Navigate to <https://afterglow.skynet.unc.edu/en/workbench?tool=marker>\
Your REF and RRL star should already be marked.

Click on the Star icon ("Show Source Catalog").\
Your markers will disappear. That's okay.

Sky Coordinate Mode
Pixel Coordinate Mode

Manually add sources by clicking on them in your image or automatically add them using the options below.

Tip: To click beneath existing markers holdAlt

Centroid clicks
Planet Centroiding
addAdd Sources...
Include sources from other files
Source Markers
Marker Labels
ID
Layer
X | RA
Y | DEC
merge_type
delete
delete_sweep
get_app

Centroid clicks
Planet Centroiding
addAdd Sources...

Choose "Include sources from other files."

This is what your settings should look like.

Afterglow will assign it an ID. In this case the ID is 0. Write that down in your assignment.

Afterglow will assign it an ID. In this case the ID is 1. Write that down in your assignment.

Click on the lightbulb icon "Show Photometry"

Choose "Source Markers", "Marker Labels", and "Auto Photometry."

Source Markers
Show Apertures
Marker Labels
Auto Photometry

Click the checkbox to select both sources.

Click the "select all" box next to the images drop down to quickly select all the images. (Make sure you only select images of the globular cluster.)

See how all the globular cluster images are selected.

When the file is ready, click "Download Batch Photometry Data - 2 source(s) in 44 file(s)". This will download the .csv to your computer. Save it somewhere useful. You will not need to open it, but you will need it for the next part of the assignment.

Download Batch Photometry Data - 2 source(s) in 44 file(s)

Afterglow: Batch Photometry (Measure the Brightness)