CCD Images - Taken with SBIG ST-7E Camera

These images represent early work where I am still coming up the learning curve.  Been at it now since Feb 2002 and its now almost August 2002 as I post these.  All these shots except M16 and M20 were taken from my light-polluted back yard probably Magnitude 4 conditions with sky glow from the city.
I have been amazed at what is possible under light polluted conditions!  For example, the shot of M51 is far superior to my film shot that appears on my Astrophotography page.  I am inclined to abandon film at this point...  Down below there are some more notes that some might find interesting.

(Click on the thumbnail images below to view a larger image)

From the back yard:



Eagle Nebula

Trifid Nebula

Crab Nebula

Globular Cluster

Whirlpool Galaxy

Black-eye Galaxy

Ring Nebula

Planetary Nebula

Planetary Nebula

Planetary Nebula

M27 (f/3.3)
29 Sep 02

M27 (f/6.3)
4 Sep 02

M17 - Swan Nebula
with new ST-7XME
19 Sep 03


Pluto Movie

This is a "blink compare" movie of Pluto on two subsequent nights.  Look for the "star" that jumps left and right in the lower left area of the frame. That is Pluto.

2002NY40 Movie (933 kilobytes)
Asteroid Close Approach
17 August 2002

5 Second exposures give it a "trail".  Telescope position was moved so it would go across the frame again.  Clouds intervened the second time...  The Asteroid was moving across the sky pretty fast (8 Degrees per hour - that's about 16 moon diameters per hour...)

Comet C/2001 Q4 Neat (2.7 Megabytes)
Taken 14 May 04 North of Phoenix
10 frames, 30 second exposures, f/3.3 spaced 2.5 minutes apart for a total time of 25 minutes.  The movie runs 15,000 times faster than real-time, i.e., the motion is greatly speeded up

From a Dark Site (Newman Park near Flagstaff - 9 and 11 Aug 2002)



Helix Nebula




Alcyone and Merope Nebulae

[I am still working on resolution and color registration...]

From a Dark Site (Newman Park near Flagstaff - 13, 14, 15 Sep 2002)

Cone Nebula

Horsehead Nebula




From a Dark Site (North of Phoenix - 14/15 May 2004)

Processed using MaxIm DL
which appears to have solved my color combining problems

Processed using MaxIm DL

Processed using MaxIm DL
For once, I am reasonably happy about how a galaxy image turned out.

Comet C/2001 Neat Q4
Processed using MaxIm DL
Combination of images taken over a period of 25 minutes.  The comet moves against the star background.  Each frame contains the stars at slightly different positions.  That is why they appear a chains of dots.

From a Dark Site (North of Phoenix - 11/12 Jun 2004)

Comet C/2002 T7 Linear
The comet was passing over a star and that is why the core looks distended.

Bright Nebula.

Technical Data:
Meade LX-200 10" with f/3.3 focal reducer.  SBIG ST-7XME camera.   30 ten second 1x1 binned Luminance frames aligned and summed in MaxIm DL 4.  Ten each 10 second 2x2 binned Red and Green frames and ten each 12 second Blue frames. Frames aligned and summed in MaxIm DL 4 resulting in LRGB frames.  LRGB frames color combined in MaxIm DL 4.  Additional processing in MaxIm DL 4 and Paint Shop Pro.

Galaxy cluster centered on NGC6050.
If I haven't miscounted, there are 41 galaxies visible in this shot.

Technical Data:
Meade LX-200 10" with f/3.3 focal reducer.  SBIG ST-7XME camera.   Ten 30 second 1x1 binned Luminance frames aligned and summed in MaxIm DL 4.  Three each 30 second 2x2 binned Red and Green frames and three each 38 second Blue frames. Frames aligned and summed in MaxIm DL 4 resulting in LRGB frames.  LRGB frames color combined in MaxIm DL 4.  Additional processing in MaxIm DL 4 and Paint Shop Pro.

Megastar Overlay of galaxy cluster centered on NGC6050 showing the identity of each of the 41 galaxies.

M20 Nebula
Another shot of it.  Believe my techniques are improving gradually.  Much credit to MaxIm DL.

From a Dark Site (South of Flagstaff - 1-5 July 2004)

The Ring Nebula

The Dumbell Nebula

The Eagle Nebula

Globular Cluster

Globular Cluster

Globular Cluster

All Arizona Star Party - Friday Night 30 Sep 05

Short Mars Movie
Frames taken with a ToUcam webcam, processed with RegiStax, and made into a GIF movie.

Galaxy that is relatively easy to image

Part of the Veil Nebula
Difficult to process in my opinion since the nebula is dim and the stars in the immediate vicinity are bright.

Sentinel Arizona, 1 Dec 05 - 4 Dec 05

Comet McNaught E2
Faint hint of a tail toward the 5 O'Clock position.
Supposedly about Magnitude 10.

Short Mars movie.  Before Arizona weather got cloudy...  Note clouds at left edge of Mars as the terminator rotates toward us.  These frames were spaced at 10 minute intervals.

NGC 1232


Moon and Mars - 23 Dec 07

(Click on the thumbnail images below to view a larger image or to view the video)

The Moon and Mars were aligned briefly on 23 Dec 07.  I was called by a friend wondering what the bright object close to the Moon was.  Closest apparent separation was an hour or so earlier than this photo since I didn't realize the alignment was going to happen or I would have shot it earlier when they were closer. 

The closest apparent separation occured at approximately 6:49 PM MST.  I simply set the Canon S3IS camera to 12x zoom and set exposure time manually. 

The camera has "Image Stabilization" so I simply held it up and shot the image.  Mars was pretty dim so I brightened it (only it) using Paint Shop Pro so you can see where it was when I took the shot.

I also created a simulation from a program called Starry Night Pro.  This is a .wmv movie created from the QuickTime movie that Starry Night Pro generated.   

The movie shows the Moon and Mars (the big yellowish dot) moving against the sky background.  The time between each frame of the movie is exactly 5 minutes and the movie is being displayed at 2 frames a second.  So you see what happened on 23 Dec over about a three hour period speeded up greatly.  Notice that the moon moves down through the background star field.  Also notice that Mars is moving up slowly through the star field.  The Earth, the moon and Mars are all moving with respect to the background stars of course. 


A few words about the CCD learning curve are in order.  There was a lot to learn when I started film photography.  CCD work is like starting all over again.  First there are all of the imaging "tricks".  Not really tricks but lots of stuff that can go wrong.  Its similar to starting with film photography but with a whole new set of  problems.  The first problem of course is that the CCD chip in the ST-7E is a lot smaller than a 35 mm film frame.  Getting your object to be centered on the chip is one problem.  I hope to find time to write about my experience with flip-mirrors, etc.  

I have eliminated the flip-mirror from the system when doing deep-sky imaging.  There is not enough mirror travel in the 10" LX-200 to allow use of the flip-mirror AND the f/3.3 focal reducer.   I have attached the CFW-8 filter wheel directly to the ST-7E.  I am now able to use the Meade f/6.3 and the Meade f/ 3.3 focal reducers.  Mirror travel is OK to accomodate them.  Centering objects is not a problem if your finder scope cross-hair is adjusted properly.  I do a very careful polar alignment then locate a star such as Arcturus in the finder scope, center it carefully then take a .11 second exposure (minimum exposure time possible for ST-7E) and see if its in the frame.  I usually do that with 3x3 binning to reduce the image upload time  If the star cannot be seen, and you can't find it, then you have to remove the camera, put an eyepiece in and get the finder scope cross-hairs aligned properly.  Then replace the camera and try again.  I have had very little difficulty getting a bright star centered.  One then "syncs" the LX-200 scope.  If you have well-aligned telescope axes so that  pointing accuracy is very good, the rest of the night is pretty easy.  My LX-200 telescope control software lets me do everything remotely that needs to be done.  (Except for setting the backlash value of the DEC axis.  Don't think Meade published that command?  Or I missed it somehow?)

I still use a flip mirror for planetary and lunar imaging.  Actually increases the f-ratio a little which is not all bad for lunar and planetary imaging.  Since the objects are bright, the flip-mirror can be of assistance in centering the object initially.

Collimation of the scope matters more than for film photography.  The chip is small but it is very high resolution.  Things that don't show up on film do show up on the CCD frame.  Look, for example, at the resolution of the Eagle Nebula and compare it with my best film shot of the Eagle Nebula.  The resolution with the CCD is amazing.

The ST7-E has a built-in guide chip.  Using it as an auto-guider is necessary for deep-sky work to keep the telescope pointed properly.  Has its own set of puzzles though.  The filter wheel will change from clear to red to green to blue if you are taking a color shot.  If the guide star does not show up brightly enough in one of the filters, you will lose it and ruin the shot.  One of my early mistakes was to lose the guide star in this manner.

Finding a guide star is a problem.  Problem has just been solved for me by Megastar 5.  It now allows you to put an "overlay" on the star map that shows the fields for the imaging chip and for the guide chip.  It also allows rotation about the center of the imaging chip so that you can see where good guide stars are and rotate the camera accordingly.  I can hardly wait for the clouds to go away to begin using it.  I was able to use it one night to calibrate the frame sizes against the star charts so I'm ready to go.

The other part of the learning curve involves image processing.  "The Handbook of Astronomical Image Processing" is essential.  Helps if you are a mathematician like me but even if you are not, I believe anyone intelligent enough to understand RA and DEC enough to find objects at night probably has the brain-power to make very good use of this excellent book.  I spent about 4 days of a recent vacation in intense study of the principles involved in image processing.  The ST-7E produces black and white 16-bit images.  Your computer only displays 8-bit images.  That means there is a lot more "information" in your image than you can display on the screen.  Those 16 bit pixels have to be "mapped" to 8-bit pixels.  You have a lot of control over that but you have to understand histograms to see how to find the optimum 8-bits worth of image data within your 16-bit image.  All covered excellently in the Handbook.

Initially when I first started taking frames, I did not know exactly what I was trying to achieve.  Now I know that I need to get as excellent a black and white shot of an object as I can get.  That image is called the "Luminance" image.  Then get reasonably good Red, Green, and Blue filtered images of the object.  You essentially use the RGB images to "colorize" the luminance image.  This is the LRGB system.  

Sub-note.  I am not happy with the "colorizing" or "color-image combine" process  in the commercial packages I have.  They tend to wash out the image, i.e., saturate the brighter areas.  My opinion is that the Luminance image should define maximum brightness of each pixel.  I have written software to do it properly. Here is an example of what I mean where the same shot was processed two ways:

        Theirs                             Mine
Note that "theirs" washes out in the white areas and obscures the detail.  The luminance frame that both were derived from looks like the image on the right rather than the image on the left, i.e., it has more gradations of brightness...  The image on the left is washed out.

Making the excellent Luminance image look REALLY excellent involves a lot of work and judgement.  Experience counts.  The more you do it, the better you will become presumably.  You need to know why you are doing things though.  You are trying to bring out contrast and definition and you are trying to increase sharpness of the image.  Sharpness involves using Lucy-Richardson deconvolution.  This is an art to some extent but can be learned through experience presumably.  (I still have a ways to go at this point but I believe I now have a handle on it.)

When applying the color images, if they are sharper than the luminance image, i.e., if their star images are smaller than the star images of the luminance frame, your stars will contain funny colored rings.  This happened to me initially and I was greatly puzzled.  And somewhat disgusted...  What you do is fuzz out the color images using a Gaussian distribution.  Places where the luminance frame is black will continue to be black even if that area of the red frame contains red from the fuzzed out star.  That is, it will be if the colorization algorithm is "correct".  Again, I am a bit skeptical about the color combine operations I see in the software packages I have that were not written by me...

Filters, Snell's law, and the SBIG CFW-8 Color Wheel

I am using the SBIG CFW-8 color wheel in order to take the Luminance, Red, Green and Blue frames.  The CFW-8 comes with Red, Green and Blue interference filters and a clear filter.  I discovered something that I had not expected when I bought a Lumicon Deep-sky filter and installed it into the fifth filter slot.  I was using the Meade f/3.3 focal reducer which essentially makes the image at the CCD chip smaller and brighter.  This also causes the light-cone between the Focal Reducer and the CCD chip to become shorter so you have a cone that is still the same size at one end but shorter.  The angle between opposite sides of the cone is increased.  Now the filters in the CFW-8 are in this cone.  The surprise is this:  If the filters have different thicknesses (or different refractive indices), the focal length will change!  This is due to Snell's law which is n1*Sin(theta1) = n2*Sin(theta2) where n1 and n2 are the refractive indices of the two materials that form the interface and theta1 and theta2 are the angle between the incident ray and a normal to the interface surface.

Here is how significant this effect is for the two filters I was (inadvertently) experimenting with:


The image on the left was taken through the clear filter that came with the CFW-8 and is in focus.  The image on the right resulted from merely switching to the Lumicon filter without making any focus adjustments.  Since focusing is usually a major effort, refocussing simply to compensate for filters of different thickness is a major inconvenience.  I do not have a micrometer (and it might damage the filters to use one) so my measurements so far are "eyeball" measurements.  I removed all of my filters from their holders and discovered that the Lumicon H-beta filter that I have appears to be 1.5 times thicker than the Lumicon Deep Sky filter which in turn appears to be 1.5 times thicker than the Meade 80A filter, which in turn appears to be1.5 times thicker than the SBIG filters that came with the CFW8.  So the Lumicon Deep Sky filter appears to be 1.5*1.5 or 2.25 times thicker than the SBIG provided filters and results in the defocussing effect shown in the images above when the filters are used with a 100" focal length, f/10 scope and an f/3.3 focal reducer.  Note that it WAS possible to focus while using the Deep Sky Filter but then the filters provided by SBIG were then out of focus by the same amount shown above.

The upshot of this is that to minimize focussing effort, you need to use filters that are the same thickness and the same refractive index if possible.  There does not appear to be any standard for filter thickness.  SBIG appears to be aware of this and their filters appear to be matched.  Note that this is another reason for them to provide a clear filter along with the red, green and blue filters.  If you were to use red, green, blue, and "empty", the filters would extend the focus but the "empty" slot would not so it would have a different focal plane and would require extra focussing effort. 

So enough for now...  More later perhaps...

Titan/Saturn Transit Events for 2009

RedShift 5 simulation movie of Titan transits of Saturn in 2009 plus movie of close approach of saturn to galaxy UGC6185:

              (Click on an image to see the video)

I used RedShift to locate the events and its video generator to capture them.

The first video shows all the Saturn/Titan transits for 2009 visible from Phoenix I THINK...

The transit events are shown by frames 20 minutes apart. The dates and approximate times for the first frame of each event (not the start of transit) are:

02/24/2009 0311 Hrs Local Phoenix time
03/12/2009 0251 Hrs Local Phoenix time
03/28/2009 0051 Hrs Local Phoenix time
04/12/2009 2331 Hrs Local Phoenix time
04/28/2009 2231 Hrs Local Phoenix time
05/14/2009 2111 Hrs Local Phoenix time
05/30/2009 2051 Hrs Local Phoenix time
06/15/2009 2031 Hrs Local Phoenix time
07/01/2009 2011 Hrs Local Phoenix time
07/17/2009 2011 Hrs Local Phoenix time
08/02/2009 1951 Hrs Local Phoenix time

NOTE that RedShift can see through the earth! Each frame contains Date/Time, Azimuth and Altitude in the upper left-hand corner in orange. NOTE that negative Altitude means Saturn is below the horizon! So look at the Altitude readings!  The sky color is "true sky color" so when it turns blue, it means the sun is coming up...

The second video shows Saturn's close approach to Galaxy UGC6185 which is a mag 14.1 galaxy. Capturing this event would be a SUPER challenge due to the differences in the brightness of the galaxy and Saturn.

This galaxy event occurs on 05/03/2009 through 05/04/2009 with closest approach perhaps at 0031 Local Phoenix time on 05/04/2009.