Sun, 10/30/2022 - 00:35
I'm sure I'm doing something wrong but I need some hints and or help. I uploaded some images to the site and they plate solved but when I try to run the time analysis it says that there is no target star found. I'm using NGC7790 as the standard and have 30 B and 30 V images uploaded. I've played with the search value to no effect.
What is more strange and perhaps indicative of the problem is that when I try to pull up the image all I see is a white screen. No stars are displayed.
John:
1. Is this the first time you have used VPhot?
2. Have you read the VPhot Guide?
3. What software did you use to collect the images?
4. What other software did you use to process images before uploading to VPhot, if any?
5. Did you load any AAVSO comps or just add AAVSO Standard Stars?
6. Did you add any targets (VSX)?
7. Did you save these in a sequence?
Ken
1) Pretty much, yes
2) Yes I have
3) Images were collected via N.I.N.A. and processed via the pixinsight batch process to do the calibration to darks, bias, and flats. I did use pixinsight to change the bin to 4x4 to reduce file size. Also, used pixinsight to go from xisf file to fits format.
4) See 3 above
5) I selected the ngc7990 sequence, but I noticed that there doesn't seem to be any entries in it. I assumed that it would have the NGC7790 stars preloaded.
6) No
7) No
I should mention that I'm trying to do a time series analysis to calibrate my filters.
John:
The white image is almost certainly caused by the use of pixinsight for processing. It changes the Bzero and Bscale fits headers as you change from signed 16 bit to floating 32 bit image. The white and black level get changed in the signal histogram which leads to a washed out / whited out image. The xisf format does lots of bad things to photometry images. Great for astrophotography . BAD for photometry. Find a way to avoid it or at least to NOT use the xifs process.
So you are trying to generate transform coeffs for your system NOT do normal target photometry? You are collecting NGC7790 images for that, as is appropriate. You do not want to process them as normal for photometry. There should be an appendix that explains this in the Guide?
Ken
Ok, thanks.
I'll redo the process with DeepSkyStacker. That would put the calibrated frames in fits format. I'll post what the results are (either good or bad).
I think I have it working now. Pixinsight did screwup the BScale and Bzero values when it calibrated the images. So I changed to use DeepSkyStacker.
Now that I've done that, I could download comps, set a target, and check stars and run the reports. I just ran it on a couple of images. I've got more but wanted to see if I could at least get to the point where there were some "white" boxes on the photometry report.
I think the manual should just say don't use Pixinsight to calibrate.
Thanks for the help
Ok,
I got to the point where it generated a .txt file in the correct format for passing off to TG.
The problem is that when I set up the file to into TG, click on NGC 7709 as the standard and do a calc, none of the stars are mapped. Do I have to do something specific to use the NGC 7709 standard stars for calculation.
Am I correct in assuming that the TG program has access to the NGC 7709 star maps and that they should be the same ones that they would be the same ones that were used as part of my sequence.
I think I'm missing something basic here but can't find any more hints in the manual or online.
John,
Send me a copy of the txt files (need one for each of at least two filters) you downloaded from VPhot, that you plan to import into TG.
Ken
kenmenstar@gmail.com
Not to make it more complicated but there are two files but not split like you were expecting.
When I read the guide AAVSO Guide to CCD/CMOS, it said that I could load both the B and V files into VPhot and generate the file from it to TG. That may have contributed to the problem.
The two files that I've attached are similar but slightly different in derivation.
The first was created from a sequence that I created requesting comp stars and the second that I created requesting standard stars.
Each has both the B and V data.
/sites/default/files/users/user59559/124%20(1).txt
/sites/default/files/users/user59559/124%20(2).txt
Both failed with errors that there was no data to match and the list of unmatched stars.
Both images should use AAVSO Standard Stars.
Why would you treat them differently? One comps; one standard stars?
Not sure what you meant by "Each has both the B and V data."?
Ken
I included the two files as explanation of the process. I wasn't sure whether to use comp or standard. So, the file that is of concern would be the second which was generated from standard stars.
The file has both B and V entries for a given star. The first group of columns are B filter the next group are V.
I was using the instructions in the guide to cmos/ccd photometry. It looks like the instructions on page 117 are not quite right (although I don't know what the problem is).
When I used the procedure in the VPhot manual, it seemed to work. I got values for Tbv, Tb_bv and Tv_bv. It takes a little longer since you're generating one file for each image but it does work.