Simbad Data Plotting
 



Data Access

Example Query

By using the Simbad Astronomical Database you can submit queries for objects by name, coordinates, catalog number, etc. This can be very handy!  Because this is an on-line data service ostensibly they can provide access to literally terra bytes of data.

 

The query can be as simple as show me everything around object Messier 51. Or very complicated similar to TheSky's Data Wizard whereby the user can create a filter limiting the search criteria. There are examples found on the Simbad page. Regardless of the query made this page shows how to take the matched criteria and plot, label, and search for it in TheSky.

 

This example uses a search by identifier where the object entered is Messier 51. Just enter M51 in the search identifier field, search 15 arc minutes AROUND the object M51, then SUBMIT the query.

Here is the query.

it.
 

NOTE: Not all 846 objects displayed. Yes there are 846 objects found in a 15 arc minute field around object M51. This is why having access to the on-line service with terra bytes of data is often useful. If you cannot find an object in TheSky's native databases this is another good way to identify it.

How do I grab the text from the page

Next drag the mouse pointer over the text starting from identifier to the end of the list of objects.

Right Mouse Drag text 

 

When the entire text is highlighted you can right mouse click in the text then "Copy" the text to the clipboard. See below.

Right Mouse Click
on the highlighted text


Choose COPY

You can also choose Select All and "COPY" everything but that will require more work since you will have to DELETE the text you do not want in the file (i.e. the page headings and search information).

 

When the text has been COPIED to the clipboard you can then EDIT | PASTE the text into any text editor. I prefer WordPad for this but any text editor will work as long as you have the option to PASTE SPECIAL (as unformatted text). See below.

 

NOTE:  You need to use the option to "Paste Special". The text should NOT be formatted in anyway. If your text editor does not have the Paste Special option use WORDPAD instead.

Microsoft WordPad

Use "Paste Special"

The point is you do not want the text to be formatted in order for the header to work. The header text will not work if you have altered the data in any way. Just one column shift causes the header to be inaccurate because the fields are not where they should be.

 

Following is the text as Copied to the Clipboard then Edit | Paste Special with no formatting here.

 
identifier                |otyp| FK5 (2000.0/2000.0)         |  B&V magnitudes  | sp. type   | nref
---------------------------------------------------------------------------------
M 51                      | Sy2| 13 29 52.37  +47 11 40.8    |  8.8  :          | Sc         | 1504
[LPS2002] 16              |   *| 13 29 52.32  +47 11 40.8    |                  |            |    1
[LPS2002] 6               |   *| 13 29 52.31  +47 11 39.2    |                  |            |    1
[LPS2002] 15              |   *| 13 29 52.36  +47 11 42.8    |                  |            |    1
.... and so on.

 

Now all you need to do is attach the header text below which defines the fields and allows the data to be compiled!   Just as you did before you can mouse drag the text that follows here and copy it to the clipboard for pasting into the query text.

>SEARCH 1,26
>ALIAS 1,26
>RAHOURS 34,35
>RAMINUTES 37,38
>RASECONDS 40,44
>DECSIGN 47,47
>DECDEGREES 48,49
>DECMINUTES 51,52
>DECSECONDS 54,57
>MAGNITUDE 71,80
>PARSE "Object Name" 1,26
>PARSE "Object Number" 1,26
>PARSE "MAGNITUDE" 71,80
>PARSE "otyp" 28,31
>PARSE "B&V Magnitudes" 63,80
>PARSE "Spectral Type" 82,93
>PARSE "nref" 94,99
>OBJECT TYPE 55
>IDENTIFIER Simbad M51 <---Add M51 making it clear when searching Simbad objects!
>CATALOG CLASS=OBJECTS
>LOADMEMORY
>OBJECT TYPE 55

 

See below showing exactly how to grab the header text.


 

Then just add the header to any query made on the Simbad page. See below.


>SEARCH 1,26
>ALIAS 1,26
>RAHOURS 34,35
>RAMINUTES 37,38
>RASECONDS 40,44
>DECSIGN 47,47
>DECDEGREES 48,49
>DECMINUTES 51,52
>DECSECONDS 54,57
>MAGNITUDE 71,80
>PARSE "Object Name" 1,26
>PARSE "Object Number" 1,26
>PARSE "MAGNITUDE" 71,80
>PARSE "otyp" 28,31
>PARSE "B&V Magnitudes" 63,80
>PARSE "Spectral Type" 82,93
>PARSE "nref" 94,99
>OBJECT TYPE 55
>IDENTIFIER Simbad Objects
>CATALOG CLASS=OBJECTS
>LOADMEMORY
>OBJECT TYPE 55

M 51                      | Sy2| 13 29 52.37  +47 11 40.8    |  8.8  :      | Sc         | 1504
[LPS2002] 16              |   *| 13 29 52.32  +47 11 40.8    |              |            |    1
[LPS2002] 6               |   *| 13 29 52.31  +47 11 39.2    |              |            |    1
[LPS2002] 15              |   *| 13 29 52.36  +47 11 42.8    |              |            |    1
 

Now since the header text does all the work all you have to do is COMPILE the data using TheSky's Database Compiler. Data | Import. See below.

Data | Import
Browse the text file on your drive

Find the text file with both the data and the header attached and Compile the text into an SDB file.

 

NOTE: Make sure the number of objects compiled makes sense. The total objects is 837 as shown. If this does not match the query you have made a mistake!

Edit Find M51

 All objects shown as red Reference Points!

I don't see the Reference Points

Make sure you have the object type Reference Point set to visible. Use the View | Display Explorer and type in Reference point. Place a check mark next to Reference Point as shown.

Turn on Object Type

Reference Point

How do I search the objects?

When the data is compiled the entries will show under Edit | Find under the Sky Databases (SDBs) entry. In this case  Simbad M51.

 

NOTE:  Use the options Frame object and/or Object information!  These are very handy. When enabled you can sroll through the list and go right to each object.

Frame object

Object Information

How do I label the objects?

Using View | Display Explorer find the Simbad M51 entry under the Sky Database (SDBs) entry. Expand the group and pick the fields you want to label here. The example shows labeling the Object Number.

Choose the fields to label

 Check fields to label on screen

Keep in mind this can be a bit confusing!  See below.

A bit messy!

All objects now labeled

How to plot more than one query at the same time

Certainly you can combine as many objects into a single text file as you like. Just EDIT COPY each match and EDIT PASTE SPECIAL into a single text file and compile. See below showing 20 degrees near M81, M51, and M40. Of course these can be ANY size/object searches you want!

Three queries plotted at once

 Be creative!

WARNING:  Keep in mind that accessing an SDB file with more than say 100,000 objects can become a bit slow. The SDB files have not been optimized for fast plotting like the other native larger datasets supplied with TheSky.
 

Stellar data Warning! Magnitude = zero Garbage in Garbage out!

Note: If the objects to be compiled are stars and you compile the data as "star" instead of object type "reference point" the use of the magnitude is crucial. I have seen datasets that don't have magnitudes for the stars only coordinates. Plotting stars that do not have magnitudes indicates a magnitude of zero and this is problematic! The stars will plot extremely large and look completely unrealistic. See below showing this. Better to use object type "Reference Point" or create your own custom symbol that is magnitude independent.

 

To demonstrate. The Trapezium in the center of M42 the Orion Nebula asking for all objects within 5 arc minutes of the objects  Plotting the data query from the NASA Extragalactic Data page we get the following when the object type is "star" before compiling the dataset.

No magnitudes in dataset

None equals Magnitude ZERO

Again, better to use the Reference Point object instead!  Or if you can filter any data to only return stars that have a magnitude <> 0.00. Because stellar magnitudes can be - negative values (brighter) you must use NOT EQUAL to ZERO. Keep in mind this may cause no objects to be found!