I was trying to use astroimagej to create an AAVSO report. The macro requests the “catalog magnitude error” for check and comp star. Where is this found? Sorry, if this is an obvious question but up till now, I’ve been using VPHOT to generate the file and haven’t had to look for this. I didn’t see anything labeled “catalog magnitude error” on the generated plot or photometric report from the plot. Any guidance would be appreciated.
Isn’t the catalog magnitude error the decimal number inside parentheses listed beneath the tabulated standard magnitude in the “Table of Field Photometry”? To make the table, use AAVSO’s Variable Star Plotter. Click the radio button labeled “Photometry.”
Best, Andy
That may be it, but here is a longer winded explanation. I’m actually taking measurements in TR, TG, TB so I don’t see that filter type in any selection as available in the VSP.
However, it looks like there is another err which does show up in the VPHOT processed image overlayed with the comps and targets. If I mouse over, say 121, it will show the magnitude and an error factor and this magnitude and error factor will change based on the filter type. That may be what I’m looking for but I haven’t found any reference specfically to it.
I think that what you are pointing out is indeed what I am looking for. The values that show up in the TR, TG, and TB images in Vphot do match the R, V, and B values.
Thanks very much.
Hi, John,
The catalog values are available only for standard photometric filters (Johnson-Cousins system). B and V are Johnson, Rc is Cousins.
You can approximate that B = TB, V = TG and Rc = TR.
Nikola
Yes, that’s what I have done.
I just started trying to use AIJ and am having issues of my own. But I may have something to offer here from my initial experience.
I was able to plate solve the images before doing the Multi-Aperture measurements and then checked the “prompt to enter ref star apparent magnitude…”. When I did the Multi-Aperture processing, and after clicking on the target star, AIJ went through a set of comp stars and, for each star, took me to SIMBAD which has magnitudes for various filters. I glanced at SIMBAD and entered the magnitude for the filter I was using in a new input box and hit OK. This makes things quite easy.
But, I have yet to figure out how to get the results into a file.
So, I did the analysis but cannot figure out how to get to the results. The documentation on line references a table that I cannot find.
I would be extremely grateful if someone would guide me through one session. I hope to see you in Portland this weekend.
Thanks,
Mark Spearman (SIQ)
Mark,
I use AIJ differently from the way you do, so be careful with the following, but hopefully it may help.
During a photometry run, my computer screen fills with windows, much like the first screenshot below. Note the minimized window at the top left, which I’ve highlighted with a red rectangle. It may not even be visible, so if not, tab through the open windows until you see it. When you do, click the maximize icon (the open square) in the middle. That should display a table of photometry results, part of which is shown in the second screenshot.
Roy,
Thank you so much for getting back to me. I did see that little icon but did not know what it did.
Clear skies,
Mark
Roy,
Thank you for your previous response to my question. That helped a great deal.
But I am still having trouble with AstroImageJ. The first time I ran it, I was impressed with the way it automatically selected comparison stars, went out to Simbad, and had me enter the particular magnitude. But the last time I tried, it did none of those things. I must have changed some setting but I cannot find it in the documentation. It may be something very simple and if so, please let me know. I
Thanks,
Mark SIQ
Hi Mark,
Sorry, but I can’t help you this time. I use AIJ differently from you - I don’t use plate solving but enter the name of the target manually in the Data Processing Coordinate Converter and after callibrating and aligning the images place the aperture and annuli manually (very easy to do in AIJ) around the target, check and comp stars. After running photometry the entire columnar output is copied into my own Excel workbook template which instantly does all the calculations I need.
Thanks, Roy
Have a blessed Christmas,
Mark
I am working with AstroImageJ and have just successfully processed one set of data with a B filter. Now I want to process more data with the V filter. But when I load the sequence and hit the multi-aperture photometry button, it loads in the data for the V stars.
There must be some way to clear out the old data but I cannot find it in any manual.
Any advice would be greatly appreciated.
Clear skies,
Mark
Hi Mark,
See the screenshots below from my AIJ workflow.
The first shows initiation of the process to import the image sequence on which photometry will be performed.
The second shows part of the dialog in which the sequence of images is actually selected. In this example, I had TB and TG images in the folder (whereas you had B and V, I presume). Note: this image has been replaced shortly after initially posted.
The box labelled “Filter” allows you to enter a text string, which in this example is an abbreviation of the photometric channel/filter name. Images will be loaded only if that text string is in the filename.
If your filenames included V or B for the photometric filters, entering one of these will result in only those images being displayed.
The above assumes I am interpreting correctly what is happening in your workflow.
Note: This post required a couple of edits during the several minutes after the initial posting. Apologies for any confusion.
Thank you, Roy
For your thoughtful reply. I look forward to trying it.
Now I am very confused. I load an image of RW Aur into Maxim and compare it with the AAVSO finder chart, both have north up, east left. When I load the same image into AIJ, it is flipped 180 deg but still says N up and E left. To make sure, I flip the image in Maxim 180 and now it looks just like AIJ but it is now S up and E left.
Could there be some setting I am not aware of?
Thanks,
Mark (SIQ)
The accuracy of the North-East overlay in AstroimageJ requires valid World Coordinate System data in the FITS header. The orientation of the image can be varied in the View menu, where you can select uninverted, invert X, invert Y or invert both. Whatever the original orientation of the North-East overlay when you turn it on (whether correct or not) it will obey whatever inversion selection you choose subsequently.
I don’t know of the above helps, but these are some things to consider