Cameras

Astro Raspberry Pi

After experimenting with afocal photography on my Dobsonian with an iPhone and my point and shoot camera, I built a Raspberry Pi based camera to use with the Questar. Similar to webcam-like planetary cameras, but not laptop required. The Raspberry Pi computer controlled the camera, captured images, and used a wireless web interface to an iPhone for control and focusing. Unfortunately the several second lag for image display and the lack of focusing aids made focusing difficult. You can learn how to build the Astro Raspberry Pi camera.

Here's are sample images taken with the Questar and the Astro Raspberry Pi camera:

Jupiter imaged with a Raspberry Pi Camera
My first good image of Jupiter with the Great Red Spot using the Raspberry Pi camera that I built. Io and Europa are to the right. Raspberry Pi camera at prime focus through a Questar 3.5". 240 of 500 images stacked using Lynkeos and sharpening via deconvolution, wavelet, unsharp masking with a little noise reduction and color balance.

Raspberry Pi Moon
This was one of my very first full disk Moon shots. Made on the Questar with the Raspberry Pi camera that I built myself. The 72 images that I stitched together here, helped convince me that I wanted a camera with a larger sensor and field of view. Full Moon + 1 day mosaic with 72 images stitched with Hugin via the Raspberry Pi and Questar 3.5. The Alpine Valley is visible in the high resolution versions.

Sony NEX-5N

I decided that I wanted a much larger sensor camera with focusing aids. An inexpensive used Sony NEX-5N body fit the bill perfectly and was used for many of the images on this site.

This image was taken with the NEX-5N and a vintage 135mm lens:

Ghost town Omega Centauri Revisited
I reworked this image from last spring including an addition half hour of exposures. A more gentle exposure stretch preserves dynamics and brings out colors. Terlingua Texas ghost town is the perfect spot to image Omega Centauri, a globular cluster believed to be the remains of another galaxy consumed by the Milky Way long ago. I found a spot down in the gully behind our cabin for this POV. Sony NEX-5N with vintage Vivitar 135mm lens on a Vixen Polarie tracking mount. Exposed March 14, 2016 at ISO 3200 for 30 sec at f 5.6 with 118 images stacked. Foreground image illuminated by open cabin door exposed for 15 sec at ISO 3200. Stacking in Nebulosity. HDR composite in Photoshop.

These samples were taken with the NEX-5N and the Questar:

Thin crescent Moon
Spicewood Golf Course, Austin, Texas, 2015-09-14 8:25 PM CDT. Last night’s low humidity was a great chance to capture a sharp image of a day and a half old crescent Moon - only 2.7% illuminated. I took frames of the Moon sinking behind the tree and then after it was out of sight I got better focused and exposed shots of the tree. I liked this image with my best Moon frame, but the overnight 8 parameter affine stacking gives the sharpest crescent Moon image that I’ve been able to take. Questar 3.5 with Sony NEX-5N at prime focus. Moon exposure 0.5 sec and trees 1.3 sec at ISO 800. 33 Moon frames stacked with 8 parameter affine transforms in Nebulosity, deconvolved in Lynkeos, stacked with in focus tree image and final tweaks in Photoshop.

Clavius Tycho Moretus region of the Moon
Stack of 6 images ISO 400 0.4 sec on 140805 03:40GMT from Austin Texas, Questar 3.5”, Dakin 2X Barlow, Sony NEX-5N. Stacked in Nebulosity, Deconvolution in Lynkeos, NR in Nebulosity, final exposure and sharpening in Photoshop.

Comet Lovejoy
It takes a village. When I started taking images of Lovejoy, I had no clue how to take nice images of a comet. I tried a couple of things and then saw some very nice results from local astronomers Anis Abdul and Laurie Allai that showed me that statistical stacking with separate layers for the star background and comet give excellent results. This is a reprocessing of my earlier images that reduces the residual blurred light from the tail in the stellar background layer and some 16 to 8 bit jpeg conversion issues giving me my sharpest image of the tail! . Comet Lovejoy 2014 Q2 from Eagle Eye Observatory Jan 18, 2015 9:00 CST with a Questar 3.5 and Sony NEX-5N at prime focus. 24 exposures of 30 sec at ISO 24600 and 7 darks stacked and process in Nebulosity and Photoshop.

Sony a6300

The a6300 is a mirrorless camera, released in 2016. It has an 24MP APS-C CMOS sensor which is very well matched in size and resolution to the capabilities of my Questar 3.5" telescope. After taking lots of images with the NEX-5N I had a good idea of the features that I wanted in my next camera. These features of the a6300 are very important to me:

  • mirrorless to minimize size, weight, and vibration
  • electronic first curtain shutter to minimize shutter vibration
  • wireless IR remote control
  • a sensor with low noise and high quantum efficiency to minimize exposure time
  • magnified focus highlighting for easy focusing
  • fully electronic silent rolling shutter suitable for long time lapse videos at maximum camera resolution
  • 1.2:1 near full resolution cropped 4k video mode suitable for stacking wide field of view images of planets and moons
  • powered operation while shooting from an external USB power pack for all night shooting
  • wireless live view mode for viewing at public outreach

This image was taken with the a6300 and the Questar:

January Earthshine Crescent Moon
Crescent Moon from Austin on 2017-01-31 01:02 UT. Questar 3.5" telescope (1350mm f14) and Sony a6300 camera at prime focus. A day-lapse HDR image. Crescent exposed 1/25 sec at ISO 400. Best 8 of 105 images stacked in Nebulosity. Earthshine exposed on 2017-01-30 00:55 UT for 5 sec at ISO 400, best 16 of 30 images stacked in Lynkeos. Deconvolution in Lynkeos with HDR composition in Photoshop.

This image was taken with the a6300 and a Rokinon 12mm lens:

Perseid Meteor shower with the Andromeda Galaxy
The Perseids with Andromeda and the double cluster in Perseus. Shot over 7 hours the night of August 11-12, 2016 from west of Burnet, Texas. First to last meteor frame 3hrs 17 minutes. Sony a6300, with Rokinon f2 12mm lens, and Vixen Polarie tracking mount. Most images shot at f2.8 for 30 sec. at ISO 3200. 42 of 440 used, images aligned and some stacked in Nebulosity. Final composite and exposure adjustments in Photoshop.

This image was taken with the a6300 and a 135mm vintage lens:

The Pleiades on a whim
The Pleiades no telescope required, with a Sony a6300 camera, Vivitar 135mm f2 telephoto lens, and Vixen Polarie tracking mount. 11 minutes of 30 sec exposures at ISO 2500 at f4. Stacking in Nebulosity and stretching in Photoshop.

ZWO ASI120MC

The ASI120MC is an astronomical one shot color video camera intended primarily for planetary imaging. Compared to my large sensor cameras it trades field of view for video rate acquisition of raw images. It's intended for acquiring thousands of high quality raw images for lucky image stacking in just a couple of minutes. It's my newest camera and I'm still learning to use it.

This is my first image of Jupiter and a shadow transit of Io taken with it. You can read more details in my blog entry about the image.

Sweet Home Alabama Jupiter with Io transit & Europa
Jupiter with Io and its shadow transiting (2 o'clock) and Europa to the left. Taken 2017-04-26 05:20 UT from Madison, Alabama. Questar 1350/89 mm telescope with Dakin 2X Barlow lens, f30. Camera ZWO ASI120MC with 63msec exposure and gain of 40. Data captured with oaCaptue. Best 128 of 2000 images stacked in Autostakkert!2. Deconvolution in Lynkeos. Final tweaks and crop in Photoshop.

Jupiter at opposition 2017 - Revisited
Jupiter with moons Io, Europa, and Ganymede (L to R) from Austin, Texas 2017-04-07 10:25 PM CDT. Questar 1350/89 mm telescope with a Dakin 2X Barlow lens and ZWO ASI120MC planetary video camera. Gain 46, exposed 77 msec captured in oaCapture running on macOS. Best 52 of 2000 exposures stacked at 1.5x in the amazing Autostakkert 2 and deconvolved in Lynkeos. RGB aligned to reduce atmospheric diffraction. Final crop and exposure tweaks in Photoshop.

Content created: 2015-05-18 and last modified: 2017-06-04

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