A Visit to “Mecca”

The American Southwest is, I think, the place that most US astronomers would think of if asked where (in the continental US) they would most like to use their telescopes. It is “Mecca”. I had the pleasure of visiting the Southwest recently and experiencing astro-imaging in October without freezing my #!* off or having to deal with dew… all while enjoying very dark and clear skies.

This visit came about as part of a recreational RV trip to Tucson, Arizona that involved stops at points of interest along the way (Mt. Lassen National Park and Bodie, CA, the well known California ghost town) and attendance of the Oregon State-Arizona football match-up in Tucson on October 9th. Astro-imaging was on my mind from the start in planning this trip, though initially I was thinking it would be in southern Utah (via Yellowstone). When our Yellowstone trip was aborted (due to my wife’s migraine and my cat’s incompatibility with life on the road), the trip was re-started with a new route and Arizona became the clear choice to take advantage of the October’s moonless nights.

Looking forward to this trip, I thought a lot about getting a new camera to take better advantage of the opportunity. The major limitations of my ST-402ME are that 1) it is not an anti-blooming chip and 2) the chip is very small. As a result, exposure times are limited to far below what I’m capable of doing with my mount and there are objects that I simply cannot fit into my field-of-view (FOV). After considering the one-shot-color vs. monochrome pluses and minuses, I was thinking I’d like to get a monochrome and use a color wheel as I had done with the ST-402ME. My thinking here was to retain resolution and flexibility in the composition of my images (i.e. filter usage and RGB processing techniques)… despite the longer times required to acquire and process the image. I had in mind the ST-8300, a new camera by SBIG that had a much bigger, anti-blooming chip and would cost around $2900 for camera + filter wheel.

I ran out of time to purchase a camera before the trip, so along the way I looked up astronomy shops in Phoenix and Tucson. Surprisingly, Phoenix didn’t have much, but Tucson had “Starizona” and they stocked the SBIG camera. When we got to Tucson, Starizona was our first stop (well, Starbucks was the first stop for my wife, who waited out my camera-buying mission there). I told Dean (my help at Starizona) about my existing equipment and thoughts about a new camera and he recommended the Starlight Xpress SXVR-M25C, a one-shot color camera, saying basically that it was a “wonderful” camera that I’d be very happy with. He showed me pictures taken through this camera and I learned that a well-known imager who visited the shop while I was there also owned one. The price was $3100. Dean mentioned that the dark-currents on this camera were particularly small, such that often great pictures can be taken even without dark-frames. I knew the chip wouldn’t be as sensitive as the SBIG chip and I knew OSC would compromise my resolution (using 4 pixels in each shot to gather the color data), but his recommendation and the time savings (plus a bit of time-pressure to buy…to take advantage of the Arizona skies) influenced me to make the purchase. I’ve since had some twinges of regret… more on that later.

I asked Dean for recommendations on a place to do my imaging and he said that one of the best places was Chiricahua National Monument in SE Arizona, about two hours east of Tucson. One can view there at about 7000 feet with dark skies from horizon to horizon. My wife and I had already been planning on visiting Chiricahua, so this sounded perfect to me. Unfortunately, sunny Arizona wasn’t so sunny during our visit. The mornings would typically be clearer, but in the evenings the clouds would start piling up and thunderstorms would blow through in the evenings. On these cloudy days we saw the Tucson area sites, while I looked forward to what was supposed to be clearer weather in the few days just before the OSU-UA game on October 9th. The plan was that we would head home Oct. 10th.

We targeted Chiricahua for Thursday October 7th and it didn’t disappoint us. We arrived early in the afternoon and let the people at the entrance to the national monument know what we wanted to do. They told us that it would be fine for us to stay in a parking lot in the park all night, but that we should have a reservation in the lone campground (only $12). What a small price to pay! We got our reservation and proceeded to check out the sites of Chiricahua, meanwhile scouting out parking lots for the best one for astro-imaging. We ended up choosing the Echo Canyon parking lot, which gave us the best unobstructed view of the horizon.

Chiricahua is an amazing place. It was worth the visit even if it weren’t for the fact that I’d be doing astronomy there. While I’ve seen places with interesting rock formations, Chiricahua has so many that there are (literally) interesting sites around every corner on its trails. The scenic vistas look out over canyons that are filled with spires of rock that are left over from thousands of years of erosion. The rock has broken such that some of these spires consist of boulders stacked upon boulder. Some are single boulders supported only by a small neck of rock at their base such that they look almost like oddly shaped mushrooms. We followed the Echo Canyon trail down to what is called the “Grotto”, where enormous boulders are packed closely together with large eroded pathways between them, such that we could walk through. The trails draw you in. You see so many interesting things that you find yourself walking just a little bit farther to see what is around the next bend until you end up walking a lot farther than you originally intended.

A typical Chiricahua vista

One of many amazing rock formations!

A ho-hum Arizona sunset... a great prelude to a dark, clear night of imaging.

While my wife was not interested in the astronomy, she said she considered that evening watching the sunset from her “room with a view” at the Echo Canyon parking lot, as being the “perfect RV moment”. The sunset was impressive, though probably fairly ordinary as Arizona sunsets go.

The weather reports were right on. The skies cleared and I enjoyed a perfect night of astro-imaging. I had experimented with the camera for a few hours at the RV park we stayed in the previous night. It was a terrible location, with power lines obstructing my view to the east (where the main objects of interest were) and there were some clouds drifting over that evening. However, that practice time was great for getting me through the necessary learning with the new camera. Issues I thought may come up did come up. The new camera is a bit lighter than the ST-402 and my scope was always at the limits of its weight adjustments. I ended up having to tape a pair of pliers onto the mount to provide sufficient counter-balance! It worked fine, though I certainly want to find a more elegant solution (the next night at Chiricahua I used an iron pipe-fitting…slightly more elegant!).

I downloaded a trial copy of Maxim DL, but found that I didn’t like its focusing tools and ended up going back to CCDSoft to control the camera. What I learned later from Dean suggested that perhaps my issues with Maxim were due simply to my insufficient training (seems likely). Two things I’ve learned about the new camera… 1) Vignetting occurs when I use 1.25” extension tubes/adaptors, and 2) with the wider field of view I’m now collecting most of the light coming through my scope and, as a result, am picking up the non-flat field effects at the edges. I can easily switch to using a 2” extension tube. For the vignetting, I can try to find field-flattening optics that will correct it or simply crop my images to exclude the defects; the latter should be fine as its seems that I can fit some of the biggest deep-sky objects easily within my FOV with plenty of room to crop.

My primary targets at Chiricahua were: M31 (Andromeda), The Soul Nebula*, M42 (The Great Nebula in Orion), and the Rosette nebula*. All are big objects and I had never viewed two of them before (those with *’s). Because of the OSC feature, I ended up having time to look at more objects, so I also imaged the Horsehead nebula*, M81 and M15 (globular cluster). On M31 I took exposures as long as 30 minutes, however the quality of that image did not seem to be good enough. I ended up backing of to 10 minute sub-frames because I also wanted to capture a few dark-frames and 10 minutes was short enough to make collection of several of them practical. I took no flats that evening, though I certainly will in the future to help with any residual vignetting. I had never been able to take such long exposures with my ST-402 because of blooming effects on the brighter stars. However, with the ST-402, the chip was more sensitive and I now have to take longer exposures to capture the same detail on the SXVR-M25C (a result of the Sony chip SX uses).

The Rosette Nebula (10' x 3)
The Soul Nebula (10' x 3)

The Great Nebula in Orion (10' x 3)

The Horsehead Nebula (10'x3): Could have used more data, but I love it!

After having gone pretty far down the learning curve of processing RGB images, I now find myself starting a new learning curve for the OSC camera. Finding the right parameters to do the de-bayering (color synthesis) has been a pain so far. I ended up going back to Starizona and having Dean help me with processing some of these images (using Maxim). While I’ve had some success with the nebulae, I’m not yet comfortable that I’m getting the right colors on stars and galaxies. I am leaning towards purchasing Maxim DL (despite its very high cost) because it seems easier to do the color conversion on it that with CCDSoft and because many imagers I know through RCA do use Maxim and “swear by it” (and not so much AT it).

I love the new capability of doing longer exposures and capturing larger objects. I have never before been able to fit all of M31 and its companions into one image. Nor could I have captured the Rosette or the Soul Nebula, which turned out to be very faint even with 10 minute sub-frames on the M25C (I ended up summing the images). In the image of M15, I am concerned that the resolution seems poorer than my ST-402… the stars not as sharp… though I think I need to experiment with this more to make sure it wasn’t just a function of the circumstances of that imaging session. The sensitivity and resolution questions are what give twinges of regret and make me think that the smarter decision would have been the SBIG ST-8300 (monochrome)… but it’s too late now!

M81 (Bode's Galaxy) - Monochrome. I still can't get good color on galaxies. I have never before been able to image it with these other nearby galaxies though!

M15 : Zooming in on this, it just doesn't seem as sharp as it should be. Also, again the color is difficult to get right.

M31 - Poor color and probably not enough data with (10' x 3). This image is uncropped and the field flatness issues are evident at the corners... but isn't it great to get so much of M31 and the companions within the image and even within the edge effects!

It’s now late October and the weather of the Pacific NW is looking a lot more like winter. The long waiting period has set in for warmer, dryer, clearer nights in the spring or summer of 2011. I am hoping that the spring will provide a few such nights within the short stretches of those without the moon’s brilliance. There are objects I haven’t imaged yet that descended too close to the horizon before I could image them in 2010. I will spend my time learning as much as I can about using Maxim DL and doing OSC processing. I also will clearly need to spend some time learning how to push the limits of the capability of my mount and guiding to provide decent long exposures.

Having had a taste of astro-imaging in “Mecca”, I’m sure to think of it often from now on as I suffer through lost opportunities and marginal conditions in this area.

Eight Days on the Road

I spent Aug. 6th to 14th on the road in the RV, spending three days at the Rose City Astronomers observing site near Maupin, OR, one day at an RV Park in Prineville (recovery time) and four days at the Oregon Star Party in the Ochocco mountains of Central Oregon.

Clouds were a problem at Maupin and there was very little time when any good images could be taken. It was a good time for experimenting and I did just that by using a new 2.5x Barlow lens the first night. I targeted four objects, Hickson 68 (galaxy cluster), M82 (the Cigar Galaxy), M76 (The Little Dumbell Nebula), and Jupiter, all of which are fairly small. Because of generally poor seeing that night, it is difficult to say much about the adequacy of the optics of the cheap APO Barlow lens (OPT, $49.95). One of my concerns was that I might not be able to easily find and center the objects, but I was successful on every one of them. The images (except for Jupiter) are shown below. Jupiter is still too bright at minimum (0.04”) exposure. I was able to see some banding in the clouds, but the disk is still very small with the 2.5x Barlow.

The picture of Hickson 68 (90” x 16) can be compared to an earlier picture posted here (July 13, 60”x 16) to get an idea of the impact of the Barlow (size only, since seeing was very different). The bright nearby star forces short exposures due to blooming. There are four galaxies pictured, but only one is a pretty spiral, with the others being fuzzy blobs.

The picture of M82 was perhaps my best during my time at Maupin (except for the photos of the dazzling sunset I captured). The galaxy offers a lot of interesting detail and I definitely want to go back to it next year under better conditions and get more data. Both RGB and LRGB images are shown, Lum 120”x17, RGB 120” x 5, 2x2 binning).

M76 is small (even with the Barlow), but colorful. It definitely needs more exposure time. This one was Lum (120” x 9), RGB (120” x 5).


Hickson 68 (Galaxy Cluster) with new 2.5x Barlow Lens


M82 (Cigar Galaxy) RGB image with 2.5x Barlow Lens


M82 (Cigar Galaxy) LRGB image with 2.5x Barlow Lens


M76 (The Little Dumbell Nebula) in LRGB with 2.5x Barlow Lens

The second night and third nights at Maupin did not yield decent results due to wind and clouds forcing shorter exposures. The next day I went on to the Crook Co. RV Park in Prineville and spent the time cleaning out the RV, emptying the grey water tank, filling up on fresh water, and of course getting showers (one in the evening and one in the morning… it was great!). I had my bicycle, so I peddled down to a small store to get some supplies.

The next afternoon, I went on to Indian Trail Springs (site of the OSP). The first night there the clouds just got worse and we had rain and thunderstorms with no opportunity to do any imaging. The next three nights, however, were great! Wednesday was the official opening day of the star party and I imaged four deep sky objects and one main-belt asteroid (Klotho). The DSO’s were NGC253 (Sculptor Galaxy), the Cocoon Nebula, the Crescent Nebula, and M51 (the Whirlpool Galaxy). Conditions were perfect, so I took exposures that were limited only by blooming of brightest stars. I was awed by the Sculptor Galaxy, as I had never seen it before and was pleased with the images I got (Lum: 6 min. X 7, RGB 90” X 9). Auto-guiding worked perfectly this evening but I realized from this experience that I should have gotten a camera with an anti-blooming chip so that I could have gone far longer in my exposures.


The jaw-dropping Sculptor Galaxy (NGC 253) in LRGB


The Cocoon Nebula in LRGB


The Crescent Nebula in LRGB


M51 (The Whirlpool Galaxy)... one of my favorites.

The third night there I failed to get images of my two primary targets (Bubble and Pelican Nebulae) due to errors in my auto-guiding (Orion Starshoot with PHD software). The errors came during calibration and indicated that there was not enough motion of the guide-star to allow calibration. One of my neighbors pointed out that this was probably due to the object being close to the pole and that was probably the case. I didn’t want to try taking very long exposures without auto-guiding so I abandoned these objects and got images of back-up targets, the Helix Nebula and globular clusters M12 and M13. I also picked up my second-night images of Klotho (the idea being to get images on two different nights to easily pick up its motion). All of these images are shown below.


The Helix Planetary Nebula


M12 - Globular Cluster


M13 - Globular Cluster





Klotho: Top image from Aug. 11 and bottom image from Aug. 12. Arrows indicate the position of Klotho, listed as magnitude +11. This asteroid is in the main belt and is fairly large at about 83km diameter. The object in the lower left corner is an irregular galaxy (IC 1613) and in the upper right corner there is a cluster of small galaxies (ACO 147). This setting was one of the reasons I chose to image this asteroid.

The next day I found out from another RCA imager that there is a setting in PHD called “Calibration Step Size” that, at my focal length, can be set higher to allow more motion of the guide star. I moved it from its default value (500ms) to 3000ms and was able to successfully auto-guide on the Bubble Nebula my last night at OSP. I still got the same failure to calibrate on the Pelican Nebula, so next time I’m just going to have to run longer exposures without guiding and see how it works out. As a substitute, I imaged a part of the Veil Nebula (NGC 6992) and also M101 (spiral galaxy).


The Bubble Nebula


The Veil (NGC 6992)


M101 (Spiral Galaxy)

Though I only had a little over 3 days (out of 7) of good conditions for imaging, I’m pretty happy with what I got out of it… both in the new learning and in the images.

Space Junk or Asteriod?

A side-light of the Trout Lake Star Party was that I picked up a bunch of objects going across my short (30s to 1min) images. In one case I actually had two different objects appear in two consecutive frames! Most of these seemed pretty ordinary and were confined to single frames. The tendency is to immediately discount them as shooting stars or man-made satellites. However, on this night, one of them stood out as special.

While I was taking a series of 30sec images of M17 (The Omega Nebula) I had four consecutive frames in which the same object drift across my FOV. Not only was this relatively slow speed interesting, the object showed up as a "dashed", as opposed to continuous line of light. As my friend Ed pointed out when I described this event to him, the object must have been tumbling and must have either an irregular shape or a varying reflectivity across its surface. The pattern suggests that it rotates approximately once in every 3.75 seconds. The four images of this object are shown below.

Of course I'm wondering what this is. Given that it is tumbling, it must either be space "junk", mankind's garbage-in-the-sky, or be an asteroid. Is there any way I can tell? What immediately occurred to me is to check the speed of the object by measuring its track in arc-seconds, calculating the distance with the assumption that it is in a circular orbit in a typical range of altitudes, and dividing by the exposure time. With orbits ranging from 125 miles to 10,000 miles, the calculated speed comes to the range of 23,500 mi/hr to 52,750 mi/hr. This is significant in that required orbital velocity for that range of altitudes is 17,500 mi/hr to 9,420 mi/hr... suggesting that it is traveling too fast to be in a circular orbit. This leaves the possibility that it is either traveling in an elliptical orbit and we are seeing it at is closest approach (where it travels faster) or we are seeing an object that is indeed traveling faster than orbital speed and not in orbit of Earth.

A little research shows that most space junk is in very close to circular orbits and only a very small fraction has high eccentricity (going as high as 0.75). I can't exclude this possibility.

If I had been able to track this object for a significant period of time I might have looked for evidence that the track length was changing, which might indicate that the object is not traveling parallel to my position... but it was traveling fast enough that this wasn't a possibility.

My ability to narrow this down at this point is running towards the end of the rope. My last check was on the Internet, to investigate whether any known object was passing across M17 at that moment. I found this link, which allowed me to make this check and alas, no such object was in the database. Unfortunately, it appears that the database for space junk is not online.

I'm left wondering...space junk or asteroid? ... but I'm spurred on now to start observing known asteroids and to further investigating the amateurs options when it comes to the NEO (Near-Earth-Object) search. At OSP, I'm going to try to look for asteroids named Klotho and Hippo.



The object enters my images and proceeds across M17 in the next three images. The date of observation was 07_11_2010 and the time on this image was 07:33:35.061 (UT).


Time stamp 07:34:06.449


Time stamp 07:34:37.867


Time stamp 07:35:09.317. Goodbye!

M33 problem

This image displays the problem I was having with an RGB combine on M33. Click on the image to enlarge it. I've described the detailed background on the RCA messageboard (repeated here below the image) an have provided them with a link to this site.



Camera: ST-402ME
Scope: 80mm Orion EON
Filters: IR filter
Guiding: Unguided
Conditions: Clear sky, but some gusting wind.
RGB Exposures:
R: 1' x 5 Binned 2x2
G: 1' x 5 Binned 2x2
B: 1' x 5 Binned 2x2
Processing: I did the reduction with both CCDSoft and DeepSkyStacker and got the same result. I've tried it with both adding images during the stacking and using a median combine (thinking that what I was seeing might be noise-like), but got the same result (picture attached) when I stacked them. Darks and Flats were used (12 each with both median and average combine).

UPDATE: Thanks to a fellow imager at RCA (Duncan) I've found out what error I made to cause this. When I take 2x2 binned R,G and B images I need to have 2x2 binned dark-frame images to use in their processing. I would assume this would apply to flat-frames too. Makes sense, but I didn't think of it... a bit more learning "the hard way".

Imaging At Stubb Stewart

On July 14th I slipped in one last night of imaging before the moon returned to the night skies. This time I went to Stubb Stewart State Park near Vernonia and took my friend Ed. The sky was clearer than Trout Lake, but once again there was wind to contend with, plus a bit of sky-glow from Portland to the east. Two other astronomers were also there, but not imaging.

Set-up and alignment went smoothly and I was able to image five objects, as follows: 1) The Whirlpool Galaxy (M51), 2) The Eagle Nebula (M16), 3) The Triffid Nebula (M20), 4) The Pinwheel Galaxy (M33) and 5) The Andromeda Galaxy (M31). I've imaged all of these before except M20, which I think has become one of my favorites. The others I chose primarily because I wanted to show Ed some of the nicer ones available... though I wanted to return to the Eagle Nebula to get a better image of the structures in the middle of it, which I found are the "Pillars of Creation" that the Hubble Space Telescope has made famous. My last color image of these did not show good detail of these features (though that was largely a function of the seeing that night and my limited image processing skills... because I have seen good color images of them by amateurs).

I tried to set up my auto-guiding camera, but when it came time to focus it I was unable to find any guide stars (or any stars at all for that matter). I'm hoping this isn't a hardware issue. I need to set up the scope in the backyard before I go to OSP and test this after aligning the guide-scope to the imaging scope; that way I'll know for a fact that there are good guide stars in the field-of-view (FOV)and will spend more time trying to achieve focus. As a result, I spent the evening as I did at Trout Lake, taking exposures of one minute or less... something I probably would have ended up doing anyway because of the wind.

Image-processing on the monochrome images came out very nice. I took no color data on M16, M51 or M31. Those images are the first shown below. The image of M51 is one of the best I've taken and is good enough data that it will be worth adding to later. The M16 data shows the pillars (star forming regions) very distinctly... just wish I could get higher magnification!! M31 needs more data to do it justice, but does show the dark dust lanes. I plan to go back to this one at OSP and use a focal-reducer that will give me a wider FOV. I'll take more data hoping to be able to show close to the full size of this object (which is actually much bigger than the full moon!).

Image processing of M20 was completed as an LRGB, but I'm a bit disappointed in the results. I had a problem on this one and M33 with extra "stars" showing up that were pure-color (red, blue or green) and therefore looked unnatural. They seemed to be someone systematic but around only a portion of the stars. It looked almost like misalignment, but couldn't have been because of the fact that not all stars showed it. I need to keep working on this because it is a major limiter. I've done color images before and haven't seen this, so I'm hoping it was another result of the wind or something unique to my setup that evening. M33 is a beautiful, large galaxy. I'll try to gather more data on it at OSP.

It was great having Ed along tonight... not only as company, but also because he helped me out in a couple of situations where I was being stupid (like... where did that darn tube extender go?...Ed-"Is that it on the camera?"). He loved getting away to a place where the Milky Way was visible and enjoyed seeing the images and how they were created.


M51 - The Whirlpool Galaxy


M16 - The Eagle Nebula, including the "Pillars of Creation", star-forming regions that the Hubble has awed people with.


M31 - The Andromeda Galaxy


M20 - The Triffid Nebula


M33 - In monochrome because I couldn't make the LRGB work... too many artifacts that I've so far been unable to understand and eliminate. This one was processed with DeepSkyStacker tools before Photoshop (instead of CCDSoft).

Trout Lake Star Party

I've marked the days on my calendar for each of the summer months to indicate which ones are best for astronomy. This month it was July 7th to 16th based upon the moon's absence. Beyond that, all plans are at the mercy of the weather, which is usually going to be pretty good east of the Cascade mountains. This month the plans were to take our new RV to Emigrant Springs State Park in the Blue Mountains of Eastern Oregon July 6-9th and then for at least me to attend the Trout Lake Star Party in Washington (north of Hood River, Oregon) on at least the night of July 9th. I would have my equipment at Emigrant Springs, so I figured I would try to do some imaging there.

As it turned out, when I tried to image at Emigrant Springs I found that I had not packed a box that contained some key cables for my imaging set-up. Lesson: Consolidate all of the critical equipment into as few boxes as possible. It's really too bad, because the clarity of the sky there was amazing. The only difficulty was that the horizon was not great at the best location in the park for viewing (in front of their Community Building). Having to decamp briefly to move equipment up to (and down from) that site was a bit of a hassle too.

My hopes for doing a significant amount of imaging in July now came down to the Trout Lake Star Party. I called my son, who was planning on meeting us in Hood River to take my wife and daughter back to Portland, to ask him to bring along my missing equipment. I was then determined to spend as many nights as I could at Trout Lake.

The plan came off without a hitch... at least the part that I could control. The first night at Flat-Top Sno Park (the actual site north of the town of Trout Lake) became cloudy after initially being clear. Not thick clouds... broken, thin clouds that would keep you guessing as to whether a portion of the sky where stars were visible was really clear or not. I tried to image in what appeared to be clear portions of the sky, but I won't do that ever again under similar conditions. Many times that night I would start imaging and, after getting a few nice frames, start seeing the image quality (noise level) change from frame to frame trending towards pure noise. I would have been better off getting more sleep in preparation for the next night. I did get a few tantalizing frames of The Eagle nebula in monochrome and a few of The Whirlpool galaxy (both shown below). Towards the end of the evening, conditions did improve a bit and I was able to capture my first color picture of a globular cluster (M92) and took a full set of flat and dark frames for the first time. The fully processed RGB image of M92 (with dark and flat frame reduction using CCDSoft) is shown below.

So my hopes were now set on the next evening. As dusk settled in, the skies stayed clear but the wind began gusting. I set up and aligned the telescope anyway (with the hope that the winds would settle down) and began imaging with short (30") exposures to avoid the effects of the wind gusts. This approach did work, but it was clear that about 30% of the frames were going to have to be tossed due to the tear-drop shaped stars created by the stronger gusts. The winds only got worse until at least 2am to 3am, when they did settle down quite a bit.

In this time, I did get some images, though the winds did have an effect on the quality. Additionally, the skies there did not have the clarity of those at Emigrant Springs (proximity to urban pollution?). While I know the images aren't the best I can do, this was a good opportunity to begin imaging some new objects and to practice new techniques.

The major accomplishments of this second night were 1) Galaxy-group Hickson 68, 2) color imaging of The Eagle Nebula (M16), 3) Color imaging of The Omega Nebula (M17), and finally 4) Color imaging of the PacMan Nebula (NGC281). Mid-way through imaging M17 I converted to taking a set of darks rather than using the "auto-dark" function in CCDSoft. I realized that there were defects I get by using single darks that can be eliminated by using a master dark created by averaging a set of dark exposures. I plan to use this approach in the future for everything except images for initial centering. I found that despite having to re-focus part way through the night, I could use the flats I generated that morning for all images I generated that night.

I finished my last image at about 3am. Though I was thinking about getting another set after that, I had made the mistake of going into the RV to lay in bed while watching for the camera's red LED to stop blinking on my last set of exposures of NGC281. Bad idea. Next thing I knew, it was 5am. I got up and very inefficiently (in a mental fog) took my flat frame images and then put away all of my equipment.

While I could have stayed more nights, I was not hopeful that the winds or seeing would be any better. However, instead of hastily driving away as early as I could that morning, I took full advantage of our new RV to take a shower, cook myself breakfast, and chat with some of the people who were still around and awake. It was SO nice! In the past, I would be feeling smelly, greasy, and worn out such that I was very anxious to get home. With the RV, it is clearly possible for me to make my imaging excursions longer and more enjoyable. I'm really looking forward to trying to stay four or five nights at the Oregon Star Party early in August. In the meantime, I'm going to try to catch one more night in July at a local observing site.



A few frames of The Eagle Nebula with some intriguing detail.



A few frames of M51, The Whirlpool Galaxy. I'm anxious to go back to this beautiful object and "go deep" with some longer exposures.



My first color (RGB) image of a globular cluster (M92).



The Hickson 68 Galaxy Group. Four galaxies are visible here in a very tight space. I had been wanting to do this for quite awhile. They are very small, but I want to come back to them and see how much more detail I can pick up with longer exposures.



The Eagle Nebula (M16) in LRGB. Considering the conditions, this isn't bad... but this is definitely one to re-image in better conditions.



The Omega Nebula (M17) in LRGB.



The Pacman Nebula (NGC281) in LRGB.

Preparations for Imaging in July

In the wake of the Skyview Acres trip I have solved some of the problems I had noted. First, I confirmed something that a friend at the star party told me... appearances can be deceiving on the filter colors. SBIG tells me that the filters will often reflect the complement of the filter color and that you can see the actual colors by using a flashlight on them. So... what I thought was Red was Green, What I thought was Blue was Red and what I thought looked yellowish and assumed was Green, was actually Blue. That still left the problem of having to specify Blue in CCDSoft to get no filter over the CCD window. It turns out that in the settings window, beside the specification of the filter, there is a button for filter settings that allows you to change the name associated with a filter position. All I had to do was change the default settings such that the one labeled Clear was actually Blue and the one labeled Blue was Clear and that solved the problem.

One more thing I will do before July is to clean the filters. I had noted that the filter I was calling green was showing some brighter stars as being bloated. This led to some green rings around those stars when I did an RGB combine. A fellow imager suggested to me that this filter may be dirty. With a cleaning I think I'm going to be ready to do some great imaging in July! Primary targets will be the "Omega Nebula" and Bode's galaxy, both of which will be more difficult to image later in the summer. I've imaged Bode's before, but want to "go deeper" with longer exposures and perhaps some color. I've never imaged the Omega Nebula. After those I will be going back to some of the Nebula I observed last year to try to get better images with some of the new techniques I've learned.

I went back to some data I collected last year at OSP on the globular cluster "M22" with the idea of applying my improved processing skills. In the first try last year, I ended up only using the 6" exposure because it was the only one in which I could avoid saturating the core of the cluster... but such a short exposure lost detail in the outer parts of the cluster. With two learnings: 1) importing the files to photoshop as 16-bit TIFF' and 2) using the Curves adjustment in photoshop, I was able to combine all of my three exposures (total of 56") and keep the core from saturating (turning into a big white blob). Both pictures are included below for comparison, as well as the 30" exposure from last year with a saturated core. The 56" exposure (6"+20"+30") is a huge improvement! The dark skies at OSP are great for getting better sharpness in the stars. I'm going to try to image another one this August and include color.



A 30" exposure without applying my new learning. Note the saturated core.



A 6" exposure from last year without latest learnings. Detail in core but lost detail in the outer parts.



Summed exposures (6"+20"+30") with latest learning applied. Best yet!

Skyview Acres Star Party

With my son, I attended the Skyview Acres star party June 11-12 near Goldendale, WA. This was the first time I've used the new RV for this purpose and it sure does make things better! Being able to go inside and warm up in front of a furnace vent is such a pleasure. In this case though, the cold wasn't so bad... it was the dew.

With temperatures in the mid-40's I was hopeful that I could start my imaging season as early as May, based upon the weather history. Last year I started late enough that I never encountered any dew. This year I've imaged twice and both times there was more moisture in the air than any time last year (when I started in August after finally getting all of the necessary equipment). In May, in my backyard, I took an image of M101 and saw some strange artifacts in the background. I suspected dew or frosting in my camera and replaced the desiccant bag in the CCD chamber just before this trip. It didn't work.

My primary suspect now is either condensation on my objective lens or inside the camera on the cover plate to the CCD chamber. There was no evidence of a cleanliness issue on that plate or the filters when I replaced the desiccant bag. Next time I image it needs to be in dry conditions to test this theory.

The Skyview Acres site was bad for dew because there was a lot of fairly tall grass and moisture in the ground. That moisture became worrisome early in the evening when it started condensing out on my table. I never really saw or felt any on my telescope, but I can't rule out that it was there in very small droplets. Conditions were certainly on the edge.

I went ahead with my imaging both nights but quit in the range of 1am to 2am, primarily because of the dew concerns. On the second night I had thought the dew situation would improve. It had been warmer during the day and a bit warmer at night, but the dew actually seemed worse.

The first night I imaged two objects (M63 and M100) in black and white only. Early on it became evident that my camera was not working right and I diagnosed that it wasn't taking dark images properly. Instead, they were similar to the light images and when they got subtracted off with slight motion of the scope (unguided) it left "shadows" beside all of the stars. I got around this the first night by taking a set of manual darks (covering the lens with the cap) and taking light images only. The next day I took apart my camera and found that I had not properly set the color filter wheel in place on its axle and it had come loose.

M63 and M100 were targets because I had never seen them before (weren't in the sky when I started last year) and they seemed to be interesting objects (not just fuzzy blobs). M100 is a pretty spiral galaxy and M63 is a galaxy with an odd dark arc around one side of its core, earning it the name "The Black Eye" galaxy. These were both smaller and fainter objects than I've typically imaged in the past. M64 is 10'x5' in size and magnitude 9.3. M100 is 7.6'x6.8' in size and 10.0 magnitude. I used no auto-guiding that night, so I was confined to getting multiple short (1 min) exposures that I would later stack together. The resulting pictures are shown below, where, for M100, I included a pre-processing image and a post-processing image, to give you an idea of just how much clean-up happens even after the darks are subtracted and the images were stacked. Total exposure time on M100 was 21 minutes and on M64 was 11 minutes. You can easily see the "black eye" feature, but little else on M64. M100 could have used more exposure time, but it's really nice spiral shape is very evident... it's just really small! Objects of this size could really benefit from using a longer focal length scope for imaging.

The second night I imaged three objects: M101 (spiral galaxy, 21.9'x21.4, mag 8.4), M5 (globular cluster, 23'x23', mag 5.7) and M8 (The Lagoon Nebula, 17'x15', mag 5.0), in that order. You can see that the sizes of these were around 2x or more larger and they were all brighter than M64 and M100. Images, post processing are shown below. M101 needs more processing work but may be too limited by the artifacts for the color image to ever be all that good. Both color images are LRGB, combining Red-Green-Blue filtered images with an image taken without any filter (Clear). This is the first time I've created such images successfully, having utilized Photoshop and instructions from Ron Wodaski's first book. In order to get the color to come out right, I had to pretend that the Blue filter (Blue based upon appearance) was Red and vice-a-versa... something I still need to explain. When I had the camera apart, I tested the filter wheel and noted that what was specified by the software was not what the ST-402 camera delivered. Instead, "Blue" was clear, "Clear" was green, "Red" was blue, and "Green" was red. I thought I may have gotten the filter wheel on in the wrong position, so I changed it 180 degrees and the got the same result. If my error is judging the filter by its naked eye appearance, that still can't explain why specifying "Blue" results in no filter in front of the CCD. An email to SBIG is warranted.

All in all, this was a good trip. The M8 photo was pretty good and I again learned a lot about what can go wrong. Hopefully future sessions will be better because of it.



M101 - Luminance image, 37 min exposure (37x1). Processing needs more work!



M101 - LRGB image (37' Luminance + 12' RGB)



The Lagoon Nebula in Black and White (Luminance 100')



The Lagoon Nebula - LRGB image (100 sec Luminance + 3 min RGB)


M5 - Globular cluster. A single 10 sec. image w/curves adjustment and unsharp mask.



M100 - Pre-processing after dark subtraction and stacking



M100 - Post-Processing (Gradient removal, Curve adjustment, blurring)



M64 - The Black Eye