Working with constellations in DOCdb

posted: 863 days ago, on Sunday, 2015 Mar 15 at 10:00
tags: astronomy, deep sky, docdb.net.

Constellations, of course, aren’t “real” objects, but they are a handy way of slicing up the night sky into more manageable chunks.

Having the sky sub-divided in this way immediately suggests an observing project: carefully examine each chunk of sky for anything and everything interesting. This raises the question: when is a particular part of the sky well-placed for observing?

With the recent addition of “constellation place holders” to the DOCdb database, this is now easy to answer, using the DOCdb List Plan option. Here’s the step-by-step guide.

Step 1. Go to the DOCdb home page, http://www.docdb.net/index.php, and log in by selecting login at top-right. This will take you to the “Welcome back” screen.

If you haven’t registered on DOCdb, click on register, fill in your basic observer details, and you’re good to go.

Step 2. Make sure the browsing sliding window is visible. If it isn’t click on show browsing near top-right (below the edit session option).

Just in case you're not familiar with the various areas of the DOCdb console, now's a good time for a recap. Follow along in the diagram below - (A) Summary of your current observing Session, (B) Main Menu, (C) List Control Panel, (D) Database Browsing Control Panel, and (E) Object Options Panel (currently blank because you aren’t looking at an object yet).

Step 3. Now load the pre-defined Constellations list by clicking on load in the List Control panel.

Step 4. You will be presented with a list of available lists: those you have defined on top, followed by the pre-defined lists. Scroll down and tick Constellations and then click the load button.

Step 5. You will be taken to the first object in the list (western Phoenix). Ignore the “Type: unverified” - this is a hack since constellations aren't really objects! Your screen should now look like the image on the right. Note the tick-mark next to the name of the “object” Phoenix (west): this confirms at a glance that the "object" you are viewing is in your currently open list.

Step 6. You can now explore this “object” - actually a region, of course - using the options in the Objects Options Panel. Click on altitude today to see how it changes throughout the current observing session, or altitude (year) to see when it is best visible.

Step 7. Explore the List Control Panel, too - the summary shows there are 176 objects, and the finder charts show their (mostly even) distribution on the sky. Best of all, maybe, is that by clicking plan you get a suggestion of how you could proceed if you wanted to observe all the visible constellations on the night of your current session!

How to create a custom list of southern constellations

You may want to create a custom list of constellations, let’s say those that are in the south. Make sure you have the Constellations list loaded (as described above): confirm this by looking in the List Control Panel.

To build such a list, you will need to apply a declination filter, which is easy to do.

Step 1. Select find ds objects from the Main Menu, and apply a declination filter: scroll down to Option 4: Search by co-ordinate block.

In the RA boxes, enter 0 in the first field, and 24 in the second field; this way you are indicating the full RA range. In the Declination boxes, enter -90 in the first field and -20 (or whatever your limit is) in the second field.

Make sure current list is selected in the "Search in" field. The default, full database, will apply your filter to the entire DOCdb database instead.

Step 2. Click the search button.

Step 3. You will then be presented with a "Results: searching with a co-ordinate block" page; click the save results button to create your own personal list. It's that easy :-)

nothing more to see. please move along.