Affiliation
American Association of Variable Star Observers (AAVSO)
Thu, 04/09/2020 - 02:51
I tried to do a two-color transform and I came up with the following error message:
Do anyone know what I'm doing wrong?
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What part of the two color transform process were you in, i.e. what were you doing when you got this error?
Phil
Images of V0580 Ser taken with the V and I filter. I can send you the images if you want. I can also send you the standard field I used as well.
Hi Tim:
Please share the images and sequence with me at MZK. I'm sure Phil will ask the same.
I assume that you have conducted successful VPhot 2-color transform on other targets with this specific scope? IOW, this is something that is unique to these target images?
Ken
I sent both the variable star images and standard field for the V and I photometric filter. Also, I try to do a standard field for any different combination of telescope, camera, binning, and gain setting.
Telescope: ES Comet Hunter
Camera: ASI183MM-Pro at 1x1 Binning and a Gain of 0 dB in ASICAP or 3.66 e/ADU natural (0.2889 e/ADU after 12-bit to 16-bit conversion)
So this is the first and only field of variable stars I have registered with VPHOT using this particular combination.
Tim:
I really can't see the target (V386 ser) in the V image. Too faint. It is reportedly less than mag 18 right now.
BTW, the I image has a white background in VPhot. Bad processing? The images were also not calibrated (BDF)?
Interesting that the Bayer pattern shows as RGGB in fits header. Is the ASI183 camera actually a monochrome version? Does your software process this correctly? I have never used Siril before? Not really sure where to start?
BTW, I noticed that VPhot reports the image as reported but did not see the data on AID. Do you have transform coeffs entered in VPhot Telescope Setup?
Ken
I tried to get V386 Ser in the image but it was too faint. I did get a check star at 14.58 magitude (V) with an SNR of 24, so V386 had dipped in brightness way past that. I even manage to get CSS_J161057.5-010952 at 16.6 magnitude at SNR of 4. So V386 would have to be dimmer than that. I did get V0580 and the B and V transforms worked so I submitted those.
My camera is a monochrome camera, so I don't know how RGGB showed up in the FIT header. Also I did calibrate my images in SIRIL. I took dark, bias, flats, and dark flat frames but VPHOT won't count it as being calibrated even though I did. I can send you the raw files and the master calibration frames if you like.
I did enter the transform coefficients in VPHOT telescope set up.
Ah, you noted above that B and V transformation worked for this target. Look at the I image. It's white scale is clearly not correct. Nothing visible. I'm sure that's why you got the error message. Correcting this problem is unclear. The software you use appears to act in a manner that VPhot did not like.for this image.
Ken
Ken, Tim,
The reason I asked about where in the process this problem occured is that I also had a problem with the two color transform process at about the same time Tim's question was posted.
My problem happened when I was culling the list of comps used in the analysis in the Color Photometry window. I unchecked one of the comp stars, clicked on refresh, and got the an error message. (Unfortunately, I didn't save it.) After that I was unable to edit the comp list. I stopped working with VPhot for the rest of that day (probably Apr. 7). I haven't encountered the problem since.
I only mention it now because, if Tim's problem occured during the same step in the two color transform process, it might indicate a pattern.
Phil