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IDProjectCategoryView StatusLast Update
0002256SkyChart1-Softwarepublic20-01-04 23:11
ReporterNikos K Assigned ToPatrick Chevalley  
Status assignedResolutionopen 
Product Version4.2 
Target Version4.4 
Summary0002256: Innacurate drawing of Double Stars when the Washington Double Star catalog is selected.
DescriptionWhen the Washington Double Star catalog is selected, zooming on a double star displays three stars, the single one from the default catalog of the programme, and two of the doublet from the WDS catalog resulting to a rather inaccurate representation of all double stars.
Steps To ReproduceSetup > Catalog > Cdc Stars tab > Activate the Washington Star catalog.
Then zoom to a double star. For example, go to the famous Double Double (ε1 and ε2) on the Lyra constellation. Zoom to it and you will see three stars on ε1 and on ε2 instead of only two.
Tagsdisplay problem, double stars, stars


Nikos K

20-01-01 08:35


Lyra e2.png (11,992 bytes)   
Lyra e2.png (11,992 bytes)   

Patrick Chevalley

20-01-01 09:53

administrator   ~0006185

It is very difficult (impossible?) to solve this problem because this is inherent to the data available in the different catalog.

The standard star catalog Hipparcos, GAIA,... give star position at a given epoch and proper motion to compute a new position at another epoch. This proper motion assume a linear displacement and not take account for any orbital motion.
The WDS do not give any proper motion but the star position at a given epoch. Also the separation and position angle are given at a specific epoch, different epoch are used for every star.

The best you can do is to make the chart using mean J2000 coordinates to nullify the effect of proper motion. Open the menu Setup / Chart,coordinates , select "Equatorial coordinates" and "Mean J2000". But this cannot be perfect because of the different epoch the measurement where done.
Or if you not need them simply disable all the other star catalog to keep only the WDS.

The final release of GAIA will include specific solution for multiple stars that may help with this case but there is no release date for now.

Do you have other idea how the program can help with this problem?

Nikos K

20-01-01 19:20

reporter   ~0006190

Indeed it is due to having two different catalogues interfering with each other. I am trying to figure a way of properly merging information from different catalogues at least for the most popular double stars.
A solution to this could be treating the available catalogues like layers with visibility toggles quickly accessible from the toolbar.

Patrick Chevalley

20-01-04 23:11

administrator   ~0006215

This is a good idea to add such a quick access to the visibility of the available catalog. At the moment you always have to return to the catalog setting.
I try to find a way to implement it.

Issue History

Date Modified Username Field Change
20-01-01 08:35 Nikos K New Issue
20-01-01 08:35 Nikos K File Added: Lyra e2.png
20-01-01 08:35 Nikos K Tag Attached: display problem
20-01-01 08:35 Nikos K Tag Attached: double stars
20-01-01 08:35 Nikos K Tag Attached: stars
20-01-01 09:53 Patrick Chevalley Assigned To => Patrick Chevalley
20-01-01 09:53 Patrick Chevalley Status new => feedback
20-01-01 09:53 Patrick Chevalley Note Added: 0006185
20-01-01 19:20 Nikos K Note Added: 0006190
20-01-01 19:20 Nikos K Status feedback => assigned
20-01-04 23:11 Patrick Chevalley Target Version => 4.4
20-01-04 23:11 Patrick Chevalley Note Added: 0006215