New Zealand is currently 12 hours ahead of UTC, so 0900 on the 28th Sept would be 21:00 local time. Please feel free to reply if you have a something to say about the aurora forecast for this week. Or start a new topic if you have a question on another aspect of the aurora and how to understand the charts. We'll be putting up an information post on how to read a forecas
  13. Many people think you need an expensive camera to do astrophotography and I love to prove them wrong with my snaps on my mobile phone. All you need is a night mode or a pro mode so you can change the exposure settings manually and a solid surface. This was my handheld shot from last night. Tell me what you can see and if it's worth having a go with a phone. The daylight effect was due to the moon 🌒 and this shot is completely edit free.
  14. A plan of the night sky, looking north at 7.30pm from Christchurch
  15. September 26 is International Observe the Moon Night. Our satellite will have plenty on display, from dark seas to bright craters and rugged mountains. After last nights conjunction of Jupiter and this mornings conjunction of Saturn, you can still see the Moon near the two giant planets after dark this evening. Look up in a northward direction to find the Moon, and all three are readily visible to the naked eye. Binoculars will reveal more detail, including Saturn’s rings and the Galilean moons of Jupiter. With our satellite a well-lit waxing gibbous today, much of its terrain will
  16. There are 4 planets visible to the naked eye during the evenings of October 2020 from New Zealand. At twilight, Jupiter, the bright object pretty much overhead at the start of the month, sets to the West as the month progresses. As the sky darkens, Saturn can be seen as the bright object to the right of Jupiter. Saturn will appear as an oval in binoculars, whilst the 4 Galilean moons will be visible in a plane to either side of Jupiter. Mars, rising from the East will appear bright and orange in colour. It reaches its closest point to Earth around the middle of October, when its a m
  17. Ah, yes, another one of those ‘named’ nebulae. Although a singular honour, I do wonder, occasionally, if the person has ever looked into the eyepiece and thought “Really? I look like that?” IC 2599 is also known as the Gabriela Mistral Nebula, in honour of one of Chile’s most famous poets and Nobel Prize recipients. It’s good to see some southern hemisphere folks getting some celestial recognition. The nebula is in the Carina constellation, approximately 7500 ly from us and spans about 40 ly across. IC 2599 is associated with the open cluster NGC 3324 – a very luminous group of hot, young star
  18. Gary

    Messier 17

    When one has been struggling with cursed objects (DSOs that, despite repeated best efforts, never seem to yield decent data), I have found that it is a good idea to go back to something reasonably basic but still interesting. Messier 17 is just such an object: big, bright, easily identified, and colourful. M 17 goes by several names. The one I grew up with was the Swan Nebula, but it is also known as the Omega Nebula, the Checkmark Nebula, and the Horseshoe Nebula. Most of these names are based on the lighter central region that is seen through most telescopes. If you squint, you can imagine a
  19. This is a wide field image of the Large Magellanic Cloud. NGC 2070 (The Tarantula Nebula) is clearly visible at centre right, an N11 (The Bean Nebula) is in the lower left corner. In fact, the LMC is chocka with what astronomers refer to as DSOs, or deep space objects. Almost any condensed knot of light has a designation in one or more astronomical catalogues. The central bar of the dwarf galaxy is clearly visible in this image. It is thought that some of the LMC's spiral arms were ripped off in tidal interactions with the Small Magellanic Cloud and our own, much larger, Milky Way galaxy, whic
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