Monthly Archive for February, 2012

[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] The 2300AD Near Star Map

The 2300AD Near Star Map

The 2300AD RPG – originally published by Game Designer’s Workshop in 1988 – presented an excellent gritty, realistic near-future hard sci-fi setting with lots of exploration, mystery, and interesting aliens. It’s also about to be republished by Mongoose Publishing as a setting for their version of the Traveller RPG!

One of 2300AD’s most interesting features is that the setting is built around a realistic (for the 1980s) Near Star List based on the Gliese Catalogue (2nd Version). FTL travel in 2300AD has a maximum range of 7.7 lightyears, resulting in the creation of “Arms” that extend from Sol to connect only the stars that are within this range of eachother (this limit can potentially be extended to 11.55 ly using Stutterwarp tugs, but this is expensive and uncommon).

There are three of these Arms, each colonised by a different political power in the setting – the French Arm, the Chinese Arm, and the American Arm. The French Arm stretches “upwards” from Sol towards Galactic North, ending at the orange giant star Arcturus. The American and Chinese Arms share the same beginning, but split off so that the American Arm heads Coreward/Spinward while the Chinese Arm sprawls around the (galactic) southern part of the solar neighbourhood.

Unfortunately the Near Star List (NSL) has not been updated for the new version of 2300AD. A lot of stars have been discovered in the solar neighbourhood since the late 1980s (as shown on my Stellar Mapping page), and the locations and distances of existing stars have been greatly refined since then too – so how does the updated stellar data affect the Arms?
Continue reading ‘[Stellar Mapping] The 2300AD Near Star Map’

[Stellar Mapping] RECONS list updated!

Oops! Gliese 667 slipped through the cracks and wasn’t included in any of the original stellar datasets on my Stellar Mapping page! This is slightly embarrassing since it’s a bit famous for having planets around it! It was within 22.8 ly from Sol, but for some reason wasn’t on the RECONS list – and because it was so close it wasn’t included in the Hipparcos dataset either.

I’ve now added Gliese 667 to the RECONS CSV files, so if you’ve already downloaded the RECONS data, you’ll need to download the new version so you can include Gliese 667! (I only found it because I was checking the stars on the American Arm for 2300AD!). There shouldn’t be any other missing stars there – I checked the border between RECONS and HIP and couldn’t find any other HIP stars within 22.8 ly that weren’t already on the RECONS list.

[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).

Continue reading ‘[Stellar Mapping] How to make your own stellar database!’