How does the uggaha nimitta look like in kasina meditation?
I know that there are three types of nimitta in kasina: parikamma-nimitta (preparatory sign), uggaha-nimitta (acquired sign), and paṭibhāga-nimitta (counterpart sign).
Parikamma nimitta is the real object that one focuses on. Uggaha nimitta is supposed to be like a mental image.
Does seeing uggaha nimitta means you can easily visualize the kasina object? I’m just wondering if I’m beginning to see the uggaha nimitta or not. I practice the fire kasina and after focusing on the kasina, the mental image sticks but I don’t know how vivid it needs to be. For a mental image to be an uggaha nimitta, does it need to be so vivid that it’s blocking our field of vision?
If one can easily visualize the kasina object, can they just focus on the mental image now?
Could someone help me?