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.