RawCam App Manual

Updated 26 Feb 2024

Thank you for using RawCam(MilkyCam Raw) iOS app. It is a way to see galaxies and nebulae in small and medium telescope. RawCam is designed for both manual and Goto telescope while the original MilkyCam and SpiralCam are designed for manual telescope. 

Some Quick Settings:

For manual telescope, RawCam shots are limited to the time when the sky object drift across the eye piece. To use with a manual telescope, choose 1/2 second or lower for EXP(exposure) and choose 1 frame for SUB(number of exposure in a stack). 

For Goto telescope with tracking, the RawCam shots duration can be 10 minutes or more. Choose 1 second for EXP and 10-30 frames for SUB.  

For stacking the Milky Way on a camera tripod with an iPhone, use 1 second for EXP and 30 frames for SUB.

Eg. If you choose 10 frames for SUBS, RawCam will add the frames up until it has 10 frames. Then it starts to align the added frames with previous 10 frames. RawCam uses addition instead of average in stacking. 

RawCam is faster in image processing because it uses the iPhone Graphic Processing Unit hardware. It does not matter if you have a EQ or AZ Goto telescope, RawCam will correct the rotation effect of the sky. Do not hesitate to contact to me at ustransit74@gmail.com if you need further assistance. 

The phone can be attached to the telescope eyepiece with a phone telescope adapter shown above. After you attached your phone to the telescope, adjust your telescope focuser so that the stars are sharp. You can also use the app Focus slider which gives finer focus. 

Combining RawCam with another FinderCam iOS app, it is easier for a beginner to find and photo sky objects. Target that used to take me hours to find, I can find it in a few seconds now. Objects that are invisible become visible with RawCam stacking. Watch how I use FinderCam and RawCam to photo the green comet ZTF at https://youtu.be/-hLPu8ssKoA with Celestron Firstscope telescope. 

After you have photo an object, use AstroEdit iOS app to bring out its beauty. It has background filter to remove sky glow and wavelet filter to bring its details. Download AstroEdit at https://apps.apple.com/sg/app/astroedit-simple-and-quick/id6478158736

Direction:

1. Point the telescope at dark sky. It works in day time too. 

2. Use Stack mode to auto rotate and stack camera images. Use Photo to take a shot in Raw format. Use Video mode to take a short video and stack it later with VideoStack iOS app. 

3. You can also shoot the Milky Way with a static camera tripod and phone.  

Algorithm:

In Long Exposure mode, RawCam works by aligning and adding up every exposure and save as a 16 bitt Tiff file. Using stacking by summing instead of stacking by average, there is more details to be revealed in desktop GIMP curve function or SnapSeed iOS app. 

Best Practise:

- The app automatically saves when you press the stop button. You can save again after you adjust the brightness MTF slider for the stacked image. TIFF format has huge amount of image information that you can further reveal on phone or desktop editing.

- The Focus slider adjusts the focus of the phone camera. However, it is easier to adjust the telescope focuser to get a sharp image. Use the + and - button to fine tune the focus. 

- For auto focus (AF) button, ensure you can see stars bright enough on your screen. Adjust the ISO and EXP. Try to have just enough EXP to see the stars so that the AF can run as fast as possible. 

- After you tap the Start button, the slider changes to Brightness slider. You can see more details by playing with the Brightness(MTF) slider. 

- To activate the autofocus, tap on the center of the screen. The app will loop through the camera lens position to get the sharpest image of day and night. 

- If you are using a non tracking telescope, choose exposure less than 1 seconds to avoid star trail. If you are using a tracking telescope, you can choose 1 seconds exposure to give maximum light and experiment with the ISO value. 

- In Long Exposure mode, use the MTF slider to adjust the curve of the stacked image. It could bring out the details of the faint galaxy. Search online more about MidTone Transfer Function (MTF). The + and - buttons adjust the MTF by 0.01 value.

- In Long Exposure mode, the app save a Tiff file after you tap the stop button and a jpg file after you tap the save button. The Tiff file can be used in desktop GIMP for further processing. 

- In Long Exposure mode, I will recommend to set EXP (exposure) to 1 second if you are shooting Milky Way or if you are using a tracking mount. Generally, if the target takes longer than 1 second to move in your camera view, then set the EXP to 1 second. 

Video:

https://youtu.be/yMwrJgzJiAo

https://youtu.be/GY5q7bp8r88

Tip:

1. Use cable/Bluetooth earpiece volume up/down button to start or stop the app. It avoids the camera shake. 

2. To find your target quickly with your telescope, use FinderCam with Plate Solving app at https://apps.apple.com/us/app/findercam-with-plate-solving/id1541018483

3. To bring out the detail and structure of the planet, use waveletCam app at https://apps.apple.com/us/app/waveletcam-image-processing/id1642594450