Astrophotography

Image Credits: Joe Haberthier, Dave Morgan, Steve Childers, and Bruce Gavett

Astrophotography is a fascinating area. The night sky is full of great objects to image and bring to life. The downside is that it isn’t one of the easier things to do. It is dark out at night and most objects are very far away. In addition, the Earth rotates, making it difficult to track objects and capture long exposures.

However, fear not! We have some information for you, although this page is very much a work in progress. Go here for more information on the Deep Sky objects visible in the night sky.

On This Page

Astrophotography with your smartphone

One of the long-time members of FAS gave a presentation on how to capture images with your smartphone. Here are several resources from his presentation along with a few more.

Image Credits: Sean Wood.

“Smart” Telescopes for Astrophotography

Astrophotography used to be the domain of the more experienced amateur astronomer. However, there are now several options even a beginner can use.

The ZWO Seestar S50 is becoming popular with several club members. It is around 5 1/2 lb., priced at $500 with a 2 MP (? um pixel size) camera, 50 mm aperture, and 250 mm focal length. ZWO has announced the Seestar S30, a smaller version of the S50. For more information, see the ZWO website.

Seestar S50 Image Credits: Bruce Gavett.

There are several choices out in the marketplace.

TelescopeWeightPriceAperture mmFocal Length mmCamera (MP)Note
Dwarf III3 lb.$50035 (1.4”)1508.3Telephoto & wide angle lenses
Seestar S303.5 lb.$35030 (1.2”)1502.1Telephoto & wide angle lenses
Seestar S505.5 lb.$50050 (2”)2502.1Portrait mode – now with a Mosaic option
Vespera II & Pro11 lb.$1,700 & $3,00050 (2”)2508.3 & 12.5
Unistellar Odyssey Base & Pro8.8 lb.$2,300 & $4,00085 (3.3″)3203.4 & 4.1Auto focusing. Pro has eyepiece
Unistellar eQuinox 2 & eVscope 215.5 lb.$2,500 & $4,900114 (4.5”)4506.2 & 7.7Manual focusing & collimation. eVscope has eyepiece.
Celestron Origin~ 40 lb.$4,000152 (6”)3356.4
Information is as of August 2024 and is accurate as possible. See Supplier’s website for up to date specifications.
  • Seestar S50 (ZWO). See above for more information.
  • Seestar S30 (ZWO). Just introduced (November 2024). At around 3.5 lb., this is a new alternative to the ZWO Seestar S50 and the Dwarf 3.
  • Dwarf III (Dwarf Labs). At just under 3 lb., this is a low priced ($500) alternative to the ZWO Seestar with a 35 mm aperture, 150 mm focal length, and 8.3 MP (2 um pixel size) camera.
  • Vespera (Vaonis). It is around 11 lb. and has a 50 mm aperture and 250 mm focal length.
    • Vespera II. It has a 8.3 MP camera (2.9 um pixel size) and is priced around $1,700.
    • Vespera Pro. It has a 12.5 MP (2 um pixel size) camera and is priced at $3,000.
  • Odyssey (Unistellar). It is 8.8 lb. with a 5 hour battery life, an 85 mm (3 1/3”) aperture, 320 mm focal length, and 3.4 & 4.1 MP (1.45 um pixel size) camera. It has an autofocus and does not require collimation.
    • Odyssey Base model comes without an eyepiece and is priced at $2,300.
    • Odyssey Pro model comes with an eyepiece and is priced at $4,000.
  • Expert Range (Unistellar). It is 15.5 lb. with a 114 mm (4 1/2”) aperture, 450 mm focal length, 2.9 um pixel size camera. It has a manual focus and does require collimation.
    • eQuinox 2 comes without an eyepiece, 6.2 MP camera, 11 hour battery life, and is priced at $2,500.
    • eVscope 2 comes with an eyepiece, 7.7 MP camera, 9 hour battery life, and is priced at $4,900.
  • Origin Intelligent Home Observatory This is Celestron’s high end 6” smart telescope. The total system weighs over 41 lb. It has a 152 mm aperture, 335 mm focal length, 6.4 MP (2.4 um pixel size) camera, and is priced around $4,000.

Please note that FAS does not recommend or endorse any specific telescope, we only provide information that is generally available.

“Traditional” Astrophotography

In general, astrophotography is all about photographing the night sky. There are generally three different levels to this. You can photograph the night sky itself (landscape astrophotography), the Moon and individual planets (planetary astrophotography), or go after deep sky objects such as nebulae and galaxies (deep sky astrophotography). Most choose the latter.

One approach is to use a DSLR camera along with a star tracker or an equatorial tracking mount.

A more complicated, but possibly more rewarding, approach is to utilize a telescope. At the most basic you will need: An imaging telescope & camera, an auto-guiding telescope & camera, and a telescope mount.

You can add a computerized controller such as ZWO’s ASiair, which makes the entire process much easier and something you can control from your smart phone or tablet.

Please note that FAS does not specifically recommend or endorse any specific telescope or setup, we only provide information that is generally available.

Additional Resources (Introduction to Astrophotography using a DSL camera)

Additional Resources (Introduction to more General Astrophotography)

Additional Resources (Astrophotography Guides)

Additional Resources (Astrophotography Equipment)

Additional Resources (Deep-Sky Objects)

ASiair from ZWO

One option for astrophotography that is getting a lot of attention from FAS members is the ASiair from ZWO. This setup was recently added to the club’s observatory near Pilot Mountain. A few images from the observatory setup are below.

Image Credits: Joe Haberthier and other FAS members.

Please note that FAS does not specifically recommend or endorse any specific equipment or setup, we only provide information that is generally available.

Filters for Astrophotography

Filters can be used to enhance your images.

Dual Band Filters

One of the most popular filter, and one that is included in ZWO’s Seestar, is the dual-band filter for viewing emission nebulae. These filters block out all but the Hα (656nm) and OIII (500nm) wavelengths and greatly reduce the effects of light pollution.

UV/IR Cut Filters

Another that can enhance galaxies and star clusters are UV/IR cut filters (aka Luminance Filters), which block UV and IR light and allow only visible light through.

Please note that FAS does not specifically recommend or endorse these or any other filters, we only provide information that is generally available.

Image Processing

Capturing images is only part of the process for astrophotography. To produce really great images, they must be processed, stacked, and combined.

In this section

Stacking

Stacking allows you to take advantage of multiple images and combine them into one. Systems such as the ASiair and Seestar will stack as you go. Although, you probably want to save individual frames (fit files) for later stacking. This offers the advantage of rejecting frames that have distortions, star trails, or other deformities.

Calibration Frames

Enhancing your images often requires the use of calibration frames. Flats, biases, and dark frames are often taken each time you use your setup. They are “combined” with your images (light frames) during your shooting and then again during your stacking.

  • Flat Frames: Taken against a white background. These smooth out differences in light intensity due to dust and other impurities.
  • Bias Frames: Taken against a dark target. These are used to eliminate camera noise from your images.
  • Dark Frames: Taken against a dark target at the same temperature as your imaging. These are used to eliminate thermal noise (temperature differences) from your images.
  • Light Frames: These are your images (fit files).
Stretching Images

Most image processing software produces “final” jpeg images, which can be viewed by most applications. They also produce fit files, which can only be viewed using other astro-image packages, and tiff files. The latter two are typically RAW images in a 14 bit (or maybe 12 bit) format. For us to see anything, the information needs to be “stretched” into a 16 bit format (or sometimes changed to an 8 bit format). The simplest way to do this is by performing a linear stretch, which multiplies by 4. A 14 bit (0 to 16,383) image is stretched to a 16 bit (0 to 65,535) image.

If the stretch results do not look good, you can manually adjust the black and white levels. (More to come here.)

Image (PHOTO) Processing settings

Here is a summary of the many image (photo) processing settings available in most software. The articles below discuss some of the steps you might go through using these settings to enhance your images.

  • Temperature: Adjustment of blues and reds.
    • Warm: More of reddish tone.
    • Cool: More of a bluish tone.
  • Tint: Adjustment of greens and magenta.
  • Exposure: Change the overall light the image captures.
    • Underexposed: Lack dark details.
    • Overexposed: Lack light details.
  • Brightness: Change how light or dark the image is.
  • Contrast: The difference between the brightest and darkest parts of your image.
  • Black Point: The darkest part of your image.
  • Color Saturation: The intensity of the image colors.
  • Noise Reduction: Removes the graininess in your image.
  • Vignette: Reduces the sharpness at the image’s edges.
  • Sharpness: The difference between an object and its background.
Simple ADJUSTMENTS

After stacking your images (with calibration frames), here are a few very simple adjustments that you might try to further improve your image. Examples are below. This is very much a work in process and actual image settings may vary from those noted.

  • Increase the Brightness [How light or dark the image is] particularly if the image is dim.
  • Increase the Contrast [Difference between the darkest and lightest parts] to +30 (or less if the color is too dark).
  • Increase the Black Point [Darkest part of the image] to +30 (or more if there are still residual light areas).
  • Increase the Color Saturation [Color Intensity] to +10 (maybe).
ZWO ASIStudio

If you are processing images from an ASiair, you might use ASIStudio from ZWO.

ASIDeepStack is used to stack and stretch images. After some experimentation, processing images with calibration frames yields some good results.

ASIFitsView is used to view fits frames.

Please note that FAS does not specifically recommend or endorse this or any other software, we only provide information that is generally available.

DeepSky Stacker

DeepSky Stacker is an alternative software package you might consider to stack your images. (More to come here.)

Please note that FAS does not specifically recommend or endorse this or any other software, we only provide information that is generally available.

Siril

As you get more comfortable with processing your images, you might take a look a Siril, which is a free open sources astro image processing package. A short work flow using Siril is as follows (this is very preliminary – more to come here).

If you are starting with individual light frames and want Siril to stack them:

  1. Create a folder for Siril with four subfolders (biases, darks, flats, lights).
  2. Load your image frames into the appropriate folders.
  3. Click the Home button and point to the folder for Siril find the images to process and to place the results.
  4. If you already have master calibration files (such as those from an ASiair), go to the Calibration tab and point to these files. Then run the script OSC_Preprocss_withoutDBF. Although, we aren’t sure if the master calibration files are taken into consideration by this script.
  5. If necessary, locate the “Without” scripts. They are not visible by default.
    • Find the location for your scripts. It should be /user/name/Siril/Scripts.
      • Click on the burger (three lines) in the top right.
      • Click on Preferences.
      • Click on Scripts.
    • Go here.
    • Click on the script.
    • Download it to /user/”your name”/Siril/scripts.
  6. Run the script.
    • OSC_Preprocess_WithoutDBF if you don’t have individual calibration frames.
    • OSC_Preprocess_WithoutDark if you don’t have individual dark calibration frames.
    • OSC_Preprocess if you have a set of all three types of calibration frames.
  7. Open the result.fit file and process it (below).

If you have a pre-stacked tiff or fit files produced by ASIStudio (or another package):

  1. Create a folder for Siril to place the results.
  2. Click the Home button and point to the folder you created in step 1.
  3. Open the pre-stacked file and process the file (below).

Process your selected pre-stacked file or your results file:

  1. Switch your view from Linear to Autostretch, which will stretch the file so you can see what it looks like. It will typically have a lot of green (RGGB format).
  2. Right mouse click and choose Rotate&Crop to crop the image and remove the stuff on the edges.
  3. Perform Background Extraction.
    • Click Generate.
    • Manually adjust background area.
      • Right mouse click to remove background squares over your object.
      • Left mouse click add background squares in the background.
    • Compute Background.
    • Click Apply
  4. Perform Color Collaboration -> Photometric Color Collaboration.
    • Click Get Metadata from Image to populate the focal length and pixel size.
    • If necessary, enter the telescope’s focal length and camera’s pixel size.
    • Search for your object from the Sinbad catalog.
    • Siril will match the color of your object to the Sinbad catalog.
  5. Adjust the shape of the stars using Deconvolution.
  6. Switch your view back to Linear from Autostrech.
  7. Stretch the image using the Histogram Transformation.
    • You must be on one of the color tabs (does not work for RGB)
    • Choose Clip % to apply the autostretch algorithm.
    • Use the three sliders to adjust the image.
      • Zoom in on the left side of the histogram.
      • 1st slider (shadows): starting point is close to 0, increase as needed.
      • 2nd slider (midtones): starting point is close to 0, increase as needed.
      • 3rd slider (highlights): starting point is close to 1, decrease as needed.
    • Click Apply.
  8. If necessary, stretch your image using the Asinh Transformation.
    • Choose (maybe) 10 to 150 for the Stretch Factor.
    • Choose (maybe) .01 to .04 for Black Point. This might be useful to get a darker background.
    • Click Apply.
    • (maybe) Repeat Stretching your image using the Histogram Transformation in the previous step.
  9. Remove Green Noise.
  10. if necessary, adjust the Color Saturation to enhance the colors.
    • Set Amount to around .4 (maybe).
    • Set Background Factor to around 1.25 (maybe). This removes the saturation from the background.
  11. Save the final image as a 16-bit fit, tiff, or png file.
    • Right mouse click and … , or
    • Use the “down” button to the right of the SAVE button on the top right. The image will be saved in the home folder.

Please note that FAS does not specifically recommend or endorse this or any other software, we only provide information that is generally available.

Astro Pixel Processor

Astro Pixel Processor (APP) is a software package you might consider as an alternative to Siril. (More to come here.)

Please note that FAS does not specifically recommend or endorse this or any other software, we only provide information that is generally available.

Pixinsight

PixInsight is a software package that seems to be gaining use among our members. (More to come here.)

Please note that FAS does not specifically recommend or endorse this or any other software, we only provide information that is generally available.

Other Software Packages

There are several other software packages that can be used to process your astro-photos.

Please note that FAS does not specifically recommend or endorse any software, we only provide information that is generally available.