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How to make my own comp sequence for VPhot.

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spp
spp's picture
How to make my own comp sequence for VPhot.

I would like to learn how to make my own comp star sequences for use in VPhot.  I mean this as no dig to the sequence team which has always been very responsive and has produced very nice sequencess in short order whenever I have asked.  

Sometimes I am curious about a star that has close companions, or is embedded in nebula, or has other issues.  I'd like to do some practice observations to see if I can produce decent results.  In these cases I don't want to waste the sequence team's time on a star which I may just drop after a few observations.   I'd just like to create at least a practice sequence myself.

I know how to access the APASS database and save a csv file containing all the APASS stars within the FOV of my system.  I have a fair idea of what types of stars are needed for a sequence.  I just don't know how to create and load a file that is recognized by VPhot as a comp star sequence.  I couldn't find this information in the VPhot manual.

Phil Sullivan

 

PVEA
PVEA's picture
How to make my own comp sequence for VPhot

It is easy,

The hint with very short explanation and images below:

Just use your own image to investigate the stars and to choose the comparison and check stars.

  • Load all known variable from the Catalog/Variable Star Index to prevent choosing them as comparison. (img 1)
  • Choose the aperture from the Tools/Aperture and Sky Annulus
  • Choose the comparison star and change the type from Tardet to Comp Star (img 2)
  • Choose the check star and change the type from Tardet to Check Star (img 3)
  • You now have Targets, Comp and Check stars (img 4)
  • Save the sequence (img 5)
  • Click on the star and click the Edit Sequence menu (img 6)
  • On the next screen fill up the known and desired by you magnitudes of that star and save them. You can use many sources to find desired by you magnitudes – APASS, SDSS, and many others (img 7)
  • Do this with all Comp and Check stars and do not forget to save the sequence after every step
  • Now you have your own sequence (img 8)
  • You can correct everything by clicking on the star and use the pop-up windows;

I hope this will help.

Best regards,

Velimir

PVEA
PVEA's picture
P.S. How to make ...

Hi Phil,

A few additions:

You can create your own sequence as text file using the rules, syntax and codes of different filters in VPhot and to put it in Admin / Sequence / Edit section…

See the screenshots.

Regards,

Velimir

 

BMAH
BMAH's picture
How to make vphot sequence txt file

Hello, is there any site, where I can check what are codes for different filters, and how this txt files are build? 

BMAH
BMAH's picture
How to make vphot sequence txt file

Hello, is there any site, where I can check what are codes for different filters, and how this txt files are build? 

spp
spp's picture
creating VPhot sequence

Many thanks, Velimir, for that very clear descripiton of the process.

Phil

CTX
CTX's picture
Creating Your Own Sequences - Not a Great idea, IMO

Observers make it difficult for others to analyze their submissions when they use non standard sequences/charts.  For consistency sakes it would, therefore, be more prudent for observers not to be creating their own sequences.

If you need a sequence then please request one from the Sequence Team:

https://www.aavso.org/request-comparison-stars-variable-star-charts

If you need a sequence revised and or extended then please file a CHEET:

https://www.aavso.org/chet

I am certainty not opposed to observers creating their own sequences, especially if they will not be reporting target star data to the AAVSO data base; along with the lack of consistency in reporting of target data, because of a lot of nuances and extensive knowledge and experience with the sequence building tools, observer generated sequences are at risk of being somewhat spurious.

The team is not in any way trying to or wanting to make a monopoly of sequence building.  Frankly, sequences consume a lot of my personal time many weeks(as they do other team members) and I think most all of the team members would love to share this responsibility with anyone with a serious interest in being a team member.

The tools are there for everyone to see and use and please feel free to explore them all; but please, if you are going to be reporting target data to the AAVSO data base then please help to insure consistency of submissions by using AAVSO created charts and sequences.

I should qualify that I am not speaking on behalf of the sequence team but only my personal opinions as a team member.

If you want to know more about the team and the whole process please contact me or our Team Leader, Tom Bretl:

Tim R Crawford, CTX, Sequence Team

tcarchcape@yahoo.com

PVEA
PVEA's picture
Creating Your Own Sequences is a Great idea

Hi Tim,

I can agree with some of your considerations but did you tell me that it is not a good idea to report my results in AAVSO data base, because the sequence team was not preparing the sequences in SLOAN type filters for the stars that I have observed?

For my needs I have prepared more than 200 sequences including SLOAN type filters, should I remove all submitted by me data to AAVSO WebObs data base?

The only optimistic thing here is that this is your personal opinion but not the HQ or sequence team… Otherwise the next step would likely be the prohibition to publish research papers worldwide before the sequence team то approve the sequences used …

Best wishes,

Velimir

CTX
CTX's picture
Sloan Sequences

Velmir:

For my needs I have prepared more than 200 sequences including SLOAN type filters, should I remove all submitted by me data to AAVSO WebObs data base?

I should have qualified my remarks to mean UBVRI sequences and not SLOAN since there is no current provision allowing for sloan values within the VSD data base.  Therefore observers have no option but to create their own sequences, at the present time,  if they are going to use SLOAN filters.

I did not suggest that anyone should remove any submitted observsations because of the use of a non standard chart.  Please do not remove any of your own.

Otherwise the next step would likely be the prohibition to publish research papers worldwide before the sequence team то approve the sequences used

I think you have over reacted with this statement.  No such thoughts were expressed with my post nor even aluded to.  Maybe you have misunderstood my intent because of lanugage differences.

Here, again, for your review and to aovid any misunderstandings, i will repeat the first paragrpah in my original post:

"Observers make it difficult for others to analyze their submissions when they use non standard sequences/charts.  For consistency sakes it would, therefore, be more prudent for observers not to be creating their own sequences."

There are always exceptions and SlOAN fitlers, at the present time, would sure qualify.

Ad Astra,

Tim

 

 

CTX
CTX's picture
A Restatement of Why Non-Standard Sequences Should Be Avoided...

A Restatement of Why Non-Standard Sequences Should Be Avoided, If Possible

If all observers report their observations using the same sequence then I would believe that the data would have a better opportunity to be consistent than if observers used their own constructed sequence.

Frankly, I would have no objection to observer A creating his/her own sequence and then to have it shared with all other observers; that way, we would have a consistency of data being reported; the Achilles heel of this approach is that for the most part there is not a real practical way for observer A to reach all potential observers.

The  best option for all observers then is to be using the same sequence that  exists with the VSP Charts and data (yes, they do get updated from time to time).

There will always be exceptions.

Tim Crawford, CTX, Sequence Team

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