Please click the link for any video that interests you to read more about it. Then follow the instructions on the Gumroad website if you wish to purchase it. Once you have purchased a video, the link you will use for streaming it will be sent to you by email immediately.
If you experience any problems or you prefer to pay for your video(s) by credit card over the phone, please do not hesitate to contact AAVSO Headquarters by phone - 617-354-0484 (ask for Owen) or by email: email@example.com.
The AAVSO Guide to CCD Photometry, first published in September 2014, is designed to be a basic introduction and guide to using CCDs to perform photometry of variable stars. With care, you can use a backyard telescope to obtain astrophysically useful data that matches the quality of those produced by professional astronomers, using exactly the same principles and techniques that are used at larger research observatories around the world.