Most linguists recognize two tenses in English, present and past, although other verb forms are often mistakenly described as tenses. I walk is present tense and I walked is past tense. A form such as I am walking would be described not as the present progressive tense, but as a construction expressing progressive aspect, and made up of the present tense of be and the –ing form of walk. In other words, to qualify as a tense, an English verb form has to show inflectional variation.
Books for foreign learners of German, in my experience, describe as tenses all finite verb forms, even though only the present and imperfect show inflectional variation.
Here’s my question: Do German professional linguists also describe all verb forms as tenses, or do they recognize that Ich bin gegangen, for example, is best understood in terms of aspect?