Tuesday, March 10, 2015

iPhone Astrophotography - Why the iPhone needs a users manual

So, (and forgive me for starting my sentence with "so") imaging Jupiter last night was a bust.

I did manage to get the electronic controls working on my telescope, which was a good thing.  Although wobbly in the mount, there is an electronic altitude-azimuth remote control with several different speeds at the push of a button.  I managed to tighten the mount the other day and get the controls working for the most part.

When I went to image Jupiter, I got a nice view of the moons, but a very over-exposed disc of Jupiter itself. Here's a single image taken with the iPhone:

I've been encouraged to use a stacking program to combine images for a better view of the disc, so I captured some iPhone video.

I downloaded RegiStax (a very quick and easy download), and went to upload the iPhone video, but RegiStax only accepts .avi, .mpg and .mp4. The iPhone records in .mov.

I went to zamzar.com to convert the videos to .avi and then uploaded to RegiStax.  Without looking at a users manual, I stepped through the program, but just wound up with an overexposed single image of Jupiter and the moons:

 It's been very frustrating.  I've been trying to find a way to trick the iPhone to have less exposure. I've tried pointing it at the moon and locking the focus/brightness, then swinging over to Jupiter, but last night the moon was not to rise till much later.

Gee.  If only there was a way.

Then, I thought that there may be a way to control the brightness. I played around this afternoon and stumbled on the following:

If you lock the exposure/focus, you will notice a sun icon to the right. Simply sliding your finger vertically on the screen will incrementally brighten and dim the exposure!

Now why didn't anybody tell me that?!

So next time I have clear skies (which doesn't look like it'll be for a few days), I'll try "dialing down" the brightness on Jupiter before taking video and then stack that. Wish me luck!

(Oh, and if anyone can tell me if it's possible to record in .avi instead of .mov, that'll help a lot!)

Clear skies!

Sunday, March 8, 2015

iPhone Astrophotography - Background

I've begun dabbling in astrophotography using the iPhone.

Inspired by the work of Andrew Symes (@FailedProtostar on Twitter), who has achieved awesome results and whose work has been featured recently in The Atlantic, I have taken my old telescope out of storage and have started to play around.


My equipment consists of the following:

  • An iPhone 5. The only camera I own.
  • A Meade Telescopes DS-127, which I bought nearly 15 years ago and which has spent most of its life in storage. The telescope mount is wobbly and difficult to aim consistently, so I need lots of patience. There is no automatic tracking, so I have to point manually and hope for the best.

  • A Celestron FirstScope ($50) that I bought for my dautghters (but really for me). It is easily portable for travelling and use in Camping. Fits in a small shoulder bag.

  • A Vista Explorer Tripod ($35). I bought this and a "Charger City" smartphone adapter to allow for long exposures on the iPhone. This works well when shooting ISS passes or Iridium Flares. This is also how I'd take some steady pictures through the telescope eyepiece, but I'd have to adjust the tripod each time I adjusted the telescope.  Not an optimal solution.  Note: I also use a portable battery pack since the battery on my iPhone quickly discharges in cold weather. The battery pack minimizes that.

  •  Orion SteadyPix Pro. This adapter holds the iPhone (in the case) and aligns the camera with the telescope eyepiece. Unfortunately, it needs a long eyepiece to grab on to, so it only work with my lowest magnification lens.  Great for taking pictures of the moon, but not enough magnification for imaging Jupiter.
  • Celestron Astromaster Accessory Kit. ($46) This provided a moon filter and a Barlow Lens, among other things. The Barlow lens provides enough hardware for the SteadyPix to latch onto, so I should, theoretically, be able to get higher-magnification images of Jupiter.

Results so far:

I've had mixed results ... but I'm working on it!

To capture passes of the International Space Station and Iridium Flares, I use the Sputnik! app on the iPhone to tell me when and where to look.  Then I put the iPhone on the tripod and use the NightCapPro app with the night, light boost and light trails settings to get a long exposure.
Iridium Flare and Orion 2/15/15
International Space Station and Cassiopea over Williamsburg 2/22/15

Initially, I was capturing the moon by holding the iPhone up to the eyepiece of both telescopes. I've since begun using the SteadyPix to attach the iPhone and align the camera for more consistent results.

Taken 1/30/15 Handheld through Celestron FirstScope

Taken 1/24 Handheld through Celestron FirstScope
4:30 a.m. 2/11/15 using SteadyPix Pro and Meade DS-127
Capturing Jupiter is my next challenge.  I've found that taking video and capturing single images has given me my best results so far.  Interestingly, the bands of Jupiter's clouds are most pronounced right at the moment that the disc is about to pass out of the field of view of the telescope. When it is centered, it is generally over-exposed.  I'm working on getting the right exposure and magnification, using filters and different eyepieces.
Single frame from iPhone video 2/2/15. Jupiter just about to pass out of field of view

3/2/15 zoomed and cropped screengrab from video
So that's where I'm starting. I'll continue future posts in this blog with the results of continued viewing sessions.  If you want to get a first look at my latest sightings, follow me on Twitter at @BeckePhysics.

Clear skies!