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Re: Mars map for backyard viewing
Hi Cathal,
Ok, now I can reproduce this. In fact, it is a "feature" that applies to the original image also. Here is a snippet of source: /* swap dark-bright color map.
?* this is used to keep mountains looking like mountains when flipping t/b ?*/ static void swap_colors() ? For the original image, to my eye at least, when the image is flipped top/bottom the shadows make the craters look like mountains and vv. I've always had this inversion of relief, it's especially bad with lunar images. To remove this feature, the simplest thing to do is just add a return as the first statement in this function so it does nothing. Elwood |
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Re: Mars map for backyard viewing
Oops - that's what I get for typing it out from memory and not verifying before reply..
Corrected URL: http://www.swibble.com/files/marsmap.jpg
There is still an issue with the view when flipping though. I'm also using 3.7.7, compiled from source and using the catalogues from my paid version, ?The colours don't change, but the bits that are dark in the normal view, such as Syrtis Major, become light when flipped top/bottom. Flipping left/right behaves as normal. Both axes flipped gives inverted brightness. -Cathal |
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Re: Mars map for backyard viewing
Hi Cathal,
Thanks for the update. This blurred version is perfect for visual observers. Your URL has a bug however, just change .files to /files. I tried the image and it works perfectly for me in XEphem 3.7.7: T/B flips vertically, L/R flips horizontally as expected, the colors do not change. Thanks for using XEphem. Elwood |
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Re: Mars map for backyard viewing
I've uploaded a copy to my website at as the link above appears to have succumbed to digital rot. I performed the same routine on the original to generate the new marsmap.jpg file.
I can confirm that the "T/B Flip" does in fact invert the brightness, but the "L/R Flip" does not change the image. Regards, Cathal |
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Re: 3.7.7 Fails to install on Gentoo Linux
I've never had trouble building Xephem on Gentoo, and I see in my 'world' file that I have
x11-proto/printproto.? "equery depends printproto" finds that x11-libs/libXp needed it. libXP is needed by a few others, mainly the old vector graphics program I do simple design with app-text/texlive-core-2008-r7 (x11-libs/libXp) media-gfx/xfig-3.2.5c (x11-libs/libXp) media-libs/nas-1.9.2 (x11-libs/libXp) x11-libs/motif-2.3.4-r2 (>=x11-libs/libXp-1.0.2[abi_x86_32(-)?,abi_x86_64(-)?,abi_x86_x32(-)?, So it's probably not much of a surprise that it may be missing in newer Gentoo setups. |
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Re: 3.7.7 Fails to install on Gentoo Linux
bsharding@... [xephem] writes:
Here is the last few lines of the build attempt.[ ... ] ../../libXm/linux86/Xm/Xm.h:59:34: fatal error: X11/extensions/Print.h: No such file or directoryOn Debian, apt-file search X11/extensions/Print.h says: x11proto-print-dev: /usr/include/X11/extensions/Print.h So I had to install x11proto-print-dev. That gets me pretty much every time I build xephem: nothing else I use needs that package. Presumably gentoo has a similar command to tell you what package owns a file? Googling found I can't do the emerge command there since I'm not on gentoo, but going to the link mentioned there and searching for print.h suggests the package is x11-proto/printproto. ...Akkana |
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3.7.7 Fails to install on Gentoo Linux
Here is the last few lines of the build attempt. make[1]: Leaving directory '/home/bruce2/xephem-3.7.7/libz' gcc -I../../libastro -I../../libip -I../../liblilxml -I../../libjpegd -I../../libpng -I../../libz -g -O2 -Wall -I../../libXm/linux86/ -I/opt/X11/include ? -c -o aavso.o aavso.c In file included from aavso.c:12:0: ../../libXm/linux86/Xm/Xm.h:59:34: fatal error: X11/extensions/Print.h: No such file or directory ?#include <X11/extensions/Print.h> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ^ compilation terminated. <builtin>: recipe for target 'aavso.o' failed make: *** [aavso.o] Error 1 Thanks? Bruce |
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Re: AZ/EL vs. RA/DEC Accuracy
On 09/05/2015 10:15 PM, Chris Maness chris@... [xephem] wrote:
One or both programs may be adjusting the positions to take account of many different effects. Precession is the largest one, but there's also nutation, aberration of starlight, parallax, the proper motion of the star, and refraction through the atmosphere. In order to compare the two programs, you have to first make sure you're looking at numbers that have been adjusted in the same way in both programs.The Xephem RA/DEC matches the J2000 Astrometric RA/DEC in Cartes du I don't have either program handy at the moment, so it's hard for me to be more specific. OK, I changed the Equinox Epoch to 2015.2.In which program? Both programs need to be set to exactly the same parameters before they're likely to give the same results. Also, the equinox and the epoch are two separate things. The epoch is the time of the observation. The equinox is the orientation of the coordinate frame. For example, mean equinox accounts for precession but not nutation, while true equinox accounts for both. does the axis location on the surface of the Earth also wanderIt does move, but not a lot. Your observing location is also moving very slowly due to continental drift. - Ernie |
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AZ/EL vs. RA/DEC Accuracy
OK, I changed the Equinox Epoch to 2015.2.? It is closer, but still not on the money.? Also, I understand that the Earth axis of rotation is processing (axis moving with respect to the galactic frame), but does the axis location on the surface of the Earth also wander significantly?? I am sure it has to at least a little as the center of mass is mobil due to the Earth's interior being molten.? However, I am not certain if this also effects the location of the stars. Chris On Sat, Sep 5, 2015 at 5:14 PM, Chris Maness <chris@...> wrote: > The Xephem RA/DEC matches the J2000 Astrometric RA/DEC in Cartes du > Ciel.? So does that mean Cartes du Ciel is extrapolating out the > geocentric star positions and that is why they match the USNO data? > > Thanks, > Chris Maness > > On Sat, Sep 5, 2015 at 3:29 PM, Ernie Wright erniew@... > [xephem] <xephem@...> wrote: >> On 09/05/2015 11:09 AM, Chris Maness chris@... [xephem] wrote: >> >>> Strangely, xephem disagrees with Cartes du Ciel on Polaris' RA/DEC, >>> but agree exactly on AZ/EL.? How could this be? >> >> First guess would be an epoch mismatch.? RA/Dec changes over time, so >> you need to be sure that xephem and Cartes du Ciel are telling you the >> RA/Dec at the same epoch and equinox. >> >> - Ernie? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? >> >> >> ------------------------------------ >> Posted by: Ernie Wright <erniew@...> >> ------------------------------------ >> >> >> ------------------------------------ >> >> Yahoo Groups Links >> >> <*> To visit your group on the web, go to: >>? ? ? >> >> <*> Your email settings: >>? ? ?Individual Email | Traditional >> >> <*> To change settings online go to: >>? ? ? >>? ? ?(Yahoo! ID required) >> >> <*> To change settings via email: >>? ? ?xephem-digest@... >>? ? ?xephem-fullfeatured@... >> >> <*> To unsubscribe from this group, send an email to: >>? ? ?xephem-unsubscribe@... >> >> <*> Your use of Yahoo Groups is subject to: >>? ? ? >> |
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Re: AZ/EL vs. RA/DEC Accuracy
The Xephem RA/DEC matches the J2000 Astrometric RA/DEC in Cartes du
Ciel. So does that mean Cartes du Ciel is extrapolating out the geocentric star positions and that is why they match the USNO data? Thanks, Chris Maness On Sat, Sep 5, 2015 at 3:29 PM, Ernie Wright erniew@... [xephem] <xephem@...> wrote: On 09/05/2015 11:09 AM, Chris Maness chris@... [xephem] wrote:Strangely, xephem disagrees with Cartes du Ciel on Polaris' RA/DEC,First guess would be an epoch mismatch. RA/Dec changes over time, so |
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Re: AZ/EL vs. RA/DEC Accuracy
On 09/05/2015 11:09 AM, Chris Maness chris@... [xephem] wrote:
Strangely, xephem disagrees with Cartes du Ciel on Polaris' RA/DEC,First guess would be an epoch mismatch. RA/Dec changes over time, so you need to be sure that xephem and Cartes du Ciel are telling you the RA/Dec at the same epoch and equinox. - Ernie |
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AZ/EL vs. RA/DEC Accuracy
I am a little confused. I am under the impression that Xephem derives
its AZ/EL data from RA/DEC and Earth position. Strangely, xephem disagrees with Cartes du Ciel on Polaris' RA/DEC, but agree exactly on AZ/EL. How could this be? Also, Cartes du Ciel is very close to data derived at the USNO website for RA/DEC. Any clarification would be helpful. Thanks, Chris Maness |
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New CSV format for downloaded GSC 2.3 data?
Hi This morning I tried to use GSC 2.3 field stars from STSCI for the first time in a while, and got an error about the connection being good but no data being found. After a bit of poking around it looks like they've changed the CSV format of the downloaded data. Since they helpfully put the definitions of each element in the first line of data I managed to modify the XEphem source code to make it work: line 33 of gscnet.c now becomes static char ifmt[] = "%[^,],%*[^,],%*[^,],%*[^,],%lf,%lf,%*[^,],%*[^,],%*[^,],%lf,%*[^,],%*[^,],%lf,%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%lf,%*[^,],%*[^,],%lf,%*[^,],%*[^,],%lf,%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%*[^,],%d"; This was on 3.7.7RC5, but I think the new stable version has the old version of the string. I hope this is useful to somebody. cheers Piero Bradley? |
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Re: Tangent Plane?
Yes because I was checking the data with the transit by spirit leveling. And the Geoid would be best for that. However it was within a minute accuracy anyhow.? I'm not completely sure of the azimuth but I imagine the vertical would be more sensitive to deflection anyhow. Chris? On Aug 27, 2015, at 9:12 AM, ecdowney@... [xephem] <xephem@...> wrote:
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Re: Xephem 3.7.7
Karl,
I'm not so sure I qualify as one of your "good folks" because my motivation is actually pretty selfish. You see, the first release of XEphem was in Dec 1990 and that, in turn, was based on ephem, an ephemeris engine I started in 1980 for a 24x80 character display. A goal from the very beginning has been to accommodate as many UNIX variants as possible, not so much for others but because I have always preferred this operating system and I wanted to have [X}ephem with me at all times. The arrival of Virtual machines has made it much easier to test on different platforms but since OS X is my development host, I don't have much motivation to build a VM of older releases. Thanks for using XEphem. Elwood |
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Re: Xephem 3.7.7
actually an online diff of the makefiles 3.7.6 and 3.7.7 helped to point me in the correct direction. I should have diffed it on the box itself and it was probably the next step but it was nice to have the problem pointed out to me in glowing neon on the web. darned useful thing on occasion. |
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Re: Xephem 3.7.7
Hi Karl,
That is not my attitude at all and I do apologize for your inconvenience. However, I admit I made the decision to change from /usr to /opt in deference to the current directory arrangement on Yosemite (10.10). I don't have access to 10.5 so I did not want to try and make the adjustment be automatic without a means to test it. There is an item in the FAQ that mentions this topic so hopefully you were able to address it without too much pain. Thanks for using XEphem. Elwood |
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Re: Xephem 3.7.7
on a recent compile on OSX PPC systems running 10.5.8 this code in the makefile messed things up for me /opt should be /usr for older systems.CFLAGS = $(LIBINC) $(CLDFLAGS) -O2 -Wall -I$(MOTIFI) -I/opt/X11/include LDFLAGS = $(LIBLNK) $(CLDFLAGS) -L$(MOTIFL) -L/opt/X11/lib |
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