Affiliation
American Association of Variable Star Observers (AAVSO)
Mon, 11/03/2014 - 22:07

Hello,

I'm new to photometry and I'm wondering which software would be "better" - AIP4WIN or Mira AL.  By "better", I don't mean easier.  I'm fine with a learning curve.  Also, I don't mean cheaper.  I have AIP4WIN but I'm OK with purchasing Mira AL.  Any thoughts on functionality and features?

Thanks very much,

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
AIP4WIN or Mira AL - neither

I went through this a little over a year ago.  At the time AIP4WIN seemed to be the workhourse.  I looked at Mira AL and can't remember the details but concluded that while an interesting toolbox, the photometry portion was not well focused for serious variable work.  I could be wrong and it also could have changed in the mean time.  

In any event I went with AIP4WIN for a time, but found it very clumsy and frustrating to use.  If you learn all its idocencracities and discover and remember all its error creating traps, and you only process images taken on the same night or at least on the same side of the meridian, or you volumn is low, it is a functional package that will generate AAVSO reports for uploading.  For me it was a nightmare to use. 

Fortunately I soon found LesvePhotometry.  You have to have a pinpoint liscens to use it, but Lesve itself is free.  It runs circles around AIP4WIN.  Very intuitive, no frustrating ideocycricies, no error creating traps, stable, quick and will generate any kind of report you will ever want along with some pretty interesting QC interpretation charts and features that other users have generated for it.  Also has a feature to down load VSP data directly, so you don't have to key in the comps data - the worst part of AIP4WIN.  Finally, because it uses PinPoint to find the target and comp stars, it never jumps the track when processing a stack of images, like AIP4WIN would madeningly do.  

Again, not an expert on Mira, but I don't see how one could possibly improve on Lesve.  

   

 

 

 

Affiliation
American Association of Variable Star Observers (AAVSO)
another option

Ken,

There's another choice- VPhot.

First I should say that I use AIP for image calibration and (non-photometry) image analysis.  I also used AIP for photometry until I learned to use VPhot.  Even if you decide not to use the AIP software for photometry you'll still need AIP, or some other package, to do the calibration.  VPhot doesn't do calibration.  

Once I learned VPhot (via the AAVSO CHOICE course taught by Mike Simonsen) I don't think I'd ever consider using anything else.  There is a learning curve involved as with any software, and I'd suggest that if you see the opportunity to take the AAVSO course snap it up.   That said, I think plenty of people have learned it on their own.  There is a very good manual available for download and an active AAVSO forum if you need help.

Phil

  

Affiliation
American Association of Variable Star Observers (AAVSO)
Another choice: Vphot -?-

I used to use Vphot a lot, but when there was a complaint about an excess number of images sent there and bad jam-ups by "You know who you are" or something of that ilk, I quit.

So beware.

Affiliation
American Association of Variable Star Observers (AAVSO)
VPhot Usage

Lew:

I'm really sad that you let someone's comment disuade you from using VPhot. I remember that comment BUT as a high volume user (lots of time series) there is no way that's going to stop me!  ;-(

BTW, LesvePhotometry is a superb piece of software that gets better all the time, with a couple of recent additions that mimic VPhot capabilities and more. It may be the best alternative available today. It's shareware (give Pierre some money if you use it regularly) and it runs on your local computer.

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Mira AL vs AP4WIN

I don't know if you have looked at the Mirametrics Comparison Matrix but Mira AL is a stripped down version of Mira Pro that has a lot of the analysis tools, graphing image set manipulation tools and scripting language not included. Mira Pro Ultimate Edition with scripting is much more powerful than AP4WIN and both have the slickest image calibration pipeline I have seen in any program. Copy all your images and callibration frames in one directory and calibrate them all in one step even if you are dong multiple filter imaging.  If you are going to be handling a lot of images then the scripting language is handy. I am just starting to learn how to use it. The author of Mira-Pro was one of the original developers of IRAF and the internal routines are robust like IRAF but with a customer friendly user interface. The manual that goes along with it is also excellent with very in-depth explanations. It gives you very detailed outputs and among other things allows you to do photometry with or without a comp star. photometry Photometry output format is a CSV file. Outputs without a comp star are raw instrumental magnitudes.You can also generate an AAVSO format output. 

Mira-Pro UE has a hefty price tag, however. AP4WIN is a real workhorse and I found it more than adequate when I was starting out. If you are computer savvy then you might want to take the plunge with IRAF or the Python scripting verion PYRAF. I found I didn't have the time in the past to conquer the learning curve for eiither of these but that is one of the things on my bucket list. You might also want to investigate another free image processing and analysis program called Image J. I have some friends who use it and really like it. For light curve analysis The free AAVSO program VStar is excellent and for periodic signal analysis, in my opinion, nothing beats Period 04 (also free). 

VPhot is a wonderful program BUT you have to upload your images and if you don't have really high speed internet that can be slow and balky. It can also get slow and balky during high traffic periods on the AAVSO servers. I have DSL and a big format camera with 24 Mbyte images and found the uploading much too slow if I had more than a few images to analyze. 

Brad Walter

Affiliation
American Association of Variable Star Observers (AAVSO)
AIP4WIN vs Mira AL

Thank you all for your comments and advice!  You have certainly provided some good information!

A few comments:

-  I live in rural New Mexico and my internet connection is slow.  Therefore, VPHOT doesn't seem like a good solution for me.  I don't have anything against the software, it just doesn't seem like a practical solution.

-  I hadn't heard of LesvePhotometry before so I'm definitely going to do some additional research and learn more.  It looks like it may be a good solution for me.

- Yes, I know that Mira AL is "a stripped down version of Mira Pro".  However, Mira AL is MUCH cheaper than Mirametrics other choices.  However, if Mira AL won't do the job then I suppose I should delete it from my list of potential alternatives.

-  IRAF or PYRAF are definitely possiblities.  I know the learning curve is daunting but it still seems to be the preferred solution for professional astronomers.  There are a lot of tutorials and online documents available for IRAF but many/most of them seem to be quite old.  I suppose that's ok as long as they're still accurate, though.  The trick is determining if they are still accurate.  I'm not sure how to tell other than trial and error.

Anyway, I sincerely appreciate the feedback you have all given me.  If anything else comes to mind please add another post!

Best Regards,

Ken

Affiliation
American Association of Variable Star Observers (AAVSO)
Photometry and Analysis Software

I can not advise on the features of Mira AL vs the current AP4WIN or  LesvePhotometry. One thing Mira AL didn't have which I used to need fairly often was an elliptical aperture tool. My old mount used to have some guiding problems I also use the histogram plotting tool frequently and the 3D plotting. 

I guess the best thing to do is to just make a comparison table of the features and if you are unsure if a a missing feature for any of them is important ask the list how much if ever they use it. One thing that is difficult to assess,however, is how accurate, precise and robust the particular algorithms are that the individual programs use. For example, how good are the partial pixel flux estimates and how well does it exclude light from stars that avoid in (a small portion of) the background annulus without introducing bias to the resulting measurement. When you have no other (better) way to estimate photometric measurement error than the program photometry error output, how good a job does it do? Does it include all of the terms of the CCD Error equation? Does the program error estimate include zero point error  (from the residuals of the least squares fit to the multiple comp star sequence values) if you are doing ensemble photometry? I have found that the zero point error is a larger error term than the CCD error equation term. 

IRAF, Mira, VPhot, and if if I remember correctly, AP4WIN have good, robust algorithms and AP4WIN has probably changed significantly from the version I used 10 years ago. I have used the photometry tool in Maxim DL versions 3 an 4 and found it limited but a lot of people seem to use it for differential photometry. I have not used the photometry tool in versions 5 or 6.  If you use Maxim for camera control you have its tools and they are well integrated into the package. You might try them and see it you like them as a starting point. Just be sure to use the photometry tool and not the info dialog tool. The manual cautions you that the info tool is not particularly accurate. It is intended to give fast, interactive but approximate data to help you set up your camera control parameters and see what is going on as the images download.  

I cannot comment about other packages, and it is often is difficult to find out exactly what algorithms a particular software package uses. I can never get comfortable using something that is a complete "black box." I want a program that is easy and fast to use, and that allows my computer to work on a bunch of images in an automated pipeline, but I also want the "parts and service manual" so that I can look under the hood and comprehend what is going on. IF you can wrap your arms around it, you cannot go wrong with IRAF or PYRAF and their associated packages and the price is certainly right. 

If you get into analyzing light curves as well as creating them, VStar is a wonderful free tool from AAVSO, Also, a  free and powerful set of tools that you may want to acquire is the R programming language. This is probably the foremost statistical programming language around. It is completely free, open source and Grant Foster published a great book, Analyzing Light Curves A Practical Guide, that applies R routines to light curve analysis. R also incorporates a really powerful plotting tool called ggplot2. Got a million observations of a Cepheid variable or a DAV that you want to analyze plot in a bunch of different ways? This is absolutely no problem for R. There are numerous free on-line courses to learn R on Coursera and edX. As mentioned in my previous post, Period 04 is an outstanding tool for Periodic Analysis of light curves.

Brad Walter, WBY

Affiliation
American Association of Variable Star Observers (AAVSO)
Photometry and Analysis Software

Brad,

Thank you very much for your very detailed reply. 

You raise a lot of good and important questions in your discussion about the precision and robustness of the algorithms.  Some/many of those questions are difficult for me to answer but they are very valid nontheless.  

I agree with you about IRAF and PYRAF. Long term they seem like the best solution and I don't really have an issue with the challenges associated with learning them.  My main concern is not learning everything by trial and error - it would be nice to have thorough tutorials or guides to help learn these programs.  Fortunately, I have been able to find some resources that look pretty good.

Thank you for the book suggestion.  Analyzing Light Curves A Practical Guide by Grant Foster sounds like a great recommendation.  I ordered it this afternoon.  I found a post here on the AAVSO Forum that had numerous recommendations for this book.

By the way, an astronomer that I follow on Twitter suggested that I take a look at SExtractor, AstroImageJ, and the Aperture Photometry Tool (APT).  I don't think she personally uses all of these programs (maybe just SExtractor) but she thought the others may be worth my review.  

Thanks again!!

Ken