Affiliation
Svensk Amator Astronomisk Forening, variabelsektionen (Sweden) (SAAF)
Mon, 11/13/2023 - 09:00
VPHOT doesn't seem to recognize manually added stars for me any longer. It worked without problem before. If on any image I load the comparison stars and then click on any star it got the green marker as a fixed target and it get the name Star1. If I then click View Photometry Report it says: THERE ARE NO TARGETS TO MEASSURE. If I load a sequence with comparison stars and targets it works fine, but if I add a target manually some or all of the targets disappear when I click View Photometry Report On the image and in the target list manually added stars are visible, but not in the photometry report.
Thomas Karlsson
When adding a star, make sure you save the sequence.
If you go straight to the photometry report it may not appear. If it doesn't appear in the report, go back to the Images page and re-select the star.
George
In this case I manged to process the image by saving a sequence as you suggested. But it seems something has changed. I often add test stars to see the magnitude depth but I can't do that now. It also often happen that VPHOT doesn't find a star (red ring at wrong place). I have always been able to delete the wrong star and add it manually. But that seems not to work now.
I'll dig into the code to see what might have changed.
Thanks for the report and sorry about the inconvenience
George
Are there any news about this problem? I can't make manually added stars work in any way. Have tried to select, reselect, rename and update them without success. Manually added stars have always worked before and is something I often have to use.
Thomas Karlsson
I see the same thing. I use that feature to do photometry on most of the stars in the image.
Ray
I should have a fix for this problem soon.
George
Should be working now. Check it out!
George
I have tested and manually added stars works perfect now!
Thomas
Wizard George,
For my own education, when you click on the image to add a star does VPhot use the exact coordinates of the click or does it recenter on the nearest astronomical source?
thx
Cliff
It works from the x/y of the click point and the WCS
The reference in the code for RADecFromPix() is http://stsdas.stsci.edu/cgi-bin/gethelp.cgi?xy2rd.src
Stars coming in from VSD or APASS may bring their catalog coordinates... It's not perfectly clear. They may get placed on the image with a PixFromRADec and then the process reversed when they are selected.
George
That link is dead. The code looks like:
Public Sub RADecFromPix(ByVal x As Double, ByVal y As Double, ByRef ra As Double, ByRef dec As Double)
' Ref: http://stsdas.stsci.edu/cgi-bin/gethelp.cgi?xy2rd.src
'x += 0.5
'y += 0.5
Dim xi As Double = c11 * (x - px0) + c12 * (y - py0)
Dim eta As Double = c21 * (x - px0) + c22 * (y - py0)
xi = TimeAndCoord.DegToRad(xi)
eta = TimeAndCoord.DegToRad(eta)
Dim ra0Rad As Double = TimeAndCoord.DegToRad(ra0)
Dim dec0Rad As Double = TimeAndCoord.DegToRad(dec0)
ra = Math.Atan2(xi, Math.Cos(dec0Rad) - eta * Math.Sin(dec0Rad)) + ra0Rad
'dec = Math.Atan2(eta * Math.Cos(dec0Rad) + Math.Sin(dec0Rad), Math.Sqrt((Math.Cos(dec0Rad) - eta * Math.Sin(dec0Rad)) ^ 2 + xi ^ 2))
Dim a As Double = eta * Math.Cos(dec0Rad) + Math.Sin(dec0Rad)
Dim b As Double = (Math.Cos(dec0Rad) - eta * Math.Sin(dec0Rad))
Dim c As Double = Math.Sqrt(b * b + xi * xi)
dec = Math.Atan2(a, c)
ra = TimeAndCoord.RadToDeg(ra)
dec = TimeAndCoord.RadToDeg(dec)
If ra < 0 Then ra = ra + 360
End Sub