As some of you may know, there is another free program called Celestia. Many talented contributors to that program have created high quality PNGs of deep sky objects as add-ons, some are even transparent such that you can see background stars.
www.celestiamotherload.com
As a test, I downloaded one of these DSO PNG’s and substituted one of the Stellarium PNG’s (say M1). It worked beautifully (remember to back up the original if you try this)! This could be the answer to what I’ve been after; including more high quality DSOs to Stellarium
Question 1: would it be legal to do this? I should probably be asking this in the Celestia forums (which I will). I’m under the impression that Celestia and the add-ons are distributed much the same way Stellarium is, though I may be wrong. This could be something worth looking into for future releases or nebula add-ons.
Question 2: If the above were possible, is there an easy way to extract the data information for the DSOs without textures from the new 0.8 release, to include them in nebula_texture.fab?
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Getting texture angles and sizes can be difficult if you do not have something to verify them with.
Firstly your texture needs to be a square and 64,128,256 etc pixels per side
I use a few different methods based on the DSS images in the Real Sky program. In the DSS images north is up with the size accurately shown and based on that I load the DSS image into an old program called Picture Publisher. I then load my texture into the same program. The size in pixels is adjusted till both images are in the same scale. I then locate two stars that can be clearly identified in each picture. I measure the distance on screen with a ruler between the stars and make minor adjustments to the texture size till both pictures are the same scale.
Next I place a straight edge (ruler) on the screen aligned with the two stars and drag the second picture (the texture)across to see where the stars line up. The program allows rotation of the pictures in 1 degree increments. I rotate the texture the necessary amount to make it line up and note the rotation angle. This is the angle I will use in the messier/nebula_textures fab.
The size of the texture is then scaled against the DSS image (which is the size already known for the DSS image).
Next I find the exact centre of the texture and look for this point on the DSS image. The DSS image program gives cursor position to fractions of an arc second.
I now have the three important measurments to accuratly place the texture into Stellarium.
The next step of fine adjustment can be done only if there are Hipparcos stars in the same field as the texture. It is done by making small adjustments to the size, rotation and position so that the texture stars overlay the Hipparcos stars. The process can be quite tedious and positioning my texture sometimes took 3 or 4 hours.
A method I used to accurately position some images where there were no stars in the field was to make a large DSS image and using the rotation and scaling technique, stitch the texture onto the DSS image. A sometimes complex process to get right. The modified image was then placed into Stellarium and usually the larger field had some stars for markers. The centre, size and rotation of the texture can now be calculated from the adjustments made in the stitching process and the original texture can be placed accurately.
Complicated isn't it.
Barry
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Hi
Q.2
I have added about 20 DSO ngc textures to my nebula_textures.fab file. As long as they can be given a unique NGC number (that is in or very near the field in case the number is already used)they will display. Textures in the nebula_textures.fab file will display regardless of the listing in the ngc2000.dat file although the position will also display when the nebulae are turned on.
Make sure that your textures are sized and oriented correctly for best effect.
This necessity to have a ngc number has been addressed in the latest cvs version and should not be necessary in the next release.
Displaying a name for the texture can be made by adding the description and ngc number to the ngc2000names.dat if the ngc number is not already in use. If the ngc number is used you will need to fiddle with unused numbers.
If you look at the ngc2000names.dat file you will see a lot of the messier objects have names also and the name takes precedence over the "M" number. So that I could readily get the "M" number displayed as well I just added it to the given name.
Have a look at the texures and data files in my web site www.geocities.com/wendygblyde
Barry
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Sorry about that. It is a free site and has a usage limit of 5 MB per hour. I just uploaded 6 MB so it is probably unavailable for a couple of hours. Try again
Barry
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Further to the above I checked the usage and the down load limit of 4 Mb /hr has been exceeded 25 times today and 286 times this month. I didn't know the site was so popular. Maybe I should put the data on the wiki.
Persevere you will get there eventually.
Barry
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Can I get a step by step process on adding textures. I've read the manual but the texture I'm adding hasn't been working. and no one's monitering the support page. I'm trying to add the Saturn Nebula to the program. What do I need to do in order to get the texture to show.
P.S. The Saturn Nebula is already in the 8.0 Stellarium Catalogue but has no texture already.
Thanks
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The 5th and 6th fields are size in arc mins and rotation from north in degrees the last field is your picture source. You will need to adjust these values to suit your picture.
Barry
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
The position of the Saturn nebula from the DSS plates is (RA)21h 4m 10.8sec and (Dec)11d 21m 48sec S which are the coords in DMS.
The corresponding decimal equivalents are
(RA) 316.048 and (Dec)-11.363
converting from DMS to dec is as follows:
RA Hrs x 15 + Min/4 + Sec/240
Dec Deg + Min/60+sec/3600
Easy with a calculator
Version 7.1 uses DMS in the messier.fab
Version 8.0 uses the decimal eqiv. in the nebula_texrures.fab
To check out my instructions I took a 10 x10 arc minute DSS image of ngc7009 centred on the coords listed above. converted it to png form and resized it to 256 x 256 pixels (any good graphics program can do this try Gimp). Then placed it in the textures folder.
I added the line mentioned in my previous post to the nebula_textures.fab with Windows Wordpad saved it and ran the program. I did a search for NGC7009 and the screen slewed there. I then zoomed in to a .5 deg FOV and there was the picture!
Unluckily there are no Hipparcos stars within the bounds of the picture to align on but I would expect that the display is within 30 arc seconds of its true position and no more than 2 degrees rotated.
Barry
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
I had many extra textures in my version 7.1 and wanted to put them into Version 8.0. To do this I wrote a filter program in Qbasic that reads a messier.fab file, does the necessary calculations and writes out the data as a nebula_textures.fab file. It took some time to write the program but it saved making a couple of hundred calculations.
Barry
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
As some of you may know, there is another free program called Celestia. Many talented contributors to that program have created high quality PNGs of deep sky objects as add-ons, some are even transparent such that you can see background stars.
www.celestiamotherload.com
As a test, I downloaded one of these DSO PNG’s and substituted one of the Stellarium PNG’s (say M1). It worked beautifully (remember to back up the original if you try this)! This could be the answer to what I’ve been after; including more high quality DSOs to Stellarium
Question 1: would it be legal to do this? I should probably be asking this in the Celestia forums (which I will). I’m under the impression that Celestia and the add-ons are distributed much the same way Stellarium is, though I may be wrong. This could be something worth looking into for future releases or nebula add-ons.
Question 2: If the above were possible, is there an easy way to extract the data information for the DSOs without textures from the new 0.8 release, to include them in nebula_texture.fab?
Getting texture angles and sizes can be difficult if you do not have something to verify them with.
Firstly your texture needs to be a square and 64,128,256 etc pixels per side
I use a few different methods based on the DSS images in the Real Sky program. In the DSS images north is up with the size accurately shown and based on that I load the DSS image into an old program called Picture Publisher. I then load my texture into the same program. The size in pixels is adjusted till both images are in the same scale. I then locate two stars that can be clearly identified in each picture. I measure the distance on screen with a ruler between the stars and make minor adjustments to the texture size till both pictures are the same scale.
Next I place a straight edge (ruler) on the screen aligned with the two stars and drag the second picture (the texture)across to see where the stars line up. The program allows rotation of the pictures in 1 degree increments. I rotate the texture the necessary amount to make it line up and note the rotation angle. This is the angle I will use in the messier/nebula_textures fab.
The size of the texture is then scaled against the DSS image (which is the size already known for the DSS image).
Next I find the exact centre of the texture and look for this point on the DSS image. The DSS image program gives cursor position to fractions of an arc second.
I now have the three important measurments to accuratly place the texture into Stellarium.
The next step of fine adjustment can be done only if there are Hipparcos stars in the same field as the texture. It is done by making small adjustments to the size, rotation and position so that the texture stars overlay the Hipparcos stars. The process can be quite tedious and positioning my texture sometimes took 3 or 4 hours.
A method I used to accurately position some images where there were no stars in the field was to make a large DSS image and using the rotation and scaling technique, stitch the texture onto the DSS image. A sometimes complex process to get right. The modified image was then placed into Stellarium and usually the larger field had some stars for markers. The centre, size and rotation of the texture can now be calculated from the adjustments made in the stitching process and the original texture can be placed accurately.
Complicated isn't it.
Barry
sorry the link should have been
http://www.celestiamotherlode.net/
Interesting!!!
Hi
Q.2
I have added about 20 DSO ngc textures to my nebula_textures.fab file. As long as they can be given a unique NGC number (that is in or very near the field in case the number is already used)they will display. Textures in the nebula_textures.fab file will display regardless of the listing in the ngc2000.dat file although the position will also display when the nebulae are turned on.
Make sure that your textures are sized and oriented correctly for best effect.
This necessity to have a ngc number has been addressed in the latest cvs version and should not be necessary in the next release.
Displaying a name for the texture can be made by adding the description and ngc number to the ngc2000names.dat if the ngc number is not already in use. If the ngc number is used you will need to fiddle with unused numbers.
If you look at the ngc2000names.dat file you will see a lot of the messier objects have names also and the name takes precedence over the "M" number. So that I could readily get the "M" number displayed as well I just added it to the given name.
Have a look at the texures and data files in my web site www.geocities.com/wendygblyde
Barry
the page don't open
http://www.geocities.com/wendygblyde don`t work!!
Sorry about that. It is a free site and has a usage limit of 5 MB per hour. I just uploaded 6 MB so it is probably unavailable for a couple of hours. Try again
Barry
Further to the above I checked the usage and the down load limit of 4 Mb /hr has been exceeded 25 times today and 286 times this month. I didn't know the site was so popular. Maybe I should put the data on the wiki.
Persevere you will get there eventually.
Barry
Thanks Barry, I'll give your website a shot.
Patrick (original poster)
Can I get a step by step process on adding textures. I've read the manual but the texture I'm adding hasn't been working. and no one's monitering the support page. I'm trying to add the Saturn Nebula to the program. What do I need to do in order to get the texture to show.
P.S. The Saturn Nebula is already in the 8.0 Stellarium Catalogue but has no texture already.
Thanks
Add this line to your nebula_texrtures.fab with a text editor.
7009 316.15 -11.344 8 10 0 7009.png Your_pic_source
The 5th and 6th fields are size in arc mins and rotation from north in degrees the last field is your picture source. You will need to adjust these values to suit your picture.
Barry
How do you figure out the size in arc mins. What formula's or units do I need, etc?
Hi
The position of the Saturn nebula from the DSS plates is (RA)21h 4m 10.8sec and (Dec)11d 21m 48sec S which are the coords in DMS.
The corresponding decimal equivalents are
(RA) 316.048 and (Dec)-11.363
converting from DMS to dec is as follows:
RA Hrs x 15 + Min/4 + Sec/240
Dec Deg + Min/60+sec/3600
Easy with a calculator
Version 7.1 uses DMS in the messier.fab
Version 8.0 uses the decimal eqiv. in the nebula_texrures.fab
To check out my instructions I took a 10 x10 arc minute DSS image of ngc7009 centred on the coords listed above. converted it to png form and resized it to 256 x 256 pixels (any good graphics program can do this try Gimp). Then placed it in the textures folder.
I added the line mentioned in my previous post to the nebula_textures.fab with Windows Wordpad saved it and ran the program. I did a search for NGC7009 and the screen slewed there. I then zoomed in to a .5 deg FOV and there was the picture!
Unluckily there are no Hipparcos stars within the bounds of the picture to align on but I would expect that the display is within 30 arc seconds of its true position and no more than 2 degrees rotated.
Barry
I had many extra textures in my version 7.1 and wanted to put them into Version 8.0. To do this I wrote a filter program in Qbasic that reads a messier.fab file, does the necessary calculations and writes out the data as a nebula_textures.fab file. It took some time to write the program but it saved making a couple of hundred calculations.
Barry
I got all the conversions from min secs deg to dec. I need to figure out the texture angular size for future additions that I would make.