Setting up an SD Card for Use with DWARF II

This guide, writen by Bob Nestor, explains how to prepare and verify the compatibility of your SD card for use with the DWARF II telescope. Follow the steps below to ensure smooth operation.

1. Check SD Card Compatibility

Key Requirements for DWARF II SD Cards

• Capacity: 64GB
• Interface Type: UHS-I
• Transfer Speed: 100MB/s
• File Format: exFAT

Before using your SD card, confirm that it meets these specifications. DWARF II will recognize only compatible cards.

2. Verifying SD Card Recognition

How to Test Your SD Card

1. Insert the SD card into the DWARF II device.
2. Take a photo using the DWARF II app (Android or iPhone).
   • If the message “Micro SD card not found” appears, the card is either missing, improperly inserted, or in an unsupported format.
3. Test the Astro Dark function:
   • If the function doesn’t activate and reverts to Astro, the SD card is invalid.

3. Understanding SD Card Formatting

Why Formatting Matters

Many SD cards come pre-formatted with a universal ExFAT partition, which is supported by DWARF II and most operating systems (Windows, Mac OS X, Linux, BSD). However, if your card is unformatted, formatted differently, or was previously used for another purpose, you’ll need to reformat it.

4. Recommended Format and Partitioning

Best Practices for DWARF II

• Disk Format: ExFAT 
• Partitioning Scheme: MBR (Master Boot Record)

Note: GPT partitioning works but may be limited to NTFS file formats.

Why ExFAT?

ExFAT is the most modern and universally supported format for SD cards. It offers better compatibility and performance compared to older formats like FAT-32 or NTFS.

5. How to Format Your SD Card

Windows

1. Open the built-in disk formatting tool.
2. Select ExFAT as the file system.
3. Choose MBR as the partitioning scheme.
4. Format the card.

Mac OS X

1. Open Disk Utility.
2. Select the SD card and click Erase.
3. Choose ExFAT as the format and Master Boot Record (MBR) as the scheme.
4. Confirm to format.

Linux/BSD

Use command-line tools:

1. Open a terminal.
2. Use fdisk for partitioning and newfs for formatting.
   • ExFAT type: 12
   • NTFS type: 7

6. Additional Notes for DWARF II Users

• BadPixelMap:
  DWARF II generates a BadPixelMap based on dark field captures. This map is stored internally and is not affected by SD card formatting or data deletion. The SD card is used only for saving user data (e.g., photos or videos).

• Reformatting Reminder:
  If your SD card was formatted for another device or operating system, reformat it to the DWARF II-compatible configuration (ExFAT with MBR).

FAQs

Q: What happens if I use an incompatible SD card?

You won’t be able to save photos or use features like Astro Dark. The card must meet DWARF II’s specifications.

Q: Can I use NTFS instead of exFAT?

No, use exFAT.