W.C. Chittick writes:
 
"Unveiling takes place when God illuminates the heart, enabling it to see into the unseen world. "Opening" (fath, futuuh), as discussed in the introduction, is for God to "open the door" to the unseen world through disclosing Himself to the heart, or to 'open up" the heart to direct knowledge of Him. The term also signifies the beginning of something, and hence it is often used to refer to that stage of spiritual ascent when a person enters into the realm of unveiling. The door is opened for him, and he no longer has to follow an authority outside himself. "

Chittick, W. C. 1989. The Sufi Path of Knowledge. p.223

Here is a description of unveiling from Ibn al-'Arabi's writings:
 
"If the seeker desires divine loci of witnessing and lordly sciences, he should multiply his nightly vigils and continually multiply within them his concentration (jam'iyya). If scattered lights should appear to him such that between each light darkness is interspersed, and if those lights have no subsistence but disappear quickly, this is one of first marks of acceptance and opening. Those noble lights will never cease becoming manifest to him through his acts of spiritual struggle (mujahada) and his striving until a greatest light is unveiled for him. Then the obstructions which prevented people from reaching these knowledges will be removed and mysteries of which he had nothing in himself and by which he was not described will be unveiled for him in their stations. (II 626.3)"

Chittick, W. C. 1989. The Sufi Path of Knowledge. p.223

What is the Difference Between Sight and Insight?
 
There are two basic worlds ..., the "unseen" and the "visible". The outward eye or "sight" (basar) perceives the visible world, while the inward eye or "insight" (basira) perceives the unseen world. Here is a description of the world of insight in Ibn al-'Arabi's writings:
 
"...The eye of insight is veiled by such things as rust (rayn), passion (shahwa), and gazing upon "others" (aghyar) within the dense world. These things come between it and the vision of the World of Dominion, that is, the World of Unseen. But when man applies himself to mirror of his heart and polishes it with invocation and the recitation of the Koran, he thereby gains some light. And God possesses a light called the "light of existence" which is deployed over all existent things. When these two lights come together, unseen things are unveiled as they are in themselves and as they occur in existence."

Chittick, W. C. 1989. The Sufi Path of Knowledge. p.223

What Happens During 60 minutes of Bandagi With Full Concentration?
 
Let us reflect on the following teaching of Imam Sultan Muhammad Shah (a.s.):
 
"Jêo das minute ek dhiyânthi ibâdat kari shakê chhê têoni chalis varasni ibâdat kartâ vadhâre ibâdatno faydo ha(n)shal thây chhê anê châlis varas karta vadhu kabul thâya chhê.Têthi tamê hamanâ ek kalak ibadat karo, te barâbar ek khayâlthi, to ghanu chhê. Tamo badhânâ dilmâ ekaj umêd hovi joee-ea. Tê kêvi ritê, jêm rasulillah mearaj par gayâ hatâ anê badan â duniyâmâ padyu(n) hatu. Têm tamâro ruh â duniyâmâthi âsman mathê pahonchê anê â badan duniyâmâ(n) hoy anê ruhnê tyâ pahonchâdo. Zikarno ek kalâk jê tamârâ upar faraz chhê tê barâbar khayâlthi karsho to tê kalâkma(n) das minute evi âvshê jè têni andar tamê fanâfi-Allah th-ee shaksho." (Karachi, 3-5-1920)
 
Literal translation: Those who can concentrate for ten minutes in bandagi will get the benefit of 40 years of bandagi (performed without concentration) and will get the acceptance of having performed more than of 40 years of bandagi. Therefore, at this time, it is enough to perform bandagi with full concentration for one hour. All of you should have only one wish in your heart: How to achieve mi'raj from the example of the Holy Prophet, in which his soul ascended the heavens and his body remained on this earth. Similarly, you should send your soul from this world to the heavens so that your body remains here but your soul goes to the other world. It is your duty to perform bandagi with full concentration for one hour. During this hour, there will be ten minutes in which you will annihilated in Allah, i.e. experience fana-fi-Allah."