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Waddensky

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Everything posted by Waddensky

  1. Wonderful, thanks for sharing! I love the annotation. [nitpicking mode]One tiny correction, what you've indicated as De Mairan's Nebula (M43) is in fact the Running Man Nebula (Sh2-279). M43 is the bright spot just above the Orion Nebula[/nitpicking mode]
  2. If the robot knows its latitude, it should be able to determine the declination of the stars by observing their altitude and azimuth. If it knows the declination of some stars, it can calculate the date using a reversed precession calculation. Provided it travels to a sufficiently distant date in the past or future. The precession circle is not a closed circle, so it should be pretty accurate.
  3. Watched the planets slowly approach each other over the last couple of days, what a wonderful event! Tonight seems to be cloudy and rainy however, in a few hundred kilometer radius...
  4. I've read reports of experienced observers catching the Horse with a 100mm. I think an excellent H-Beta filter, very dark skies and a well-chosen exit pupil are as important as aperture.
  5. The magi from the East were probably acquainted enough with the movements of the planets to know exactly what a planetary conjunction was and how to predict it. The question is, what kind of omen did they connect to it. Also, Jesus was most likely born around August.
  6. The difficulty is that Wikipedia is a tertiary source with a multitude of authors (including myself) without prior QC, and not all authors cite their sources correctly or sufficiently. The quality ranges from excellent to very poor and that makes it unsuitable as a source without assessing the solidity of the citing and the sources first.
  7. Interestingly, the -1 notation for inverse functions was introduced by John Herschel 🙂. The sine and cosine give the ratio between two sides of a right-angled triangle, the inverses (arcsin and arccos) are used to calculate the angle that result from that ratio. They are used a lot in astronomical calculations, because these calculations often result in angles. Be careful, it's addictive 😉.
  8. From an urban location, a few days from the peak, this is not a bad result at all! The ZHR (zenithal hourly rate) of the shower is around 120 the last years, but this is a theoretical maximum (radiant overhead, clear and dark skies, right at the top of the peak). So if your are able to catch a few in less than two hours, that's wonderful :). Unfortunately, nothing but clouds here lately so I completely missed the peak. That's a shame, the conditions were very favourable this year (new moon and peak right in the middle of the night). The great thing with meteor showers is, they're back next year.
  9. Lovely report, thanks! M33 is by far the most elusive of the objects on that list, so no wonder it isn't that obvious. It can be done though with binoculars if your skies are dark enough. I've never heard from this Moore Marathon list too, but I really like it. It's full of lovely and very varied objects.
  10. The Pleiades nebulosity is very hard to observe visually, but not impossible from a really dark location with a sufficiently large scope. The nebula around Merope is the brightest part. Here are some interesting visual reports. I've never seen it with my 8" though, even from a dark site. But in most cases, glare from the brightest stars or an atmospheric haze may be mistaken for the nebulosity.
  11. Universe simulators like SpaceEngine demonstrate that if I move at a speed of about 2 light-years per second, the nearby stars clearly start to move in the field of view. In reality, this is impossible of course.
  12. Yes: From here. Almanacs often use this kind of numbering.
  13. Thanks for the heads-up! It's visible even in my 10x50s if I hold them steady enough. It's a great night to observe the Moon: two reasonably bright stars are occulted later this evening: Ï„1 Aqr (+5.7) and Ï„2 Aqr (+4.1).
  14. Yes, but there's a lot more to it, like there always is in astronomy 😉. The Moon's orbital speed is perturbed by (mainly) the Sun and Jupiter, and there's the orbital inclination, as wulfrun says, and the precession of both the nodes and the line of apsides. It all depends on the amount of accuracy you wish to achieve and the date range of the graphic. Chapters 47, 48 and 49 of Astronomical Algorithms (2nd edition) by Jean Meeus have some in-depth information and formulae to calculate the position and illuminated fraction of the Moon accurately. Be careful - it's addictive.
  15. The phase of Mars is currently around 95%. Could that be the reason?
  16. I guess it's mostly because the orbit of the Moon is not a circle, but an ellipse.
  17. We need a bit more information ;). What kind of things would you like to observe? Only visual or also photography? Do you mind finding objects manually? Do you have the space to store a large telescope? Are you able to lift the weight of the base? But in general: yes, 8" dobsons are great telescopes that will give you a lot of observing pleasure. So in that sense they're worth it.
  18. You're more or less in the correct spot, turn on deep-sky images in Stellarium to exactly see where the galaxy is located. Messier 33 is just a large, dim patch of light, no individual stars visible.
  19. Hard to blame them. The whole society is arranged around a disconnection from natural flow and rhythm imho. People are expected to set out for work at the same time in summer and winter, regardless of daylight. Not to mention the denial of seasons with the use of leaf blowers and lawn mowers 😅. I try to follow the natural rhythms as much as I can. I enjoy darkness, and not only from a stargazing point of view. I like to take long walks in the night, the sound of migrating geese, a sudden encounter with a deer, well that kind of stuff 😉.
  20. In all weather models, the accuracy of the forecast decreases over time. In my experience, models can predict a clear night a few days ahead, maybe a week depending on the local circumstances, but not much further. "A seven-day forecast can accurately predict the weather about 80 percent of the time and a five-day forecast can accurately predict the weather approximately 90 percent of the time. However, a 10-day—or longer—forecast is only right about half the time. " Source
  21. It's great that they name the brands they compare this wonderful scope with, so we can objectively see why this wonderful scope outperforms them all. It's not the wasted money I am concerned about, it's the disappointment it causes.
  22. I heard that Tapatalk was removed from the Play Store too. Your browser should do the trick. The mobile version of Stargazers Lounge is fully functional and works excellent on my phone.
  23. This value indicates the estimated effect of light pollution on the darkness of the sky. It's measured in magnitudes per square arcsecond, just like the surface brightness of celestial objects. You are right, a higher value is better: 22.00 is about as dark as it can get, a value lower than 18.00 is an indication of heavy light pollution. Here's a classification of night sky brightness with sky quality listed in the column 'Approx. SQM'. The values on the Clear Outside website and app are 'estimated' because they are calculated from light sources as seen by satellites. If you want to accurately measure the darkness of a location yourself, you can use a Sky Quality Meter (SQM).
  24. Yes, as AstroRookie says the challenge to see them all in one night is called a Messier Marathon. They're not all visible at the same time, but every Messier object can be observed through the night if your latitude is not too northerly (because of the shorter twilight duration). This is possible in a few weeks in March and April. A 'half marathon', when most objects but not all can be observed, can be held around the September equinox.
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