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Can anyone give me any general direction on what commands I should use once I'm in apphot to determine the magnitude of a star? Or what information I need other than the image files? If this is too vague, I'm sorry - I'm a student who began using IRAF two weeks ago and just finished correcting the images I needed and there aren't any IRAF experts around. I've tried different things from different on-line guides and just have a steady stream of errors. Any suggestion of any kind would help.What I have: Corrected .imh files
What I need: To determine the magnitudes of some stars in the corrected imagesThank you.

Probably the best and also an easiest way is to follow two manuals:https://iraf.net/irafdocs/photom/and specially: https://iraf.net/irafdocs/daophot2.pdfSection "Getting started" is worth of reading multiple times, many important details are described there. In section 3 you find a step by step guide how to measure your stars using task phot from apphot (or preferrably? daophot) package. Don't worry that the title of the chapter is "Standard Star Photometry and Reductions" - it cowers actually all you are asking about.You have to set up some parameters to get meaningful results, important ones are in datapars, fitskypars, photpars, and centerpars. Good starting values are also presented in document. Measuring aperture(s) are described in photpars, you can set up several apertures (separated by commas), sky aperture can be changed in fitskypars... Don't forget to set correct gain and read-out noise values or corresponding FITS keywords!When you have set up all needed parameters, follow subsubsection 3.4.2, "Photometry by Eye". As far you want to measure just some stars and you don't have hundreds of images, you could stop at subsection 3.6.I have used daophot/phot to estimate the quality and S/N of my images during observations. When all parameters are set up correctly, I have to display my image(s) using DS9 and tell: phot <image>
Choosing right star from recently exposured image takes actually more time than executing IRAF and already set up phot task :-)Tõnis

Thank you for the guidance!

Jen, I am working with someone long-distance on IRAF apphot. Are you doing OK now, or would you like to join in our chatting? Andywcorvi@yahoo.com