"Cartes Du Ciel" (CdC): Grid Settings

One thing that irks me to no end in CdC from day one is the grid spacing: When you zoom in, the grid lines jump around, as the grid spacing changes. One possibility would be 30°, 15°, 5°, 1°, 0°30' and 0°15'.

But the default grid spacing is 20°, 15°, 10°, 5°, 2° and so on – which is utterly utterly UTTERLY braindead.

But, do not fret! One can change the settings!

But fuck you very much, there are bugs: Because once you start to set the grid spacing to sensible values, the grid lines start to appear horizontally and vertically at different zoom levels. Seriously, WTF?

But that isn't the worst bug, not by far! At certain zoom levels the grid lines disappear completely! Instead, the "compass rose" appears for no apparent reason whatsoever… (at least here on my Macintosh). I think it is a problem when the grid spacing does not change from one so called "field of view number" to the next – but I could not quite nail the problem. Changing the field of view for a "field of view number" moves things around.

Before I started to curse, I initially wanted to simply write down how to set the grid spacing to sensible values – but it didn't seem possible, so I had to vent some air.

But after some fiddeling I managed to cobble together some working settings (the working values might change with different versions, as the code handling the grid spacing seems buggy…).

Setup > Chart, coordinates > Field of vision

Set the following values:

Field Number	"From" value
1	0.75 (was 0.50)
2	1.0
3	2.0 (was 1.5)
4	5.0
5	10.0
6	30.0 (was 20.0)
7	45.0
8	90.0
9	180.0
10	310.0

Setup > Chart, coordinates > Grid spacing

Set the following values:

Field Number	"Declination grid" value
0	+00 05 00
1	+00 15 00
2	+00 30 00
3	+00 30 00
4	+02 30 00
5	+05 00 00
6	+15 00 00
7	+15 00 00
8	+15 00 00
9	+45 00 00
10	+45 00 00

For me, these values result in a halfway useful grid being displayed most of the time. Occasionally the jumps between zoom levels are not smooth, but hey…

[Update] I hate CdC. Now that I have set the grid spacing to sensible values, I can now see the grid moving relative to the stars when I scroll around with the cursor! WTF? This is a cesspool. The code for displaying the grid in CdC seems to be horribly buggy.

"Cartes Du Ciel" (CdC): Setting Star Catalogs And Limiting Magnitudes

While there are some quite irksome UI particularies in Cartes Du Ciel, I find the software somewhat useful (considering it is free!) and haven't found an free alternative (and I don't expect to find anything better).

One thing I had to change is the amount of stars visible: It was far too few, and I could not related the view through my scope with the display by CdC. I was looking for the "tail" in the Pleiades, but wasn't able to find it. For these faint stars to become visible, one hast to change some settings:

Setup > Chart, coordinates > Object filter > Deep sky filter

Set "Limiting magnitude" to 13 for "Field of vision number" 1 to 4 – the rest should be fine. I don't know if 13 is the best choice, but for me it works OK (and it should show somewhat more than I can see with my scope).

Setup > Catalog > CdC stars

Make sure these two are selected:

• "Extended Hipparcos" (min 0 to max 10, cat/xhip)
• "Tycho 2" (min 0 to max 5, cat/tycho2)

The last one has apparently replaced the "Hubble Guide Star Catalog".

With these changes, one should see more stars, and get a view that resembles more the view through the scope.