Imaging galaxy M83 with iPhone

[yong54321]

Hi, manage to capture the subtle spiral arm of m83 using iphone 6 and 114mm manual telescope. It is exciting to see a galaxy (above the blue square in the image). The second photo is shot with iPhone 6 and Dobsonian 8" manual telescope. The spiral arm comes to sight in about a minute for 8" scope. 

 

 

[yong54321]

Thought I should write a very brief description on how I capture spiral arm of a galaxy with an iPhone and a small telescope. It will benefit other beginners like me who want to see his first galaxy in his telescope. It is natural that beginner goes from looking at the moon to saturn to deep sky objects with only a small telescope.  

 

It comes to me that choosing the right bright galaxy is very important. I would advise to start with M51, ngc2903 in leo, M66 and M83 if you live in the south. M83 is face on, pinwheel and spiral galaxy so it should be easy to identify. 

 

To be familiar with the position of the  galaxy is very important. Galaxy is so dim that it is not visible to the eye in a small scope. At least for my case when I do not want to use a GOTO telescope. I do not want to wake up my children and neighbours as GOTO telescopes are noisy. This is the impression I get when I view YouTube videos of them. I use manual telescope Meade Mini 114mm. If you can use GOTO that will be the best. But again, I got the kick when I find the galaxy manually. I always start with a binocular 10x50 and skysafari. Once i find its location in the sky,  i slowly bring my binocular view downward to the horizon.  I note the point at the horizon. Eg a building.  Then i use my telescope to start at the point in the horizon and slow move upwards to the galaxy. It takes 30 minutes to find the galaxy in the beginning.  Have patient. With practice,  it takes me a minute to find m83 and always bring a smile to my face.

 

Using GOTO or manual telescope, you have to deal with field rotation. Often with a small 114mm telescope, the M83 spiral arm come to sight only after 5 min of long exposure. It takes only a min if you use a Dobsonian 8 inches.  Since I am not using any tracking or EQ mount, I have to depend entirely on software to track and de-rotate the images. So if you get any app that can do long exposure, track the stars and align and stack the images, you should be able to see the galaxy structure. I use SpiralCam app which i wrote myself.  

 

And for manual telescope, the galaxy will float across the eyepiece view. You will not have this problem if you use a GOTO telescope or EQ mount with motor drive. So for every 1 min, I have to shift the telescope so that the galaxy comes back to view. As such, the software also needs to identify the stars and match them when they reappears again.

 

One last thing, the timing needs to be right so that the galaxy is at the highest point in the sky. There are more sky glow near the horizon.  So I only try to image when M83 is above 40 degree over here. I read somewhere online that you have to deal with sky glow if you want to see a galaxy. So the software has to calculate and substract  the skyglow from the images. Note that i am trying to image in Singapore.  A light polluted city. 

 

And that is all that I could think of now. It is fun and most people say it is not possible with phone to see a galaxy.  Just to add that another option to see the galaxy fast and beautifully is to use specialise video camera but it needs tracking mount and a laptop in the field which I do not want. I want something easy and instant. 

 

Have lots of fun!