Observatorio de la Ballona

Last week there was a magnitude 5.4 earthquake northwest of Borrego Springs and east of Lake Riverside. It was only 25 miles from our house and the observatory. I was worried about the roof of the observatory jumping the rails.

During construction, there was a lot of discussion on how to protect the roof in windy conditions. We never thought about earthquakes which are probably a greater risk for a 3,000 lb roof. Nonetheless, we devised a good hold down mechanism for the roof, with steel flanges preventing any full derailment at virtually all open positions. The upshot of this protection is that we did not provide for any tie down of the roof.

Upon hearing of the earthquake, I became concerned that the shaking might derail the roof. While we had dealt with a move from the wind, I was concerned that the quake might have introduced movement we hadn’t anticipated.

All is well. As far as a nighttime inspection can find, we have no earthquake effect, let alone damage. It’s a good thing we didn’t take any lava home from Hawaii, so Pe’Lee is on our side.

A couple of weeks back, during the last quarter Moon, I was able to get some decent data of M101, the Pinwheel Galaxy. M101 is a spiral galaxy in Ursa Major and is 27 million light years away.

The image is from 160 minutes of LRGB data. That’s 90 minutes of luminance, and 23.3 minutes each of red, green and blue, binned 2×2. LRGB imaging takes advantage of the fact that we perceive most of the detail in an image from the black and white, or luminance part of the image and less detail from the color. I obtained 90 minutes of high-resolution black and white data and combined it with lower resolution color data to produce the image. The color was obtained by binning the pixels, or adding four pixels to create one. This allows for more data collected in a shorter period of time but at half the resolution.

Here is the result. Click on the picture to go to the gallery where you can see a full-sized version of the image.

160 Minutes LRGB (90:20:20:20 subs 300:200:200:200×18:7:7:7)

It has been three months since clear skies, the new Moon, and being in Lake Riverside have converged on the same day and allowed for imaging. These factors came together on May 15th. I collimated the C-11 back at the full Moon and was ready to go. (Dew foiled my attempt to get even any Ha data that full Moon night but that is another story.)

I used my general approach for finding targets. I use The Sky’s database manager data wizard to query objects above 40 degrees or so. Moving from object to object I record my interest, the transit time, and the availability of a guide star. Up until this weekend I have tried to capture all of my data on one side of the meridian, preferably the east. This simplifies the taking of flats (with the ST-10 the camera rotates 180 degrees to maintain framing after a meridian flip) and the east has a better view from the western pier in the observatory.

I chose to image NGC 5033, a spiral galaxy in the constellation Canes Venatici. Is looks very interesting and has a very bright star that can be used for a guide star. Astronomical twilight would occur at about 9:15 PM PDT and the galaxy would transit at 10:32 PM. I hoped to get data both before and after transit, that being the best time to image as the object is highest in the sky.

I had my usual troubles with autoguiding and initial start-up but got imaging going by 9:40 or so. In the first of many little glitches, I had set CCDCommander to send me a text message when the first set of luminance images were done, but the message didn’t get sent because Zone Alarm had interrupted the request to send e-mail. Security software can be annoying. I was in the house watching Midway with the family, so I didn’t go back to get the next series started and lost 20 minutes of imaging time before the meridian crossing.

I planned on getting 50 minutes of luminance data and 20 minutes each of red, green, and blue. After having trouble on my last imaging outing with dark pixels on the color images, I wanted to make sure I had at least six sub-exposures and adequately dithered the frames—six frames to enable a sigma reject algorithm and dithering to move the dark pixels. So my luminance exposures were 300 seconds and my color were 200 seconds. I had other little issues with losing sync on the meridian flip and FocusMax acquire star not returning exactly to the original framing but overall things went fine the rest of the night. These problems would be solved if I were able to spend several days in a row in the observatory—a good goal for the future. I was able to use the new window shade to take flats after putting the white lights on the dimmer for the rope lights.

I ended up with 110 minutes of LRGB data, 50 minutes of luminance and 20 each of red, green, and blue. The RGB images were binned 2×2. I performed my data reduction, alignment, and combination in CCDStack. To simplify alignment, I process the luminance first, then save a binned copy of the final image. I then use that binned image as the master to align each of the sets of color images. This means that frames are only re-sampled once for alignment and that all combined frames are fully aligned.

Once I was processing the data it was clear that I really had inadequate imaging time for this object. At magnitude 10, it is quite dim. When the image was processed to bring detail to visibility, it was quite noisy and grainy. So I did the best that I could with it.

I did most of the processing in PixInsight. I have a standard approach when starting on an image that makes the later combine steps easier. The basic idea is to get a standard crop of the images that will work across all frames, eliminating any artifacts around the edges from the combine / integration process. The RGB frames are scaled up two times to match the luminance. Then, using the dynamic crop tool, I select a crop that will include solid data from all frames. I save an instance of the crop settings on the desktop and then save the process icons. This allows me to start and re-start work on each frame from a consistent point.

On the luminance, I used both the histogram tool and curves to bring out the details. A very nice feature of the histogram tool in PixInsight is the ability to see the number of pixels you have clipped so there is no guesswork. Generally I take several quick passes through the data before settling on a final processing approach. On this image, I took a copy of the luminance and applied a four-level HDR wavelet transform, recombining it with the original using PixelMath. This brought out the dust lanes in the center of the galaxy. I did need to create a star mask to preventing ringing when doing the HDR wavelet transform.

I tried to keep things simple on the color data. I used a channel combine to create an single RGB image, then used histogram to eyeball the black points across the colors. There is are some new tools in PixInsight that really helped the color. The first is Background Neutralization. In my experimentation with this tool, it will allow you to drop out the noisy background in a color image. I used the tool in truncate mode to eliminate most of the background data in the RGB frames. This is consistent with what RickJ suggested in the BAUT Astrophotography Forum. There is also a color calibration tool that appears to correct your color balance. I’ll have to work on understanding that.

My processing approach on images is to create solid luminance and RGB images. I then use channel extraction to pull the individual red, green, and blue components out of the RGB image. The final combine step is to use LRGB
Combination to create the final LRGB image. I touched up color and contrast and then moved to Photoshop.

In Photoshop, I used clone stamp and healing brush to fix a couple egregious color issues. I also used Noel Carboni’s Astronomy Tools actions to reduce noise in the image and tweak the star size. The final step was to add a layer processed with a high pass filter, masked to reveal only a few key locations, and merged with “soft light” blending mode to highlight some details.

Here is the final image. Still a bit noisy and needing more data, but I think it looks OK. Click on the image to go to the gallery and a full sized image. Comments and suggestions are always welcome.

A while back (two years, so quite a while) I wrote about our experience at a LA Philharmonic concert. The concert that time was a avant-garde, modern, and interesting in the not so complimentary sense. Today we saw another fine concert at Disney Hall, and I was worried it might be interesting in the same sense.

The piece today was La Pasión según San Marcos, composed by Osvaldo Golijov. This is St. Mark’s Passion of Christ set to music. I was worried that a piece composed in 2005 by an Argentine Jew who had an atheist father might fall into the unpleasant side of avant-garde. I could not have been more wrong.

This piece, with strings, percussion, horns, a chorus, and soloists, was beautiful. The use of Latin rhythms fit well in places that were surprising. The music fit this important subject. The aria of St. Peter, his lament after realizing he had denied Jesus three times was very moving. It needed the screens that provided a translation to follow it, but with that it was a great musical experience.

This would make an excellent Good Friday concert. P.S., iTunes has it too.

We hosted a Cub Scout troop tonight at our house and the observatory (in Los Angeles). Some friends of ours son is a member of the troop and they asked us to help with a night of astronomy focused on getting the troop members their Astronomy Belt Loop.

It was great fun and I think a great success. We had 6 Scouts, parents, and a sister as our guests. After they completed their opening ceremonies, my wife went through the specific learning about astronomy that is required for the belt loop (what is a planet, etc.). Once it was dark — well, time for a digression. It is dark a bit late this time of year because of the early start of daylight savings. It is starting too early. End of digression.

I had opened the observatory at the start of the meeting. Good hoots and hollers from the scouts at the opening. Once it was dark and the lessons were complete, we started observing.

Mars was first and was not too exciting. In the 8″ SCT and a 9mm Nagler (225X magnification), it was just a small disk with almost no features. We were pushing the seeing in any case.

The next target was M42, the Nebula in Orion. The Trapezium was a clear four stars and there was a nice haze of nebulosity around it. This got a few aahs from the Scouts and other guests.

We then moved on to the Moon. This turned out to be the hit of the night. In the 35mm plossl, it was a full disk view with the terminator right in the middle of the Moon. Great detail in the maria and the peaks. Lots of oohs and aahs. I then went back to the 9mm Nagler for a closer look and this brought some serious study by one of the Scouts. Aimed at the north pole of the Moon, we had a view that showed the shape of the Moon with lots of crater detail. A big hit.

We had reached 8:40 pm or so, so the troop left except for our friends and their son. We chatted a bit and were looking at the constellations (we could pick out Orion, Gemini, Leo, Canus Major [Sirius anyway], and the Big Dipper). Then I saw a bright object at about 25 degrees and realized we had a jackpot view — Saturn!

Saturn was low but we could see the rings well and two moons clearly, Rhea and Titan. Saturn is always a big hit. So we finished the night on a high note.

It was really nice to be able to share both the knowledge of Astronomy and the experience of looking through the telescope with a bright and eager group of kids. Well behaved too. They were all very thankful. And I am very thankful that I had the ability to share the view of the sky with them.

Dennis Prager has recorded an excellent short lecture on the basic issue current political discourse is facing. And he hits on the crucial issue: More government means less for the individual. Watch.

For quite a while, and even more after my cardiac event, I’ve been a regular reader and, I suppose, a user of Magnificat. This is a monthly publication that has the liturgy of the hours and the mass for the day. So here are my selected quotes from January 2010.

Isaiah 58:8-9a

Then your light shall break forth like the dawn,
and your wound shall quickly be healed;
Your vindication shall go before you,
and the glory of the LORD shall be your rear guard.
Then you shall call, and the LORD will answer,
you shall cry for help, and he will say: Here I am!

Psalm 8:4-5

When I see the heavens, the work of your hands,
the moon and stars which you arranged,
What is man that you should keep him in mind,
mortal man that you care for him?

Matthew 6: 30, 34

If God so clothes the grass of the field, which grows today and is thrown into the oven tomorrow, will he not much more provide for you, O you of little faith?
Do not worry about tomorrow; tomorrow will take care of itself. Sufficient for a day is its own evil.

Proverbs 2: 6-11

For the LORD gives wisdom, from his mouth come knowledge and understanding;
He has counsel in store for the upright, he is the shield of those who walk honestly,
Guarding the paths of justice, protecting the way of his pious ones.
Then you will understand rectitude and justice, honesty, every good path;
For wisdom will enter your heart, knowledge will please your soul,
Discretion will watch over you, understanding will guard you;

Romans 12: 14, 18-21

Bless those who persecute (you), bless and do not curse them.
If possible, on your part, live at peace with all.
Beloved, do not look for revenge but leave room for the wrath; for it is written, “Vengeance is mine, I will repay, says the Lord.”
Rather, “if your enemy is hungry, feed him; if he is thirsty, give him something to drink; for by so doing you will heap burning coals upon his head.”
Do not be conquered by evil but conquer evil with good.

Back over the holidays, we had a clear night but the Moon was out — almost full. After taking some Ha images of M1, I decided to try the Moon itself. It turns out that with the C-11, the new 0.75 focal reducer from Optec, and an Ha filter, a 0.11 second exposure is not blooming or over saturated on the ST-10.

So I took three series of images, one of 20 and two of 40 exposures. February’s Sky and Telescope has a very good article Lunar Photography with AviStack. Based on the advice there, I used AviStack to align and stack the images. I then took them into Photoshop where I used the Photomerge feature to create a mosaic of the three images. Here is the raw image.

Raw Moon Panorama

The next group of steps were performed in PixInsight. I will go through how I used mask and several of the image enhancement functions to produce my final image.

The first step in processing was to change the areas that weren’t part of the Mosaic from white to black. To do that, I cloned my original image by dragging the name tab onto the desktop. I used the histogram tool on the cloned image, moving the black point almost all the way to the top. I then inverted the image, producing a white background with the missing corners black. Using Pixel Match, I created a new image that was the minimum of the original image and the black corners.

The next thing I needed was a mask that would allow me to apply deconvolution, A Trous Wavelets, and HDR Wavelets to the image without creating artifacts around the edge of the Moon. I cloned my new image and reduced it to almost pure black and white using the Histogram tool, moving the white and black points to just above the background sky glow. This gave me a sharp-edged mask, but what I needed was a smoother edged mask. Without a gaussian blur function, I used A Trous Wavelets to blur the image. Here are the settings I used to blur the mask (click on the image for a larger view):

Wavelets Setting to Blur Mask

This produced the following mask image. The basic idea is that you set wavelets to many levels, drop the lower levels and slightly increase the bias near the top level.

Moon Mask

With this mask set on my main image, I went through key image enhancement steps with minor curves adjustments in between each. My first step was deconvolution. I had found that larger standard deviation settings brought out noise in the image, with single pixels leaping in brightness. After trial and error, I settled on a standard deviation of 1.5 and 80 iterations of Regularized Richardson-Lucy deconvolution. Here are the settings I used.

This had the effect of subtly sharpening the details of the Lunar surface. While this was good, I wanted to expose more of the details in this image. So at this point I turned to A Trous Wavelets. I didn’t want to over-process the image (although some might argue that doing wavelets on top of deconvolution is already that) but I wanted more detail. I applied the following, somewhat subtle, A Trous Wavelet transformation.

From there I wanted the global contrast change that you get from HDR Wavelet transformation. Note that for all of the prior sharpenings, I have been using my mask. For this transformation, I needed a sharper edge to the mask and even that left behind some brightness I needed to fix. Here is the HDR Wavelet setting I used. The number of layers is one greater than the default of 6. This matched the scale where I wanted the contrast adjustment.

This process did leave a minor artifact. The mask left a somewhat bright area around the lower edge of the Moon. Rather than tweak the mask again, after applying a very light noise reduction using ACDNR, I took the image into Photoshop. In Photoshop, I burned the lower edge of the Moon very slightly. I also added black shapes around the missing mosaic area to hid the edge artifacts from the A Trous wavelet processing.

This is the final image:

Through the auspices of Smitty at Robert Stacy McCain’s blog, I have a link in from a prominent source. Not only is The Other McCain a fine blog, but it is written by a real journalist, who adds real reporting to the blogging. This is something few, if any, other bloggers do.

Check out his blog. It’s good reading, and the blogroll there is well worth exploring.

And thanks for the link!

Back in October, I took some data of the Bubble Nebula (NGC 7635) and open cluster October Salt and Pepper (NGC 7634). I took 180 minutes of data:

• 90 minutes Hydrogen Alpha (Ha) in 9, 10-minute sub-exposures unbinned
• 30 minutes Luminance in 6, 5-minute sub-exposures unbinned
• 60 minutes, 20 each of Red, Green, and Blue in 2, 10-minute sub-exposures binned 2×2.

I’ll start with the finish. Here is the final image. (Click on the image for a larger version in the gallery.)

While I do think this is a nice image, it does have the pale salmon reds typical of Ha LRGB processing in basic combine method I used. My basic approach was to make an Ha-Luminance image which was then combined with the RGB to produce the final image. This started off all right as the HaL image looks fairly good. I created the image by adding 3 times the Ha to the Luminance using Pixel Math (most processing was done in PixInsight). I used both HDR Wavelets and A Trous Wavelets to sharpen up the image. Here is the HaL image used to create the final.

I then created an RGB image, adding 3 times the Ha to the red before combining with blue and green. I processed the image, stretching with histogram and curves to end up with a final RGB image. I brought both the Ha-Luminance and the RGB into Photoshop, pasting the Ha-Luminance on top of the RGB and changing the blending mode of the pasted layer to luminance. There was a lot of noise in the color image, with hot pixel color spots from each different color. Selecting the bottom, color layer, I used the spot healing brush tool to clean up the bad spots. This worked very effectively underneath the luminance layer, since only the spurious color was removed, not the details in the image. I now regret that I didn’t save a separate layer version of the image at this stage. Given the results, I figured I would go back to the beginning (and I still may).

I spent a fair amount of time tweaking the color balance, and passed the image through PixInsight’s GREYCstoration noise reduction algorithm.

Since the original processing, I have tried PixInsight’s “A New Approach to Combination of Broadband and Narrowband Data,” but my color data binned 2×2 is too noisy for it to work. I may yet try Rob Gendler’s approach. At this point, I think I am tired of working on this image.

One lesson learned from this is that when one is doing narrowband imaging, it is better to get full resolution color. This provides better data to use when creating the final image, and allows the luminance combine that creates the peachy / salmon red tones. I got better results on the Heart Nebula, but I’m not done processing that one so it will be another post.

I did try a highly stretched Ha-Luminance image to see what detail I could get out of the image. This is stretched very hard and it has brought out the noise, but there is a lot of detail in the image. This is created from the maximum of 5 * Ha or the Luminance image in Pixel Math, then stretched with curves and some blackpoint adjustment in the histogram tool. I did average in an HDR Wavelet and A Trous Wavelet to enhance the detail in the nebula. Click for a bigger image as the thumbnail is pretty small.