The program acts very much like the astronomer's night assistant at an observatory. Imagine you are the astronomer, getting ready for a night's work on say, double stars. You might have the following dialog with the night assistant:
Astro: What doubles are in the sky right now? NA: Do you want all the doubles, or just those you've not measured yet? Astro: Let's have just the new ones. NA: OK. What else? Astro: Hmmm, the seeing's only fair tonight, so only show me ones farther
apart than 2 arc seconds. NA: OK. Astro: But closer than 30 arc seconds. Those wide ones are pretty much
CPMs. NA:Yep. Do you want equatorial or alt az views? The 'scope is alt az. Astro: I know. Hmmm. Let's go for alt az... But give me a fiducial on the
charts that indicates north. NA: Right. Astro: Remember to enter our latitude, longitude, and time. NA: I'm way ahead of you. Astro: Great! NA: (pauses) We've got about 1200 stars to look at. Astro: Whoops! Better limit it to primaries brighter than 8th magnitude...
and secondaries should be within 2 magnitudes of that. NA:(another pause) OK. Now there are only 350 doubles to observe. Astro: Still too many. How about only the Struve list? NA: OK, Let's see... STF... All right, it's down to 125. Astro: That's manageable. Lets get started.
That's pretty much what the program does, but it's only the first part. Once you've made your list, it makes a finder chart of the object if you want, showing stars down to 12th magnitude. The charts can be between 1 and 5 degrees on a side, and oriented with north (equatorial) or the zenith (alt az) at the top of the chart. The charts can also be reversed (for viewing through a star diagonal) or inverted (for straight through viewing) with a click of a mouse.
Once you've made the observation, the program allows you to type in an observation, on a form tailored to variable stars, doubles, NGC, and solar system objects. It uses the list of observed objects you've made to filter them out of an observing list if you want, or mark them as "seen".
The double stars are taken from the Washington Double Star Catalog.
The variable stars are taken from Moscow's Sternburg General Catalog of Variable stars.
The galaxies, clusters and nebulae are taken from the Revised NGC and IC.
Overall, there are upwards of 145,000 objects to choose from.
Not yet. Your author is a confirmed stellar astronomer. As will be pointed out in these notes in numerous places, the source code is included, and you are welcomed, nay encouraged, to rectify this shortcoming.
To really understand these, you'll have to download, install, and run the program. That said, I'll try give a short introduction. When you click on an object and then hit the "Create Finder Chart" button, the program goes off and works for a few seconds (A modern machine will be faster) and soon up pops the chart. It is a square of sky 3x3 degrees in size (the default) and it contains all of the objects in the above mentioned databases that are in that field. That's the least of it. It also contains all of the Hipparcos, Tycho, SAO, and Bright star stars that are in the field as well.
The narrow rectangle to the right of the chart lists the information from all of these databases on all objects within 5 pixels of any object in the chart you click on. The chart can further reverse (actually it's the default) and invert, so if you use a Newtonian, the chart can be set up to look like an eyepiece view. If you're a refractor or SCT user, the chart is already set up for your eyepiece view. The eyepiece field itself is set to appear as a one degree field inscribed on the chart (Again, this is a default, you can change it).
The program "pickles" (to use Python's delightful terminology) an object's chart once it's made it, so if you want to look at it again, the chart comes up much faster.
There are over 6.7 million stars in Hipparcos and Tycho (it's pretty much every star in the sky brighter than 12th magnitude. SAO, at 1/4 million stars, and Bright Star, at 7000 or so stars hardly make a dent.)
Go to mainsequence.org and click on the button marked " Download Night Assistant, an astronomer's assistant". A window will pop up on your browser asking if you want the Linux/Unix/Mac or Window version. Click on the Linux/Unix/Mac version. Another window will pop up asking if you want to open it or save it. Click on save it.
To unpack the program,
Make a directory for it (Unix instructions, for Windows, do this with MyComputer file manager in windows. Directories are called folders in Windows. )
Unpack the program
Optional:
If this is done, you won't have to run Night Assistant from its classes directory.Run the program:
java GetParams
It *should* come up.
Documentation written in HTML is in whateverSuperDirectoriesYouWant/observe/docNote: You need to have the Java JRE installed in the computer and in your path for this to work. Go here to install Java
Go to mainsequence.org and click on the button marked " Download Night Assistant, an astronomer's assistant". A window will pop up on your browser asking if you want the Linux/Unix/Mac or Window version. Click on the version version. Another window will pop up asking if you want to open it or save it. Click on save it.
Create a new folder for the program. Copy the file you just downloaded, nightAssistant06_2.zip (your version number will be the latest stable version, if not 6_2) to the new folder.
Unzip the program using your Windows Unzip or PK_Unzip program.
First test: From a command line terminal (Run->cmd) cd to your new folder and then to the classes directory under it. Enter "java GetParams". The program should come up.
Using a text editor (If you do this in word you must save it
as a text file), enter the following program
cd C:\Folder_Path\Of_the_Night_Assistant_Program\classes
java GetParams
Save it as RunNightAssistant.bat in
C:\Folder_Path\Of_the_Night_Assistant_Program\src
From your desktop, right mouse and select create a folder. The program
you're to run is the one you just created above:
C:\Folder_Path\Of_the_Night_Assistant_Program\src\RunNightAssistant.bat
Finish creating the shortcut. Clicking on the new icon should bring up the program.
The bandpass (range of colors) used to determine stellar magnitude varies widely between the various catalogs. There is no "right" way to do this, it's a matter of definition.
This is a difference in opinion between the GCVS and other catalogs. If you need a definitive answer, have a look a the WikiSky chart of the star. here
I'd like to say that after a careful consideration of all of the
programming languages out there, it was the best.
It's not.
It's what
I have to use at work, and it works pretty well, and your humble author is
familiar with it. FORTRAN also works pretty well, for that matter, or
<gasp> COBOL! However, Java is quite sesquipedelean (overly wordy)
and has so many disparate library features as to be almost as bad as the
language it was designed to replace, C++. However! Had he written this in
Forth or Lisp, very few of us (Including your aforementioned humble author)
would have understood it. It also does a fairy good job of being cross
platform compatible.
It's pretty much impossible to write to a jar file, and one of the features of this program is it's ability to save your observations. This means it needs to write to something.
Emailing the author: send your rant (compliment? :-)) to rkk_529 at sign Hotmail.com and there's a slight chance he'll respond. He's worth what you're paying him, 'ya know.
Actually, he loves feedback, and, delicate ego aside, tends to take user comments very seriously.