0. Once Astrometrica is up and running on your machine, you're ready to see if you have new images to search. Those are accessed on the Asteroid Search link on the Astrometrica page, which has a list of participating schools. Click on Cabrillo College (top of the list!), and enter the
login = iasc, and password = iascsearch09 in lower case only.
You'll see the list of files; a short readme.txt which you can skip and hopefully some obscurely named .zip file which contains your new image files. Click on it to download the .zip file(s) that you don't already have. Then unzip them (camzip is a freeware program for un-zipping files. Google for it, or maybe you've already got such a utility on your computer) to a convenient location on your computer. For me, I put them in a folder called "imagesF09" in the c:\Programs\Astrometrica folder. In their on-line instructions, their example is HSU Blackboard to the desktop. Forget that, and I suggest you too make a folder c:\Programs\Astrometrica\imagesF09, just so we're all on the same page. Now that you've downloaded the new images, it's time to search them for asteroids!
1. Click the blue Astrometrica icon on your computer's desktop
2. On the toolbar click Internet | Update MPCorb and then in the Select Files popup box, click on all the little boxes and then OK. Why? because the worldwide database is constantly being updated with new observations and you need the latest data before you can claim a new discovery or to do confirmations on recent candidate discoveries. You must do this EVERY time you start up Astrometrica. Because this can take several minutes, it's a good reason not to sit down with Astrometrica unless you can finish analyzing an image set in one sitting.
3. Click File | Load Images and navigate to where you've stored your images. I like to store them in the ImagesF09 folder inside Astrometrica inside Program Files on the c: drive on my computer. Now hold down the shift key and click on all 3 images of a set. A little popup box will appear and just click OK on each.
4. Click on the green bullseye on the toolbar. In the coordinates popup box just click OK. It should produce a popup box with the plate solution. The plate solution is a set of numbers which show how well it was able to match up the stars to its database. You want to see dRA and dDec at a small fraction like 0.13. That means it's a great fit. In my experience, you either get a good solution, or you'll get an error box saying only a few stars were able to be fit. That usually means you have the wrong .cfg file. In such case, you click on the blue wrench at the left of the toolbar, click Open at the bottom left of the popup box, then in the Open popup box click on the rainbow colored filename for the other telescope ARI-24.cfg or ARI-32.cfg, whichever isn't currently shown at the bottom right of your Astrometrica layout. Then click the Open popup box's Open and Save and then try the green bullseye again. This nearly always solves the problem. However, rarely, you might have one of the 3 images which is offkilter or cloudy or something and it can't find enough stars. In that case, instead of changing telescope.cfg files, instead in the error box click on the option for doing just 80 stars.
Why? This will tell Astrometrica to search through the stars database and match up stars to those it identifies on the images. That calibration is essential so Astrometrica will have a coordinate system to work with and be able to assign coordinates (Right Ascension and Declination) to the asteroids found.
Now you'll want to get an idea of what is the limiting magnitude that you can hope to see. Find the faintest star you can see and click on it. The pop up box will have the magnitude. Click on a few more extremely dim (but definitely there) stars. This will give you an idea of the faintest things you can reliably see. Some of your redbox asteroids may be much dimmer than this - Don't expect to find them!
Searching Your Images for Asteroids
5. Now you're ready to begin searching for asteroids. Click on the toolbar Tools | Blink Images. Then click the little + magnifying glass to expand the image of the blinking pane. I like to drag pull the sides of the image so it takes up a convenient piece of the total image space; like 1/2 of the length, and 1/4 of the up/down width. That gives me a close up view with not too many stars to confuse my vision. First thing to do is essential - Notice how the 3 images are not perfectly stacked on top of each other. The STARS are stacked perfectly, but the images themselves are not quite. Now, the digital chip has hot pixels and other noise associated with it. Lots of noise. Noise that will confuse you into thinking its an asteroid when it's just noise. Stop here and read this page on identifying true asteroid traces from noise. You MUST identify the noise direction! Usually, the noise direction will have some curvature between the 3 image placements and this makes it easier to not confuse noise with asteroids. But sometimes the noise is perfectly linear and constant velocity from one image to the next. In that case, you should assume that ALL asteroid-like things that march in that direction between your images are noise and to be ignored.
6. Now click on Tools | Known Object Overlay. It'll think for a moment and then up on your screen will appear perhaps a few red boxes with names next to them. One of these will be the key asteroid for which this image set was taken. I like to begin by trying to measure these asteroids before doing any searching for discoveries. Note that the asteroid may not be inside the red box, especially if it's the one they're taking the photos for! If the orbit is new and not well determined, the asteroid might be up to an arcminute or so away. Probably not more than 1.5 or 2 arcminutes away.You should make every effort to identify the asteroids associated with these boxes. Measuring the positions of these known asteroids is as important as any new discoveries. You can slow or speed up the blinking by changing the number in the speed box to 1, 2, or 3. You can stop the blinking by clicking the red filled circle on the toolbar, and start it again with the green triangle.
7. Click on objects CAREFULLY!! MEASURE CAREFULLY!!
I am getting reports which do not satisfy the requirements of being linear and constant velocity. Often there may be a star which interferes with one image. Or it is just so faint that the centroid ends up being wrong. You can usually tell by looking just where the center of the asteroid really is when these issues are there. Measure each image separately by stopping the blinking and click on image 1 and your object, then image 2 and then image 3. Make sure that when you click on the object you are careful about clicking exactly on the center of the blob of light as best you can. If the software doesn't centroid where you think it should be, click reject and try again. You can often get the centroid to move by clicking slightly away from where the offending faint star is, for example.
VITAL POINT! - known objects may not be at the exact red box location (after all, that's why you're measuring them, to improve the orbit), but they WILL be moving with the same speed and direction of motion as the red box! If you find a genuine-looking asteroid candidate which is very close to a red box, but the red box is moving in a different speed and/or direction, then your candidate is NOT the red-box asteroid, and if you mistakenly identify it as such, you'll really be causing trouble for astronomers downstream!
8. When you like the way the software has centeroid'ed your object, then inside the Object Verification popup box at the bottom center you'll see a little button with a dotted box inside it. Click this and Astrometrica will put up an Object Identification popup box with a list of possible identifications for that object, with the closest object first. If the dRA and dDe values (delta Right Ascension and delta Declination) are both within 1.0' of being zero, then that is the proper identification and you should click OK. This will place the name of that object into the Object Verification popup box so you can then click Accept. Repeat for the other 2 images. If the object is farther away from the red box by more than 1' it might still be the object if its not too far away. Check the direction and speed of motion. Is your red box moving just like the object you think might be it? Look at the magnitude of the red box. If it's larger than 21 (i.e. fainter than 21st magnitude), then it's really faint and unlikely you'll see it, especially if these are 24" telescope images. Whatever you do, do NOT just click on a red box which is empty!! Each time you click Accept, you are adding a line to the MPC report file kept by Astrometrica automatically.
9. After you've measured the known objects, you're ready to search for new discoveries. As I said, I like magnifying the blinking page twice, so that the resulting pane is halfway across the full image horizontally, and 1/4 or 1/5 of the way across vertically. Then I carefully go from pane to pane looking for anything faint that isn't noise and might be an asteroid. When you find something, stop the blinking. Click on the little button with the dotted box on it to see if anything known is nearby, and measure it on image 1, then 2, then 3, making sure the centroid is what you think it should be, by eye. Only click Accept when you're happy with the centroid. If there's nothing known which corresponds to your candidate asteroid, take another good look and make sure it isn't likely to be noise. Does it follow the noise direction? (if so, reject it). Does its light profile fall off gradually over a couple of pixels or more like a proper object should, or does it look like a hot pixel? Does it move in a line with constant velocity? It can be very faint and be valid. In fact, that's what likely new discoveries will be like.
10. Naming new discoveries. Each object must have a name which has 3 capital letters and 4 numbers, with no spaces. Example JFB0001 would be the first discovery candidate for Joe F. Blow. You should follow this convention. Take your 3-letter initials (first, middle, last name) and then numbers starting with 0001. This is the name you enter into the space on the Object Identification box if your moving object is not close to a known object and can't be therefore identified with a known object.
11. Once you've clicked Accept, it is permanently in the Astrometrica MPC report file. You can view the file as you go along by clicking File | View MPC Report. Note to yourself on scrap paper any editing you'll have to do to the report later.
12. When you've searched the entire image and ID'd all the known asteroids that are bright enough to be seen as well as any candidate discoveries, then click File | View MPC Report and then use your mouse to click/drag to highlight it all, then cut/paste. Now open up Microsoft's Notepad software (free and included on all Windows machines) and paste in the report.
12. Change the report's 3rd line to have MEA followed not by R. Holmes but by your name. Then insert a line with the image set name e.g.
Image set: 2009 QH2.
Then put a blank line between each triplet of asteroid lines. You do have a triplet of lines, right? Delete bad lines. You must have only 1 line per image and with 3 images per set, that's 3 lines for a given asteroid. Look again at the data in the lines. The RA and Dec positions should look roughly linear and constant velocity. The magnitude should not be more than 1 magnitude different between the 3 images, and should be reasonable compared to the stars on the same image.
13. Now in Notepad click File | Save and save it as a filename like SuzyJones-2009QH2.txt so it has your name and the image set, so I'll know what set you've sent me. Now email me and attach the .txt file as an attachment. Do NOT cut/paste the report onto an email. Do NOT send me a Word .doc file. I need a .txt file.
14. I'll take a look at it and if you've submitted it quickly and you've done it right, and especially if you've made new discoveries, I'll include it on the final report which I submit to IASC. Warning - the 48 hour time limit is very important and I must send off my own report on the image set before 48 hrs. I can't be online 24/7 waiting up to the last minute, watching our data's value deteriorate and hope I'll get a report from a student. I wait at least 1 day after the set appears, but after that I'll just send in my own report. I'll attach your report onto my report if it is satisfactory and timely, but not otherwise.
Click here to see an example of an MPC report prepared properly.
Notice it has 3 possible new candidate discoveries CAB0001, CAB0002, CAB0003, and one known NEO (Near Earth Object). If you have a candidate new object, name the object with the 3 letters that start your first, middle, and last names, followed by 4 numbers. Start with 0001. So if Joe F. Blow finds his first possible new object, he'll name it JFB0001. It must have 3 letters followed by 4 numbers, don't get cute - no exceptions!