plot-constellations vs limited number HD objects

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László Heller

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Mar 27, 2022, 4:28:31 PMMar 27
to astrometry
Hi!

Can somehow the plot-constellations utility also limit the number of tagged HD catalog objects on the output image?
For me, it apparently can't. Displays everything detected, so the final output image becomes weird, see the below screenshot:
Sas-plot2.png

When I run
plot-constellations -B -b 5 ...

It only tags the 5 brightest well known stars on the output.

But when I run
plot-constellations -D -d <Path_to_hd.fits> -b 5 ...

In this case, it tags all the detected HD objects, no matter, how the -b parameter was set.

BR,

Ladislav

László Heller

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Jun 18, 2022, 4:17:44 PM (10 days ago) Jun 18
to astrometry
Hi Dustin!

Any comments on the above question?

BR,

Ladislav

Dustin Lang

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Jun 20, 2022, 10:39:31 AM (8 days ago) Jun 20
to László Heller, astrometry
Hi,

Unfortunately, the HD catalog we've had floating around forever doesn't include magnitudes, so there's not an easy way to cut to the N brightest...

One could of course go back to the catalog source (eg http://vizier.u-strasbg.fr/cgi-bin/VizieR?-source=III/135A/catalog) and re-grab that catalog.  I would prefer to add that functionality to plotann.py (Python) rather than plot-constellations (C).

cheers,
dustin


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László Heller

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Jun 21, 2022, 3:01:44 PM (7 days ago) Jun 21
to astrometry
Hi!

OK, I understand. Anyway could be possible to simply cut the HD list before plotting but not to the N brightest, rather only simply N whatever star? In other words to plot only N of HD stars with plot-constellations utility.

BR,

Ladislav

Dustin Lang

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Jun 21, 2022, 4:09:26 PM (7 days ago) Jun 21
to László Heller, astrometry
Sure -- you probably want to draw a random sample of N, otherwise if you take the first N they'll be in some order (maybe all in one part of the image).


László Heller

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Jun 24, 2022, 4:16:02 AM (5 days ago) Jun 24
to astrometry
Yup. BTW is there any tool to create a new HD.fits file also with magnitudes from the Henry Draper catalog source ?

Dustin Lang

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Jun 24, 2022, 9:21:45 AM (5 days ago) Jun 24
to László Heller, astrometry

Dustin Lang

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Jun 24, 2022, 9:23:13 AM (5 days ago) Jun 24
to László Heller, astrometry
but one would probably be better to just grab a FITS table from Vizier and add Python code to plotann.py to read it.

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