Document Type

Dataset

Publication Date

2017

Description

The Mayo Dark Skies Community Group, in collaboration with the Dublin Institution of Technology, is pleased to launch a digital virtual experience of the Mayo Dark Sky Park. Following its designation as an International Dark Sky Park (Gold Tier), it is now possible to experience a part of this magnificent and pristine skyscape on your computer. This has been made possible using open source software (Stellarium http://www.stellarium.org/) and a specially commissioned digital panorama of the horizon surrounding the Ballycroy National Park Visitor Centre.

Stellarium is an open source planetarium for your computer and shows a fully realistic digital sky. The customised landscape file for Stellarium has been specially developed for this collaborative project. Once installed on your computer, this situates your viewpoint at the summit directly above the Visitor Centre. Real horizons are seen on the screen and, for the first time, the changing skyscapes throughout the year can be experienced and enjoyed. User control over the programme’s location, time and direction settings provides an incredibly powerful educational tool to learn practical astronomy.

A customised landscape file for Ballycroy, a display poster of the panorama surrounding the Visitor Centre and installation instructions are available here.

DOI

10.21427/D7Z107

Methodology

DESCRIPTION

Stellarium is free open-source software which provides the user with a high-accuracy virtual planetarium. It is available at http://stellarium.org/. By specifying an input geographical location and the date/time, it is possible to view and dynamically animate a fully realistic sky populated with a large number of celestial bodies and astronomical phenomena. The software has resident default landscapes chosen by the Stellarium Development Team which visualise actual horizons. These increase the realism of the scenes and the virtual viewing experience for the user.

In this project, a landscape file specific to the National Park Visitor Centre at Ballycroy, County Mayo was created by the author for the client, making it possible for the user to be virtually situated at that place. This permits the user to view the specific local landscape at Ballycroy and to accurately generate/simulate the actual astronomical sky at seen at Ballycroy. The essential data file to make this possible is named ballycroy.zip and its content and the methodology used to create it is described here.

FIELD SURVEY DATA COLLECTION

A photographic 360° panorama of the landscape centred at the Visitor Centre was recorded by the author on site. This consists of 12 digital images with each having an overlap of about 30%. The free open-source panorama photo-stitcher Hugin available at http://hugin.sourceforge.net/ was then used to join the 12 images into a single strip of photography. The strip was next equally sliced into eight segments and the sky was digitally deleted from each image. Each new image was sequentially numbered ballycroy1–ballycroy8.

For code please see below

MODEL CALIBRATION

Field survey measurements of azimuth and altitude were measured on-site by the author so as to calibrate the digital panorama model for errors in orientation and angular altitude.

DATA DISSEMINATION

The above data is compiled as ballycroy.zip and this file is made freely available on DIT's Library Repository Site ARROW along with a digital poster and an installation instruction file. The Zip file should not be decompressed but, instead, directly installed into Stellarium using the software function available for this purpose.

Disciplines

1. NATURAL SCIENCES

Publisher

Mayo Dark Skies Community Group

Language

639-3

Code Lists

A Stellarium landscape code file was next compiled with the eight images embedded. Once installed in the Stellarium directory, the user can select Ballycroy landscape as opposed to the other generic samples provided by the Development Team. The program code is:

[landscape]

name = Ballycroy

author = Frank Prendergast

description = Ballycroy Visitor Centre :)

type = old_style

nbsidetex = 8

tex0 = ballycroy4.png

tex1 = ballycroy5.png

tex2 = ballycroy6.png

tex3 = ballycroy7.png

tex4 = ballycroy8.png

tex5 = ballycroy1.png

tex6 = ballycroy2.png

tex7 = ballycroy3.png

nbside = 8

side0 = tex0:0:0.005:1:1

side1 = tex1:0:0.005:1:1

side2 = tex2:0:0.005:1:1

side3 = tex3:0:0.005:1:1

side4 = tex4:0:0.005:1:1

side5 = tex5:0:0.005:1:1

side6 = tex6:0:0.005:1:1

side7 = tex7:0:0.005:1:1

groundtex = ballycroyb.png

ground = groundtex:0:0:1:1

fogtex = fog.png

fog = fogtex:0:0:1:1

nb_decor_repeat = 1

decor_alt_angle = 44.6

decor_angle_shift = -21.4

decor_angle_rotatez = 97.3

ground_angle_shift = -21.4

ground_angle_rotatez = 45

fog_alt_angle = 20

fog_angle_shift = -3

draw_ground_first = 1

[location]

planet = Earth

latitude = +54d01'25"

longitude = -9d49'14"

altitude = 66

File Format

software program

Viewing Instructions

All instructions are located in the Readme file.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Share Alike 4.0 License.

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