Activity for VReijs
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VReijs posted a comment on discussion Feedback
By the way, the improved page of Larry Bogan (at least according to my knowledge) is here: http://www.archaeocosmology.org/eng/vislimit-Bogan-vr.htm <it coefficient="" wrongly="" that="" astronomical="" an="" does="" behave="" have="" error="" not="" the="" extinction="" makes="">.</it> On Wed, 27 Jan 2021 at 21:28, Andrey Nakin andreynado@users.sourceforge.net wrote: Hello Georg. Please execuse my long silence, I was trying to find the articles mentioned. I only managed to find a poor quality copy...
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Hello Andrey, Swiss Ephemeris is an open source program indeed. But it is a C library, so no nice GUI as Stellarium. All the best, Victor On Thu, 28 Jan 2021 at 00:19, Andrey Nakin andreynado@users.sourceforge.net wrote: Hello Victor! It would be great to have a copy of the 2000 year article. I've send you a message (via SF messenger) with my private e-mail. Thanks a lot! BTW is Swiss Ephemeris an open-source project? Formulas for a limiting apparent magnitude https://sourceforge.net/p/stellarium/discussion/278769/thread/af0ceb4a2f/?limit=25#1416/5d4a/cc70/9df2...
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Hello Andrey, The 2000 article is the best (according to Schaefer himself also). But it has (still) some errors in it (as I discussed these with Brad Schaefer): http://www.archaeocosmology.org/eng/archxv.htm ) http://www.archaeocosmology.org/eng/archxv.htm S&T code en Bogan javascript have gotten a new error (IMHO) between 2002 and 2016 (compared to Schaefer 2000): KA=KAMath.pow((1-.32/Math.log(RH/100.0)),1.33)(1+SLMath.sin(RA)); which should be (according also to Schaefer): KA=KAMath.pow((1-.32/Math.log(RH/100.0)),1.33)(1+0.33SL*Math.sin(RA));...
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Hello Georg I am interested to help (I gave a year ago some feedback on the Stellarium code, I think). But if wanted I am willing to help (but coding in C [or a larger programming environment] is not something I want to do;-) I can check code and give constructive feedback on results, etc. All the best, Victor On Sun, 24 Jan 2021 at 13:23, gzotti gzotti@users.sourceforge.net wrote: Ah, thanks. I agree there are some typos/unclear differences/bugs between the 1993 and other of his works, and also...
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I think his latest article is better (Schaefer's texts and code can have some small bugs): Schaefer, B.E. New methods and techniques for historical astronomy and archaeoastronomy Archaeoastronomy, Volume XV [2000], pages 121-135 <see <span="" my="" comments="">[and checked with Schaefer] here: http://www.archaeocosmology.org/eng/archxv.htm ></see> All the best, Victor On Sat, 23 Jan 2021 at 22:49, gzotti gzotti@users.sourceforge.net wrote: Most relevant may be this: @Article{Schaefer:Limits, author...
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Don;t look at the date, look at the Julian day number! What do you see then? Or only use proleptic Gregorian calendar. I can't imagine there is an error, so I hope it is related to the date... (and not the Julian day number). All the best, Victor On Tue, 3 Nov 2020 at 10:27, "Victoriano Canales Cerdá" nanocanales@users.sourceforge.net wrote: Hi, The problem is not in the date. If you put the date of the autumn equinox of 1582 and 1583, you will see that at sunrise there is a difference between the...
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Did you use julian date, as you also close the change over from Julian to Grgorian calendar. Using the Julian Day Number input is perhaps better. Using the proleptic Gregorian calendar would keep the equinox day around 21 september, otherwise in the Julian calendar the autumnal equinox will be on another day (that is why they introduce the gregorian calendar;-). Check the declination of the Sun (should be zero on equinox day). All the best, Victro On Tue, 3 Nov 2020 at 01:46, "Victoriano Canales...
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I am glad you now recognised it. Indeed the proleptic gregorian calendar is perhaps a month out from the proleptic julian calendar. It is always a discussion about what to use in the past (as no calendar is correct as it is unknown what they used back then;-). Best is perhaps using the Julian Day Number... In some way the proleptic Gerogorian calendar is the nicest (as it keeps the solstice/equinox more or less in sink (but of course not fully over long periods of time). But using that needs a decision...
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What calendar system are the programs using: proleptic gregorian calendar (and equinox could be close to 22 March in -3080) or Julian date (which is the case for many programs)? For (Proleptic) Julian calendar the date will be different.. All the best, Victor On Mon, 28 Sep 2020 at 10:06, Khayree Billingslea postcopernicus@users.sourceforge.net wrote: I could be using the wrong word, book look at the screenshots where the sun is relative to the horns of taurus around the March 22 -3080 in mobile...
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Hello all of you, HeyWhatThat now has Stellarium horizon as a clickable item, that make sit all somewhat easier: On the right (more or less on the top) is a clickable link: 'In Stellarium'. Have fun . All the best and stay healthy, Victor
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Hello all of you, I think I got somewhat closer to the code;-) In stellarium/util//ParseHip.C in function ReadTyc2File I find this: EpRA += 1990.0; EpDE += 1990.0; ra += (2000.0-EpRA)(0.001/3600)pmacos(decM_PI/180); dec += (2000.0-EpDE)(0.001/3600)pmd; I don't really understand where the 1900.0 comes from (as Tyco2 is normally in J2000.0 or orginally in J1991.25), but that is not so important for my quest;-) But still important to know at some moment. To get things into a common epoch (J2000.0) it...
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Hello all of you, On Tue, 11 Feb 2020 at 14:27, gzotti gzotti@users.sourceforge.net wrote: How does this not answer your question? Even though you can follow stellar proper motion for tens of thousands of years, please note that the computation only takes the linear components Da, Dd into account. For times far from today, a true 3D computation would be required, so that also changes in distance (and thus, brighness) could be simulated. I don't know if the dR is even known (which database holds that...
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Hello all of you, Is there some one interested to look with me at the Stellarium code around stars (perhaps beside the already busy and very good non-a-days programmers). To start with, I want to investigate two things: . were in the code are the Hipparcos RA/DEC coordinates (which are ICRS, barycentre reference model) transformed towards geocentric/topocentric coordinates? . When is the influence of Declination (cos(Declination) on the proper motion of RA included in the code? I looked in Star.cpp,...
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That is why I try to add always a designator to 'declination': apparent, topocentric and geocentric (assuming that aberration and nutation are always included). Coudl be done by adding an 'a', 't' or 'g';-) All the best, Victor
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That is difference between Grgeorian calandar and Julian calander: https://www.answers.com/Q/What_is_the_difference_between_Julian_and_Gregorian_calendars
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In earlier post some solution to this DPI issue has been provided (it is a work around,but it works and it can also be used for the many other programs that are not DPI aware). On 5 August 2017 at 10:13, noreply@in.sf.net wrote: Now everything is rendered in half resolution. I can see every single logical pixel (because it takes up 4 physical pixels), the font has that 70s boxy look to it. Are there any plans to do high DPI properly by scaling everything and using the pixels as they are? That would...
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Hello Georg, On 10 July 2017 at 14:46, gzotti gzotti@users.sf.net wrote: From Robinson's note 15 it seems we are in best company being confused about those terms. I am not confused;-) As long as you define it well yourself and read the definitions of the others well. But at least we have documented how we understand them, and fulfill these definitions. It seems what is known as heliacal rising (HELIACAL, not HELICAL! There is no spiral involved. And I think we all agree that "heliacal" refers to...
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Now looking at this "Observability analysis" plug-in. There is considerable difference with PLSV (while I personally find tPLSV an ok-ish program: it follows the criterion of Schoch (which is not that far off from Scahefer [whihc latter is depending on the atmospheric conditions]). I have the idea that Ivan uses different definitions ofor the word acrynochal and cosmical than some other people. It is becoming a kind of wild west looking at the naming, IMHO;-) http://www.archaeocosmology.org/eng/starphases.htm#Multiple...
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I now see the observable plug-in, I tink it is not using Schaefer. Can't really detemrine what it does, I will e-mail the author. Thanks.
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So Georg there is something in Stellarium now? Was my input included? Would be very interested indeed. Perhaps I need to update my Stellarium (I am still running a test version).
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I am interested in this. By the way I am planning a lunch/dinner meeting around this subject at SEAC17. It would also be great if Stellarium would include these heleical events |(or at least the visibility of the celstial object at the moment of the screening). It is relatively easy, but as always someone needs to program it (I gave feedback on the formuala to be used in Stellarium, but I am not able to get it into a code thread of Stellarium, no experience with that). As I don't wnat to type in...
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Do you have this reference Robinson, M., Classical Philology 104, 354 (2009)? I am interested in the definition of apparent cosmical and acronychal phases. See my ideas here: http://www.archaeocosmology.org/eng/starphases.htm and http://www.archaeocosmology.org/eng/Ptolemy-Phases.htm These heliacal events I implemented using Swiss Ephermis (using Shacefer's critrion). All the ebst, Victor
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Do you have this reference Robinson, M., Classical Philology 104, 354 (2009)? I am interested in the definition of apparent cosmical and acronychal events. See my ideas here: http://www.archaeocosmology.org/eng/starphases.htm and http://www.archaeocosmology.org/eng/Ptolemy-Phases.htm These events I implemented using Swiss Ephermis (using Shacefer's critrion). All the ebst, Victor
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Do you have this reference Robinson, M., Classical Philology 104, 354 (2009)? I am interested in the definition of cosmical and acronical events. See my ideas here: http://www.archaeocosmology.org/eng/starphases.htm and http://www.archaeocosmology.org/eng/Ptolemy-Phases.htm These events I implemented using Swiss Ephermis (using Shacefer's critrion). All the ebst, Victor
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It coudl be that Stellarium presents is the topoccentric decliantion (aka with the parallax included). If it was the geocentric declination then it should not change. For the Sun and stars the topocentric and geocentric declianation are the same (for th Sun a little less the same;-). Perhaps Stellarium should add the word topocentric to the Declincation term (certaily because some people will indeed think only in geocentric declination). All the best, Victor
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Of course implementing this is great. Temperature en pressure have influence, but remember that the influence on a screen (as Stellarium is a screen based program) is IMHO not really visible. But as Georg, say if you have the time you can code it. All the best, Victor On 30 June 2017 at 10:45, gzotti gzotti@users.sf.net wrote: Do it. Refraction settings: saner defaults? https://sourceforge.net/p/stellarium/discussion/278769/thread/a44b1d39/?limit=25#2ce3 Sent from sourceforge.net because you indicated...
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Are you using the parabolic formula mentioned by SMH2016 in option (a)? To make such that the large inaccuracies of (a) are overcome thet porpose option (b): spline for past dates and option (c) smoothing for more recent dates. Of course we don't know what the DeltaT does in the future, but hopefully the smoothing curve in (c) (period 2013-2016) is not that far off for the near future (otherwise one could use the near term prediction from IERS)... All the best, Victor
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Another source (or recent): http://maia.usno.navy.mil/ser7/deltat.data Although not predictions...
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Georg, are you sure that SMH2016 does not use DeltaT table? I can't imagine that they would use this (too generic) formula for recent times. I would have thought they used (would allow) something more modern, like this past and pediction graph: http://astro.ukho.gov.uk/nao/miscellanea/DeltaT/dt_current.pdf or http://maia.usno.navy.mil/ser7/deltat.data JPL uses a table for recent dates. All the best, Victor
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Georg, are you sure that SMH2016 does not use DeltaT table? I cna't imagine that they were use this (too generic) formula for recent times. I would have though they used (woudl allow) something more modern, like this past and pediction graph: http://astro.ukho.gov.uk/nao/miscellanea/DeltaT/dt_current.pdf JPL uses a table for recent dates. All the best, Victor
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Another slightly related question. By the way, can I add my own stars? Say I have...
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Success Georg! On 11 March 2017 at 15:33, gzotti gzotti@users.sf.net wrote: Only...
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On 10 February 2017 at 17:12, noreply@in.sf.net wrote: But consider an Astrologer...
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I support Georg's reaction. From a cosmological point of view:how important is it...
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On 9 February 2017 at 02:06, noreply@in.sf.net wrote: To compute refraction for objects...
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Refraction is not really defined below an altitude of minus 3 or minus 4 degrees....
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It now also works for my benchmark eclipse at Athens (484CE Jan 14th, total (r close)...
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I think it is in 1971 for whole Europe: http://www.irishstatutebook.ie/eli/1971/act/17/enacted/en/print...
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Hello Joe, There is another way, not in Stellarium, but through a javescript page;-)...
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I fully support this. Applaud these hard working people and be constructive!!!! All...
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What is truth? IMHO Stellarium has an accurate ephemeris. Certainly for archaoastronomy...
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I also have some (GPL) formula;-) http://www.archaeocosmology.org/eng/refract.htm...
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Hello Anon, The formula that Stellarium has are all based on such past observations....
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I thought the dotted line had something to do with the prenumbral. See that attachement...
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I am trying to detemrine the timing lunar eclipses (greaterst and U1, to U4 eclipse...
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I think what you describe is the glare you see of the Sun (and the way how Stellarium...
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I now tried the GUI for the brightness and that works fine. THANKS Alex. On 31 July...
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Thanks Alex and Georg
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I still have the problem. I am using Stellarium 0.13.3 and changed the config.ini...
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I like the remark of Jun 10th, it reads authoritative. So if some graphics don't...
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Thanks Alex, that helped!
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I added daylight_color = 1.0,1.0,1.0 in the color section of a config.ini (I made...
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I think this formula can be reverse engineered to provide the color of the text perhaps:...
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I don't know if this helps: http://webdesign.about.com/od/color/l/bl_contrast_table.htm...
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Here is an example of the text and background issues (but it also happens with a...
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The problem with the background is also that it depends on the sunshine;-) I will...
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I see the object description text, although it is still sometimes very difficult...
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Thanks for adding this info text contrast request. On 26 August 2014 15:25, Alexander...
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Hello Alexander, On 26 August 2014 10:51, Alexander Wolf alexvwolf@users.sf.net wrote:...
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