Masjid Aschabul Kahfi merupakan sebuah gua yang kemudian dialihfungsikan menjadi masjid dan mulai digunakan pada tahun 2002. Pembangunan masjid tidak bisa dipisahkan dari penentuan arah kiblat, karena fungsi utama masjid merupakan tempat untuk sujud kepada Allah SWT, tempat shalat, dan melaksanakan ibadah-Nya. Masjid Aschabul Kahfi Perut Bumi Al Maghribi Tuban setelah ditarik garis lurus ke Ka’bah menggunakan google earth belum presisi jika dilihat dari sudut bangunan diatas gua dan merupakan masjid yang letaknya berada di bawah tanah. Serta penentuan arah kiblatnya melalui penunjukan langsung dari ilham hasil Istigasah yang dipimpin Waliyullah Abdurrahman Wahid dari Jombang bersama para kyai lain yang tidak menggunakan alat-alat canggih seperti yang sekarang sudah ada ataupun metode-metode penentuan arah kiblat secara ilmiah.
Rumusan masalah yang ingin dipecahkan dalam penelitian ini yaitu Bagaimana kalibrasi arah kiblat Masjid Aschabul Kahfi Perut Bumi Al Maghribi Tuban dan Bagaimana respon masyarakat/tokoh sekitar setelah dilakukan kalibrasi arah kiblat.
Jenis penelitian yang digunakan adalah jenis penelitian lapangan dengan pendekatan kualitatif. Data didapatkan melalui observasi, dokumentasi, dan wawancara. Setelah data terkumpul kemudian dipelajari dan dianalisis dengan teknik verifikasi melalui observasi pengecekan arah kiblat masjid Aschabul Kahfi menggunakan Istiwaaini dan Qiswa Portable dengan bantuan Line Laser Bosch GLL5-50 X serta analisis isi (Content Analisis) deskriptif dari wawancara dan dokumen.
Penelitian ini mendapat dua kesimpulan yakni: pertama, arah kiblat masjid Aschabul Kahfi Perut Bumi Al Maghribi kurang akurat. Data yang dihasilkan terdapat kemelencengan 15° 13' 34,01'' ke arah utara dari arah kiblat seharusnya. Kedua, respon masyarakat setelah kalibrasi arah kiblat masjid Aschabul Kahfi yaitu mayoritas mempercayai dan meyakini bahwa arah kiblat masjid yang memiliki histori, yang diyakini adalah orang-orang pilihan Allah seperti abah Subhan dan Gusdur (Abdurrahman Wahid) mereka meyakini apa yang sudah ditetapkan adalah sudah benar daripada arah kiblat yang ditentukan penulis menggunakan metode ilmiah. Terlebih kondisi sosio mitologis kepada penentu arah kiblat pada masjid Aschabul Kahfi sangat dipercaya dan diagungkan. Namun demikian kemelencengan 15° 13' 34,01'' masih dalam batas toleransi kalangan ulama madzhab. Dimana Ulama Syafi’iyyah memberi limit 20°, Ulama Hanafiyyah 35°, Ulama Hanabilah 45°, dan Jumhur Ulama 45°. Jadi kemelencengan arah kiblat masjid Aschabul Kahfi saat ini masih dalam batas toleransi kemelencengan yang diperbolehkan.

ABSTRACT:
Aschabul Kahfi Mosque is a cave which was then converted into a mosque and began to be used in 2002. The construction of the mosque cannot be separated from the determination of the Qibla direction, because the main function of the mosque is a place to prostrate to Allah SWT, a place of prayer, and carry out His worship. Aschabul Kahfi Perut Bumi Al Maghribi Tuban Mosque after being pulled a straight line to the Kaaba using Google Earth is not precise when viewed from the point of view of the building above the cave and is a mosque located underground. As well as determining the direction of the Qibla through the inspiration direct appointment of the results led of the Waliyullah Abdurrahman Wahid Istigasah from Jombang along with other Kyai who do not use sophisticated tools such as those now exist or methods of determining the direction of the Qibla scientifically.
The formulation of the problem to be solved in this study is how the calibration of the Qibla of the Aschabul Kahfi Perut Bumi Al Maghribi Tuban Mosque and how the response of the community/figures around after the calibration of the Qibla direction.
The type of research used is a type of field research with a qualitative approach. Data obtained through observation, documentation, and interviews. After the data is collected, then studied and analyzed by verification techniques through observation checking the direction of the Qibla of the Aschabul Kahfi mosque using Istiwaini and Qiswa Portable with the help of the Line Laser Bosch GLL5-50 X and the content analysis of the descriptive content of interviews and documents.
This study received two conclusions namely: First, the direction of the Qibla of the Aschabul Kahfi Perut Bumi Al Maghribi Mosque was less accurate. The resulting data is that there is a demander of 15 ° 13 '34.01'' to the north from the Qibla direction. Second, the response of the community after the calibration of the Qibla of the Aschabul Kahfi Mosque, namely the majority believes and believes that the direction of the Qibla of the mosque that has history, which is believed to be God's chosen people like Abah Subhan and Gusdur (Abdurrahman Wahid) they believe what has been set is correct rather than the Qibla direction determined by the author using the scientific method. Moreover, the mitological socio condition to the Qibla direction determinant at the Aschabul Kahfi Mosque is very trusted and stated. However, the number of 15 ° 13 '34.01'' is still within the tolerance limit of the scholars of the school. Where Shafi'iyyah scholars give a limit of 20°, Hanafiyyah scholars 35°, hanabilah scholars 45°, and jumhur ulama 45°. So the diligence in the direction of the Qibla of the Aschabul Kahfi Mosque is currently still within the limits of the permissible tolerance.