Too bad you have to sleep . . . but oh what a night!

January 28-29, 2008 - This was one of those nights when I wish I had more energy and less need for sleep. Had a wonderful observing session with Jim in the early evening from about 7 to 10, went to bed about midnight, got up at 4:30 and observed from 5- 6:30. Almost all of this was with the Astro-Tech 66mm in the observatory mounted on the 5-inch NexStar "go to." But it included a look at Comet Holmes and some surprising video - through the tiny scope - of M42, M81-82, and M1.

Straining to see Comet Holmes with binoculars and M110 with either the 66mm or the 15-inch (375mm), proved a hard lesson in the real world complexity of magnitude vs. surface brightness and that will be a major theme of this post. But before going there, let me tell you what blew my socks off. It was the first look at M42 on the computer screen using the MallinCam Color Hyper and the tiny, Astro-Tech 66.

The above is a "snapshot" taken with the video software. I made a contrast adjustment in Photoshop Elements, but did no other processing and this is pretty faithful to what was seen live, though the live screen images always seem better. I used the MFR-3 focal reducer with 10mm extension for this shot, but M42 was also nice without the focal reducer.

M42 was gorgeous in the 15-inch Obsession as well, but the two views - video and visual - were roughly equal. We could see more detail in the clouds - and more intense color - in the video on the 66mm, but the greater dynamic range of our eyes meant the Obsession gave us the Trapezium, plus the nebulosity with some significant color. In the end the two compliment one another and make for a good instructional combination. It's easier to discuss what you see with the video of course, but for me the visual experience continues to be critical.

That wasn't my first "wow" of the session, however. What shocked me almost as much was that when I turned the AT66 on M31 in visual mode I immediately saw not only M32 (i expect to see it), but M110, a much more difficult object. Hey, visitors have trouble spotting M110 when we use the 15-inch. The AT66 has 3 percent of the light gathering area of that scope!

I'll have to try the the AT66 and video combination another night. For the most part I try to separate the two observing experiences - video and visual - because the video certainly impacts your night vision, although not as much as you may think. But if you really want to go after faint fuzzies, you need to dark adapt again after using the video.

Ok, back to M31, 32, and 110 - the Great Andromeda Galaxies - and visual mode. M110 is a good introduction to the pains of surface brightnes. Stephen O'Meara lists M110 in "The Messier Objects" as being magnitude 8. Read that and you think seeing it will be simple. Any decent pair of binoculars under decently dark skies should show you a magnitude 8 object and a scope like the AT66 should reach to magnitude 10.8. (Astronomy Technologies says 11.6 - but if you can see an 11.6 magnitude star with this scope than you have far better eyes - and more transparent skies - than I do. )

But I think folks new to observing faint fuzzies get fooled by these magnitude numbers - I know I was for years. The reason is simple. The number refers to the total light coming from the object - but on a galaxy, or for that matter, a comet, that light is spread out over a huge area, not concentrated in a point source like a star. Enter "surface brightness." The surface brightness of an object is supposed to represent the brightness of a small unit of it's total area, such as a single minute of arc. O'Meara lists a surface brightness for M110 of 13.9! Now that's faint. While it's well within the range of the 15-inch, it's challenging in that scope and it's totally out of reach of the AT66.

But wait! I was seeing M110 in the AT66. So what gives? Well, the short answer is neither magnitude figure tells the whole story. If you look at O'Meara's drawing of M110. you'll see a bright, star-like nucleus, surrounded by a slightly less bright core, surrounded by some dimmer patches. And this whole thing is set on a relatively faint oval haze that's three times the size of this central area. All of this together adds up to magnitude 8. Average the light from the whole area and you get an average surface brightness of any given portion of it of magnitude 13.9.

The physiology - and maybe the psychology - of seeing enters into the equation as well, but the bottom line is you should not expect to see a magnitude 8 object and you should not expect to see a magnitude 13.9 object - but you should expect to see something. Exactly what? That is what is tricky. O'Meara sees an object that is roughly 22' X 11' - and that's pretty big. (The moon is just 30 minutes.) In Burnham's Celestial Handbook the area is given as 8' X 3' - much smaller. M32, by comparison is seen as about half that size and round, though again the two sources differ tremendously on the exact figures. While I admire O'Meara, I really wonder how many folks see M110 as large as he does. I don't doubt him. I just think his observing skills allow him to see faint extension of this galaxy that escape most of us.

In practical terms, my advice is to look at M31, then locate M32. It will first appear as an out-of-focus star. Study it. Use averted vision. You will see it has a dim halo. When you go looking for M110, look for something about the brightness of that dim halo and and expect it to be a bit better than twice the size of M32 and much more oval than round. As with M32, you'll spot the bright core first - but it won't be as bright. Then trust O'Meara. Whatever you see, there's more to be seen - be patient ;-)

And the same rule now applies to Comet Holmes. Boy can the numbers be misleading.

The comet of late October and November is long gone. Then we were looking at an explosion. Now we're seeing a puff of smoke that has spread out to be three or four times the size of a full moon. Yet the email alert from CalSky.com - and that's an e trmeely useful and reliable site - said it is magnitude 4.8. Hey, that should be naked eye! Fat chance. Certainly not in light-polluted skies. CalSky isn't wrong - but surface brightness enters into the picture in a big way. That 4.8 magnitude glow is spread out over something like a degree and a half!

Think about it. Can you see the seven main stars of the Little Dipper? Well think of taking the faintest of those and spreading it's light out so it almost reaches its faint companion at the other corner of the bowl. Now you have an idea of what you are seeking when you go after Comet Holmes on a moonless night right now. So detecting it with 8X45 binos was a challenge.

I didn't give this a serious try with the video, but did track it down with 8X45 binoculars - a used pair marketed by Garrett which seem well worth the $80 I just paid for them. This was their first real test. I wantt o yse them in my public programs, but I want to be sure theyc an do the job. Seeing Comet Holmes in binoculars is very much like seeing M110 in the scope. Fortunately, it is still very close to Algol, so you have an excellent, easy to find starting point - and it's very high in the sky in the early evening. Add to that superbly transparent skies, such as we had last night, and you would think this might be easy.

Again, I found it relatively easily. But Jim wrestled with it, as have others who have been here on recent nights. Sketching the star field as a guide helped. Right now it's a couple of degrees from Algol in the general direction of Aldebaran. And it was sitting roughly in the middle of a fairly bright triangle of stars, occupying the entire space inside that triangle. But I think what might have been more helpful is simply sneaking up on the subject. This is a variation on the standard advice of tapping the side of the telescope to get a little jiggle to help see a faint object. With binoculars you can simply swing them across the target a bit and it helps. In this case if you started a couple degrees away at Algol, then panned smoothly in the direction of the comet, it tended to "pop."

While outside looking at Algol we also tracked down Mira, a simple task these nights since it's near maximum. We both rated it at about magnitude 3.5, but boy I find this difficult. When you have several comparison stars near the variable and you're looking in a telescope, I find estimates much easier. In this case we were using nearby 4.1 and 3.8 stars for comparisons and quite frankly each star I looked at tended to look like the brightest for that moment - I find it difficult to look at all three stars at once and make an accurate evaluation. But my guesstimate was Mira was as much brighter than the 3.8 star as the 3.8 was brighter than the 4.1 - thus 3.5. Jim came up with the same estimate independently.

Back inside the observatory with the 66 andvideo camera we went to M1, which I thought would be more of a challenge for the little scope. It was. But I like the result, especially for instructional purposes. Too often people look at fantastic pictures of objects such as M1 that are no help at all. They are wonderful in themselves, but they don't prepare you for what you will see in the telescope. I think the image below gives a much better idea of what someone will see visually in an 8-inch or larger scope. My plan right now is to use the video camera side-by-side with a larger scope for instruction of visual observing.

In fact, I find the 66mm scope helps learning in two ways. Learning to see difficult objects in it improves your observing skills and means you get more out of the view in a larger scope. (That's true for me, at least.) And, of course, putting the video camera in it gives me an opportunity to discuss the image with visitors before they look in a larger scope and attempt to see it visually.

Where the little scope shines, of course, is in delivering pristine star images. We started the night on M45, the Pleiades cluster, which at 31X was beautifully framed. (Eyepiece was a 13 mm Hyperion with a 68 degree AFOV .) We went from that to Almach, a charming double because of its color, then to Gamma Aries, a charming double because the pair are so close in brightness, separated by only a tenth of a magnitude.

We called it quits around 9:30 and Jim helped me put away the 15-inch. But after he left, i went back out. The Winter Milky Way, the reflected light of stars on snow, the crisp but not punishing air . . . I just couldn't let it go. I still had the MallinCam in the AT66 and i tried a few more objects with it. I took a stab at the Horsehead - dreamer! What I got was a decent shot of the nebulosity that is roughly on the other side of Alnitak from the Horsehead. (Alnitak is the eastern-most star in Orion's belt.)

Given how this was showing up I should have just scrolled the scope around some until I had the right target. But I didn't have the patience and I couldn't remember the relative position of this nebulosity and the the dark cloud that forms the Horsehead. So on I went to M81 and 82 - and that was much more satisfying. Hey - it doesn't blow you away like M42, but remember this is a 66mm scope and we're looking at a pair of galaxies about 8 million light years away. Notice the detail - the two dark bands - in M82, the irrregular galaxies to the upper left. Anyway - I love it when you can get more than one galaxy in a single field! ;-)

I can't recall what I did after that. I eventually put the scope in "hibernate" mode. It had been doing an excellent job with the "go to." putting targets well within the fov of the video camera, which isn;t easy, though certainly easier because on this scope that field is quite large. I still have to experiment with more adapters to see if I can get an even larger field - not sure it will reach focus with anything beyond what I was using last night.

I have more to say about the morning session. No video, but I thoroughly enjoyed myself with double stars and the moon. But right now I need to get ready to help Bren with pet assisted therapy - we have a regular class with some special needs children each week - very satisfying in an entirely different way than the astronomy.

Morning session - a double star delight

A week ago I had prepared a short list of double stars in and around Bootes I wanted to check witht he 66mm and when I woke up i realized that while the last quarter moon made deep-sky hunting difficult and we would soon be getting into twilight conditions, there would still be plenty of time to track down some doubles and to enjoy the moon.

I started with Izar and it split cleanly with the 3.5mm Hyperion giving 114X on the 66mm scope. This was a revisit. I had caught it a few days ago, but seeing was better on this morning and so the split was cleaner.

I went on to Cor Caroli, an old favorite - the "heart of Charles," as in King Charles the second (I believe) of England. This is an easy split but what gave me real pleasure was that with the "high power" 3.5 mm eyepiece the "go to" actually put it into the field of view. Ooops! Later I realized this wasn't such a great stunt. When you're using a 66mm scope, even at near maximum power, your field of view is still quite large. With the 3.5mm Hyperion it's about 36' in diameter - which means the whole moon should fit in it comfortably - and it does. Use that same eyepiece on the Meade LX90 which i usually have in the Observatory and the field would be one-fifth that size - and if the "go to" put its target in that field, well, that would be extraordinary.

Bottom line - what I was thinking of as really good "go to" performance was just ordinary. I should have known that - I had thought this whole business of "go to" accuracy and wide fields through the other day. That's why I am gambling on this new, inexpensive "cube" mount for this scope. With the wide fields the "go to" just doesn't have to be that accurate.

Anyway - I love Cor Caroli. The secondary star is a wonderful shade of royal lilac to me. Plus the name rolls off your tongue in a royal way. What I had never seen before was a fainter double right near it - Struve 1702. Since this was only about 30' to the east both Cor Caroli and Struve 1702 could fit comfortably in the fov of the 5mm Hyperion. (80X, 51' fov.) this is a very wide pair - 36" apart - of fairly evenly matched stars - magnitudes 8.3, 9.0. Good opportunity to reinforce the difference between minutes and seocnds of arc in your mind, however. The distance from Cor Caroli to Struve 1702 is roughly the same in minutes as the distance in arc second between the two stars of Struve 1702. Put them all in the same fov and it these dimensions should start to become more intuitive.

The next star on my list was an embarrassing SNAFU - whatever I observed, it wasn't right. My notes just don't jibe with the record. I won't go into detail. I was looking for a triple known as Alkalurop , or Mu Bootes. The two close star in this group would be a real challenge for the 66. I thought I split them. Now I'm sure I was looking at the wrong thing because my sketch doesn't match the position angle in the published data. So this will have to wait another morning session.

I also tried another challenge - in twilight - with the little scope. I went after the "Double-Double" in Lyra. This is a favorite target, well known, but at 6 am it was still fairly low in my eastern sky which was getting quite bright. I think the twilight conditions can actually make it easier to split some doubles. In this case only got a partial split.

The easier of the pair of doubles are evenly matched and have a 2.4" gap. As I stared the view varied. sometimes I saw a figure 8 - sometimes the two stars were "kissing" - but never was there a clean split. The other pair have more separation in magnitude, and less in arc - 2.1" and they varied with the seeing conditions from being a rod shape blob to a figure 8, but they didn't get to the "kissing" stage, let alone a clean split. Still, this was encouraging. had they been high overhead I think they would have split cleanly.

Who cares? So what? I really don't know. This is the kind of activity that has no significance as far as I can tell, but sure is fun. It's a game - a challenge - and using the small scope makes the game more engaging for me.

Last stop on my double star tour was Zeta Corona Borealis. This was an easy split with the 5 mm (80X), since there's about 6" between a pair of 5.1 and 6.0 stars.

Now it was time for the moon - well almost. I had to wait for a tree to move, so I straightened up the observatory, putting stuff away while the tree got out of my way.

This is a grand little telescope for seeing the entire moon. With something like an orthoscopic eyepiece you would get equally high power, but with a smaller field, but you would still see most of it. But 114X is plenty and again, what this does for you is get you to concentrate on the detail you do see - which is plenty. I did a rough estimate and decided that I had no trouble picking out craters down to about 10 miles in diameter.

Again - different lighting conditions, different magnifications, and the different resolving capabilities of smaller scopes simply give you a fresh perspective. It isn't better. I'd still rather be flying over the moon in a helicopter - which is the feeling I get with binoviewers when used on the 15-inch or 8-inch. But using the 66 was fun in its own right and if this was the only scope I had with me - say on an excursion away from Driftway Observatory - I could keep my self entertained for hours just looking at the moon.

On this morning I had a particularly nice view of a chain of three favorite craters near the terminator - Ptolemaeus, Alphonsus, and Arzachel. These seems to show a clear progression in aage, with Ptolemaeus, the grizzled old veteran of the group, Alphonsus the mature one still holding some of its youthful looks, and Arzachel younger still and very rugged. This isn't just my romantic streak. The evidence does point to this kind of age difference.

But this morning I also got interested in Hershel, a bump off the top - north side - of Ptolemaeus, not simply for itself, but for the dark line near-by. This looked like some sort of valley, but as I studied the maps I think it was just the a prtion of the eastern wall of the flooded crater Flammarian. Trying to cipher out such features and put a name to them and learn a little more about them is part of the lunar game. No significance - but fun in itself. Little puzzles to keep the grey matter exercised and keep you enjoying the solitude and night air.

The big view - and the lighting of the moment - also gave me pause as I looked at the eastern edge of Mare Imbrium. Both the isolation of the Alps with its wondeful straight valley, and the apparent straightness of the Appenines chain, clearly separated from the Carpathians, made these look to me more like the mountain chains they're named for, then the walls of the Imbrium basin, formed, presumably, from a gigantic impact roughly 4 billion years ago.

Then it was 7 am - time to come back from the moon and get Eliza and Higgins up for their morning tour of the yard. Great evening in the cosmos, great morning nearer to home, and what joy those two little bundles of fur bring to each new day!