Volunteers wanted: nebulae outlines for Stellarium/SkyChart

[alexwolf]

Today Stellarium's development team published version 0.90.0.9732 with support of outlines for deep-sky objects.

We use the compatible with SkyChart (Cartes du Ciel) format of file for storing an outlines data for deep-sky objects. For example the outline for M42 is represented by this lines:

05.56401 -05.49880 start  M 42 
05.56759 -05.39201 vertex 
05.56635 -05.31749 vertex 
05.57158 -05.21922 vertex 
05.57601 -05.21716 vertex 
05.58830 -05.30164 vertex 
05.59140 -05.34341 vertex 
05.59028 -05.37076 vertex 
05.59008 -05.38175 vertex 
05.59581 -05.37159 vertex 
05.59943 -05.47123 vertex 
05.59912 -05.65838 vertex 
05.59520 -05.73212 vertex 
05.58490 -05.68102 vertex 
05.56948 -05.57675 end

First column is right ascension in decimal hours, the second column is declination in decimal degrees and third column is command (start, vertex, end). The command 'start' has name of DSO also.

Our outlines.dat file was partially got from CdC/SkyChart.

Now we want to get a volunteers, who can help us create a good outlines for big deep-sky objects for two projects - Stellarium and Cartes du Ciel/SkyChart.

[Skipper Billy]

Hi Alexander - you have put SO much into this project which you freely share with us and I would love to be able to give something back.

The above is mostly gobbledegook to me but if its something my tiny brain can get to grips with then count me in !

[alexwolf]

On 07.08.2017 at 01:10, Skipper Billy said:

The above is mostly gobbledegook to me but if its something my tiny brain can get to grips with then count me in !

Could you say what is confusing you? Maybe I can explain it?

[han59]

Hello Alexander,

Good initiative.

It would be nice to have more outlines in the public domain. The make outlines of deep sky objects, a good tool is required to become productive. For people who are interested, HNSKY provides a drawing tool where you can draw lines and edit the points with DSS images as background. Result is saved in CSV format.

Here a YouTube video from 2015 showing how it is done:

https://www.youtube.com/watch?v=tW-kU6ghTcs

Work flow:

- Download a DSS image as background.(red or blue) Or load any other  plate solved image.

- Draw the outline by clicking with the mouse.

- Edit, remove or add points as required.

- Save result supplement 2 (CSV format)

It is not a full CAD program, but a simple routine. However, it allows making a deep sky outline in 5 minutes. The CSV format can be quickly converted to another format. Every line contains a RA, DEC position and move or draw line instruction.

Note that most deep sky objects don't have a clear boundary and are better represented by an image of different gray levels. I have tried to make a new outline of the Milky Way with a software program but noted that the outlines can be placed almost everywhere depending on the detection level and gave up on that idea.

Some outline examples are available in HNSKY

Regards,

Han

An example: