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Posts Tagged ‘10X30IS Canon’

Binoculars set up in Observing Shelter awaiting darkness for testing with doubles - and really testing me more than the binoculars. Unitron is there to check seeing conditions and acts as control of sorts - so to the Sparrow Hawk. (Click image for larger view.)

Until the past week I have never seen really sharp stars in binoculars – and what’s more, I assumed that was normal – that what I wasn’t seeing, others were not seeing.

Wrong!

Maybe decades worth of wrong. How many decades?  I’m not sure simply because it’s been relatively recently that I made a serious attempt to see double stars with binoculars and splitting close doubles is the most demanding resolution task of both the instrument and the observer.

From my experience I’ve developed some basic guidelines for splitting doubles with binoculars.  They are:

1. Wear your glasses if you have astigmatism – otherwise do without

2. Sit down – or better, lie back in a lawn chair – you must be comfortable

3. Hold the binoculars steady – even 7X50s will benefit from being on a tripod, or parallelogram mount unless, of course, they are image stabilized types

4. Focus carefully – very carefully –  first the left eye with center focus, then do the diopter adjustment for the right eye while keeping the left eye closed

5. Spend time on target – Look for at least one solid minute – don’t expect instant success.

6. Relax your eyes – let them focus at a distance and get used to it

7. And if all else fails, maybe you have a problem similar to mine – back off from the eyepieces an inch or two, move your head about some – find the correct head position – the one that works and yields sharp stars.

What follows is all about my own special case of “if all else fails” – because believe me, points one through six didn’t make a difference for me until I could settle the issue of point 7 and right now I’m not sure how many others have a similar problem, but I think it’s relatively few.

OK – the point is, I have been happily using binoculars for years without realizing I wasn’t getting the most out of these instruments – not even close to the most. Oh, I’ve seen galaxies out to  50 million light years or more – and I’ve gotten all sorts of expansive views of star clusters and nebulae. But I suspect what I discovered a few days ago may actually enhance  viewing of those objects as well.  What did I discover? That binoculars can, indeed, deliver “refractor-like” images of double stars. Let me be as clear as I can about this.

Double stars should look like the stars in the images to the right. That is, they should look like nice round discs with clean edges. Now any star that is low in the sky is  likely to throw out spikes of light, change colors, and dance about in any instrument just because in that instance you are looking through an awful lot of moving air.

But, if they are overhead or roughy 45 degrees or higher – and the air is average steady, then you should see nice sharp images when your instrument – binocular or telescope – is properly focused.

I do with telescopes – I don’t with binoculars – or didn’t up until recently and still don’t unless I am especially careful.  Is this my special problem? It may be. I have evidence there are some others who share it, but I suspect most people see the sharp stars they should, assuming their binoculars are held very steady – or are of the image stabilized variety – and they have been focused well.

Now let me emphasize that telescopes give me no problem – I can always see sharp, clean images with telescopes when seeing conditions are good. And while I am most likely to see the best images of doubles with either a long focal length refractor, or an apocromatic refractor, I get good, clean star images with any well-adjusted telescope of any design. Not so with binoculars. There the images have been consistently poor for me and I’m still not sure why. but lately I’ve come to suspect that my head simply isn’t screwed on straight – something critics have been telling me for years 😉

Determining what to expect with binoculars – that is, which doubles will split with binoculars  –  is much different than with telescopes. Double star fans know that all doubles aren’t created equal – and that the main problem is how far apart they are in angular measure – usually stated in seconds of arc.  A typical binocular has a field of view of between 2 and 8 degrees depending on how powerful it is. A typical binocular double is separated by less than one minute of arc. So when we are talking about stars separated by, say 30 seconds of arc, we’re talking about a distance that is just 1/120th of a degree. If your binoculars show a six degree field, then this pair of stars is taking up  about 1/700th of that field of view. Darned little.

So you also typically put the pair of stars in the middle of your field of view and the middle of the field of view is where even poor quality binoculars tend to perform quite well. Stars half way out to the edges may start to deform and stretch, but in the center they are sharp.  That’s why I say – and my experience confirms – that quite inexpensive binoculars can perform reasonably well when splitting doubles.

That is the first piece of big news I pulled out of my recent Eureka Moment.

The second was a handy rule of thumb I stumbled across when researching this subject trying to figure out what the heck was wrong with me. Telescope resolution – or expectations of resolution – are typically guided by something called the Dawes Limit which is entirely dependent upon the size of the objective  – a bigger objective creates smaller star images (in terms of angular size)  and will thus split stars that are closer together – it’s as simple as that. Now double star observers no it’s not really that simple – that frequently when the pair of stars have one that is much dimmer than the other, this rule crumbles because the dimmer star gets lost in the glare of the brighter one.

But if we are talking about stars that are within a couple of magnitudes of one another in brightness, the Dawes limit is a good starting point for determining how close stars can be and still be split.  The problem is, this rule assumes you are using fairly high magnification – say 30 times your objective diameter in inches. With binoculars you are almost always using much lower magnification. For example, my 10X30 image stabilized binoculars deliver only about eight times the objective diameter in inches. And my 25X100 binoculars have a power just four times the objective diameter in inches.

But Gary Seronik, in his small book “Binocular Highlights” suggests another rule of thumb that applies to binoculars – simply divide the power of your binoculars into 300. The answer is the separation, in seconds of arc, that those binoculars should be able to split. Thus my 10X30 binoculars – or 10X50 – should be able to split two stars that are separated by 30 seconds of arc. Albireo, a very popular double, is separated by 34 seconds of arc, so the 10X glasses should split it. My 25X100 should be able to split  stars that are 12 seconds of arc apart – that means the very popular double Mizar – which is separated by about 14 seconds – should split in the 25X binocular – and, indeed, it does. However, my 20X glasses will probably have problems with it  – 300/20=15 – and they do, though I have been able to split Mizar with those glasses, it’s difficult. So I think this is an excellent – though rough – guide. (The Dawes limit on those 25X100 binoculars, btw, is  barely a second  of arc – but that is a totally unrealistic expectation for binocular performance. Dawes limit = 4.56 Arc Seconds / Objective Diameter (inches) so 4.56/4 = 1.14. In fact, it is rare for a telescope to achieve this resolution on a double, but something like 1.8″ of arc is a reasonable expectation for a 4-inch t eleescope.)

But these numbers have not mattered much to me when using binoculars. I have only split the widest doubles. So, for example, over the years I really needed 15X binoculars to get a good, obvious split of the Dragon’s Eyes – Nu Draconis – a charming pair of 5th magnitude stars a wide 60 seconds of arc apart. Now, the new me finds them simple with just 10X30 binoculars.  Fifteen power glasses should, by this rule, be able to split stars just 20 seconds apart. The Dragon’s eyes should fall to binoculars as low as five power!  What’s more, in the past when I split this pair I didn’t get the kind of clean, “bullet hole”, stars shown in the image – I got dancing stars – bloated, jiggly stars throwing out spokes of light. It’s just that the 15 power binoculars – and the wide split – made it possible for me to see this pair as  two stars – and I assumed everyone was seeing the same thing.

But I was puzzled how observers I respect and admire like Seronik and Ed Zarenski, to mention just two, routinely split stars that were far, far closer together and instead of bragging about their amazing eyes and observing skills, seemed to think that others could routinely do the same. I know I couldn’t.

It must be my eyes. They must have problems I’m not aware of. That was my first train of thought and I’ve been pursuing that one for the better part of a year – without staisfaction. And a recent trip to the eye doctor confirms my practical experience – there’s nothing seriously wrong with my eyes. In fact, I have what the doctor describes as a “slight astigmatism” – so slight that they say that if I get corrective glasses I will barely notice the difference – and though this doctor worked with folks who sold glasses, she didn’t recommend them for me. (I ordered them anyway – there was  a special on where they’ll cost just $50 and this is something i have to see for myself because this whole business is driving me more than a little crazy.)

The Breakthrough

My breakthough came on a morning when I had decided to test five different binoculars –  10X30IS Canons, 15X70 Celestron Skymasters, 20X60 Pentax, 20X80 Celestrons,  and 25X100 Zhummels.  With the exception of the image stabilized Canons, all would be tested mounted on one of two parallogram mounts. The largest of these mounts was on a pier and really too tall for me to use sitting down, so I was using that one standing.  As a way to check the seeing and to make sure I could actually split these particular stars at low power, I had two small refractors set up as well – a 60mm Unitron using a 40mm Kellner eyepiece for roughly 24X and a 50mm Stellarvue Sparrow Hawk that was a lot like a single binocular in that it used a prism diagonal and was of very short focal ratio – F4.1. I used a 20mm eyepiece in this to get 10X, so it was, in many ways, a good match for the Canon 10X30IS.

My targets were the doubles Albireo (34.4″), Zeta  Lyra (44″), Nu Draconis -Dragon’s Eyes–  (62″), and Mizar (14.3″) – all were at a good altitude on this spring morning.

Initial tests

And the notes from my initial test showed nothing went particularly well at first.  This was the old me.

Actually, I started in the early evening with Mintaka – a wide  split at 52.8″ of arc that should be easy with all the binoculars I was testing, except there also is quite a difference in magnitude –  2.4, 6.8. That 4.5 magnitude difference makes Mintaka a bit of a challenge.  But the 25X100s showed it well. The 20X80s gave me a good look, though not quite as good as the larger binoculars. Actually, the best view came with the 20X60s – not sure why, but this is the old me talking.  I’m seeing a split, but the primary is shooting fire. The 10X30IS gave me an occasional glimpse.  The best view came with the Unitron with the 40mm Kellner, so this was roughly comparable to the 20X60 binoculars, but the star images were much better. I assumed that was because it was a long focal length refractor – and that probably was part of the reason, but as I later learned, didn’t account for all the difference.

The point here is that even the old me could split some doubles – just not nearly as well as I later learned was possible.

I moved on to the much more challenging Mizar. The 10X30IS couldn’t split it – no surprise. The separation is too little for those binoculars. Here I drew a quick sketch of what I saw with the 20X60s because the stars were so bloated and dancing so much I couldn’t be sure I was seeing a split, but I thought I was.  When I checked with the 60mmUnitron I was sure – the binocular view was correct – but, there was absolutely no comparing the two views. The Unitron – at roughly the same power- was far, far cleaner than the binoculars. (Remember, at 20X you should barely be able to split  Mizar – the formula says 15″ is  the minimum separation. Mizar is 14.3″ – though the stars are fairly close in magnitude –  2.2    and  3.9.) The 25X100 gave me a certain split, but certainly NOT “refractor-like” stars.

But something strange was starting to happen. As I maneuverd the binoculars on the parallelogram mounts they were sometimes a few inches from my eyes and once in a while I got a glimpse of sharp stars such as I saw in the Unitron. This first happened with the 20X80 Celestrons and it came when I seemed to bend my head back and literally look down my nose from an inch or two behind the eyepieces. I was tired. I was getting cold. And I really didn’t know what was going on, so I went in with the intention of getting four hours sleep and trying again when I was refreshed.

Morning session

Field notes on Albireo - at last, a clear view.

Nothing comes easily to me – especially in terms of binoculars. I wrestle with mounts, I fiddle endlessly with focus, and mostly I have ended end up seeing something like this:

I have a sense of two stars here, of course, but theimages are dancing, the colors swapping sides, and sometimes I think I see the secondary in one place, sometimes in another.

When I should see – and now do see –  this:

What a delight! This is what I'm used to seeing with a telescope and now - with more and more consistency and less and less hassle, can see with binoculars.

In one sense the change was nearly instantaneous – that is, I would go from a terrible image to a perfect one – no inbetween.  But it only happened after a lot of work and a lot of false steps.

What made me put in the extra effort was I justc ouldn’t reconcile the diffferent experience of using two very nice instruments on Albireo. The first was the Stellarvue Sparrow Hawk aka Little Rascal. This is a 50mm finder, essentially, but  it takes standard eyepieces and is easy to focus. But like a binocular it has a very short focal ratio – F4.1 – and it uses a prism to deliver an erect image. And as my notes show, when I pointed it at Albireo on this particular morning with a 20mm eyepiece (10X) I got a “clean and delicate” split just as I would expect with any telescope – though this wasn’t any telescope. this was essentially half a binocular.

Then when I switched to the 10X30IS Canon’s I was back in Blursville with dancing stars.  And then I started to notice something. I noticed it with the large, mounted binos – the 25X100 Zhummel and the 20X60 Pentax, and 20X80 Celestrons. If I backed my eye way off – I’m talking two or three inches from the eyepieces – and tilted my head so I was in effect looking down my nose  there were long moments when the two stars snapped into sharp focus. Crazy? I’m not sure. When Ibrought this up in a Cloudy Nights discussion forum a few people came forward to talk of similar experiences – but on a few.

Believe me , my heart was racing. I have looked at countless double with binoculars and I had never seen them like this.  This was a real breakthrough and I quickly skipped about from Albireo to Zeta Lyre, to the Dragon’s Eyes and then to Mizar. With these kargerf binoculars everything was great – really great with the bright image sof the 25X100,

I couldn’t believe my luck. I hadn’t even brought out the 10X30IS for this session because I had about given up on them. Twilight was starting to grow brighter in the east. I quickly went back to the house, got the 10X30IS, and voila! There was a perfect Albireo – a yellow star with a scrumptious blue pinpoint right next to it.  I simply couldn’t believe it.  It was every bit as good as I had seen in the tiny Sparrow Hawk refractor.  The only question that remains is why the heck did it take me half a century of observing to discover this?

Well, not the only question. Since this breakthrough I have had three more sessions under the stars and I have expanded the variety of stars I’m looking at to include 16 & 17 Draocnis, Regulus, and Psi Draconis.  I have had my eyes examined by a professional and asked her for ane xplanation – why the heck do I have to look down my nose at doubles? And I have discussed it in online forums and with Larry Patriarcha, the guy who makes and sells the best parallelogram mounts  I know of.  Allt hese people had ideas, but no really firm answers.

But here’s the rub. This is getting easier and easier for me to do – that’s good news, but doesn’t solve the puzzle. I am finding with practice I now achieve this state of double star nirvana without half trying. But it still is easiest to reach if I back off form the eypieces, then, once i get it, approach them slowly being careful to maintain my head position.

So I think it does have something to do with head position – after all, with binoculars you look up – with many telescopes using diagonals you look down.  And it may have some tiny thing to do with astigmatism, and it may have to do with stressing my eye muscles by tiltilting my head back and looking down my nose. But two things are clear to me – first, most observers don’t seem to experience this problem. Second, I don’t understand fully why I do, nor do I understand fully the solution because the ground rules seem to be slipping out from under me. There definitely is a groove and I find it easier and easier to get in it. And believe me, I’m not complaining. This opens up a whole new area of especially enjoyable observing for me.

Doubles I love. I always have found a magic in seeing two perect little globes next to one another.  But now I can see them with both eyes open and while leaning back in a comfortable lawn chair and looking up at the sky – and that, for me, really is double star nirvana.

 

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Windy, cold, but clear! I’ll take that any day over the muck we’ve had recently, though I must say seeing was poor and the older I get the less fond I become of cold. But what was keeping me warm last night was the fun of opening up the 30mm Universe – the night sky as seem through 10X30 IS Canon binoculars. It’s awesome.

Now I know a 30mm objective seems small, but here’s a summary of what I saw in a series of brief observing sessions in both the evening and early morning hours. (Yeah, I did a lot of going out for half an hour,then coming in and studying charts while I warmed up.)

In Draco I started with Nu, got a clean split (60″ gap) and so went to the fainter, 16/17 Draconus. Another cleansplit. Here the gaps is about 90 seconds. So I went to the more challenging Psi Draconis which I have not split before and has just a 30 second gap and despite passing clouds and unsteady skies I got “kissing” stars which occasionally steadied enough to give me a hairline split

Went to 56 Andromedae, which I had split several nights ago, and found it easily – and it splt very easily – but my real goal here was something more subtle – the open cluster NGC 756. And I found it – a faint sprinkling of star dust with two or three stars that easily stand out. But this is a real rich area of sky as the following chart shows, for it also contains two of the largest galaxies we see – M31, the Great Andromeda Galaxy, and M33, a much more subtle patch of white . So with relative litte movement of the binoculars – afterall, look at thai six degree field – you can go from an easy double stars to a subtle cluster to a great galaxy and to to a more ghostly one.

Click image for larger version - from Starry Nights Pro screens hot.

What I saw, though, does’t capture what I regard as a remarkable – and repeated – experience: One moment you have a star dancing around and then, almost like watching a photo print develop in a tray of chemicals, you realize you’re seeing two perfect stars. This happened more than once and I don’t know if it’s the image stabilization reaching a new level, or just my brain adjusting to the new scene and kicking into gear,

I experimented with the 11X56 Garrett Optical and the 15X70 Celestrons and I have to say, they just couldn’t deliver. The images were brighter, of course, but when push came to shove the resolution wasn’t there -especially where bright stars were involved. They simply won’t quiet down in any binocular I have, but they’re better in the 10X30IS. What’s more, even though the larger ones were gathering more light – and I was using them on a parallelogram mount – they rarely  allowed me to see any more details than the 30mm binoculars. Generally, whatever I could see, I could see with either, though extended objects, such as galaxies, were easier to see in the larger binoculars.

This raises real questions in my mind as to what is the best binocular for scouting and area while star hopping with a telescope. The 15X70s make extended objects pop more easily – but they give a significantly smaller field of view thanthe 10X30s. I need to experiment with this aspect of binocular use more.

What’s fun with Draco and the binos is you can go on a neat progression from 16/17 at 90 seconds, to Nu at 60 seconds, to Psi at 30 seconds – and all with stars that are pretty close to one another in magnitude.

On to galaxy land! Morning with Ls and Js.

After a few hours sleep I returned to observing in the morning and this time my first target was  M3 rising above Arcturus in the east. A quick scan and there it was, an obvious fat star with with crumbling edges among much “cleaner” ones.

This one's too easy - just draw line between Cor Caroli and Arcturus and you'll find M3 a bit closer to Arcturus and with a magnitude 6 star right next to it. (Click image for larger version - prepared from Starry Nights Pro screen shot.)

But I was  interested in bigger – and much more distant – game.  First up was M81/82, the famous pair up behind the bigBear’s ears.  I say that. I don’t know howmany times I’ve seen them – certainly more than a hundred. But I always get lost looking for them despite some obvious clues. I think it was Sue French who said something like the “Big Bear has ear mites.”  That helps. It also helps to draw a line between two of the bow stars in the Big Dipper. But in the typical finder and these small binoculars they can be too faint to readily jump out at you. You need something more and I think I have it – three radily distinguishable asterims in a row 0 a bold triangle, a ragged “L’ and a 7.   The pair of galaxes we want is right off the end of the L as indicated inthe chart. To get in the right area, scratch around behind the Bear’s ears – or use the two bowl stars to make an arrow pointing the way.

I use the two indicated stars to cut across the Dipper's Bowl and get me in the right general vicinity. Then I look for the asterism in the next chart. (Click image for larger version - prepared from Starry Nights Pro screen shot.)

Sigma is actually a wide (19') optical double of fifth magnitude stars and forms a bold triangle with another star of similar brightness. The ragged "L" leads you to the two galaxies and if you see the "7" you know you've gone too far. The galaxies are fainter than the bright stars int hese asterisms, but keep in mind you are looking at objects about 10 million light years away shinning with the combined light of billions of stars.(Click image for larger version - prepared from Starry Nights Pro screen shot.)

OK – traveling 10 million light years or so with objects I can easilyhold inmy hand is a real trip – but I wanted to go deeper and M51 provided thenext step. Seeing the famous “Whirlpool” galaxy takes you  out  about 23 million light years  and it’s a much easier trip – from a star hopping perspective – though the galaxies are a bit fianter and, of course, mushed together – quite different from the M81-82 pair.

Start with Alkaid, the last star in the handle of the Dipper, and head in the general direction of Cor Caroli. We really have two triangles here, as shown, the second consisting of magnitude 7 stars. Since all this fits in the same binocular field as Alkaid it's apiece of cake - that is, assuming your binoculars have a field of 4 degrees or more. The 10X30s I'm using have a 6 degree fov as indicated y the circle.

That encouraged me to take a look at the lion’s hip – Leo was rising in the east and he carries with him a slew of galaxiws, the brightest being M65 and M66 – and they’re also just plain simple to find.  These are my “J” galaxies – that is, I find them because of a pair of “Js” in the sky near them. In fact, the brighter J sort of hooks them.  Here’s what I mean.

Finding the Leo Triplet of galaxies starts with identifying th ebright triangle of stars that represents the Lions rear haunches. One of those is Thea and if oyu get it in your binoculars the two "J" asterisms should jump out at you. The fainter, larger one is there just to fool you - and I've been fooled by it sometimes, especially in a finder that reverses the image. But the smaller, brighter one is actually easier to spot and from there it's clear where the galaxies are. (Click image for larger version - prepared from Starry Nights Pro screen shot.)

Now don’t get me wrong. I didn’t “see” these galaxies. I “detected ” them. Tome there’s a difference. “Seeing” means you can discern shape, texture, and form. “Detecting” means you know the object is there – that this tiny patch of sky is different in brightness from its surroundings, but where you to draw a picture of what you detected it would be an indistinct smudge. So what you see is a ghostly presence at best in such small binoculars, but I felt confident with M66, a little less so with M65 – and I might have seen the third member of this famous triplet, NGC 3628.

This all defies somewhat the common warnings you here about viewing extended objects. M66, which I certainly found easier to detect,  is listed as magnitude 9.7  and M65 a bit dimmer at magnitude 10.1. But in terms of surface brightness – taking into account how spread out their light is – they are both listed close to magnitude 12.5. Now given that I have a darned hard time seeing magnitude 9.5 stars with these binoculars, you would be justified in assuming that I am either crazy, or a liar, if I say I can see a galaxy with a surface brightness of 12.5.

But all that really illustrates is how puzzling this phenomena of sight and faint objects is.  Stephen James O’Meara, observer and writer par excellence, syas in his book “The Messier Objects,” that all three of these galaxies can be seen with 7X35 binoculars! (He wrote that before the time of image stabilization and I am sure he is not using amount for those.)  If that’s the case, then it certainly isn’t ridiculous for me to claim I’m seeing them with 10X30 image stabilized binoculars. So I have confidence that I am seeing what I think I am seeing.  It is also interesting that O’Meara finds M65 brighter and I find M66 brighter – and again, I have some confidence in what I saw because O”Meara also notes that other observers disagree with him and find M66 brighter.

This whole business of what you can see with what is variable at best and the role of magnification and field size and steadiness all complicate the question, not to mention light pollution and the atmospheres transparency at the moment.  So you really have to try these things for yourself. For me, I count it as great fun that with these tiny glasses I easily hold in my hands I have travelled 38 million light years out into the universe to pluck ancient photons from billions of stars. That’s awesome.

 

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