vphoto * is a perfect example of the benefits of the software on the network, as applied to astronomy. With the term network software I mean programs installed on a website running on your browser and does not require any component installed on your PC, except in the case of applications in java or adobe flash, which will require the beginning of the corresponding compiler (if available free). This kind of software and we are familiar, for example, chat applications from many internet portals, which are usually run on java.
* Henceforth, when we say Photometro we are referring to vphoto since the AAVSO had to change the name to the application for copyright issues .
* Henceforth, when we say Photometro we are referring to vphoto since the AAVSO had to change the name to the application for copyright issues .
function Photometro is to analyze the images of star fields made with our team. Automatically sets the scale and orientation of the image (using the existing values \u200b\u200bin the fits file header) and the star itself located variable or variable stars in the field, select a comparison star and makes the calculation of magnitude.
As you might guess, is a very comfortable tool for photometric measurements, without relying on any image analysis program. As it only requires the browser, we can perform photometry from any computer with internet connection, we need only write images to the server fits Photometro through the same application.
What is the bad news? Photometro that is restricted to members of the AAVSO , since it is this organization that has sponsored the development of the program to make it available to the observers associated with this. However it gives a user the option to test the program either by clicking the DEMO option top right.
From there we came to a picture menu, which is hung a collection of real images taken with a telescope and a CCD, available for ourselves we must try to do photometry and learn the operation of this tool. If at first the list is empty, giving the refresh button full list will appear.
Do we want to measure? we click on the link of the images. For example, the number 76, named BL Cam, which is an image that is supposed to have registered the field of variable BL Camelopardalis.
appears stellar field image and calibrated scale. If pass the cursor over this, we indicate the RA and DEC coordinates of the point x, and selected. The most important thing is that thanks to this calibration, Photometro is the variable star and comparison star alone. Go to menu catalogs, top right, and select GCVS (General Catalogue of Variable Stars). Then displays all variable stars present in the image field.
As you can see, the variables have been located and LZ BL Cam CAM. Now we can download the valid comparison stars contained in database of the AAVSO about these variable stars, for which we again catalogs and select the option Load AAVSO Stars Comp.
V Eremos then marked the comparison stars that have been assigned the AAVSO. Each is surrounded by several circles, which are respectively the measuring aperture photometry, and the two apertures that limit the area of \u200b\u200bmeasuring the contribution of the sky.
turn in a box to the left of the image to see a list reflecting the variable star and comparison have been found by allocating the value of signal to noise ratio calculated and the width or FWHM obtained. If we make a photometric measurement with this set we must, by mandate of the program, choose a star field to be a star check. Once this is done we can see the results of photometry calculation giving the Report button Photometry View . This selection of stars can be saved by giving the link to save as , we can also load a previously made selection in a dropdown box above the title Load Sequence:
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loaded sequence previously made to work with Photometro with BL Cam, two stars of comparison and checking. The use of these sequences prevent the passage saved us from having to load the GCVS and the comparison stars in the AAVSO. With this set of stars we calculate the magnitude of BL Cam.
The report states that the application has been determined magnitude 12,904 for BL Cam. The report, for convenience, can be exported as text file or xls for excel. It can also be saved as a report with the format of the AAVSO, which can be sent through the tool WebObs the website of this organization.
It is highly desirable that this tool, Photometro , or similar, could be made available to the public, thus, any observer interested in making photometric measurements could carry out its purpose without investment programs without additional headaches, with very simple procedures. For the moment, for any fan with a strong interest in variable stars has Photometro an additional reason to become a member of the AAVSO.
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