Deep Sky Astrophotography What am I Doing? Howard C. Anderson 25 July
Overview Location (Dark skies help) Observatory Hardware Software Figure out what to shoot Shoot images Process images
Location Dark sky helps a lot. Main reason for locating remotely… My observatory is in New Mexico south of Lordsburg where we have really dark skies. Bernard’s observatory is close by as are several others including Eric Africa’s both of whom take truly excellent images. I didn’t know remote operation was possible until I saw Bernard Miller’s presentation at an EVAC meeting some time ago… I used his presentation as a guide: I’m still learning image processing – Maybe always will be…
Rancho Hidalgo – ~250 Miles
Observatories at Granite Gap
Observatories at Rancho Hidalgo
My Observatory at Rancho Hidalgo
Hardware Meade LX ”, SBIG STL Camera, Astrodon filters for LRGB and Hydrogen Alpha, water cooling system for camera (CPU over-clock cooler), Optec TCF- si focuser. Takahashi TOA-130 (5 inch) refractor, SBIG ST- 4000XCM single-shot color camera, Celestron CGE mount, Optec TCF-si focuser. 32-bit PC computer running Windows 7 Foster roof control board 4 inside video cameras so I can see position of the roof and the scopes (… Just in case…) Foster weather monitor (clouds, temperature, wind)
Software Remote Desktop (Free) (Operate remote computer) (All-sky plate solver) TheSkyX Pro (Display sky, choose objects to shoot, get coordinates) VMware Workstation (Computer within a computer so to speak) Foster Dashboard (roof control) and AstroAlert (weather) Web Power Switch (Turn stuff on and off) NexRemote (Celestron CGE control software) ACP Observatory Control Software (Controls roof, scope, camera) Maxim DL imaging software (camera control, image processing...) FocusMax (Freeware) (Automatic focus system) CCDStack (Image processing. Best deconvolution algorithm) eXcalibrator (Freeware) (Color calibration using known star colors) Photoshop (Image processing – Essential, expensive, hard to use) Paint Shop Pro (Image processing software) Software I wrote: CheckPorts, ComputeFocus, FixBadPixels, etc.
Web Power Switch
CheckPorts
Attention Span Relief Your secrets are safe in England
Roof and Weather Check
Cameras Inside Observatory
Remote Desktop view of Virtual Machine
ComputeFocus
Optec Focuser
TheSkyX Pro Mosaic
ACP Script to automate mosaic imaging of Pelican Nebula Target #waituntil 0, 02:30:00; UTC == 7:30 PM #domeopen #waituntil 0, 05:30:00; UTC == 10:30 PM #chill -10 #autofocus #AFINTERVAL 60 ;Pelican Nebula mosaic region. #sets 2 #count 1 #interval 1200 #binning 1 Pelicana #count 1 #interval 1200 #binning 1 Pelicanb #count 1 #interval 1200 #binning 1 Pelicanc #count 1 #interval 1200 #binning 1 Pelicand #shutdown
Run the Script in ACP I start script running in ACP Script waits until time I say it should start doing things Opens roof (allows things to cool down - summertime) Waits again until specified time to begin imaging Sets camera temperature and waits until camera temperature is what I specified FocusMax then finds a suitable star, moves scope, and focuses camera I told it to refocus every hour. It does that automatically between shots
Run the Script in ACP After focus, ACP moves scope back to designated object ACP takes 30 a second image, plate-solves, moves scope dead-on ACP then runs auto-guider subsystem and starts auto- guiding If guiding is OK, ACP starts taking an image using the exposure time I specified (1200 seconds in this case, i.e., 20 minutes) ACP will take all the images I specified, refocus periodically between images, and store the images in a default location I will be sleeping during this… I am a “morning- person…”
ACP Image Folder for Pelican Target (Single-Shot Color Camera)
Attention Span Relief Victor Borge
Single-shot color cameras Bayer Mask You initially have a gray image that needs to be CONVERTED to RED, GREEN and BLUE gray images which are then combined to give a full color image… (Green light contributes roughly twice as much to our perception of brightness than does the combined effect of red and blue.)
My Video Monitor
Red, Green and Blue Images Combine RGB images to get color image Small star on monitor - magnified…
Example: IC FixBadPixels (i.e., color convert, calibrate) Then Stack – Image Excerpts Single Original Single Original Fixed 10 Fixed, Stacked
300X Excerpts to Show Improvements Single Original Single Original Fixed 10 Fixed, Stacked
Transfer Stacked Image from Observatory computer to local computer and start image processing In Maxim DL, “Convert to Mono” to create Luminance (L) image Use CCDStack to deconvolve the L image Deconvolution is a process that undoes the "blurring" obtained after convoluting data. See Save the deconvolved image as the new L image
Correct color using eXcalibrator In Maxim DL “Split Tricolor” to create Red, Green and Blue images (If I start from a full-color image) Do “Pinpoint Astrometry” (plate solve) Red image and save it (Creates World Coordinate System (WCS) data) Use R, G, and B images in eXcalibrator. Use R image as WCS image Use NOMAD database “Calibrate Image” “Remove Outliers” Get correction values for R, G and B images
eXcalibrator Color Correction Coefficients
Combine LRGB with Color Correction In Maxim DL, combine LRGB images using the correction values Save image as a 16-bit TIFF image for use with PhotoShop
Attention Span Relief Remote Control Roundup
Photoshop Processing Read in 16-bit TIFF image Looks pretty dark Use “Curves” successively to brighten (as recommended in “Photoshop Astronomy”)
PhotoShop “Curves”
Successive Curves
Levels Adjust Use Levels to adjust dark level
Photoshop Add-on: Astronomy Tools V1.6 I apply “Make Stars Smaller” 3 times usually. I apply “Space Noise Reduction” and “Deep Space Noise Reduction as needed to reduce graininess of the image. I apply “Increase Star Color” until I am happy with star colors. Then additional tweaking of Curves and Levels in PhotoShop until I am happy with amount of detail visible.
Additional PhotoShop Operations Vibrance: If I err, it is on the side of too colorful I guess… I like color…
Vibrance Result Tweak Curves, Levels, Vibrance, etc., in PhotoShop then save as JPG
Paint Shop Pro Final tweak of brightness, contrast, etc., resulting in this:
Pelican Mosaic (4 images)
M51 – Whirlpool Galaxy
Cone Nebula
Flame Nebula and Horsehead Nebula
M109 and Flashlight of God
Finis See my images at: Questions?