Belt of Venus

Markarian's Chain is overflowing with galactic treasures and is the subject of the April 2010 column.

Inverted, Positive Sketch of Markarian's Chain

Move mouse over image to view labels
Click for larger version.

Original Pencil Sketch of Markarian's Chain

Click image to view larger version.

Sketch of 90 Leonis (Struve 1552)

Click image to view larger version.

Observation Notes:

The trio of 90 Leonis appeared sky blue, cream, and dull orange. Sissy Haas sees yellow, yellow, gray and Smyth saw silvery-white, purplish, pale-red.

Sketch of 35 Sextantis (Struve 1466)

Click image to view larger version.

Observation Notes:

This nice yellow-orange/pale blue binary was also seen as citrus-orange/blended-blue-green (Haas) and topaz-yellow/smalt-blue (Smyth). The faint C star showed to the southwest, but I didn't realize it was a component, so I didn't measure it.

Orion, Canis Major, and the Winter Milky Way soar over Sunset Crater

Click for larger image
FEB 13, 2010 - 01:00 AM MST
Canon EOS 300D + Kit Lens @ 21 mm • ISO 800 • f/4.5
Composite: 11 x 30 sec. aligned, stacked, and composited separately for sky and foreground

I said I was going to try this again. Things worked a little better this time (including remembering to check my ISO setting). I arrived early (12:30 AM :) at Cinder Hills Overlook to work on an observation and sketch of Messier 101. Orion and Sirius would be in good position over Sunset Crater between 12:30 and 1:30 AM. After getting the series of shots I wanted, I couldn't resist shooting another set to the northwest showing Orion, the Hyades, and the Pleiades all setting behind the hills and trees.

Mars, Procyon, and Sirius line up over Sunset Crater

Click for larger image
FEB 13, 2010 - 01:00 AM MST
Canon EOS 300D + Kit Lens @ 21 mm • ISO 800 • f/4.5
Composite: 6 x 30 sec. aligned, stacked, and composited separately for sky and foreground

I got three shots into that series before Rigel winked out behind the mountain. At that point, I noticed that Sirius, Procyon and Mars were making a brilliant alignment over the peak of the volcano. So I worked on a vertical series to capture them.

Mars, Procyon, and Sirius line up over Sunset Crater

Click for larger image
FEB 13, 2010 - 01:00 AM MST
Canon EOS 300D + Kit Lens @ 21 mm • ISO 800 • f/4.5
Composite: 6 x 30 sec. aligned, stacked, and composited separately for sky and foreground

Shooting 30 second tripod exposures makes random course-corrections pretty simple...perhaps too simple.

Processing one set of images is hard enough. Adding a second and third gave me a workout. It was a much needed workout too, since it forced me to refine my process. I made some improvements on the second image, and then again on the third image. By that time, I felt I had to go back and re-do the first and second again.

I've felt pretty confident handling stacking and compositing for sky and foreground. The processes I find challenging are:

1. Removing green/red blotchiness from the dark sky background
2. Removing just the right amount of noise without making the sky look plastic or crystalized
3. Reducing the appearance of vertical and horizontal bands in these short exposures.
4. Tamping down light pollution gradients with some level of finesse

Briefly, some of the solutions I arrived at:

1. To color balance the background, I create a temporary layer, blur it extremely, and read RGB values in different parts of the sky that aren't hit hard by light pollution or air glow on the horizon. I then apply a curves adjustment layer to balance the background to an average of neutral. Unfortunately, that doesn't remove the color blotches. So I add a Hue/Saturation adjustment layer to substantially reduce saturation, and then use Astronomy Tools "Select Bright Stars" to create a mask for this layer that blocks out the stars, and leaves their color intact. Unfortunately, this removes the ability to feature any photographic color in the Milky Way, but for the type of color noise I have to deal with in these 30 second exposures, I think it's a good sacrifice. I also like the way it better conveys the more neutral visual experience of the sky.
2. I use Neat Image to tackle noise. Wide field images like this tend not to have decent sized empty areas that the software can sample for average noise. As a result I have to play with the settings over and over again to get what I like. I still don't have a good system here. Just experimentation. I've saved my latest setting in hopes that I can use it again, but I have a feeling I'll still have to fiddle with it quite a bit every time.
3. The Astronomy Tools "Horizontal/Vertical Banding Noise Removal" action really does a great job removing much of the banding. However I've got some pretty huge bands in these frames, and it doesn't remove those. Wherever these hit a soft hint of Milky Way, they become impossible to remove. A new camera may eventually help this situation :)
4. A couple of the shots contained a pretty ripe light pollution tongue that tore right into the Milky Way. It doesn't seem that obnoxious visually, so I did want to tame it a bit. I found that examining the individual color channels tended to give me some options. The green channel is the cleanest representation of the sky, but the blue channel hides the light pollution the best...the blue channel also seems to do a nice job of giving star groupings and the brightest blue stars a nice glow. I can do some channel blending operations to merge the best of these two channels to create a "Luminosity" layer. By setting this layer to Luminosity mode, I can trim the light pollution, bring out the Milky Way a little more, and in an added bonus, it blunts the horizontal/vertical banding a bit more if I'm careful how I blend blue and green (the blue usually has much worse banding than green). Adding a Hue/Saturation adjustment layer that subtly reduces the intensity of the yellow in shadow and midtones (to exclude stars) helps too.

I've still got a lot of improvement to do, but with the system I've scripted out, I have high hopes it will go smoother on my next attempts.

Sketch of Markarian's Chain in the Virgo Cluster

Move mouse over image to view labels (magnitudes listed in parentheses)
Click for larger version.

Observation Notes:

The heart of the Virgo Cluster is a wonderful place to visit from a dark site. Every nudge of the telescope brings another galaxy...or three or five into the eyepiece...and it's hard to beat the density around Markarian's Chain.

In preparation for a tour of the area, I printed a chart and pre-traced 31 of the brightest stars to serve as a multi-field framework on a 9" x 12" sketch sheet. This saved a lot of sketching frustration as I panned across the 2.5° x 4° field. Over the course of the three hour observation, I ended up with 27 galaxies from 8.8 magnitude Messier 87 to 13.1 magnitude IC 3258. Most were quick catches, but a few required some star chart scrutiny to locate.

The list of galaxies observed:

• Messier 84 (vMag 9.4)
• Messier 86 (vMag 9.0)
• Messier 87 (vMag 8.8)
• Messier 88 (vMag 9.7)
• NGC 4351 (vMag 12.3)
• NGC 4377 (vMag 11.9)
• NGC 4387 (vMag 12.1)
• NGC 4388 (vMag 11.3)
• NGC 4402 (vMag 12.2)
• NGC 4413 (vMag 12.3)
• NGC 4425 (vMag 11.8)
• NGC 4431 (vMag 12.9)
• NGC 4435 (vMag 10.8)
• NGC 4438 (vMag 10.0)
• NGC 4440 (vMag 12.1)
• NGC 4458 (vMag 12.1)
• NGC 4459 (vMag 10.4)
• NGC 4461 (vMag 11.1)
• NGC 4468 (vMag 13.0)
• NGC 4473 (vMag 10.1)
• NGC 4474 (vMag 11.8)
• NGC 4476 (vMag 12.1)
• NGC 4477 (vMag 10.4)
• NGC 4478 (vMag 11.3)
• NGC 4479 (vMag 12.6)
• NGC 4506 (vMag 12.9)
• IC 3258 (vMag 13.1)

Each of these galaxies is worth its own dedicated observation and sketch, but I wanted this to be more about the swarm than the individuals. Fortunately, the full page size of the sketch allowed some leeway for conveying a little detail in most of the galaxies--particularly Messier 88 and NGC 4438. As David Moody often advises, don't let your eyepiece field stop dictate the extent of your sketch. It's good advice.

Tau and 83 Leonis make a stunning and colorful low power double-double and are the subject of March 2010 Drawn to the Universe Column in Astronomy Now.

Digital Sketch of Tau and 83 Leonis

Click image to view larger version.

Original Pencil Sketch of Tau and 83 Leonis

Click image to view larger version.

Cinder Hills Overlook is a cul-de-sac at the top of a small hill on the eastern edge of Sunset Crater National Monument. The site is situated amid a stunning volcanic landscape with gorgeous, dark skies after evening twilight. The entrance to the park is a mere 12 miles north of Flagstaff on Highway 89.

Because this is within the boundary of a national monument, be sure to obey any posted signs. One standing rule is that there is no camping allowed inside the monument. So, if you need some sleep after packing things up for the night, you will need to move down the road a bit. There is a forest service road just across the main road from the Cinder Hills Overlook entrance. This forest service road heads outside the monument, and there are a number of places to pull off to get some rest.

This is common sense, but it bears stating--please treat this site with respect so that others will be able to enjoy it in the future:

• Park and set up equipment in a way that does not block vehicle traffic that may need to pass
• Pack out all trash
• Do not hike off road or off trail inside the monument
• Obey posted signs
• Cooperate with park personnel

The site can accommodate several vehicles. However, if you wish to plan an observing event, please contact a ranger at the visitor center beforehand to discuss your plans.

Updated February 11, 2010.

Orion and Canis Major setting over Sunset Crater

Click for larger image
JAN 15, 2010 - 03:00 AM MST
Canon EOS 300D + Kit Lens @ 21 mm • ISO 200 • f/4.5
Composite: 5 x 30 sec. aligned and stacked for sky + 5 min. foreground

While observing at Sunset Crater a couple weeks ago, I was struck by the beauty of Orion and Canis Major setting over the snow-covered volcano. So I took a break at about 3 AM to take some photos. It was a spur of the moment decision, so I didn't get everything right. The photo above is a combination of 5 30-second shots aligned and stacked for the sky, and a 5 minute exposure of the foreground. I adjusted exposure on both sky and foreground to try and convey the relative brightness of both as naturally as possible. The moon wasn't out, so the snow is lit by starlight.

A couple of the things that went wrong--
I was in a hurry to get the shot before the bright stars in Canis Major's legs dipped behind the peak, so I rushed through focus, and think I could have done better there. I also goofed up and didn't check my ISO setting...which was set to 200. D'oh! If I had set to ISO 800, I think I could have pulled the Milky Way out nicely. As it is, the Milky Way barely breaks through some severe horizontal banding noise, so I had to leave it alone. It's all about signal to noise, and I didn't grab enough signal. I did have the foresight to shoot in RAW, so I had otherwise decent data to play with. I could probably do better with the processing, but astro photos are really hard to process--especially when sensor noise wants to demolish the sky with every tiny curve move. So I called it good where it's at.

I do have plans to shoot this again when I head back out there in a couple weeks to work on a sketch for the May column. There should still be plenty of snow up there to catch the starlight. Also: ISO 800...ISO 800...ISO 800...

Mars is making its closest approach of 2010 on January 27. The red planet can be challenging to observe, but sketching your observations will help you get the most from the view at the eyepiece. In the February issue of Astronomy Now, we cover methods you can use to sketch Mars.

Sketch of Mars - CM 265°

Click image to view larger version.

Sketch of Messier 42 and Messier 43 (Orion Nebula)

Click image for larger version.

Observation Notes:

In my ongoing effort to refine my observation and sketches of M42/43, I made a new sketch on January 14. I used most of the previously sketched star field as a starting point so I could spend more time on the nebula. Working within a larger 6 inch circle really helped. The minty green color was striking throughout the nebula, particularly around the trapezium. As for structure, the sketch pretty much tells the story, except for the fact that there was a lot more detail to be squeezed out. I can tell that I'll be coming back again and again for more.

Object Information:

The Orion Nebula lies 1500 to 1600 light years away and is the brightest diffuse nebula in the sky. It is the brightest portion of a much larger cloud of gas and dust which extends over an area of 10 degrees. This cloud also contains Barnard's Loop, the Horsehead Nebula and the reflection nebula around M78. The brilliant M42 extends to a diameter of 30 light years.

The incredible complexity of the nebula is so great that various aspects of it have been given some creative names. Some of the more prominent are: Fish's Mouth = the dark lane extending from the north into the brightest portion of the nebula
Wings = the bright regions to both sides
Trapezium cluster = the bright cluster of stars pointed to by the Fish's Mouth
The Sword = the wing extension to the south on the east
The Thrust = the bright nebulosity below the Trapezium
The Sail = the fainter western extension

The Hubble Space Telescope discovered dark, protoplanetary discs called Proplyds around the region of the Trapezium. These investigations have shown that the blazing radiation of the Trapezium stars is eroding the Proplyds so that the lower-mass stars forming there may not maintain enough material to form planetary systems.

M42 was discovered by Nicholas-Claude Fabri de Peiresc in 1610, but it seems strange that its nebulosity was not discovered sooner, since it is easily visible to the naked eye. Charles Messier cataloged it in 1769.

*Based on published data.

Click image for larger version.

Observation Notes:

I've been looking forward to making another low-power sketch of this beauty. It continues to amaze me that the patch around the trapezium is so boxy. There is a break on the west edge of this patch, which brightens again on the other side. The northwest side of the larger extent of the nebula is the brightest. The southern wing has a nice sharp edge with a hook that points inward. After fading out to the southwest, there is some patchy brightening that subtly picks up again. I noted a minty green color that was strongest in the trapezium box, but extended subtly through the other bright portions of the nebula.

After having some trouble with the regular sketch paper I used on 2006/M4 (SWAN) earlier in the evening, I used a nice, sturdy sheet of smooth bristol for this sketch. It worked very nicely and took multiple layers of graphite without resistance. I did feel that my standard 3" sketch circle is not big enough for the amount of fine detail available in this object. I may need to consider a 5" circle for some objects in the future. The sketch took an hour and a half to complete and contains 103 stars.

Observation Notes:

Boy, I was fighting fogged eyepieces on this one. For this first sketch of M42, I decided to go without the Ultrablock filter. It still looked great. One common comparison is that it looks like a bird, but the way the 'wings' of the nebula are swept back reminded me more of: A) a Shadow Vessel from Babylon-5, B) a face hugger from Alien, C) a brine shrimp. Heh. Man that's not flattering for such a beautiful nebula. It was bright, and minty green in the lightest area.

When I viewed it yesterday in Bill's 18" dobsonian, it was a great aqua green with a sliver of salmon pink along the linear south edge of the trapezium pocket. It was so detailed, it looked like a dark storm cloud lit from within by a great bolt of lightning--setting its innards on fire in brilliant, ominous 3-D.

Back to my scope...the notch that flowed toward the trapezium from the east looked like a mitten reaching into a bright pocket to snatch the brilliant stars within. The larger, more diffuse interior of the nebula seemed brightest along the northern region. The outer boundary of the 'wings' on the eastern edge was gilded brighter than the rest of the inside...except for the trapezium pocket which is the brightest. I could just make out the E and F stars at 120X. The F star was very tightly bound to its bright companion. M43 punctuated the northeast section of the view with its comma outline.

M42 is also catalogued as LBN 974, Sh2-281, h 360, and GC 1179. M43 is also catalogued as H III-1, GC 1185, CED 55G.

*Based on published data.

Sketch of NGC 2244 (NGC 2239) and Sh 2-275 (Rosette Nebula)

Click image to view larger version.

Observation Notes:

If you find yourself at a dark site with Orion and Monoceros sprawled across the meridian, don't pass up this gorgeous showpiece of the winter sky. While at Sunset Crater National Monument, working on a set of observing/sketching projects, I spent an hour re-observing the nebulosity surrounding the cluster. I used a tracing of my previously sketched star field as a starting point to save time.

As before, the nebulosity was visible unfiltered, but adding the Ultrablock filter helped immensely. The central hollow was bordered by a rather straight run of nebulosity to the north. The western edge of the hollow peeled away along the northwest edge, forming a beak-like appendage. The nebula seemed to curl away on the southwestern side, allowing an opening to form on the south edge of the central void. Two nested arcs of nebulosity wrapped the east side to complete the shroud. Further out on the north east edge of the field, some more smoky structure emerged. That striking yellow-orange star still popped out along the southeast edge of the central rim.

To allow better control over the shading, I prepared this sketch in a large, 6 inch (15 cm) circle. I used an artist's chamois loaded with graphite to softly rough in the broad swaths of nebulosity. I then followed up with a graphite-loaded blending stump to build up the details and variations in luminosity.

Object Information:

The common designation NGC 2244 refers to the cluster of stars at the center of this stellar nursery. The nebulous region is described by the designations NGC 2237, 2238 and 2246. This nebula and star cluster is more than 1 degree across. Star formation is still in progress. This object lies about 5,500 light years away, and is about 130 light years in diameter. The open cluster (NGC 2244) was discovered in 1690 by Flamsteed. The nebulous regions were later discovered by John Herschel, Marth, and Swift.

Sketch/DSS Photo Comparison of NGC 2244 (NGC 2239)
and Sh 2-275 (The Rosette Nebula)

February 24, 2006 Observation:

Move mouse over image for labels.

Observation Notes:

This is really an incredible nebula from a dark site. While the nebulosity is only hinted at without a a filter, once the Ultrablock filter is inserted, its beautiful form really takes shape. The central region is home to a bright, but sparse open cluster and is mainly clear of nebulosity, with softly glowing petals of light encircling it. The brightest portion of the nebula appeared to be north of the core, and the western quadrant appeared to be lacking in stars. A bright yellow star sparkled just east-southeast of center as shown in the sketch.