January 29, 2008

NGC 2903's Environs - Final

Here is a completed map of the NGC 2903 image.

Folks from the NHAC have helped me answer some of the questions I posted about it. In particular, Kenneth (drako) Drake confirmed that the potential galaxy is actually a galaxy. I had looked at the POSS prints, and some deeper amateur photos, and it looked like a galaxy to me, but drako reported that Larry Mitchell, a long-time deep-sky observer---a real expert, had catalogued it as a galaxy. Here are the stats: Mitchell Anonymous Catalog [MAC] 0932+2121. Mag: 16.5. Size: 0.5'x0.1.' RA: 09h 32m 18.7s. Dec: +21° 21' 25."

Drako also inadvertently helped solve another puzzle in the image. An object appeared to be moving during the exposures. On the combined image, it appears as a short streak rather than a point. A few weeks ago, drako gave the NHAC listserv a notice of near-earth asteroid TU24 and pointed out the JPL website that calculates ephemerides for asteroids. I had earlier found a Lowell Observatory website (here) that would identify asteroids in the vicinity if I entered a time and coordinates. After finding an asteroid in the vicinity on the Lowell site, I obtained an ephemeris from the JPL site, then plotted the path of the asteroid in a detailed online atlas. Sure enough, asteroid #1210 Morovisia, mag. 14.7, was right in the image while it was being taken. It was right where the streaky line is, going in the direction of the streak, and the magnitude is within range.

Amazing! I still can't believe I can do this from the backyard, and I can't believe what one can catch with such a simple camera and simple procedure.

Thanks NHAC and Kenneth Drake, for sharing.

January 18, 2008


I was delighted to get this image, but I have several questions about it. To aid in asking them, I have posted a key. Neither reduction on this page does the image justice. For a clearer view, please click on either. The clicked-on, non-key version is less damaged by digital interpolation.

The large galaxy in this image is NGC 2903, in Leo. There are three and maybe four other galaxies in the photo, also. I was delighted to see these only after the data was processed. The (apparently) next largest galaxy is UGC 5806 or PGC 27115. It is the smudge near the bottom of the image. It is called a dwarf galaxy in some papers. A few call it a satellite of 2903, but the distances to these galaxies vary as reported. The distance estimates I have seen for both would at least put them in the same group.

Three more galaxies are to the right of 2903. One is PGC 1648681. I find this galaxy very interesting. Not in my image but in other images (here, a slow-loading link, as are the next two links) this galaxy appears to have a central bar and spiral structure, much like NGC 2903. Can dwarf galaxies have such a shape? If not, then is this galaxy far in the background? How far?

Further up in the top right corner of the image is another smudge that is PGC 1647510. Lower and a little to the right of PGC 1648681 is another shape that I have been unable to identify. But I have seen it on the deeper images that I have found on the web (here), and it looks galactic in them to me. It does not form a stellar shape in my image, as I see it. I would be interested in others' opinion of what it is.

Just below that is an apparently moving object. There is nothing that bright there and nothing that shape in any other image that I have seen (for instance, here). This is about 26 minutes worth of consecutive images. Whatever it is appears to have moved that much in that amount of time. How would I find out what it is?

As usual, this image is a DSI Pro set gathered through the Vixen R135S, unguided on the LXD75.

January 16, 2008

My First Horsehead Image

The Horsehead Nebula! It was gathered, like all my ccd images so far, on an unguided LXD75 mount with the DSI Pro. This image was taken through the R135S newtonion at f/4.8 and is about 26 minutes worth of 6-second exposures. What amazing things I can see from my own backyard!

January 15, 2008

January 12, 2008

Later church meetings on Sunday and a clear sky Saturday night meant I could spend some time imaging. I was hopeful to go to the dark sky sites where club members were gathered, but my bride preferred me to be home, and I was able to see my kids, too. I saw some great things in the sky, though! I collected my first images of the Horsehead Nebula! I had never seen it before Saturday either visually or through the camera! Also, I collected images of NGC 2903. I'll post these later when they are processed. I also obtained data from the Cone Nebula, but I'm not sure how it will come out. If it works, I'll post it. If not, maybe next time. Preliminarily, that one looks like a good candidate for longer exposures and auto-guiding.

January 8, 2008

Deep Sky Standby Survey

The Deep Sky Standby Survey, conducted right here at Polaris B, has closed. Many thanks to the 11 participants!

The question: What deep sky objects do you always look at if they are up?

The winner? Seventy-two percent of you always look for M42, M31 & its companions, and M45 (the Pleiades).

Next, 63% of you (myself included) always view the Double Cluster.

M57 attracts 54% of you when it is up, as does Polaris (which I usually split, but it is also a great place to collimate a Dob, because it does not move).

Forty-five percent view Omega Centauri, Albireo, M22, M13, M51, and M8.

Thirty-six percent view M16, M17, and M27 when they are up.

Everything else on the list received a vote or two or three: M6, M7, M33, M81&82, M97, M101, M104, the Horsehead & Flame (I look for these all the time and never see them (from suburbia)), the Veil, the Helix, the Cat's Eye, and some "other." There were no comments, so I don't know what this "other" is, but after I put up the poll, I realized I'd forgotten Mizar and Alcor, Gamma Leonis, Rigel, Sigma Orionis, and a host of other great double stars that I look for all the time. Perhaps a poll just for doubles later!

Thanks for participating. I am going to look for some of these more often and remember what we like to see most next time I think of what to show the public at an outreach.

End of Year Open Clusters

On December 31, I viewed M38, then M36, then M37! I recommend that order of observation. First, they are easier to find in that order. M38 is near a group of brighter stars just south of central Auriga. From there, one can pan east and a little south to M36 and then to M37. The sequence is also nice in that order because M37 is the grandest of the three! What a sight! I was observing with the XT8 through a 30mm, 80-degree eyepiece. At 40x, M37 fills just the middle portion of that view, and the stars in the cluster's center are tight enough together to seem a fuzzy background of light. Of course, all this fuzz disappeared at 240x, and the view was then filled with stars sprinkled across black!

I also found Lalande 21185 in Leo Minor. It is one of the nearest stars to us, and as a consequence has been well-studied. I had a good time reading about it after seeing it "up close."