Useful Stellarium customisation.

[inksmithy]

I originally posted this on another forum, but since I wrote it and came up with the modification, I figure I can post it here as well.

I've been finding myself beset by that age old question "but what will I see through xxxx telescope?"

Now, I played with Stellarium a long time ago, and since this opportunity first surfaced, I've been playing with it again and I've found there is indeed a way to get an idea of what things will look like in different telescopes, if you use one of the plugins which comes standard with Stellarium.

The plugin is called Ocular, and is invoked by selecting a target (I chose Saturn), then pressing the CTRL-O button combination. What you should find is that your field of view shrings and your view suddenly resembles that of a really nice telescope which is far beyond a beginners scope.

So, with that in mind, I went through the details of most of the telescopes which have crossed my shortlist at some point and created a file which will allow 18 of those telescopes to be simulated in Stellarium.

Its simple stuff, its only text, but the file you need to copy this into is in a tricky part of the Windows filesystem to get to, because Microsoft tends to assume everyone is a yokel and hides a lot from you.

So, if you want to try these 18 telescopes, open up Windows explorer and type the following into the location bar at the top, substituting "USERNAME" with your username on the computer.

C:\Users\USERNAME\AppData\Roaming\Stellarium\modules\Oculars

Linux users, I assume the file you are looking for is in the .stellarium directory of your home directory, but I could be wrong.

Mac users, I'm afraid I have absolutely no clue how your operating system works. I think Steve Jobs kidnapped The Woz's pixies and has bribed them with beer, to be honest.

Anyway, in that directory, you should find a file called "ocular.ini".

Right click that file and choose to open in notepad.

Once it is open, there should be a section called "General". In that section, find the line which says "telescope_count=4" and change the 4 to 18.

Scroll down a little further, past the sections labelled "[bindings]" and "[oculars]" and you should find the section labelled "[telescope]".

Highlight everything from the word "[telescope]" to the next section down, which is called "[ccd]" and press delete.

After that, paste this text in its place.

[telescope] 0\name=SkyWatcher SKYHAWK-1145P Newt 0\focalLength=500 0\diameter=114 0\vFlip=false 0\hFlip=false 1\name=SkyWatcher EXPLORER-130 Newt 1\focalLength=900 1\diameter=130 1\vFlip=false 1\hFlip=false 2\name=SkyWatcher Explorer 130P Newt 2\focalLength=650 2\diameter=130 2\vFlip=false 2\hFlip=false 3\name=SkyWatcher Explorer 150 Newt 3\focalLength=750 3\diameter=150 3\vFlip=false 3\hFlip=false 4\name=Explorer 150PL Newt 4\focalLength=1200 4\diameter=150 4\vFlip=false 4\hFlip=false 5\name=SkyWatcher Explorer 200P Newt 5\focalLength=1000 5\diameter=200 5\vFlip=false 5\hFlip=false 6\name=SkyMax 127 Maksutov-Cassegrain 6\focalLength=1500 6\diameter=127 6\hFlip=true 6\vFlip=true 7\name=SkyWatcher SkyMax 102 Maksutov-Cassegrain 7\focalLength=1300 7\diameter=102 7\vFlip=false 7\hFlip=false 8\name=SkyLiner 200P FlexTube Newt-Dob 8\focalLength=1200 8\diameter=200 8\vFlip=false 8\hFlip=false 9\name=Meade ETX90 Mak-Cas 9\focalLength=1250 9\diameter=90 9\vFlip=false 9\hFlip=false 10\name=Meade ETX125 10\focalLength=1900 10\diameter=125 10\vFlip=false 10\hFlip=false 11\name=Celestron AstroMaster130EQ Newt 11\focalLength=650 11\diameter=130 11\vFlip=false 11\hFlip=false 12\name=Celestron Omni XLT 102 Refract 12\focalLength=1000 12\diameter=102 12\vFlip=false 12\hFlip=false 13\name=Celestron Omni XLT 150 Newt 13\focalLength=750 13\diameter=150 13\vFlip=false 13\hFlip=false 14\name=Celestron Omni XLT 127 Schmidt-Cass 14\focalLength=1250 14\diameter=127 14\vFlip=false 14\hFlip=false 15\name=NexStar 102 SLT 15\focalLength=660 15\diameter=102 15\vFlip=false 15\hFlip=false 16\name=NexStar 4 XLT SE Mak-Cas 16\focalLength=1325 16\diameter=102 16\vFlip=false 16\hFlip=false 17\name=Celestron NexStar 5SE Schmidt-Cass 17\focalLength=1250 17\diameter=125 17\vFlip=false 17\hFlip=false

After thats done, save the file, then go ahead and play with them!

Once you have a target selected, (as I said, I chose Saturn) press the key combination CTRL-O to invoke the plugin.

Once you have done that, other key combinations will change telescopes and eyepieces.

To change telescopes, use SHIFT-] to go up through the list and SHIFT-[ to come back down.

To change eyepieces, use CTRL-] to go up and CTRL-[ to come down.

If you press ALT-O, you should see a dialog open up, clicking the "About" tab on that dialogue will tell you more about the plugin.

As soon as I've figured out what the abbreviations in the eyepieces section of the ini file mean, I'll add some standard eyepieces and digital cameras.

When you are using this, remember that Stellarium, while fabulous, is still just a simulation. On Stellarium, every day has perfect seeing, or very close to it. This customisation should help get an idea of what things will look like, neither I or the creators of Stellarium can guarantee that what you see is what you get.

Hope this is helpful, it certainly has been for me!

Alan

Edit: I've been trying to fix the bad formatting of the [telescope] text, but it wont let me. My blog has a repost of this on it, grab it from there if all else fails. Sorry bout that.

[david o]

Nice one Alan

There's plenty of people that should find that useful.

[red dwalf]

sounds like great addition to stellarium,

cheers

[NickK]

It was easy to setup the scope, ep and ccd using the standard configuration window. I did that with the baader hyperions, pentax and atik 16ic easily enough - on the mac.

If you want to edit the file, it's probably in the Stellarium.app bundle under Resources or under your home directory Library/Preferences/Stellarium/... - can verify exactly where once I get back home.

We should really create a full list of scopes, eyepieces and ccds.

[inksmithy]

It was easy to setup the scope, ep and ccd using the standard configuration window. I did that with the baader hyperions, pentax and atik 16ic easily enough - on the mac.

If you want to edit the file, it's probably in the Stellarium.app bundle under Resources or under your home directory Library/Preferences/Stellarium/... - can verify exactly where once I get back home.

We should really create a full list of scopes, eyepieces and ccds.

Thanks for the response guys.

You are right, its easy enough to do it inside Stellarium itself, but I found when I wanted to page through loads of websites looking for focal lengths and diameters and so on, editing the textfile was faster. Also, I use Stellarium on two computers, it saved time.

Cheers,

Alan

[rowan46]

thankyou for that

[The Sailor]

Something has gone wrong with my Stellarium, followed the instructions, copied, pasted and saved, opened Stellarium, indicated a target and hit Ctrl O, the whole screen became ocluar!!! Have now deleted all above and will return to inputting from inside Stellarium

Jim

[inksmithy]

Thats what its supposed to do, the screen becomes ocular, then when you hit CTRL-O again, it goes back to normal.

Alan

[The Sailor]

Yes correct but not the whole screen as in seeing all the Cardinal Points through a telescope eyepiece!! Redone to all my own telescopes and all back to normal .

Jim

[inksmithy]

Weird, wonder why it did that? You are running the latest version of Stellarium?

Alan

[NickK]

If you have a mac open a finder window with your user home directory then navigate to Library/Application Support/Stellarium/modules/Oculars - you can then use "Open With..." then select TextEdit to edit the file.

This location is your own personal config. I you have other users that log in to use the machine they will have their own copy of this ini file in their home directory.

[Stargazer Jack]

On stellarium, I want to use the ocular view but I don't know the information for the eyepieces and sensors. Do you know what the answers are?

EYEPIECES: Skywatcher 25mm & 10mm. I need aFOV, focal length and field stop.

SENSORS: Philips SPC900NC. Resolution x and y (pixels), Chip width and height (mm) and pixel width and height (micron).

Thanks

[inksmithy]

I believe aFOV is Apparant Field of View. Focal length as far as I'm aware is printed on the side of the eyepiece, field stop I'm not sure of.

As far as the CCD section goes, that one is a complete blank to me at the moment, I just haven't had the time to do the research into it. I will though, being able to get an approximation of what I would see through these telescopes has been very useful, I imagine the ep and ccd sections will prove equally so.

Alan