tag:blogger.com,1999:blog-41103733083746661612024-03-06T03:07:58.785+11:00Uranometria: Stars and AstronomyThe future of Astronomy. Why do stars have the names that they do? How come there's so much confusion? I'll be talking about why, and putting forward my ideas for, finally, bringing stellar nomenclature into the 20th century. And there's catalogues to download too!richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.comBlogger22125tag:blogger.com,1999:blog-4110373308374666161.post-32675846891940249472012-05-19T14:17:00.001+10:002012-05-19T14:17:25.281+10:00I discovered the following <i>errata</i> page, published in the <i>Uranometria Argentina</i>, hasn't been incorporated in the various transcriptions:
<div class="separator" style="clear: both; text-align: center;">
<a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg218B3L9Rg9key4KzeG3-UeQeVhhelJ4iiKiwN_8pqLFg_IUReKnV1e9VRKeRtLJZEVAikX3js546zTWZ_gykTrMwxD600Z2d_XOzAciKY2lQDmKeQgY1DfHGHrJPKAfPEA6Fp-rx9gNyg/s1600/errata.jpg" imageanchor="1" style="margin-left:1em; margin-right:1em"><img border="0" height="400" width="333" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg218B3L9Rg9key4KzeG3-UeQeVhhelJ4iiKiwN_8pqLFg_IUReKnV1e9VRKeRtLJZEVAikX3js546zTWZ_gykTrMwxD600Z2d_XOzAciKY2lQDmKeQgY1DfHGHrJPKAfPEA6Fp-rx9gNyg/s400/errata.jpg" /></a></div>
I'll be updating the data for Vizier and <a href="http://www.uranometriaargentina.com/">http://www.uranometriaargentina.com/</a> in due course.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-10867630898477771642012-01-16T18:39:00.000+11:002012-01-16T18:39:35.527+11:00Uranometria Argentina: a Labour of LoveWe have Frederick Pilcher to thank for the <i>Uranometria Argentina</i> making its way on to the <a href="http://www.uranometriaargentina.com/">web</a>, and subsequently on to <a href="http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135%2Fcatalog">Vizier</a>. What most people won't realize was that he entered all the data (original, as well as modern magnitudes and catalog references) <b>by hand</b>! In his own words:<br />
<br />
<blockquote>After some investigation I learned that there was a copy of the original <i>Uranometria Argentina</i> at the library of Steward Observatory, University of Arizona, and arranged with the library staff to photocopy the entire tabulation plus a few additional pages of explanation. The photocopies I took home to type character by character into a plain text file, all 7700+ lines of data. Likewise all the modern data were added by hand. The entire task, fitted into spare time, required more than a year. I did exhaustive proofreading and found most of the typographical mistakes before ever putting the text file on-line. <br />
<br />
Likewise by hand I entered the Gould numbers on to personal star charts, went out at<br />
night, and using binoculars identified most of the <i>Uranometria Argentina</i> stars north of declination -50 degrees.</blockquote><br />
A remarkable effort. I came along later and helped with further proofreading, and the resulting data was loaded into Vizier. But without Frederick's herculean perseverance, none of it would have been possible. Thank you Frederick!richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com2tag:blogger.com,1999:blog-4110373308374666161.post-64562816324794658782011-08-28T23:30:00.000+10:002011-08-29T08:33:44.785+10:00Uranometria Argentina: AtlasThe Uranometria Argentina catalogue was accompanied by a Star Atlas, which you can view <a href="http://translate.googleusercontent.com/translate_c?hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&u=http://historiadelaastronomia.wordpress.com/documentos/uranometria-argentina/ua1877/&usg=ALkJrhhYKcePIipuftmLo2djnYwgY-D8DQ">here</a> (courtesy of Google Translate), or <a href="http://historiadelaastronomia.wordpress.com/documentos/uranometria-argentina/ua1877/">here</a> if you're comfortable in Spanish.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-47385755122063751052011-08-27T22:58:00.000+10:002011-08-27T23:06:10.733+10:00Gould update at VizierThanks to <a href="http://cdsweb.u-strasbg.fr/~francois/">François Ochsenbein</a> from CDS/Simbad and his helpful team, the Gould Catalogue at Vizier (<a href="http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135">http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=V%2F135</a>) has been updated. The Gould Name has been added to the search results and the data record, as well as the original 1875.0 coordinates from the catalogue.<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="float: left;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT_AEI4yTzcr8odUFmAhMgqwFBVEaeaE9-Y7TPM-47CXoVAQpS6MQ_HcacPjBousMpbL0CrN1CxKF6n7cinPfZAUq9xLVGNhy0Ojc9nf80IFd8_8lGgUuLoNJ-5NH_mwdySL41F8_lgxMA/s1600/82G.png" imageanchor="1" style="clear: left; margin-bottom: 1em; margin-left: auto; margin-right: auto;"><img border="0" height="52" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgT_AEI4yTzcr8odUFmAhMgqwFBVEaeaE9-Y7TPM-47CXoVAQpS6MQ_HcacPjBousMpbL0CrN1CxKF6n7cinPfZAUq9xLVGNhy0Ojc9nf80IFd8_8lGgUuLoNJ-5NH_mwdySL41F8_lgxMA/s640/82G.png" width="600" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><em>Uranometria Argentina entry for 82 G Erindani</em></td></tr>
</tbody></table><br />
<br />
This rectifies any potential ambiguity that existed previously with Flamsteed numbers with stars such as 33 G. Librae (which does not equal 33 Librae). How Gould's Uranometria Argentina came to be transcribed in the first place is a remarkable story in itself, which I will relate shortly in another entry.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-34162536263910237312011-07-29T14:05:00.000+10:002011-07-29T14:06:43.449+10:00EBSC Vol. 1 designations complete . . .Updating of the final constellations to be included in Vol 1 is complete. I am updating an add-on for celestia to include these changes; it should take a few days to get the documentation organised.<br />
<br />
The bulk of the work has been on designation cross-referencing, including correcting updates in existing ids (HD, SAO etc). The plan was to leave the rest of the data (proper motion etc etc) for a later stage. However it seems like it may be a good idea to at least do some updates now to make the data set more useful. It will probably consist of replacing old astrometric data from the original BSC with Hipparcos data (2nd reduction). I am toying with adding a flag if the star is contained in A. A. Tokovinin's Multiple Star Catalogue. Not sure if it will make the cut this time around, but let me know if you think it would be a valuable enhancement.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-37307660061797973372011-07-08T06:35:00.000+10:002011-07-08T06:35:55.997+10:00EBSC Vol. 1 is comingWork on the EBSC has been put on hold for a little while, but now I am editing the <a href="http://uranometria.blogspot.com/2011/01/ebsc-update-part-2.html">final constellations</a> that needed it in "part 2". The 22 constellations included in "parts" 1 and 2 will now be combined into Volume 1 when this editing process is complete. As there are 88 constellations, there will ultimately be 4 volumes of the <a href="http://uranometria.blogspot.com/p/extended-bsc.html">EBSC</a>, released for download over time.<br />
<br />
Centaurus done. Crux, Norma and Phoenix to go...richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com1tag:blogger.com,1999:blog-4110373308374666161.post-40661249619451603662011-06-24T22:10:00.000+10:002011-06-24T22:10:14.756+10:00Gould Designations: G. or no G. ?I had a disagreement a while back with a scientist/astronomer about Gould numbers. Do Gould Designations have a G. or not? (e.g. 82 G. Eridani). He claimed he'd never even heard of the G., and felt that few people would be, or would <i>want </i>to be.<br />
<br />
Historically, the G has always been present. I can also say that all atlases and publications I've come across include the G (his put-down of Sky & Telescope as publications for amateurs--what's with that?). So I said, as I still believe, that the G. is correct.<br />
<br />
But I've been thinking. If the G. were dropped, it would be 'incorrect', but perhaps it would lead to Gould numbers being more popular. Pithy is good. Even though the G. is correct, maybe for the future they <i>should</i> be dropped. 33 G. Librae would have to keep the G. (33 Librae, a Flamsteed designation, already exists), but in most cases it could be done.<br />
<br />
Thinking about it.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-523126616493395812011-01-21T12:26:00.000+11:002011-01-21T12:26:04.380+11:00RECONS update contains new "Near Star"The team at RECONS have updated their list of the <a href="http://www.chara.gsu.edu/RECONS/TOP100.posted.htm">closest 100 stars</a>. Parallaxes from the 2007 Hipparcos revision have been included, which results in a slight reordering of the entries.<br />
<br />
There is one new stellar entry, for <a href="http://simbad.u-strasbg.fr/simbad/sim-coo?CooDefinedFrames=none&CooEpoch=2000&Coord=09%2039%2035.5%20-24%2048%2028&submit=submit%20query&Radius.unit=arcmin&CooEqui=2000&CooFrame=FK5&Radius=2">2MASS J09393548-2448279</a> , which is a new candidate for the NSTARS database. As the designations have been assigned for all the initial entries, this would get the next number in the sequence for its constellation (which would be <i>N10 Antliae</i>).<br />
<br />
Interestingly, it is the second brown dwarf in Antlia to be included. <i>N1 Antliae</i> is also in the top 100 (under the name "DEN 0255-4700"), about 4-5 pc away.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-5630909698205164192011-01-18T08:08:00.000+11:002011-01-18T08:08:20.939+11:00NSTARS: tiny correction for N9 Puppis / 171 G. PuppisThe star <b>N9 Puppis</b> (171 G. Pup) has 171 in the Flamsteed column as well. It's one of those Gould numbers that continually finds its way into references as a Flamsteed designation. I haven't updated the spreadsheet for now until thereare further corrections to be made, but if you're using the spreadsheet, please remove this incorrect Flamsteed designation.<br />
<br />
The server logs indicate that the NSTARS update has been very popular. Please do write a comment if you are finding the database useful, or if you have any suggestions or corrections. Being "between versions", I am not actively maintaining it for a while until my other projects have a rest, so I'm relying on you to tell me if anything is amiss.<br />
<br />
Future enhancements will probably complete missing data as far as possible (magnitudes, motion and spectra), and perhaps add additional columns for data that is useful and available. Stellar mass? Other suggestions? Also, the database doesn't incorporate the Hipparcos 2 parallaxes, except where alternatives weren't available. The current parallaxes (as provided by the original database) uses weighted averages between the original Hipparcos data, and ground-based measurements. If the best strategy can be identified for updating/combining these, it's another possible new feature. Let me know what you think.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com1tag:blogger.com,1999:blog-4110373308374666161.post-86314204767038457672011-01-10T15:20:00.001+11:002011-01-10T15:30:26.631+11:00EBSC update: part 2It's been a while coming, but I have posted part 2 of the Extended BSC. This contains stars in the following southerly constellations:<br />
<ol><li>Carina<br />
</li>
<li>Musca<br />
</li>
<li>Circinus<br />
</li>
<li>Triangulum Australe<br />
</li>
<li>Dorado<br />
</li>
<li>Ara<br />
</li>
<li>Horologium<br />
</li>
<li>Reticulum<br />
</li>
<li>Pictor<br />
</li>
<li>Centaurus*<br />
</li>
<li>Crux*<br />
</li>
<li>Norma*<br />
</li>
<li>Phoenix*<br />
</li>
</ol>The 4 asterisked constellations have some final additions to confirm, so I may update these with some additional entries in the future. There will also be further work done on star designations, but in the meantime, I encourage you to use the supplied Gould Numbers or Near Star numbers if there is otherwise only a HD/SAO/HIP number.<br />
<br />
See <a href="http://uranometria.blogspot.com/p/extended-bsc.html">Extended BSC</a> to download.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com2tag:blogger.com,1999:blog-4110373308374666161.post-30436743776954703302010-10-26T06:28:00.000+11:002010-10-26T06:28:04.921+11:00Extended Bright Star CatalogueI have uploaded the first of my files for the <a href="http://uranometria.blogspot.com/p/extended-bsc.html">Extended Bright Star Catalogue</a>, which is currently under development. Comment is welcome for this catalogue, as it is for the <a href="http://uranometria.blogspot.com/p/near-star-catalogue.html">Near Star Catalogue</a> and my <a href="http://uranometria.blogspot.com/p/iau-recommendations.html">Nomenclature Recommendations for the IAU</a>.<br />
<br />
The first file (of 9) contains 10 constellations surrounding the South Celestial Pole, from Octans to Carina. Note that designations in angled brackets (e.g. <r>) are obsolete, having being assigned by Lacaille and others before R-Z were reserved for Variable stars. These are not to be used, but are temporary markers only so that it is clear what stars did have designations once. My IAU Recommendations include the addition of new designations, and once these are finalised, these obsolete designations will be removed.<br />
<br />
For more information, see <a href="http://uranometria.blogspot.com/p/extended-bsc.html">Extended Bright Star Catalogue</a>.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-51453591867034913082010-09-27T22:38:00.000+10:002010-09-27T22:38:51.239+10:00Pocket Sky Atlas: Great atlas, with one unfortunate drawback<div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW91gYD6SF6MB62kGbYETh6_J1oyGb-Acdb_XlJivchfgrf9HqIWkar_7cQTVOBkdGxVxIwRlmufRegeDiQZsIebF0z_h72TVNlkURS5hVUR2GddqIrQleIv2NlG4whranzPGPdv6w920v/s1600/PocketSkyAtlas.jpg" imageanchor="1" style="clear: right; cssfloat: right; float: right; margin-bottom: 1em; margin-left: 1em;"><img border="0" px="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhW91gYD6SF6MB62kGbYETh6_J1oyGb-Acdb_XlJivchfgrf9HqIWkar_7cQTVOBkdGxVxIwRlmufRegeDiQZsIebF0z_h72TVNlkURS5hVUR2GddqIrQleIv2NlG4whranzPGPdv6w920v/s1600/PocketSkyAtlas.jpg" /></a>Many reviews have already extolled the virtues of this atlas from <em>Sky & Telescope</em>: the wonderful look and feel (in the tradition of Becvar and Tirion's Cambridge atlas), the convenient size (take it on field trips or read it in bed), the spiral binding that allows it to lie flat, the hard thinking that has obviously gone into the layout. Constellation figures, tick. Clear constellation names, tick. Extensive inclusion of star names, plus locations of some nearby stars that didn't make the magnitude cutoff, tick.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">Some reviews have called it your ultimate reference, but because of its one downside, this it cannot be. I purchased it to be something midway between Tirion's Star Atlas 2000.0 (1st ed. to mag 6.5, yes I know it's old now...) and the 3 volume Millenium Star Atlas (too heavy for anywhere but the desk). But despite covering more stars with a higher zoom than Tirion's atlas, it uses less star labels.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div>Take Leo Minor for example, hardly a constellation where congestion would be a problem. Tirion's map is about 50% smaller, yet I had to copy the following Flamsteed numbers from Tirion into Sinnott's: 7, 9, 13, 22-24, 27, 32-35, 38, 40, 43-44, 48, 50. It seems like more are omitted than included, and the fact that I was able to pencil them in means that there was plenty of space for the publishers to be a bit more generous. In the southern hemisphere, e Eri/82 G. Eri is a large, nameless dot (an important star, one of the closest to the Sun). This was extremely disappointing, and I considered giving only 3 stars (after all, these labels are one of the primary reasons to buy an atlas), but the other positives persuaded me, at length, to award it 4 . . . just.<br />
<br />
To finish on a positive note, they did print Rho Aql correctly: it recently slipped into Delphinus, and now has to be printed with its constellation name as well as its Greek designation. Good one.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-56443550111177425102010-09-22T06:45:00.000+10:002010-09-22T06:45:21.384+10:00PeacockWork on the <a href="http://uranometria.blogspot.com/2010/08/extended-bright-star-catalogue.html">EBSC</a> (Extended Bright Star Catalogue) continues with speed: 18 constellations have been edited, and I'll be able to put some up on the blog soon.<br />
<br />
But here's a random musing: don't you think that the name Peacock is the worst star name ever? You can read <a href="http://en.wikipedia.org/wiki/Alpha_Pavonis">here</a> how it came to be named, but one wishes that they came up with something better. Pavo the Peacock . . . let's just call the star Peacock and be done with it. Surely an Arabic scholar could derive an Arabic equivalent for us? <em>Please?</em><br />
<br />
Let's be thankful they didn't get their hands on Circinus. Alpha would have been named <em>Draftsman's Compass</em>.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-34618617161760332010-08-26T11:59:00.000+10:002010-08-26T11:59:06.003+10:00Extended Bright Star CatalogueThe 5th revision of the Bright Star Catalogue (BSC) was released about 20 years ago, and is one of the primary sources for information about stars brighter than 6.5V. A supplement exists, adding a couple of thousand extras down to a magnitude of 7.1V.<br />
<br />
Of course, there are many stars brighter than this cut-off that are not included. Also, the current version was released prior to the Hipparcos catalogue, meaning that some of the information is out of date, particularly parallaxes.<br />
<br />
My current project is to edit a new catalogue, perhaps called the Extended Bright Star Catalogue (for now at least), that will attempt to bring together all the stars brighter than 7.1V i.e. the same magnitude range as the BSC Supplement. Data from the Hipparcos satellite will be included, and I will be looking carefully at the identifiers, not only correcting omissions, but proposing some improvements here and there.<br />
<br />
I'll be starting at Octans and working my way north, constellation by constellation, and be blogging my results. Hope you can join me.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-66959837487039162912010-08-24T23:02:00.000+10:002010-08-24T23:02:46.530+10:00Where did all Bayer's letters go?Johann Bayer published his celebrated <em>Uranometria</em> atlas in 1603, and it's from there that we get many of the Greek designations, such as <em>Alpha Centauri</em>. But did you know that, when he'd exhausted all 24 letters of the Greek alphabet, he assigned stars Roman letters?<br />
<br />
He started with A (because <strong>a</strong> could easily be confused with <strong>α</strong>), and the proceeded from <strong>b</strong>, down the lower-case alphabet, only ocasionally getting into the 2nd half of the alphabet. It's where we get names such as <em>h Persei</em>, <em>p Eridani</em> and so on.<br />
<br />
But have you noticed that they've been disappearing over the past thirty years?<br />
<br />
In 1979, Dorrit Hoffleit (astronomer at Yale University) in her paper, "Discordances in Star Designations", pleaded that all roman letters, other than that for Variable stars, be excluded from future catalogues. When she released the 5th edition of the Bright Star Catalogue, that's exactly what she did. The letters were gone. In the popular Sky Catalogue 2000.0 (1982), all but a few Bayer letters were expunged.<br />
<br />
But not everyone wants to lose these designations and be forced to use cumbersome catalogue numbers for these stars. Atlases continue to use them, and Morgan Wagman, in his book <em>Lost Stars</em>, goes as far as saying that this practice is patently unfair and discriminatory against stars with Roman letters.<br />
<br />
I have sympathies both ways. Without roman letters, many stars remain unlettered, and we're forced to use long catalogue numbers. This is particularly so in the Southern Hemisphere (until we make better use of <a href="http://uranometria.blogspot.com/2010/08/gould-numbers.html">Gould Numbers</a>). We need further simple designations to use. But I also understand the other side of the argument. Many of the lower-case Roman letters are frequently confused with the Greek ones, meaning that most atlases and catalogues over the past fifty years have multiple errors.<br />
<br />
What's the solution? Should we restore them or not? Or should we make some sort of compromise?richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com1tag:blogger.com,1999:blog-4110373308374666161.post-90059918250242882912010-08-19T20:41:00.000+10:002010-08-24T21:02:04.610+10:00Lost Star Profile: Omicron Octantis (ο Oct)I thought I would start to profile some "Lost Stars", in the sense of Morton Wagman's book of that name. These are stars that, for one reason or another, have temporarily 'lost' the names that they once had.<br />
<br />
<table cellpadding="0" cellspacing="0" class="tr-caption-container" style="clear: right; cssfloat: right; float: right; margin-bottom: 1em; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9C2cyDtaNlWZBWoFPfEAcmtGXlJtP4n_qpmajzNEJWo9LKeUFiIlJv0i8TkIeaLcTYPXeDRgje4dWiCUor8hIEFvwKR7q29M_TG68eyflyqAL22i-U9Y7mcf4BQ9exxNbZj5dGxv_m9rc/s1600/OmiOct.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" ox="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg9C2cyDtaNlWZBWoFPfEAcmtGXlJtP4n_qpmajzNEJWo9LKeUFiIlJv0i8TkIeaLcTYPXeDRgje4dWiCUor8hIEFvwKR7q29M_TG68eyflyqAL22i-U9Y7mcf4BQ9exxNbZj5dGxv_m9rc/s320/OmiOct.png" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;">Omicron Octantis is marked. Sigma, the Pole Star, is the 2nd<br />
star to the 'N-E'.</td></tr>
</tbody></table><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">Omicron Octantis is a blue subgiant (B9.5IV) about 550 pc away. In Octans, most catalogues and atlases omit Omicron, but it does exist. It's HD 1348, and it's very close to the South Celestial pole. In fact, it used to be even closer, which is probably why it was given a Greek letter even though its magnitude is only 7.2V. </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">It was named in Rumker's catalogue, but Benjamin Gould obviously accepted the designation, for when he came to assign the Greek letters that hadn't yet been used, he omitted omicron. However, it was too faint for inclusion in Gould's catalogue, and too faint for the Bright Star Catalogue or its supplement, so it tends to get forgotten, even by editors of atlases where the magnitude limit is far fainter. Hopefully, they won't make the same mistake in the future!</div>richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-86311324317594212122010-08-14T10:13:00.001+10:002010-08-14T10:14:43.573+10:00Designations for Nearby Stars<a href="http://uranometria.blogspot.com/2010/08/nstars.html">Last time</a> I wrote about my update to the NSTARS database (the original of which seems to have gone to internet heaven). But now I want to talk about how we designate near stars.<br />
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The NSTARS database used a notation popularised by the CCDM and WDS double-star databases, in which the position in the sky is truncated and converted to a code. For example, the star Arcturus which is located at ra=14 15 39.7, dec=+19 10 56.7, has an original NSTARS designation <strong>NS 1415+1910</strong>. Scientists like it because of its precision and (mostly) self-ordering properties, but for a topic like near stars, which you expect will get much public attention, it is terrible for communication. Can you imagine an article written about the discovery of an otherwise unnamed near star, having to repeat the mouthful over and over?<br />
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We have simple ways of referring to bright stars (<em>Alpha Centauri</em>), variable stars (<em>CN Leo</em> or <em>V645 Centauri</em>), but no uniform designations for nearby stars, even though the availability of accurate parallaxes now means that we're in a better position than ever to accurately determine just how near a star is.<br />
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My proposal is simple. See the variable designation I used above? Let's swap N for V, and gloss over all the subtleties involved with that system (e.g. inclusion of Bayer designations, R..QZ letters). Order the current catalogue in order of increasing distance from the Sun, keeping multiple systems together (this is only for initial designations). We then follow these simple steps:<br />
<ol><li>Our own Sun gets the special designation, <strong>N0</strong>;</li>
<li>The other stars are ordered N1, N2 etc., followed (& grouped) by their Constellation, in the same way as bright and variable stars are. So the next system, <em>Alpha Centauri</em>, becomes <strong>N1 Centauri</strong> (<em>Proxima Centauri</em> is <strong>N1 Centauri C</strong>);</li>
<li>Designations are assigned down the list. Barnard's Star is <strong>N1 Oph</strong> for short, 2MASS J10481463-3956062 is <strong>N1 Ant</strong> (better, yes?). LHS 337, the next closest star in Centaurus, becomes <strong>N2 Cen</strong>;</li>
<li>Once assigned, designations are never modified if new parallaxes become available. The sorting is only for a convenient initial list. If a new near star in Cygnus is discovered, the next available designation is given (<strong>N41 Cygni</strong>), regardless of distance.</li>
</ol>What do you think? I'm hoping that this system will be adopted, and a suitable body take over the maintenance of the list. As things stand, no universal system exists (we use PLX, LHS, GJ, 2MASS etc as needed), save for the NS system, which is apparently defunct, not widely used, and in my opinion, cumbersome.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-38503596980613064862010-08-11T22:59:00.000+10:002010-08-24T20:41:57.316+10:00NSTARSStars that are designated as being 'nearby' are usually those within 25 parsecs of the Sun. In 1998 a project was begun at Northern Arizona University, called <a href="http://nstars.nau.edu/nau_nstars/index.htm" rel="nofollow" target="_blank">NSTARS</a>. It used a nomenclature that seems currently in vogue (converting the position in the sky to a nine character identifier), but to me it seemed too cumbersome for general use beyond the scientific community. Their website has been down for a few years for a "redesign", and there's no word when it will be back, if at all.<br />
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<em>But</em> I kept a copy before it disappeared. And now I'm pleased to release my unofficial update of the NSTARS catalogue, entitled the <b><a href="http://uranometria.blogspot.com/p/near-star-catalogue.html">Near Star Catalogue</a></b>. With it, I propose a new nomenclature for nearby stars that I hope will be adopted. I will blog about that next time.<br />
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I acknowledge the hard work done by the NSTARS team to compile the original database. Thank you also to the folks at <a href="http://simbad.u-strasbg.fr/simbad/" rel="nofollow">SIMBAD</a>, the <a href="http://www.chara.gsu.edu/RECONS/" target="_blank">RECONS </a>team, Dr. Carolin Liefke of the University of Hamburg (see her <a href="http://www.hs.uni-hamburg.de/DE/For/Gal/Xgroup/nexxus/nexxus.html" rel="nofollow">NEXXUS</a> database), and to Ken Slatten, whose corrections to the original NSTARS database had been passed on to me. If you're out there, Ken, please send me a mail!richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com1tag:blogger.com,1999:blog-4110373308374666161.post-21550813775507415392010-08-06T23:09:00.000+10:002010-08-06T23:09:07.830+10:00Gould Numbers<a href="https://secure.wikimedia.org/wikipedia/en/wiki/John_Flamsteed">John Flamsteed</a>, the first Astronomer Royal, assigned numbers (known as <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Flamsteed_designation">Flamsteed numbers</a>) to bright stars in each constellation, but he did so only for stars that he could see from London. Because of this, there are no Flamsteed number assigned within about 65 degrees of the South Celestial pole.<br />
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<a href="https://secure.wikimedia.org/wikipedia/en/wiki/Benjamin_Apthorp_Gould">Benjamin Gould</a> later did for the Southern Hemisphere what John Flamsteed did for the North. In his Uranometria Argentina (1879), he numbered thousands of stars south of +10 degrees N. Several of these have been in use ever since (think <a href="http://simbad.u-strasbg.fr/simbad/sim-id?Ident=82+Eri">82 G. Eridani</a>), and they can be distinguished from Flamsteed numbers by the character G that follows the number. Though as you will see by the link to 82 Eri above, often the G somehow disappears!<br />
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In recent times the Uranometria Argentina hasn't been widely available, but that has all changed. Frederick Pilcher has transcribed the entire catalogue and published it at <a href="http://www.uranometriaargentina.com/">http://www.uranometriaargentina.com/</a>. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/List_of_stars_by_constellation">Wikipedia</a> is also slowly being updated to include these designations.<br />
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So next time you're tempted to use a long catalogue number for an 'unnamed' star in the far south, check Gould's catalogue first.richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-62711058783119048992010-08-05T20:48:00.000+10:002010-08-05T21:18:34.403+10:00Alpha Leonis Minoris (alpha LMi)Okay, here's a prime example of what I'm talking about. The above designation seems clear enough: the brightest (alpha) star in the constellation Leo Minor (Leonis Minoris, LMi for short). Except you won't find it in any atlas.<br />
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Francis Baily was a British astronomer in the first half of the 19th century. He did many great things, but he was a scrooge with Greek letters. He lettered a few constellations that Bayer hadn't already done, but Baily would only add one if the star's magnitude was 4.5 or brighter. This was an idiosyncratic decision, because Bayer, who started everything off, was far more generous than that.<br />
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But inexplicably, Baily omitted Alpha in Leo Minor. He assigned a Beta (magnitude 4.2), but the brightest star Alpha (magnitude 3.8) he left unlettered. This was surely an oversight, given his stated objective, but in over 160 years since then, no one has corrected the oversight. Bode (1801) gave it the letter o, but this is confusing, and some atlases have called it omicron, the Greek letter, by mistake.<br />
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Truly. In 2010, we are still without an Alpha.<br />
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It's not hard to rectify. Gould would surely have fixed it if it had been within his purview, but Leo Minor is too far north to be included in his catalogue (Gould lettered stars of 6th magnitude or brighter). How about we finally put things right?<br />
<ul><li>Alpha: 46 LMi (3.8V)</li>
<li>Beta: 31 LMi (4.2V)</li>
<li>Gamma: 21 LMi (4.5V)</li>
</ul>There we go, the three brightest stars in Leo Minor now have letters, as they should have all along. I may assign some more, but I will be scientific about it and check the surrounding constellations to see what magnitude limit to use. I'll let you know!<br />
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<table align="center" cellpadding="0" cellspacing="0" class="tr-caption-container" style="margin-left: auto; margin-right: auto; text-align: center;"><tbody>
<tr><td style="text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEht4oKGdxkDdvmY6aHN6N23TjFXwg8bGsOAKRBxpQaHLwoYsgiOTxIR-JsThka4IfF9b8VuCNoAa1XK4MtnO8tLZnNMZfLzbtx0ZV1wLUwLpYQYkkW7pnEh8dPVyMptcUjDGKl3iCwpzH2e/s1600/LMi.png" imageanchor="1" style="margin-left: auto; margin-right: auto;"><img border="0" bx="true" height="226" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEht4oKGdxkDdvmY6aHN6N23TjFXwg8bGsOAKRBxpQaHLwoYsgiOTxIR-JsThka4IfF9b8VuCNoAa1XK4MtnO8tLZnNMZfLzbtx0ZV1wLUwLpYQYkkW7pnEh8dPVyMptcUjDGKl3iCwpzH2e/s400/LMi.png" width="400" /></a></td></tr>
<tr><td class="tr-caption" style="text-align: center;"><em><span style="font-family: Times, "Times New Roman", serif; font-size: small;">The 3 brightest stars of Leo Minor. From L to R, what should be: α, β, γ.</span></em></td></tr>
</tbody></table>richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0tag:blogger.com,1999:blog-4110373308374666161.post-47603190120055130422010-08-04T23:06:00.000+10:002010-08-06T23:17:42.108+10:00A History of Modern Star Designations<em>(condensed, with tongue slightly in cheek)</em><br />
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In the 1603, <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Johann_Bayer">Bayer</a> assigned Greek letters to stars in each constellation, but some were so badly drawn, you couldn’t tell what star he meant. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/John_Flamsteed">Flamsteed</a> tried to fix things up, but he was missing the catalogue that went with the atlas, and he only made things worse.<br />
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Then <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Nicolas_Louis_de_Lacaille">Lacaille</a> mapped the southern constellations and used so many letters, people couldn’t discriminate the ο with the o, the χ with the x, and atlases still get them confused (I kid you not!). <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Johann_Elert_Bode">Bode</a> added some designations, but people forgot most of them. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Francis_Baily">Baily</a> spent considerable effort tracking down Flamsteed's errors, but not everyone listened to him. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Friedrich_Wilhelm_Argelander">Argelander</a> reckoned if he couldn’t see a star, it didn’t deserve a designation--so he removed it, no matter what Baily said. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Eduard_Heis">Heis</a> had better eyesight, but he sided with his buddy anyway. <a href="https://secure.wikimedia.org/wikipedia/en/wiki/Benjamin_Apthorp_Gould">Gould</a> then removed some more designations, and re-added others had deleted...<br />
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Finally, in 1930, the <a href="http://www.iau.org/">IAU</a> stepped in and defined the Constellation boundaries once and for all. But they didn't think to standardize the nomenclature of stars at the same time, so we're left with a mess where stars designated Norma are in Scorpio, stars designated as being in Orion are in Monoceros. Astronomers and cartographers follow whatever convention they see fit to. And they call astronomy a science! ☺richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com3tag:blogger.com,1999:blog-4110373308374666161.post-77329132231269898762010-08-04T22:39:00.000+10:002010-08-04T22:55:04.527+10:00Welcome to my blog!<span style="font-family: inherit;">When you look up into the sky and see a star, have you thought how it got its name? Or, even whether it <em>has</em> a designation at all?</span><br />
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<span style="font-family: inherit;">The very brightest stars have names, like Sirius and Arcturus. Once you get further down the list, stars are designated with Greek letters (e.g. Alpha [α] Centauri) or numbers (61 Cygni). However, these designations are not always as certain as you would think. Some are ambiguous, and have gradually disappeared. Particularly in the Southern sky, many bright stars have to do without a designation, primarily because most of the astronomers active in cataloguing stars lived in the Northen Hemisphere. Some other useful systems for designating stars that were formerly in use have fallen out of favour. Again, I wonder whether there is a Northern Hemisphere bias at work here.</span><br />
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<span style="font-family: inherit;">I've started this blog to talk about the way we designate stars. The average person with a pair of binoculars can see thousands more stars than many famous astronomers of old, yet for various reasons we have less labels to use. My basic manifesto is this:</span><br />
<ol><li><span style="font-family: inherit;">We need more designations to cover most stars that we can see;</span></li>
<li><span style="font-family: inherit;">We need simple designations;</span></li>
<li><span style="font-family: inherit;">We need unambiguous designations;</span></li>
<li><span style="font-family: inherit;">We need to use the same designations as each other.</span></li>
</ol><div><span style="font-family: inherit;">In short, all the points above encourage communication. And I think for most of the above points, the astronomical community is in a bit of a rut. We'll need some resurrection of old ideas and some innovation to produce new ideas to make it happen. I look forward to reading your thoughts.</span></div>richardhttp://www.blogger.com/profile/18263909051314646527noreply@blogger.com0