Sunday, February 01, 2015

 

More DSLR Adventures...


This was originally supposed to have been a “My Favorite Fuzzies” installment, muchachos; specifically one about everybody’s favorite nebula, M42. But I’ve decided to hold off on that. One of the goals I’ve set for myself astronomy-wise is to finally get an outstanding image of the Great Orion Nebula. Oh, I’ve gotten some OK ones over the years, but not one I consider “perfect,” even by my modest standards. So what then? How about more on Unk’s efforts to shoot the sky with Canon DSLRs?

Before we get to that, though, let me tell you my asteroid story. Last Monday afternoon found Unk scurrying around to set up Big Bertha, his C11, on her new CGEM mount.  Our quarry for the evening was to be 2004 BL86, an asteroid that was to fly by the earth at a (sorta) close distance. It was supposed to be close to magnitude 9, and would sail through a pretty region of the heavens, the area of Cancer’s M44, the Beehive Cluster.

I was all het up to see the flying mountain, and didn't think there was any way me and Bertha could miss. I had the IDs of several stars the asteroid would pass close to over the course of a couple of hours on Monday night. I’d send Bertha to one of these (SAO) stars, we’d wait, and when the asteroid passed it would be “GOT HIM!”

Monday is my teaching day at the university. I’d be home by 8 o’clock, though, and Cancer wouldn’t be high enough to fool with till 9. Still, I wouldn’t want to be lugging Bertha out into the yard and setting her up after dark. I got the CGEM assembled and the C11's OTA on it before I left for the University of South Alabama at 3 p.m. Monday afternoon.

Arriving back home after spending hours stuffing young minds with astronomical knowledge, I had to admit I was a tired. But with no setup required, I wasn’t too worried about that. Got the mount goto aligned, and testing showed Big B. was putting anything I wanted from one side of the sky to the other in the center of a 27mm Panoptic eyepiece. That silly little asteroid? I figgered “no sweat.” Uh-huh...

You know what they say about those doggone best-laid plans, doncha? With the list of my SAO stars in hand, I punched the first one into the hand control. Sucka wouldn’t take it. Tried again. Same-same. Tried the 9:30 p.m. star. Nope. The 10 o’clock one. No way. At first I wondered if my HC was inflicted with an old Celestron bug that made entering SAO stars fail. Nope, a check of the version showed that the firmware load that came with the HC was later than the afflicted build. What the hell…was something broke? Then a light went on.

The Celestron HC has a catalog of SAO stars. But not all 258,000 SAO stars. It only goes down to about magnitude 7. Hmmm…  I ran inside, fired up SkyTools 3, checked the magnitudes of my waypoint stars in the program’s Interactive Atlas, and determined that—shoot—all were dimmer than 8 and would not be in the database of the NexStar hand controller.

That was just OK. I was weary, but I reckoned I could scare up a serial cable, hook the Toshiba laptop to the mount, and send Bertha to my stars with SkyTools. As I was thinking about that, I happened to glance up and to the east and realized my target area was in the boughs of a pine tree and would be for some time to come. I shut B. down, headed inside, and had a couple of drinks.

Backyard Comet
I was in a snit, but not a huge snit. Such are the reefs and shoals of amateur astronomy, as your Uncle well knows. In other words, “You can’t win ‘em all,” “There Ain’t No Justice,” and the kind attentions of Mssrs. Murphy and Finagle are always part of our game. Luckily, my modest successes are frequent enough that I manage to carry on in spite of all my foul-ups.

“Carrying on” meant your Uncle was still bound and determined to get a convincing image of Comet Lovejoy's beautiful but elusive tail. I’d captured it (barely) with the Canon 60D and the Patriot refractor from the backyard, but you really had to hold your mouth just right to see much of it. With the comet past its peak and fleeing the inner Solar System, I knew I had to get a move on if I were to succeed.

I sure didn’t want to be caught out like I was in the days of Hale-Bopp. Back then, I was just barely getting back into astrophotography after a long hiatus. Before the Boppster left, I was able to assemble some pretty good (film) imaging gear, but by the time I figured out how to use everything again, the comet was on its way out. I never got the shot I longed for of Bopp's beautiful blue ion tail.

Saturday seemed to be D-Day for Lovejoy. There'd be a Moon in the sky, a 4.5 day old crescent, but it would be toward the west. With the comet near zenith in Aries, I hoped there wouldn't be too much interference. What would come after Saturday was more Moon and probably more clouds. I rang up my astrophotography buddy, Max, and it turned out he had the same thing in mind that I did, one last comet campaign from the Possum Swamp Astronomical Society Dark site.

I was tormented all the way out to the private airstrip we use for our observing by the suspicion that I’d forgotten something. One time I nearly pulled over to see if I had left the laptop at home, though I really knew I hadn't. I was at sixes and sevens, it seemed. What was going on? Your normally optimistic and ebullient Uncle had been in a subdued mood for days and days. Why? In part, that was simply what winter does to me. I am a spring – summer kinda guy, and my head probably won't be back on straight till the flowers are blooming and bees are buzzing again.

When I arrived at our dark site, I was all by myself at first. That didn't bother me. While my imaginary (perhaps) friends—Mothman, the Skunk Ape, and the Little Grey Dudes from Zeta Reticuli II—often keep me company on the observing field when I am alone, I knew they wouldn’t bother me tonight. Even if Max didn't show. I didn't have that creepy feeling that presages their visits. Instead, I had the blahs, which are a click up from the blues, if not quite to the level of Holly Golightly’s Mean Reds. When I am like that, the fantastical baddies have no power over me.

As I began unloading, it was clear I needn't have been paranoid about leaving some important piece of gear at home. I’d been reasonably careful with the packing, but the mainly there just wasn’t that much stuff. At least as compared to, say, a Mallincam run with the C11. There was the evening's telescope in her case, once again the little 66mm WO. She'd have enough field to take in plenty of tail, should I be able to capture much tail. There was also the VX mount and tripod. The Toshiba laptop. The Gadget bag with my Canon DSLR bodies in it. Couple of accessory boxes. Three jump start batteries. And that was it. That may sound like a heap of gear to you Dobbie fans, but for Uncle Rod that is “traveling light.”

Alright. How was the sky looking? Good, very good. Entirely cloudless. There was occasionally a light breeze, and the air felt dry. Yeah, the crescent Moon was burning surprisingly bright in the gloaming, but I knew it would be like that going in. I’d rather have the Moon than the cotton-picking clouds that have deviled me all fall and most of the winter thus far.

When the scope was assembled, next step was checking balance. I would be going unguided, and even at the short focal ratio of the 66mm scope, just a smidge less than 400mm, good balance would be important. I attached the Canon 60D to an SCT prime focus adapter (as noted in last week’s blog, the 66mm SD scopes of yore all had SCT rear ports) and adjusted the counterweight on the declination shaft till the mount was east heavy by a small amount. That ensures the gears are always engaged and improves tracking on almost any mount.

Alternate take...
Balancing done, I removed the camera and re-installed the 2-inch SCT style diagonal. Yeah, I could do the goto and polar alignment with the camera, but I find it quicker just to use my old Meade 12mm MA crosshair eyepiece. Did a 2+4 goto alignment, and dialed in polar alignment using Cetus’ Diphda as my AllStar Polar Alignment star. Since I'd moved the mount a fair distance in altitude and azimuth to polar align, I redid the 2+4 to ensure bang-on pointing. Given the wide field of the scope, I could probably have gotten away with not redoing the goto alignment, but I could, so I did. The closer the mount put objects to dead center in the field, the quicker I would be able to work.

Hokay. Started Nebulosity 3, plugged the camera’s USB cable into the PC, and focused up. I was still sitting on my last calibration star, Aldebaran, so I used that to achieve rough focus. When it was nice and small, the dim field stars began to be visible in the successive 1-second exposures in Neb’s Frame and Focus mode. When they were as small as I could get them by eye, I switched to Fine Focus, clicked on a small field star, and made its Half Flux Radius number as small as I could get it.

Onto Lovejoy. Just as I had for my previous expeditions to the visitor, I’d printed out an ephemeris with my favo-right planetarium program, Starry Night Pro Plus 6. I entered the set of coordinates closest to the current time into the NexStar HC using the “goto R.A./Dec” utility, pressed “Enter,” and away went the VX mount. When it stopped, I fired off a 5-second exposure using Neb’s Preview function. There the hairy star was, well framed and not looking any dimmer than she had a week previously.

Before I spent an hour or more on the comet, however, I wanted to know whether the tail was doable or not. I set the ISO of the Canon to 3200, which might be pushing it a little in the Moonlight, but which might help with the subtle tail. Set the exposure time to 2-minutes, and mashed “Preview.” What did I see when the finished picture appeared on the laptop screen? The stars were nice, round pinpoints. It sure is nice the VX - Patriot combo doesn't require guiding for 2-minute exposures. The tail? Easily visible, but not exactly putting my eye out.  It was good enough, though, that I thought I might really get something if I stacked 30 2-minute subs.

I set up the exposure series, hit the “go” button, and Nebulosity and the Canon began doing their thing. What now? I wandered the field, spending some time watching Max, who’d arrived as I was setting up the telescope, work with his VX, his wide-field 5-inch Newtonian, and his Sony Camera. He was getting some nice frames already. Another PSAS buddy, Gene, had showed up at sunset, and I enjoyed observing this and that with him using his nice visual rig, a 6-inch f/8 Celestron refractor on an Atlas mount. I’ll tell y’all, if the six-inchers weren't so blamed heavy, I’d have one.

Mostly, though, I scanned the skies with Miss Dorothy’s prized Canon roof binoculars. They are “just” 32mm glasses, but they are finely made, and with a magnification of 8x they don't give up much—if anything—to a pair of el cheapo 10x50s. I looked at all the obvious binocular stuff, including M42, which is now getting nice and high in the east early in the evening, and Gemini’s M35. Mostly, though I looked at Lovejoy.

It was bright in the glasses. No tail, but a prominent nucleus and plenty of coma.  My main goal was to pin down the comet’s position exactly and see if I could detect it naked eye. I’d thought I’d maybe glimpsed the fuzzball from the backyard on one good night not long before Lovejoy’s peak, but was not totally sure. On this night? I was pretty sure. There seemed to be a dim fuzzy in approximately the correct location, but it was not an easy observation even with the comet riding high and in skies considerably darker than those of the New Manse’s back-forty.

There was still quite a while to go on the exposures, so I did a little more binocular gazing and had a peep at M82 in Gene’s refractor—just doesn't seem possible Ursa Major is back already. As Max waited for his sequence to complete and I waited on mine, we got to talking comets. Sure would be cool to get a great one soon. The last comet we had that even comes close to that appellation was weird Comet Holmes (which is undergoing a minor outburst right now), and hard as it is to believe, that was seven freaking years ago. We are almost in a comet drought like the one between Halley and Hyakutake.

Just as I was getting warmed up on the subject of My Favorite Comet of All Time (West), the Toshiba Laptop played the little fanfare that is Nebulosity’s way of saying “Sequence is done, Uncle Rod.” Hmm. What now? I could do more comet frames, but I believed I had enough for a reasonable image. I wanted to do one more target, though, and the natural seemed to be M31, which was not too high and not too low.

As I mentioned here, I’ve been after a good picture of the famous Andromeda Nebula (Galaxy) for a long time, and I thought the little Patriot would have the field to do a nice job on the huge object. Did a preview shot of the galaxy, and the framing was good without me having to touch a thing other than change the camera angle (the Patriot has a rotatable focuser) so the galaxy was a little more horizontal. The Moon, not too far away, was obviously making the background brighter than it would normally have been, but watcha gonna do?

Set up for thirty subs of the beast. That would take a while, and it was now a bit on the chilly side, but I figgered if I were gonna do it, I’d do it right. Once the sequence was underway, I walked over to the fire-pit near the hangar where the remains of a fire built by one of the airfield’s owners still burned. I sat in a lawn chair and warmed myself while waiting for M31 to finish.

Actually, it was not terribly cold. It should have been chillier, but the humidity had spiked up at mid-evening and so had the temperature. I knew what that meant:  clouds coming. And more than a few were now visible on the western horizon. There was no doubt, however, that I’d get M31 in the can before they arrived.

When the galaxy finished, me and my two companions were not quite ready to call it a night, though we thought the end was in sight. Just for the heck of it, I slewed over to the Horsehead Nebula and did five 30-second frames. After that, I packed up and pointed the 4Runner for the New Manse, quitting the site well before midnight.

As is my usual wont, I studiously avoided looking at any of the images when I got home. They always look horrible at the end of a long night, and I knew they would appear far better in the morning. Instead, I surfed the cable TV channels for a little while, warmed myself with the aid of the sainted Rebel Yell bottle, and, finally toddled off to bed as midnight came and went.

Next morning I copied all the subs from the laptop to the desktop in my office over our home network and went to work, starting with the comet. Only problem I had was that in these fairly long subs, the nucleus was not a “star.” It was a sizable ball, and it was a little hard to position the cursor in Nebulosity dead center enough on it to ensure good stacking. In the end, I did two separate stacks.

The verdict? I’ve seen far better images of the comet’s tail on Facebook, but given the Moon’s presence, I’m pleased. The coma is, as in my backyard pix, a pretty green. More importantly, the comet’s tail and spiky secondary tail(s) are just as distinct as I’d hoped they would be. Perfect? No, but I most assuredly did not let this one get away.

M31 was another winner by my humble standards. Oh, it would have been better without Luna nearby, but not bad. I hope to do better still, but I would not be surprised if that has to wait till next year. In a month’s time, assuming the clouds leave me alone, it’s possible I might tackle it again, but it will be beginning to get low by the end of any decent exposure sequence, and I am skeptical the weather gods will cooperate. We’ll see.

Perhaps the biggest surprise of the evening? The Horsehead Nebula. With only 150-seconds of data (though I did crank up the ISO to 6400), there was no way this was going to be a pretty picture. However, I did get a picture and not an entirely horrible one considering. The Horse is there, and there is even a little detail in the red background nebula, dim IC434.

Which makes a point I’ve been talking up for some time. Novice imagers who spend their time reading in the Internet astronomy chat-rooms have the idea that you must have your DSLR modded (have its built in IR filter removed) to do any deep sky imaging. Clearly not true. Modding a camera helps, muchachos, especially with dim red nebulae, but you can still get ‘em with your stock DSLR. It’s a little harder and takes a little longer but you can do it. If your fumbling and bumbling Uncle can image the freaking Horsehead with his unmodified Canon 60D with less than 5-minutes of exposure, the sky is, quite literally, the limit.

Next Time: Big Time…

Comments:
If the Horsehead doesn't require a modified DSLR, neither does anything else. Nice work! This is very similar to the astrophotography I'm doing these days except that I'm using a Canon 300/4 telephoto lens. (AVX mount, 60Da camera.)
 
I was able to capture the North America Nebula with an un-modded Canon 1000D.

I really had to work it in post-processing to make out a shape, but it's definitely there.
 
Good photos, especially as they were in the spirit of experimentation
That little asteroid skunked me too. I still do it the old fashioned way, plotting on a chart and star hopping. I have successfully hunted down 2 close flyby asteroids before but only found this one for about a minute. I foolishly tried to change eyepieces and lost it. I was sure I could get it back as it went by the Beehive but never recovered it. I don't know if my plotting was off or I was just tired.
Clear skies and clean glass,
Mike
 
Really Fantastic job on those images Rod! The AVX mount really performed nicely without guiding. I was shocked to see your Horsehead and Flame, really impressive for the amount of data you captured. I agree one does not need a modded DSLR, I use my stock T2i all the time with a clip in Astronomiks LP filter and it performs extremely well. Nice Article and images! Clear Skies

J. Turner
 
Hello Rod. I enjoy reading your blog very much! I am just getting into Astrophotography with my new 80mm ED Refractor and discovered your blog while looking for a good program for OSX. Thanks for the article on Nebulosity and for all your posts! Who has more fun than us! I'LL BE BACK. lol
 
Hello Rod. I enjoy reading your blog very much! I am just getting into Astrophotography with my new 80mm ED Refractor and discovered your blog while looking for a good program for OSX. Thanks for the article on Nebulosity and for all your posts! Who has more fun than us! I'LL BE BACK. lol
 
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