Suggestions on how to pronounce my name:

1. Generally, in English-language/international contexts, I recommend pronouncing my name in some anglicized way "as it's written". You can find an example pronunciation here. I don't care too much about the details. For example, you can pronounce "Caspar" like "Casper" or pronounce the "par" like in "on par".
2. For German speakers: If you'd like to pronounce my name in the German way, that's also fine, though consider that for non-German-speaking listeners it might be harder to tell whom you're talking about.
3. For Dutch speakers: Note that the "Oe" in "Oesterheld" is an anglicization of the German umlaut "Ö". The pronounciation" of the German "Ö" is different from the pronounciation of "oe" in Dutch.