Posts Tagged ‘Pleiades’

Oh boy! Been having a discussion on Cloudy Nights about astigmatism, etc. and the last post.  What was bothering me was, among other things, how to separate the impact of power increase from the impact of exit pupil change.

See, in my last experiment, detailed here, what I did was take a 50mm objective and repeatedly change the power.  This resulted in  a smaller exit pupil – good for negating the impact of astigmatism in my eyes – but also a higher power which, of course, makes it easier to split doubles. So the experiment is interesting, but inconclusive. Someone on Cloudy Nights suggested that what I needed to change, of course, was the aperture – not the eyepiece. Keeping the eyepiece – and thus the power – the same, and cutting down the aperture would give me a shrinking exit pupil and a better guide – at least with bright stars – as to the impact of the smaller exit pupil.

So off I went immediately to make a 40mm mask for the 20X60 Pentax binoculars – which I did and the skies cooperated by giving me a cloudless early evening – something that wasn’t predicted, but I was delighted to take.

I used the masked 20X60 Pentax  as is and stopped down to 40mm, first on Albireo, then the Pleiades, Jupiter, M34, and the Rams Eyes. Very interesting – and I’m a happy camper because at last I’m seeing pinpoint stars with binoculars! (You can’t imagine how many excellent pair of binoculars I’ve owned and sold because they did not deliver this – and they all had fairly large (4-5mm) exit pupils!) But there are still a combination of factors involved, the most important one being the relatively small exit pupil which seems to overcome my astigmatism and the second most important, finding the correct head position. I did play some with IPD, but couldn’t see that as an issue.

The most surprising situation came after spending about 20 minutes trying to get a really good view of Albireo. That wasn’t a matter of splitting it, but one of trying to come up with clean, refractor-like stars – bright, round little bullet holes in the night sky – and in this case, showing lots of color.

As I settled on Albireo I kept fooling with head position – the binos were on a p-mount, of course – and focus and just couldn’t get the primary to settle down completely. Then suddenly I accidentally moved the image off center – about half way to the top of the field, and bingo! There were my two perfect stars, bright orange (not gold, as I usually see it) and blue.

This blew my mind and I kept repeating it – bringing the image back to the middle of the field where there was still significant flare on the primary, then moving it up and when I did so, having it clear. I can’t explain this. I don’t think it had anything to do with the binocular. I think it had something to do with my head position. When I moved everything around and went after the stuff in the east later I could not repeat this in any form – in fact, as time went on I was getting good crisp stars throughout the field of view, so it just didn’t matter.

Could it be the binocular cooling down? I doubt that very much for I had left it out for at least an hour before going out to observe.

The stopping down produced obvious and predictable results in all the tests. I got a little less light, but I got sharper star images with it stopped down to 40mm and thus yielding a 2mm exit pupil. I did try 15X70 glasses as a test case and while I could split Albireo with them, the split was very, very sloppy and there was no way I could get it to even remotely look like what I was seeing in the 20X60/40.

Binocular doubles in the Pleiades - modified from SkySafri screen shot.

The Pleiades provided a terrific experience. I’m planning a post on binocular doubles in the Pleiades for the double star blog I share with John Nanson, so I was real pleased to go over several doubles, some of which I had split before – they’re ridiculously easy – and some of which I had never split with binoculars. One thing that revealed itself nicely is that triangle near Alcyone towards the center of the cluster. (See the inset in the above image.) It’s easy enough to get the 6th mag star there, but the other two are fainter and I hadn’t seen them before because of the glare from Alcyone. I could just detect them with the 60mm stopped to 40mm and could see them clearly when using it unmasked. This was the clearest indicator of how much light I was losing by going from 60 to 40mm objective.

But most satisfying was the whole cluster of sharp stars.

Jupiter was certainly better when I stopped down to 40mm. That way I could just pick out Europa which had recently transited and was still quite close to the planet. Ganymede and Callisto were obvious and Io was in eclipse.

Being in the neighborhood I decided to give the Ram’s Eyes a try. There the split is 7.5-seconds and I just couldn’t do it, though with the 40mm masks on I did have a distinctive figure eight that was oriented in the correct north/south direction. Maybe with more practice and a better night . . .

With M36 I could pick up two or three of the pairs that make the body of what I think of as a Klingon War Cruiser.

Bottom line – many thanks to Ed Zarenski for telling me about astigmatism and exit pupil and others here on CN who joined the discussion and have helped me work through this to the point where I can now enjoy binocular astronomy a lot more. It’s good to see sharp stars and it’s good to have some rationale for why low power views have never worked well for me with binoculars or telescopes.


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Wow! Now that I like! Mintaka in the 10X30 IS Canons. A bright, flaring second magnitude star with a little pin point of light nearby.

What’s the big deal, you may ask?  Mintaka, the western most of the three stars in Orion’s belt, is an easy split, as I wrote in some detail here recently.  Sure it is – in a scope. The separation is a whopping 53 seconds of arc. But let me tell you why it has stymied me over and over again in recent weeks – in fact, ever since I wrote that post I’ve been trying, at every opportunity, to split it with binoculars. But even the 15X70s when mounted haven’t done the job for me.

The reason is simple – there’s 4.6 times difference in magnitude – 2.2 for the primary and 6.8 for the secondary. That means the primary is about 58 times brighter than the secondary. And as far as I’m concerned I haven’t met the binocular yet that will give a nice, round version of a second magnitude star. This may be me. it may be conditions. Or it may be the binoculars, but that’s the way it is.  But the Canons come closest to delivering that goal – maybe in part because with 30mm objectives they just aren’t delivering that much light.

So what I at last saw – and I was able to repeat it after a 15 minute break – was a bright, dancing Mintaka  with just a faint dot of light next to it – and at just the right position angle, so I knew I had it.  I then tried the 11X56 Garrett Opticals and the 15X70 Celestrons – mounted – with no luck. So this is a big score for the 10X30IS.  And I’m having a ball.

News Bulletin:While still drafting this I had an email conversation with Ed Zarenski, the guru of all things binocular, and he threw some real light on my problem – in a word, astigmatism.  And the above is the perfect example of it. 

He wrote:

Simple astigmatism in the eyes is most affected by the size of the exit pupil.  Mine kicks in at exit pupils over 2mm.  So I have to wear my glasses with all binoculars, but not for scopes at 100x or so.  Astigmatism will prevent you from ever achieving fine focus.  That would have a significant affect on your ability to focus on doubles.

 Bingo! The exit pupil for the 10X30 is 3mm, the 11X56  5mm , and the 15X70  4.6mm – or in that ball park. I don’t trust the numbers on inexpensive  binoculars. But the trend is obvious – the stars get sharper for me as the exit pupils get smaller. In general, high powers results in small exit pupils, though it depends on the object diameter as well – you simply get the exit pupil by dividing the power into the objective diameter.

So do I have an astigmatism issue? I’m not positive, but this certainly seems to indicate it. i do remember that my ancient (c. 1960 ) copy of  “The Amateur Astronomer Handbook” by James Muirden has one of those astigmatism test of radial lines pictured in it  and also says  “luckily, astigmatism makes itself really objectionable only when low magnifying power are    being used.” Which, of course, is what Ed pointed out with the exit pupil.

 Anyway – when I look at that radial pattern the four lines nearest the vertical are much sharper – bolder – than the lines nearer the horizontal.  Wasn’t that way the last time I tried this test – about 1967 😉

Truth is, I suspect my astogmatism has been there – I think I have heard words in the past from the doctor like “slight astigmatism” and so he has not recommended glasses because it was slight – but I suspect it has gotten worse with age and while in normal situations it still doesn’t present a serious problem – in this special situation it does.

OK – back to the excitement of splitting Mintaka in binoculars. See, as someone once said, it’s all relative. It doesn’t matter what instruments you use, or what talents you bring to the show, it just matters that you’re pushing the envelope – that you’re doing things you couldn’t do before and you thought you couldn’t do now, given what you had in hand.  That’s what makes it exciting. So for me each instrument opens up a new universe and there’s a fresh sense of exploration.

I had two other examples in this session. The first  took me back to the Pleiades and its brightest member, Alcyone. When you look at this star in a small telescope at low power two things jump out at you: on one side there’s a wonderful cascade of half a dozen stars – and to the other side – sort of the inside of the Pleiades – there are two 8th magnitude stars that form a triangle with  a third, brighter one, 24 Tauri.  It is these three stars that I have been trying to see with binoculars and until now I could only dig out the sixth magnitude star. but on this night I also pulled out one of the others.

There are several other binocular doubles in the  Pleiades, some ridiculously easy, but quite nice.   These include the very easy Atlast and Pleione – 27 and 28 Tauri.  But there are several more challenging ones. Here’s a working chart I’ve developed for my own use.  I have a pair of 20X60 Pentax on order – I purchased them because they get good reviews, but mostly because  of the 3mm exit pupil. I think they will work better for me and my astigmatism than the usual 20X80, at least when it comes to doubles.  (Yes, I’m going to see the eye doctor and get a new prescription, but I really don’t look forward to wearing glasses while observing with binoculars, though it may be the only solution.)

Here’s my working chart of the Pleiades showing key binocular doubles. Fidning them is a good excuse to spend some serious eyepiece time with this most beautiful of clusters.

Click image for larger view - developed from Starry Nights Pro screen shots.

While in the neighborhood I decided to see if the 30mm objectives could dig out M1. The answer is barely.  I had to check the charts to be absolutely sure where it was. It was a bit easier with the 11X56 when mounted. It was a whispy ghost, barely detected in the 10X30IS.  On the other hand, the nearby “Thirties” were  a piece of cake – that’s M35, M36, M47, and M38.  Oh, and I swung over to “ET”  – the Owl Cluster in Cassiopeia and have to admit that most of what I saw was the nice binocular double that are ET’s (or the Owls) eyes.

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More gleanings from recent exchanges on the Club board and  observations made here:

You’re right, Bob – the UFO galaxy is a keeper. Thanks for calling my attention to it.  I followed your “staircase” tonight (Friday) – transparency left something to be desired and there was a tad of interference from the moon, but hey, it was nearly at the zenith, so quite easy.

I was using the 80/8 combo  on the Double Star mount with the 30mm Clearvue in the 80, so I had a 5-degree fov. This easily takes in the Beehive, my starting point, with it’s two asses. I used them as pointers and moved up a couple of fields to Iota Cancri and just to be sure I was on the right star, I switched to the 8-inch. Since it’s a beautiful double – the “winter Albireo” – it was easy to see i had the right star and  now it was just a matter of climbing your stair case for another 5 or 6 degrees and looking for a pair of stars the galaxy forms a triangle with. Bingo – found them and thought I saw the galaxy. When I switched to the 8-inch there was no doubt.  Jumps around on you some, though – seems to benefit a lot from averted vision and as I think you mentioned, has a chunk out of one side from a  dust cloud.  The almost north-south orientation was striking. I can’t say I would have spotted it as a flying saucer immediately, but with that image in my head already, that’s what it looked like. Light seemed pretty even – felt like a chalk smudge on a blackboard.

I switched to the 80mm and with slightly more power it was easy to see in that scope as well. When I really cranked up the power there to 96X it was very easy to see. There’s a little quadrangle of sorts of four 10th and 11th magnitude stars about 10 minutes south of it that I found were a handy marker.

So, while I could see this in the 80mm and it looked quite nice in the 8-inch, I have to admit that it would really shine int he 15-inch which I assume is what you were using. Maybe during the next spell of bad weather I’ll get it back together 😉

Bob commented on this, then added:

BTW, I’m surprised you were able to see both of the donkeys at the Beehive, since I swear that the ISS ran over poor Asellus Australis while I watched with my binos earlier in the evening!  😆  😆 A near-perfect hit!!! Very ethereal to be watching this bright blob of technology through the binoculars and suddenly see the much fainter Beehive racing past the field of view.[/quote]

You sure pulled a lot of stuff out of those murky skies, Bob. But yes, that was a great pass of the ISS – we watched it too thanks to the head’s up from Pete – but in the 80mm and 8-inch and I have to admit, I wasn’t even conscious of the Beehive! Funny – my little lesson of the night was on field of view and I was just too wrapped up in the tracking  – and probably using too narrow a field of view  😳 – to see the little ass get kicked in the – well tail 😆

I had a couple of the “star hoppers” out and I asked them to come a few minutes early just to see that pass. But my plan was to line up the ISS in the Telrad, then jump quickly to the 80mm with the 5-degree fov – then I would hold it in the center of that while the others took turns getting a good look at it in the 8-inch with a 24mm Panoptic – 83X. It worked perfectly and they both got good views, then I switched to the 8-inch – Wow! I could see four rectangles of light, the two outboard ones dimmer and kinda reddish. Best view of the ISS I’ve had so far.  But at that power it is sure moving fast. The DoubleStar mount is smooth, but I felt like I was using a pair of 40mm Bofors and was holding off fighter attacks 😆

Assellus Australis must have had a good laugh, though – let’s see, I think the Space Shuttle missed it by about 136.18 light years – give or take a few fractions of a light second  🙄

I noticed the high clouds you mentioned as we watched the ISS go over. Some of them were thick enough to totally block stuff  – but we still had fun with my visitors learning to track down the two Christmas Trees – M103 and what I think of as the real one over at the tip of the Unicorn.(http://www.wired.com/wiredscience/2008/12/xmastreecluster/ ) Also on the agenda for Rose was ET. Joe wanted to track down M67 – and did – and Rose wanted to go after that obscure little cluster in front of the Hyades – NGC1647  –  and did.

Well not so little – it’s about 30 minutes across -but It really doesn’t make a good first impression! It’s interesting for all its doubles when seen with enough power. But it was also a good illustration of how difficult it is for someone just learning the sky to even know they’ve found an object when they’ve found it. It just doesn’t look much like a cluster. Especially in the 80mm at 15X. It easily sits in the same field as Aldebaran (with the 30mm eyepiece)  and with a dab of moonlight plus the deceptively murky skies she stared at that area for quite a while, looking directly at NGC1647 and not realizing that she was on the cluster.  However, putting the few stars you do see that way in the center of the 80mm and then switching to the 8-inch does reveal it’s true nature.

It drives me a bit crazy, then, to read what O’Meara has to say about this cluster in [i]Hidden Treasures.[/i] He had never seen it either – until his wife, standing in their driveway halfway up Mauna Kea, thinks she has discovered a comet with her 7X35 binoculars! What she saw turns out to be NGC1647. Oh for skies like that! With really transparent one here it would look a little more cluster like in binoculars I guess, but O’Meara calls it an easy naked eye object. Not here!

Hope folks get out tonight and watch the Moon’s close encounter with the Pleiades. It’s going to be murky again, but still should be a nice binocular sight  and I think this is the last such event for several years???  According to Starry Nights software, the view from here should have it just clipping the bottom off that wonderful chain of 7th and 8th magnitude stars that trails down from Alcyone. That should happen between 9:30 and 10 when the Moon will be pretty low in the west. Of course you’ll probably need  a telescope to see those stars so close to the Moon, but it leads with its dark edge. If the weather gives me a break – and the CSC is ambiguous on this one – I’ll be watching.

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Well, you could never have convinced me, even just a few years ago, that I could have a very satisfying observing experience with nothing but a 60mm telescope  – especially when there’s  a full moon with perhaps 70 % cover of drifting cirrus/stratus clouds! But I just observed for over an hour last night. And I followed up with two hours this morning – moon still full, but no obvious clouds, just some high haze. It was wonder full.

Major thing learned? In a word – context!

I’ve frequently pushed context as important, which is why I want folks to look through binoculars or a smaller telescope at low power before stepping up to the 15-inch. But what I have never encountered before is the context that can be provided by moonlight. This first hit me last night when I turned the little scope on Jupiter and at 40X found I had a nice view of the planet, it’s four bright moons, and the leaves of a foreground tree! It was the tree, of course, that provided a unique context. Sure, we’ve all seen Jupiter with our naked eye near some foreground object –  a building, or mountain, or whatever.  It was the impact of seeing it magnified with the foreground object clearly lit by the moonlight that gave me the unique experience. And yes, the fact that I was using a small scope at low power with a correspondingly wide field of view certainly helped.

That experience was repeated this morning when I looked at  the Pleiades at 15X as the branches of a nearby cedar reached up to enwrap them.  Tennyson’s fireflies became tiny Christmas tree lights, tangled in the branches. Context?  Yes – the branches were about 40 feet away, the Pleiades about 400 light years! Nice thought to tickle your mind.


This is a simulation from Starry Nights Pro planetarium software - not a photo or drawing - but represents wel what I saw.

And  I had entirely forgotten about Mars and the Beehive. But near the end of the morning I turned the little scope towards Mars and here was a different sort of context, not aided by the moonlight, but not diminished by it either.  At 40X the planet revealed a small disc as it nibbled at the edges of the star cluster in which I quickly counted 60 stars visible under these conditions in this small scope. So now I had Mars, perhaps 10 light minutes away at that moment, playing dodge ball in a star cluster roughly 600 light years away. Nice!

All of which I think makes the point that you can not only have an essential astronomy experience with a small scope, but you can actually expand your experiences breaking new ground. Don’t get me wrong. I’m not recommending everyone switch to small scopes. And I’m not at all certain they’re a good idea for beginners. All I’m saying is that for me using a small scope offers some special advantages that move me closer to  my essential goal of experiencing the universe. Perhaps the key is it’s a machine that is of a size I can easily accept and incorporate as an extension of my eye. In any event, three hours of use were filled with several highlights, including, in chronological order:

  • Splitting the Double Double in Lyra at 144X using a 2.5mm Nagler eyepiece. The split was clean and steady, which also says something about the seeing last night and got me off to a great start.
  • Picking out the Ring Nebula – M57 – at 40X. Hard to believe this is larger than Jupiter in angular size, but I’ll leave careful examination for a darker night.
  • Splitting Albireo – easy, of course, even at 15X, but real nice at 40X.
  • Capturing the Coathanger cluster with plenty of room to spare using the 24mm Panoptic.
  • Splitting Almach – Gamma Andromeda – at 40X. The gold of th =e brighter star has more orange in it than the gold of Albireo’s primary.
  • Examining the full moon with plenty of space around it – again, the 9mm Nagler at 40X gave a real nice perspective,

And in the morning:

  • Splitting Castor, high overhead, with a 5mm Nagler delivering 72X. The fainter of the two companions was, well, quite faint.
  • Splitting Rigel about as well as I have ever seen it split in any scope – no kidding. This is a challenge star. Again, 5mm was used, as well as 2.5mm.
  • Context came into play again, this time all in the sky, as I took a wide field view of the Great Orion Nebula. The 13mm (28X) gave such a view, yet enough power to split the Trapezium – charming!
  • Mintaka split in the 24mm at 15X which gave a wonderful view of Orion’s Belt with plenty of breathing room around it.
  • Fainter star clusters like M35 did not fare as well, diminished by both the small objective and the moonlight. I look forward to seeing them under dark skies, though.
  • Only real frustration came in trying to track down W Orionis, a carbon star. I think I eventually did, but I need to go back and make my own charts so it isn’t such a challenge in the future.

Bottom line – wow! This was fun. Of course, being seated in a rolling office chair in the observatory while using the little scope on the massive (for it) Universal Astronomic T-Mount certainly helped!

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I felt it first as I tracked down M27, the Dumbell nebula.

M27 - Driftway video image.

M27 - Driftway video image.

This shell blown off by a dying star suddenly looked more than three dimensional to me with faint stars blinking on and off at the edge of my vision as they shone through it. Here, I thought, is the universe as kaleioscope. For this star the kaleioscope has been turned, the pieces are being scattered – and in time they will come together again with other material and form a new pattern – perhaps a star, perhaps a planet – and perhaps they will find their way into the formation of life, perhaps even intelligent life. To paraphrase John Dobson, give it 3 billions years or so and it will be chewing bubblegum.

And this is why I get up at 1 am when I think it might be clear. This morning it wasn’t. No large clouds, but transparency was horrible – until about 2:45 am when I check one more time and am met by cool and clear air, though not all that steady. I grab my tea, still warm in its insulated cup, and the Ethos eyepiece case and head for the observatory. In just a couple of minutes the 120mm is taking in the Andromeda Galaxy, as well as M32 and M110, its companion galaxies. They all fit in the 17mm Ethos eyepiece when used on the 120mm Skywatcher. Nice. But no magic. I rotate the dome about 60 degrees. The last time I remember looking for M27 there was a lot greater distance between Albireo and the point of Sagitta – the arrow. That’s the path I follow when homing in on M27. Of course the distance hadn’t really changed, but everything looks so much smalller as it passes the meridian. When Ilooked at it before it was much nearer the eastern horizon.

I’m not explaining it, am I? I can’t. The feeling – the knowing – is ineffable in the final analysis. All i can say, is it’s not for the seeing – the seeing with your eye. That’s only th ebeginning. It’s for the seeing with your mind’s eye, supplement by the whole experience.  The result I can’t articulate, but it’s there this morning. I couldn’t squeeze meaning out of a galaxy 2.5 million light years away – but I could out of this gas cloud. However, I didn’t spend nearly as much time with it as I would have liked, for Jupiter and Neptune were moving through an open gap in my trees to the south and I really wanted a good look at them both.

A real suze comparison of Jupiter and Neptune.

A real suze comparison of Jupiter and Neptune.

And as I thought it would, the 10mm Ethos nicely took in both. But Jupiter is so bright I quickly abandoned the 10mm for the 6mm and as I came in tight on Neptune, was able to exclude Jupiter from the fov. It is so small! – 2.3 seconds of arc, about one twentieth of Jupiter’s apparent diameter right now. You can tell its a disc and its dominant blue color is – well prominent. But your mind wrestles with its true size, far closer to Jupiter’s true size than its apparent size would indicate. I can see the disc, but . . . once more it grabs me. Another moment where I feel I have a legitimate grasp of what I am seeing. I can picture the huge, frozen globes in my mind – memories of images taken by spacecraft. There is and overwhelming feeling of reality brought about I suspect by how close the two planets are to one another. Nice. But the trees soon close in on both planets and I moved on to the double cluster in Perseua. It is captured nicely in the 17 mm with plenty of shoulder room, yet I don’t stay but a moment because dawn is starting to wash them out and I have an urge to move to the “captain’s seat” for Space Station Earth – my little area where I have a couple of chairs that give me a great view of the eastern horizon, Here there’s a real sense of sitting at the viewport of a space station where the scene constantly – but very slowly – changes.

I take my tea and the low-power, wide angle (11 degrees) Bushnel binoculars. And the little excursion is well worth it, for not only does Venus dominate this section of sky, but it is forming a beautiful triangle right now witht Mars and the Pleiades. And here to the naked eye comes that third revealing event of the morning, for I can easily see the true relationship between Venus and Mars, as well as our own place between them. Your mind has to do twist and turns here and they need to be done effortlessly. It’s a cosmic high dive, of sorts, and practice helps. Here’s what I mean.

The Orrery view of the inner planets on the morning of July 5, 2009 when these observations were made. (from:

The Orrery view of the inner planets on the morning of July 5, 2009 when these observations were made. (from: http://www.fourmilab.ch/cgi-bin/Solar

In front of you in the sky is a simple triangle. Venus is the dominant object, the rough twin of Earth, absolutely brilliant as sun light bounces off its cloud-shrouded body. That’s easy to visualize. It’s also easy to see the scene from “above” – that is from the perspective shown by an orrery where you look down on the orbits of all the planets. I can place Earth at its correct location and see Venus off in the distance, oriented to us and the Sun in such a way that it shines like a quarter moon displaying to us half of its lit side, half of its dark one. (This is fresh in my mind from having looked at it in the scope during twilight of the morning before.) And in that same mental picture, I see Mars, almost half its size and diminished even more for being in an orbit far more distant, yet still nearly in a line of sight, from our perspective, with Venus. And between the two I can see our future path. Then I switch to the Pleiades and here the line of sight game continues – Mars is to the right of Venus in this mental model, the Pleiades to the left – but oh my, the gap is huge! We’re talking perhaps 7 light minutes between us an Venus and maybe twice that between us and Mars – but when it comes to this most favored of star clusters, light has been traveling for 400 years – that is something in the order of 40 million times as far away. I have a sense of a huge zooming out – that’s all. The scale between the solar system’s little playground and the stars is too great and my mental model crumbles.

But it’s been a good morning. I feel so fully awake with all these impressions rolling in on me whole. These are the experiences I seek. They are nothing less than revelations. Yes, they remain beyond my ability to fully share – but they are certainly worth having and I am well paid for having ogttenupa nd gotten out at this hour.

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Bren, Joe C., Sybil and I were dutifully out on Gooseberry last night  at 8 pm, hoping to see this despite heavy clouds!

The Moon, the Pleiades(M45), and Mercury, all within a single binocular field of view - as depicted on Starry Nights Pro software.

The Moon, the Pleiades(M45), and Mercury, all within a single binocular field of view - as depicted on Starry Nights Pro software.

What we saw was the Moon – stunningly thin – and a couple of the brighter Pleiads – but no Mercury. What a tease! The sky was at least 90 percent overcast – and heavy stuff. But there were several holes right where they were most needed and the Moon put in several appearances for three or four minutes at a time. As it got darker we could see some stars of the Pleiades under it – but no Mercury. We knew right where it should be and each hole in the clouds seemed to be just a fraction too small to reveal both the Moon and Mercury which were about 4-5 degrees apart.

It was refreshingly cool, though, after a day of record high April 26th temperatures – and a two-day old Moon is a special treat, somehow made more intriguing by it’s little fan dance with the clouds. Yes, sometimes the Moon would vanish and you would think Mercury might pop out, but the clouds stubbornly hid it.

Why is this so appealing? just pretty – and a good lesson in angular size. The Pleiades always appears quite tiny to the naked eye – yet when you see the Moon near it, you realize it is about twice as big! Of course this is all a matter of where things are – the Moon is only a light second or so away – the Pleiades about 400 light years from us! Even if the Moon could block out the Pleiades, it would be roughly akin to the way we can blot out the moon with a finger tip, even  though our finger is half an inch across and the Moon roughly 2,100 miles in diameter.

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So what’s that little cluster above M38 and how did I miss it all of these years? Too much computer control?

Uh oh – this is more of a mystery than I thought. Can’t find it on my charts!  It was a beautiful night last night, but this was the first time I had uncovered the 15-inch in a couple months – maybe closer to three, the weather has been so bad – and since I had had a little trouble with the computer, I set it aside and decided to go manual all the way. I was expecting just one visitor, Joe Black, and so that would be easy enough. After Joe arrived we stepped out into a cool (30 degree) night with some wind and sparkling skies. Seeing was poor, but transparency great.

Near the end of a two hour session, we arrived at M38 using the 22mm Nagler that gives me about a one degree field. I was looking for M36, but stumbled on M38 instead and to my surprise, noticed a little cluster just “above” it – roughly southeast.  I don’t recall seeing that before and I suspect it’s because I’m used to seeing M38 at higher power and just locking on it with the computer.  Now, nearly eight hours later withm emory fading, I can’t make any positive identifictaion on my star charts, but I think it’s just a little knot of about a dozen 9-12th magnitudes stars.  I’ll have to return another night and take a closer look and make some notes.  Meanwhile, score one for manual control versus the computer and tracking motors. If I wasn’t on manual I probably would have locked on M38 and stayed there.

That was lesson one for me for the night – the other lesson was I really need an optical finder on the 15-inch if I’m going to do more of this type of prowling.  I had a heck of a time finding my favorite cluster, M35, using the Telrad.  Mind  you, I was going from memory and my memory was playing tricks on me – but an optical finder would have grabbed it much quicker. I could find it in half a second with binoculars.

Speaking of which, even the 8×45 Garrett binoculars did a fine job of revealing M37, 36, 38 and 35 to Joe who was meeting these clusters for the first time. They were directly overhead when we had naked eye visibility to at least 5.5  so we spent a significant amount of time just studying the stars with our naked eye and binoculars – noting the the Winter Hexagon, the Pleiades, Hyades and all the stars around Orion’s belt. We also prowled about M42 with both the 15-inch and the 4-inch Orion ED. Interesting. The main advantage of the view in the 15-inch of M42 was it did reveal some color. I could clearly see blue with a fringe of red around some parts.

It’s been a rough winter. Good to get some telescope time. But the old chemical handwarmers I had grabbed didn’t work for more than half an hour  – they were in my pockets and when I reached for them they were cold -so after two hours my hands told me it was time to quit!

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