TransformApplier (TA) ready for testing

Affiliation
American Association of Variable Star Observers (AAVSO)
Tue, 06/24/2014 - 13:53

The AAVSO is promulgating a set of tools to make it easier to submit transformed data. These are described at http://www.aavso.org/transforms-everything-you-need-transform-your-ccd-observations

Gordon Myer's PTGP tool helps you compile your transform coefficients. Another tool is the TransformApplier which applies your coefficients to your WebObs submission.

I'm looking for volunteers to try out the new program. Please do give it a try!

George Silvis

SGEO

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Testing of TA, the TransformApplier is progressing

 

A number of volunteers have stepped forward to start testing the TA. With their advice and suggestions it has been upgraded to version 2.07, available as an attachement in http://www.aavso.org/transforms-everything-you-need-transform-your-ccd-observations

I especailly invite those who currently do their transforms with excel worksheets to come and try out the TA with datasets that they have already transformed to demonstrate that the TA is doing it right. I'm also looking for suggestions to make the TA fit into your workflow smoothly. Changes have been made to cope with Maxim output formats and so forth.

Thanks,

George

SGEO

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Testing TA

George,

I have been providing files generated in Maxim v6.03 and AIP4win 2.4.8 with TA version 2.07.  So far everything seems to be working well.  I am not getting any errors.

In the future will it be possible to import the coefficients generated by Gordon's PTGP so that they don't have to be entered manually?

 

Barbara

Affiliation
American Association of Variable Star Observers (AAVSO)
TA and PTGP integration

I'm working with Gordon to make it easy to take the coefficients PTGP generates and put them into an INI file compatible with TA.

George

 

Affiliation
American Association of Variable Star Observers (AAVSO)
Testing TA

To:  Barbara,

Does Maxim DL 6 have any better photometry tools than V5?  I'm using V5.23 and have tried to use AIP4WIN, but perfer to use MaximDL.   Thanks Dr. U Sco!

James Foster

Affiliation
American Association of Variable Star Observers (AAVSO)
Maxim DL

James,

There has been a complete revamping of the photometry module in V6.  I really like it but there are a few things that I would like to add to the wish list.  One of the main things I want added is to be able to save your comp star data for a particular star instead of having to re-enter the data every time you perform photometry on that star.  That is one of the features that I like in AIP4Win.  It also has the ability to create a csv file but you tell it what data you want in the CSV file.  For example, for the PTGP, I only wanted instrumental magnitudes.  I got a file with instrumental magnitudes, JD, and also standardized magnitude.  I didn't want the standardized mag but for some reason they will not let you remove it.  The PTGP is geared toward accepting a txt file from AIP4Win so I had to import the CSV file into Excel and manipulate the data (I had to transpose the columns and rows, Filter needs to be the first row and it has to be Filt not Filter, Maxim uses Timestamp and PTGP wants Julian Day).

Anyway, you can download a demo version of Maxim 6 and test it.  I like it but I have always been a Maxim user and I also was a beta tester so I gave it quite a workout.

 

Barbara

Affiliation
American Association of Variable Star Observers (AAVSO)
Explain some of the terms in TA

George,

Can you explain some of the terms in the report portion of TA:

Vraw, Vzp, Vex, TranMag, Vrep.

Also, like Gary, there seems to be a big difference in the instrumental magnitudes and the transformed magnitudes in the report.  For example here is EE Cep data from 7/8/14.

EE Cep,2456846.8240567129,10.790,0.001,V,NO,STD,000-BCQ-031,11.884,000-BCQ-040,13.383,1.132,na,13514FEJ,na
CREFMAG= Vc= 10.399 +/- 0.007
ABS or STD inst mag: VMAGzp= 12.275 = 10.790 + 11.884 - 10.399
CMAG with extinction: 11.642 = 11.884 - 0.214 * 1.1320
VMAG with extinction: 12.033 = 12.275 - 0.214 * 1.1320
vc= 11.642 +/- 0.000 (assume correlated with v error)
vs= 12.033 +/- 0.001
# BVRI AAVSO recommended 
#  variable notation: filter/star. Star s is the target, c is the comparison. Capital filter is ref, lower case is as observed
#  Bs = bs + (Bc-bc) + Tb_bv * ((Bs-Vs)-(Bc-Vc))
#  Vs = vs + (Vc-vc) + Tv_bv * ((Bs-Vs)-(Bc-Vc))
#  Rs = rs + (Rc-rc) + Tr_vi * ((Vs-Is)-(Vc-Ic))
#  Is = is + (Ic-ic) + Ti_vi * ((Vs-Is)-(Vc-Ic))
Star: 2456846.8157291668  Bs= 11.204, bs= 11.765, Bc= 10.699, bc= 11.271
Star: 2456846.8240567129  Vs= 10.791, vs= 12.033, Vc= 10.399, vc= 11.642
Star: 2456846.8243344910  Rs= 10.439, rs= 11.606, Rc= 10.235, rc= 11.387
Star: 2456846.8152662036  Is= 10.126, is= 11.495, Ic= 10.028, ic= 11.391
VMAGreport= 9.306= (10.791 - 11.884) + 10.399  
EE Cep,2456846.82406,9.306,0.007,V,YES,STD,000-BCQ-031,11.884,000-BCQ-040,13.383,1.1320,101,13514FEJ,na

Here are my TC and extinctions (used sea level values) calculated using PTGP with NGC 7790 data.

#   transform coefficients:
#Tbv= 1.0770, +/- 0.0230
#Tbr= 0.0000, +/- 0.0000
#Tbi= 0.0000, +/- 0.0000
#Tvr= 1.0110, +/- 0.0160
#Tvi= 1.0440, +/- 0.0100
#Tri= 1.1080, +/- 0.0130
#Tb_bv= 0.0940, +/- 0.0370
#Tb_br= 0.0000, +/- 0.0000
#Tb_bi= 0.0000, +/- 0.0000
#Tv_vr= -0.0220, +/- 0.0000
#Tv_vi= -0.0120, +/- 0.0090
#Tr_ri= -0.0340, +/- 0.0290
#Tv_bv= 0.0130, +/- 0.0130
#Tr_bv= 0.0000, +/- 0.0000
#Ti_bv= 0.0000, +/- 0.0000
#Tr_vr= -0.0270, +/- 0.0270
#Tr_vi= -0.0500, +/- 0.0090
#Ti_vi= -0.0200, +/- 0.0070
#   extinction coefficients:
#Eb= 0.3680, +/- 0.0000
#Ev= 0.2140, +/- 0.0000
#Er= 0.1650, +/- 0.0000
#Ei= 0.1300, +/- 0.0000
#Eu= 0.0000, +/- 0.0000

 

There is 1.484 mag difference between the instrumental and the transformed mag I am suppose to report.  That seems way to large!  Am I doing something wrong?

 

Barbara

 

 

 

Affiliation
Magyar Csillagaszati Egyesulet, Valtozocsillag Szakcsoport (Hungary) (MCSE)
TA in Linux?

Will it be possible to run TA in Linux (Ubuntu) environment too?

Thanx,

Robert

Affiliation
Magyar Csillagaszati Egyesulet, Valtozocsillag Szakcsoport (Hungary) (MCSE)
Meanwhile I've seen in the

Meanwhile I've seen in the handbook that the Python software should work in Linux as well. I'll check it later.
 

Affiliation
Magyar Csillagaszati Egyesulet, Valtozocsillag Szakcsoport (Hungary) (MCSE)
Test fields for DSLR observers?

Around 3 years ago I tested some Landolt fields, but it seems they are for CCD observers with largish telescopes. Since I do DSLR photometry with a 300mm focus (zoom) telephoto lens the Landolt fields are too dense for me and contain too faints stars only.

Arne told me he made some photometry with the BSM in order to provide standard fields for DSLR observers. As for as I know an area near GN Com can be used for transformation. Some 2 years ago I made a set of DSLR images for the GN Com field, and it would be good to have it included in the transformation softwares. Maybe it would also be good to have a similar field for DSLR observers on the summer/autumn sky as well.

Thanx,

Robert

Affiliation
American Association of Variable Star Observers (AAVSO)
TransformApplier Testing

Yes, a number of people are reporting very large transformations when running their observations through TA.

We've checked methodology and computation and I think it looks right, but am willing to be corrected.

The cross check that I find interesting is to run a known star through the TA and see if the result matches the published value.

The procedure:
Copy a set of BVRI observations and replace the VMAG with the KMAG data of that record. Now note that the KMAG field is instrumental, so it will need to converted to differential by subtracting the CMAG value of the record and adding the CREFMAG.

When you run this set through TA, does the resulting transformed magnitude of the K star match the AAVSO photometry? Note that TA is still reporting the transformed result in differential mode, so study the detail report on the report tab. I submit that if the TA result matches the reference data, then the TA is doing it right and the big transform corrections are in fact needed to bring your data into the standard framework.

Comments on this as a means to validate the TA's result?

If you want to send your data and INI file  to me, I'll be happy to do this test.
George
SGEO@gasilvis.net

 

Affiliation
American Association of Variable Star Observers (AAVSO)
TA version 2.23 available

Version 2.23 is available from the google driver listed at AAVSO

This includes a bug fix:  The BV transform for altenate and classic models was in error. It provided very errorneous results, so hopefully anyone who used it would have spotted the issue. Remember: Trust but Verify!

Two features added:

Aggregation: If you submit 5 x BVRI (eg) this feature will aggregate them into one set. This is just a subset of the more advanced aggregation offered by the Boxter program.

TC Testing: Ever wonder how good your transformed results are? You should be able to observe a standard star and get transformed results that match the reference magnitude. This feature will help you examine this by transforming your K star observations, performing the transform and then show your results vs the standard magnitudes. If you see a big difference, then your system is not reporting its data properly and you should investigate.

Please try these new features and report any issues.

George

 

Affiliation
American Association of Variable Star Observers (AAVSO)
TA bug report; version 2.27 available

A problem was reported and fixed in TA. This affects versions 2.22 to 2.25.

The issue affects the application of extinction to VMAG. If you used any of these versions with extinction applied, you should reprocess that data.

Version 2.27 fixes the problem and is available on the google drive .

My thanks to Ken Menzies who spotted the problem and helped me persue it.

TA is a complex piece of software checked as carefully as I can. Remember, trust but verify! Any time you run your data through a complex process, spot check it!

George

 

Affiliation
American Association of Variable Star Observers (AAVSO)
TA version 2.28 available

When working on the 2.27 release, fixing the problem with applying extinction to the instrumental magnitudes, I realized that as presently configured, first order extinction doesn't matter to the TA transform process. If you assume that the target and comp star have the same airmass, as forced by the extended file format, then first order extinction corrections cancel out of the transform equations.

Extinction is still an issue that we want to learn to correct for. When we start working with wide angle images from the DLSR's that assumption of one airmass figure being applied to all stars in the image will break down. At that point we will work out a mechanisim to get extinction applied correctly by TA. Meanwhile, TA 2.28 will turn off extinction application.

TA 2.28 also has a refinement of the error computation (OK, a bug fix). It was not major, but understated the final target error.

One thing to note is the different methodologies (AAVSO and Alternate) have different implications to the final error. You should try both and review your results. I believe the AAVSO methodolgy will result in a lower error; that in part is why it is the recommended methodology.

George