Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 06/28/2016 - 03:19
Hi--I'm having trouble with getting consistent chart info from the Variable Star Plotter. I printed a chart and photometry table of ET Aur (chart X15912W) and got the B,V,Rc(no comps), and Ic data that I needed. Good so far.
But when I go back to view and print the same photometry table X15912W, I now get only B and B-V, even though my web form is requesting B,V,Rc, and Ic. And when I download the JSON representation of that same chart, it gives yet a different filter set: B,V,J,K,H, and Ic.
Can someone enlighten me on what is going on? One specific question: will the JSON download always have a superset of the original chart's filter set?--if I can count on that, I can make that work.
Thanks for any guidance.
Sorry, just came across another bit of inconsistency: should the JSON representation of a VSP Chart give zero or null, for a missing error value? I'm getting both (example Chart X15912W again: 000-BBM-450 V filter gets error of zero, but 000-BBM-475 V filter gets null. They look the same in the printed table). I've worked around this OK in my own software, but thought I'd mention it on the off chance there's something unsavory going on internal to VSP. If it's just a typo in the db, no worries.
Thx
Eric,
I suspect the problem you are having is that your chart designation: X15912W is for a Chart and not for the photometry sequence which will always have a different designation than that shown on the chart...
near the top of each sequence (photmetry table) is shown the following:
Report this sequence as X16276ALA in the chart field of your observation report
The X1462.... is only an example
Try creating a new chart and this time use the code shown on the photomety table for a recall of that sequence data.
If you are still having problems understanding how this works, please feel free to email me directly: tcarchcape@yahoo.com
Two additional comments:
1) This is really a terrible sequence and I would advise you to file a CHET and request that it be updated:
https://www.aavso.org/chet
2) Your chart Designation brings up a visual chart. I strongly urge CCD observers to select the DSS (digital sky image) option which will provide you with an image that will better match that which your CCD is showing you.
Tim Crawford, CTX
Sequence Team
Actually, the "Field photometry for ET Aur" photometry table page I printed 1/23/2016 does say "Report this sequence as X15912W in the chart field of your observation report." The graphical chart I printed at the same time is X15912V.
1. Yes, the comp stars seem pretty poor.
2. I like the DSS image--thanks for the tip--but the schematic plot will still be my primary, as it displays interfering double stars more clearly, and its white background is much easier to mark up by hand than is the DSS's gray background.
I think I have control of my chart identifications so far--my much smaller questions was about the filters represented, and happily I think I've figured that out. Thx