Tag Archive for 'VizieR'

[Stellar Mapping] Extended Hipparcos dataset added!

I’ve now replaced the New Reduction Hipparcos data with the new Extended Hipparcos (HIPX) dataset published in 2012 by Anderson & Francis (see this paper for all the details). The HIPX dataset expands the original dataset to include luminosities, spectral types and much more useful astronomical data from a variety of sources, making this the definitive source of information about these stars! The searchable online HIPX catalogue is located at http://vizier.u-strasbg.fr/viz-bin/VizieR-3?-source=+V/137A/XHIP.

The HIPX data replaces the New Reduction Hipparcos data on this website – Astrosynthesis and Galactic XYZ data have both been updated! In most cases the HIPX XYZ data is identical to the New Reduction Hipparcos XYZs, but issues with the parallaxes for some of the multiple systems in the New Reduction data led to significant inaccuracies there – in those cases, the parallaxes were reverted back to the original Hipparcos parallax data (again, refer to the XHIP paper for further explanation).

The XHIP data includes more star names (including common/arabic names), which are also presented here. However, note that Gliese numbers higher than 3000 have been removed for ease of reference. Technically these numbers aren’t “Gliese numbers”, they’re “NN” or “Wo(oley)” numbers. Because this could cause confusion, I decided to remove them instead of editing them all, but this isn’t a huge loss since the stars can still be tracked using their HIP numbers or other names.

If you’ve been using the New Reduction data, then be sure to head over to my Stellar Mapping page to download the new Extended Hipparcos dataset!

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In other news, my Stellar Mapping page now has the Atomic Rockets Seal of Approval! This is Winchell Chung’s way of saying that he likes my work, and I’m very happy about that because I’ve been a fan of his Atomic Rockets website pretty much since it first appeared online (it’s a great resource for any SF fan)! His 3D Starmaps site is also one of the main inspirations for my own stellar mapping efforts! Thanks, Winchell! 🙂

[Stellar Mapping] CTIOPI dataset added, Stellar Mapping page reorganised!

I have now added the CTIOPI (Cerro Tololo Interamerican Observatory Parallax Investigation) dataset to my Stellar Mapping page! CTIOPI is another dataset from the RECONS group, aimed at locating red, white, and brown dwarfs that are within 25pc of Sol – it adds 164 stars that are mostly contained within 300 ly of Sol. However, it only covers (roughly) the southern sky as viewed from Earth, so only about half of the volume around Sol contains stars from this dataset – that said, the distribution of CTIOPI stars could be used as a guideline for adding fictional stars in the rest of the volume.

CTIOPI dataset, looking corewards.

I have also edited the DENSE dataset to remove all the stars that were duplicated in CTIOPI and HIPPARCOS datasets – the most accurate data has been retained (the original DENSE dataset is no longer available here, though I may make it available again in a later blog update). The CTIOPI dataset has also been edited somewhat to remove duplicates (none of the CTIOPI stars have HIP numbers though, though it does include one star – HIP 3856 – that is missing from the Hipparcos dataset). All CTIOPI entries within 22.7 lightyears have also been removed to avoid overlap with RECONS.

This means that there should now be no duplicated stars at all if the RECONS, DENSE, CTIOPI and HIPPARCOS datasets are used together, so the combined dataset is now about as accurate as it can be. Full details of these edits can be found in the “CTIOPI-DENSE merging details” section in the Astrosynthesis.txt and Galactic.txt files contained in the new RECONS-DENSE-CTIOPI.zip file available from Section 2 of the Stellar Mapping page.

I’ve also updated and reorganised the Stellar Mapping page to (hopefully) make it easier to decide which datasets to use. If you have already downloaded the DENSE dataset then you should download it again to make sure you have the latest version!

[Stellar Mapping] How to make your own stellar database!

Looks like my new Stellar Mapping page has been well received so far – thanks to everyone who has shown an interest in it, I hope you’re finding it useful!

In this article I’m going to show you how to make your own stellar database, with the same tools I used to construct the ones I presented on my mapping page. For this exercise we’ll be relying on something called VizieR, which is a huge online database of thousands of star catalogues. You’ll need to have a basic understanding astronomy to make the most out of this, but it’s not that tricky.

Let’s say you want to make a database of stars in a corridor between Sol and the famous Pleiades star cluster (if you’re familiar with the 2300AD RPG, this is essentially the path the Bayern took to the Pleiades). We’ll be using the Hipparcos star catalogue, since it has the most accurate parallax measurements (from which we can derive distances).

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