Actual Astronomy - Saturn at Opposition

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0:00It's the 365 Days of Astronomy podcast, coming in 3, 2, 1.

0:20Saturn at opposition and doing some optical testing on my giant refractor on episode 550. Is this 555 or 556, Shane? I think I might have messed up the numbering. Oh, let me just have a quick look. I think it should be 555. So I'm going to change it. I'm Chris, joining me in Shane, we're an amateur astronomer who's who love looking up the night sky in this podcast. Everybody who enjoys going out under the stars, we're giving away some hats, three hats for three Patreon supporters.

0:57Yeah, we've been talking about this for a little while, Chris, and we're finally at that point to pick a winner. So what we've done is anybody who's a paid Patreon supporter, your name is automatically entered. So we have, I think, about 75-ish, maybe 80 active paid Patreon supporters. And should I list the names, Chris?

1:27Go for it. I'm going to send you some interesting photos in our chat while you do. Oh, sure. So the three lucky winners are Peter Monson, Ian Donald, and Jacques Pelletier. Hopefully I pronounced all of those names correctly. We will be in contact with you. We have your email addresses. So we'll reach out to get a mailing address and get these hats off to all three people. So thank you very much to all of our Patreon supporters. We really appreciate it.

1:58And, you know, once or twice a year, we do like to try to give back a little bit if we can with some random draws like this. Yeah. Thanks so much to everybody who became a Patreon supporter. And for those who have been for a long time, we do certainly appreciate it.

Testing the Chromacore optical device

2:15I think one of the strange things about doing a podcast versus some of the other outlets online that creative people use, Shane, is that a lot of those other outlets can be free or nearly so. And podcasting is not. Yeah, there is some expense for us to provide this thing. But the support from our Patreon folks really helps out a lot. Yeah, for sure. So before we get into Saturn, I'm just sending you some photos here, Shane, on what we've been doing with the 7-inch.

2:54So I got something called a Chromacore. Now, I'm not sure if you're familiar with it or maybe we should explain it to the listeners. Yeah, I'm somewhat familiar with it. I'm aware of them. But, yeah, maybe let's start at the beginning. So the Chromacore is a very rare and unique optical device. It was made by Ares Optical out of the Ukraine about 20 years ago or so, perhaps even longer.

3:30And very simply, what it does, if you have a large acromat, you really want to be using about a 6-inch F8 is the general rule. That's kind of sort of what they were originally designed for. And then people with as large or larger ones have used them on their acromats as well. And what they do is they bring in your secondary chromatic aberration colors into focus some magical way.

4:05It's like a long cylinder with a whole pile of fancy, rare optics in it. And what it does is when you look through your acromatic telescope at a bright white star, like I was looking at Vega, or if you're looking at the moon, or if you're looking at something else, you'll see, often you'll see like around a bright star, a purple halo or a blue halo. And you might get some red in there. If you're looking at the moon, you might see some red on one side of craters, some green or blue on the other side of craters, and that sort of thing.

4:40Is that kind of what chromatic aberration looks like to you, Shane? Yeah. Yeah, just unwanted color that's not natural. Yeah. Now, it doesn't mean there's anything wrong with the telescope. This is just the nature of acromatic telescope design. They're not apochromatic, and apochromatic simply means that they're totally corrective for color or nearly so. So, typically, by my explanation. And to get a fully apochromatic 7-inch telescope, what would that run, Shane?

5:10Maybe an American dollar. Apochromatic, oh, thousands and thousands and thousands of dollars, I would assume. Tens of thousands, yeah. Yeah, yeah. Like, I don't know what those ASCARS are worth. I think they claim to be apochromatic. Yeah, I think you're getting to about $10,000 on one of those Canadian. I could be wrong. Wow, for the ASCARS? Yeah, for the least expensive one. And so, I have a 7-inch F6 Acromat by TMB, which is an older model, but it has excellent optics and excellent other characteristics.

5:45And it's a doublet, not a triplet. And the challenge here, where we are in trying to use a triplet design, is cool down, especially when you get into larger apertures. And as well, my telescope didn't even cost a half. I'm really probably more into, like, about a third the cost of what those ASCARS were when I was buying mine and they were brand new. So, that's a pretty big difference. And it's also, my scope is also about, I think it's about, now that I've got it tweaked out, it's probably three or four pounds-ish lighter than the ASCARS.

6:21And, of course, it's shorter by about eight or nine inches or so, which is not insignificant, you know, as far as having a scope goes. But one of the things I always thought I would do is to get one of these Chromacores to help sort of tame that secondary color, as a lot of people have noted with using these Chromacore devices. But there's not very many around, but sort of oddly enough, I kind of had a line on three of these at the same time.

6:53There was one in Italy, there was one in the States, and there was one in Canada. All the same, the Chromacore Type 2N, and they make them or made them in different corrections. So, you could get an overcorrected one that, and this gets a little confusing, but you buy an overcorrected one if you have an undercorrected telescope, and an undercorrected one if you have an overcorrected telescope, and you buy the N neutral one if you have a sort of well-corrected telescope.

7:23And then, to make matters even more confusing, they came out with a version 2, which has more aggressive color correction. Now, with my telescope, I've got just a little bit of undercorrection, which means that when I'm inside of focus, my most external Fresnel ring, or the most external ring on my star test, is very bright and clear and well-defined. And when I rack back through focus and go out of focus, that star test shows that that ring is still there,

7:53but it's quite a bit fainter, but still quite well, somewhat well-defined. So, this telescope is just slightly undercorrected, and I'm just trying to sort of recall my star test off the top of my head here while I explain it. But I had wanted to get a neutral one because they're a little bit more usable, and then there's some other things I can do to help correct for that undercorrection. For example, I have a 2-inch APM prism diagonal, and if you use a large 2-inch prism diagonal

8:23on a slightly undercorrected telescope, that will introduce slight overcorrection and theoretically cancel out that correction anyway. And I have tested this, and I think it works. Okay. So, that's the good part. And the other good part is that, you know, and as many people might even guess, if you're into telescopes and such, that a large 7-inch F6 Ackermatt is going to have a lot of color.

8:54You've looked through a chain, it has color. Yeah, there's certainly color on brighter objects. Yeah. I don't know that I'm as sensitive to it as some people. I think that factors into it as well. Yeah. But regardless, it's there. It's there, yeah. With this device, there's no color. Like, it's gone. Wow. So, that's the good part. Yes, yes. But the image is soft, and without the chroma core in, I get a good star test. Everything is a circle, and the star test is evenly illuminated.

9:26But with the chroma core in, I get, like, almost a chromatic teardrop type of aberration. And as I rotate the chroma core, because what I can do is sort of undo, and it is a fairly complicated thing. And what you have to do is you, it looks like a cylinder about the size of, like, a toilet paper tube, about that length, not quite as big around, I guess. It's threaded M48, so it would thread directly onto your diagonal.

10:00But you have to space the chroma core about 161 millimeters from your focal plane to the eyepiece. And then because I have the Pentax eyepieces, which come to focus at the focal plane, which is flush with, like, the collar, then it's pretty easy to calculate with Pentax eyepieces. So what you have to do is you have to put extensions onto the nose piece to push that chroma core down your focuser tube to get that distance between the chroma core and your focal plane, okay?

10:34Okay. And in doing so, this can introduce, well, you're really pushing your optics. And so if anything is out by just a scooch, then you can get some strange star test patterns. So kind of in a way I wasn't surprised. I just thought maybe it would be, like, maybe there would be some sort of minor error. But it does make things pretty soft. And then what is kind of interesting about this experiment is that you still have it as a color-free 7-inch.

11:08And, like, when you're looking at Saturn or a bright star or the moon, there's no color. The color is essentially gone. Like, there might be a little bit on the edge of field or something, but it is what it is. But at the center of the field of view, there's essentially no color. But it is softer. And then when I switch it out, when I take all that apart and just run normally, yes, I get color. But you can see a heck of a lot more detail.

11:39Like, you can see the bands on Saturn, a lot of fine detail in the rings and that sort of thing.

11:48And you get a better star test, like, on the star. And the moon, yes, it has color. But you can see, like, way more detail. Looks like you can see, like, just, like, the fine creases and folds on the lunar surface, which are completely washed out with the Comacor. And this is interesting to me because oftentimes people debate, like, Acromat or Apocromat or people really want the color-free instrument. But in doing this experiment, it just proves to me that really you want good quality optics that are well aligned over color-free optics.

12:28Without question, nobody would ever take the soft image over the sharp image that just has a little bit of color to it. In fact, I found the color much, much less annoying than I did the soft images. And really, Shane, what they look like is, like, if you didn't – if you weren't doing a star test and you were just sort of brand new to it, you would just think you had bad seeing. It just looks like really bad seeing is what it looks like. Oh, okay. Yeah. Okay. And I've often thought that with other telescopes I've looked through over the years.

13:01Okay. Is that, you know, in telescopes that have poor star tests or aren't as high quality as, like, the next telescope, that's kind of what it looks like. And a lot of the time when you're reading through posts online, you'll see people saying stuff like, oh, well, the seeing's never good in my area or other things. But I often wonder, well, I wonder how often it's the case that, you know, something is just amiss with the optics.

13:31But anyway, I digress. So we found – I found this bit of a problem there. And so I've been chatting with an individual, Dan Cleveland, and this person is somebody who has, like, a full collection of these Comacores and knows way more about them than pretty much just about anybody else and has talked to the manufacturer, you know, for years and years and years. So this guy is very generous with their time and has really been helping me out.

Aligning the refractor and focuser

14:04So one of the things you have to do is to make sure that your focuser is square to where the center of the objective should be. And in order to do that, you need to make a little paper mask that goes over your optics. And, Shane, if you look at our chat, I've actually sent you a shot of – I used a newspaper because it was easier to cut than all the other paper I had, and which is kind of funny because it looks like I maybe lined it up so that you could see, like, there's, like, a crossword puzzle.

14:38And I'm, like, shooting right through the center of this little crossword puzzle or something. And what you do is you use your compass, like your drafting compass or geometry compass, and you poke a hole. And then you draw your circle around or kind of draw your circle around and make your hole larger, and you make it the exact same diameter as your objective saw. So I made this circle of paper, 180 millimeters across, and then you use, like, a piece of tape to make a little handle.

15:09And you drop it in and then pat it very gently down around the edges to make sure that it's center with your telescope. And kind of surprisingly enough, when Mike brought his laser out last night, we turned it on, it just shot straight through that little hole. It was like a little bit of magic. It was pretty cool. That's awesome. Yeah. So you've got to make sure that that focuser is aligned with where the center of the objective should be. And the reason why I'm using that language is that just because the center of the focuser and the center of where the objective should be are lined up, like, where that center of the objective should be, doesn't mean that the center of the objective is lined up with the focuser.

15:56And what we're trying to determine now is if that is the case. So you need to use a Cheshire eyepiece. And I'm not sure, have you ever used a Cheshire eyepiece on a refractor before? Not on a refractor. I've used them on my Newtonians in the past. Right. I've never used them on a refractor either. And what was funny is back during the time of the pandemic, right at the very start of the pandemic, I thought I was going to have all this spare time. My workplace had other ideas for me, unlike everybody else around me, it seems, because everybody else is out doing gardening and biking and who knows what.

16:35Meanwhile, I was stuck inside working like a busy person, like a sucker, I guess. But anyway, so I had bought a Cheshire eyepiece at that time. And I was going to start figuring out how to take a look at refractor optics using this and using these sort of methods, but never had gotten around to it. So I actually had that sitting around here anyway, which was kind of cool. And stuck it in last night after Mike and I did this laser test.

17:08And we really couldn't get it to work. It's kind of a tricky thing to get to work on a refractor. So what the Cheshire is, is a, it looks like an eyepiece. It's got this slice out of the side at this angle, 45 degree angle. And it has a round metal, looks almost like a tiny secondary for a Newtonian reflector with a little hole in the middle. Almost looks like your secondary holder. And light shines off that.

17:41Now with the Newtonian reflective mirror, the light shines off that, goes down your tube, hits your mirror, bounces back up to your eye. And then you can use that image to line it up. With the reflector, you're just reflecting off your coatings. So it's much, much dimmer, Shane. Let me tell you, it is freaking dim. Okay. Well, you're passing through a lot of glass, I guess. So a little more loss each time. Yeah. And that's what happens is it goes through, a lot of it goes through the glass and then it reflects back.

18:17But, you know, like if you look at your optics, you know, you will see some light reflecting back. But, you know, under, you know, these sort of conditions, you could imagine with this tiny little thing, how much light is actually getting bounced back. So I'm trying to get the hang of that. And a lot of folks online, what they have done now is built these, they've taken like an inexpensive guiding camera and made an adapter and then made an image amplifier.

18:54Or you can buy these online for like 30 bucks or something that will magnify that image and then create like a bit of an optical train and then plug that into the computer with a bit of software. And then you're able to actually amplify it and see it and play with it while you're looking at a screen instead of just kind of trying to look through the tube. Right. Okay. So this is what I was asking you just before we hit record is that I might need your kind assistance to make one of these little adapters to connect.

19:29Mike and I got to try to find a camera and an amplifier, make a little lens system in order to sort of bring this together and to be able to do this in real time. And because the other thing is Mike has his Takahashi, I've got several refractors, you've got refractors. And we were thinking this could just be a handy thing for us to be able to do just for our own purposes, even outside of what I'm trying to do here. Yeah. It sounds like it would definitely have some utility or purpose for a lot of things with us.

20:04Yeah. So that's what I've been working on. Okay. It's quite the little project, but if this can be made to work, and I don't know, I thought that perhaps the focuser was, I don't recall, but I may have mentioned it in the previous episode, that I had a stuck adapter on the end of my focuser. I had to take it off, and I had to get an oil pan wrench or a strap wrench or whatever you want to call it.

20:39And my wife and I are two sets of hands to finagle it off using that. And I was like, ooh, I probably knocked the focuser out of alignment when I did that. However, we tested this a whole pile of different ways for like an hour last night. And that focuser is for sure aligned with the center of that telescope because we spun that little paper disc around a bunch of different ways. We tried a bunch of different things, and we're fairly confident. And I did communicate with the gentleman who's been helping me out down in Cleveland.

21:14And so we're all in agreement that that telescope and that focuser are at least the end of it are in alignment. And now it's just a matter of trying to figure out if the lenses are also in alignment. But I've got to think that if they weren't, I don't know. I feel like if they weren't, something would be off with my star test. And when I star test without the Comacorin, I get like a pretty much perfect star test. Wow. That's exciting.

21:45But I've always had that. I've never really questioned the star test too much with the scope because it's never shown astigmatism. It's never shown anything other than, like I said, the slightly brighter ring on inside of focus, which is under correction, which is pretty much what most acromatic refractors will show. In fact, that was like just the standard correction of them pretty much from like 20-odd years ago when this telescope was designed. That's just the way they're there.

22:16Okay. So, yeah, we're going to try to set something up to do like a better optical test on the lenses. But I think the image looks pretty cool though. Yeah, it does. Yeah, it's neat. How long did that take you to kind of work through?

22:35Most of the day yesterday. Okay. Okay. Yeah. Like it took me a while to figure out how to get the, like the paper. I went through quite a few paper circles here. I'm actually living in the shambles of, looks like a grade six, you know, math homework disaster here, but did eventually get it. Okay. Cool. Yeah. Yeah. So, it took quite a while to figure out how to do that. And then one of the other things I did is I made an aperture mask, but the sky didn't quite cooperate last night enough to test it out.

23:10But I made an aperture mask to take it down to pretty much like 135 millimeter aperture, which will give me an F8 on this instrument. And since it's designed for F8, I thought, well, that might be another test I could run. But I chatted with the guy in Cleveland today and he said that I should try it in the daylight as far as the shisher goes.

23:41And because of the way I have my, my observatory set up, I should be able to get quite a bit of light in there and that should do the trick. So, uh, I'm kind of keen to, uh, to give that a whirl after we get done recording today. Right on.

Observing Saturn and Astrochron model

23:56But one of the things I've been doing is a fair bit of Saturn observing, Shane. Shane, I'm not sure if you've been out observing Saturn. I have not, um, I was just in Grasslands National Park for a, uh, fall hiking trip with my brother, which was phenomenal, but, um, I woke up at about 2.30 and we were in an authentic and I did have a visual observation of Mars, um, which was kind of neat. That was my first view of Mars this year, but, uh, have not looked at Saturn.

24:29Ah, yeah. Um, cool. Well, you didn't take a telescope down with you or anything? No, no, this was, uh, this was a hiking trip and I've learned from previous mistakes. You pick one or the other. And by the end of each day, we were, we were pretty gassed and it was a struggle just to stay up for, uh, kind of a normal bedtime. Yeah. Yeah. Yeah. I've been there before. I did that when I first was going down and did some early morning hikes in that and just about died.

25:01Because you're really, you know, you're, you're getting up to go for like a hike at whatever time and then trying to get some sleep sometime during the day and then do astronomy at night. You're just trying to do too much is what it boils down to. Yeah. Even apart from the tiredness of the fact that you're out hiking in some pretty harsh conditions. Yeah, exactly. So, um, we've got Saturn come around for, uh, opposition, um, and sort of in that, in that line, we had a note, uh, from Alexio, uh, about something he's come up with.

25:35It's pretty cool. I was checking this out, Shane. Not sure if you've had a chance, but maybe you can read the email there. Um, yeah, just let me pull it up here. Um, hey, Chris and Shane, I saw Saturn in your observer's calendar show notes. I'm an amateur astronomer in Mississauga and thought you might enjoy a website I've built called Astro-Shron? Cron? Cron, I would say. Yeah. C-H-R-O-N. Yeah. It's a pretty cool website. But, uh, anyway, I'll just finish this email. Um, it's Saturn, it's Saturn model lets you move through past and future years and watch the rings open wide, narrow to almost edge on, then open up again with the other face in view.

26:18Uh, and the link to this is, uh, astrochron.app slash objects slash Saturn, uh, for anybody that wants to check that out. Yeah, it's pretty cool. I, uh, certainly checked it out. Well done, uh, Alexio. I'm just going to go and take it. Yeah, the interface is really, really neat. Like, it's, it's very smooth. Uh, I appreciate the design and the function. Yeah, I was, uh, I was, uh, chatting last week, I think about, um, I think it was when Saturn was last edge on.

26:53And then, like, then I was thinking, oh, I should mention, uh, I should mention this because I think it was, I think it was last year that, uh, that Saturn was, that Saturn was edge on. I'm just going to punch it in here. And then we can see, yeah, that, uh, yeah, kind of was, uh, uh, last year, uh, about this time that we had the rings almost edge on. Uh, but now if we look at them, uh, we can see that they're, uh, they're sort of angled more, uh, towards us, like sort of from the bottom of the rings now.

27:31Okay. Very cool. Thanks so much for that, uh, Alexio.

History of viewing Saturn

27:36Um, so Saturn is named after the, uh, Roman god of agriculture, wealth, and time. Often seems like, uh, we only have one of those three things around here, Shane. Lots of agriculture. Lots of agriculture, yes. Um, and it's been, Saturn's been known as, uh, as one of the planets, which, uh, I think the, the loose translation from, the old words is, uh, a wandering star and sort of, it's been known, uh, since, uh, before antiquity, probably since, uh, the very early peoples on this earth probably had noticed, uh, that Saturn was, uh, a star that didn't follow the usual rise set pattern.

28:16Like with the other stars and follow the similar, uh, course as, uh, other outer planets like, uh, Mars and Jupiter, uh, you know, which are slightly different from the interior planets. Mm-hmm. In 1610 Galileo, uh, he, he was the first person to see Saturn through a telescope and was, uh, he was pretty confused with what he saw. I noted Saturn is having ears or being. I can see that. It kind of makes sense. Yeah. I think so.

28:47I feel like ears are probably a pretty good, uh, explanation of it. And, um, kind of unfortunately for Galileo, the ring soon went edge on and, uh, and vanished. And that just kind of baffled, uh, Galileo back in those days. And I, I think perhaps, uh, sort of, uh, you know, kind of made some, made it look like those were like questionable observations. So he did note them, he did publish those, but it didn't really, uh, catch anybody's attention for a few more years after that.

29:23Uh, and really it wasn't until Christian Huygens, uh, named after the, or who invented the Huygens eyepiece, which I think some of those really old ones probably weren't as bad as the new ones. Uh, no, I have some old, older Zeiss ones that are actually fantastic. There you go. Probably made not long after 1655, knowing you, Shane. No, there are more current, but, but don't, don't use those if you like wide fields or eye relief. They're, they're a little challenging.

29:54Um, and then, uh, he proposed that, uh, that they were actually, uh, rings that did not touch, uh, the planet. And then, uh, a few years after that Cassini in 1675, uh, realized the rings were composed of, uh, multiple distinct, uh, structures and such as the Cassini division is named after him, which is the big blank spot in, uh, in the middle of the rings or middle ish of the rings. But then there's also quite a few, uh, other, uh, sort of, uh, I guess like blank areas in between the rings as well.

30:31Okay. So we're, uh, I think we're at opposition today as we record this Shane, uh, October 4th, but I don't know.

Opposition timing and finding Saturn

30:39Does this, is this podcast coming out tomorrow or is it next week? Uh, I believe next week. Okay. Yeah. Which is fine because in, in essence, what you want to do is, uh, is enjoy it in the early evening hours or in the evening hours. And up until this point in time, up until next week, um, really your best views of Saturn, uh, would be coming, uh, after midnight. I've been observing it sort of in the later evening, which is fine. Uh, but looking forward to next week when it will be well placed in the, uh, in the evening sky.

31:15As it's rising, it will be high enough and dark enough, um, you know, by about eight, eight 39 o'clock and be able to get some pretty good rings. So, uh, opposition occurs when earth passes between the sun and Saturn in a straight celestial alignment. And so Saturn appeals, appears basically opposite the sun in the sky. And as I was mentioning, it's coming into the evening sky now, but today right at opposition, it is arising in the east at sunset and setting, uh, in the west at sunrise.

31:49And it reaches its highest point in the sky at midnight. So I've been having to stay up till about, uh, 11 or almost 12 o'clock in order to see it nice and high in the sky. But as we get into next week, Shane, it will be fairly high in the eastern sky. And then, uh, should get about a nice, uh, uh, five or six weeks of Saturn evening viewing before it starts getting a little bit low over on the, uh, western horizon. But because it's getting darker, um, earlier every night now, uh, that will certainly extend probably into December and, uh, perhaps even just at the start of the Christmas holidays should still be fairly high.

32:29Yep. Yep. Agreed. So you can recognize Saturn, um, because it's, uh, kind of looks like a little bit of a golden, uh, star in the evening sky. And one of the things that I've told to it, you know, like it, it kind of reminds me of a coffee that has a lot of cream in it. You know, it just, it's not quite the same whitish as the rest of the stars around it. Yeah. And doesn't twinkle either. Right. No, no, it's usually pretty solid.

32:59Um, like most planets, they really don't twinkle too much. Yeah. Right now it's in Cetus, which isn't, uh, a constellation which rises, uh, too high in the evening sky. But, uh, over the past few years, it's been rising, uh, higher and higher because, uh, you know, five or six years ago when we started this podcast, you know, it was, uh, way down coming out of, uh, I think Sagittarius or Ophiuchus. And now it's, uh, it's coming up into Cetus. So it is getting, this is, this is the best Saturn has been since we've started recording the podcast, Shane.

33:34Okay. Okay. Uh, because right now when we're at the, uh, Meridian at about midnight, it, uh, it's almost about halfway. I'd say it's about halfway to the Zenith, uh, from, from, uh, from the horizon. So, uh, that's not too bad. Uh, it certainly, uh, is looking a lot better than it did, uh, even just about three years ago when, uh, Alistair was out and we were looking at it in the early morning sky.

Ring tilt and visual appearance

34:05So the ring tilt, as we were saying, and, and people can use Alexio's Astrochron Saturn website if, if they want to check out that ring angle. Um, Saturn goes around the sun in a 29 half year orbit and because of our perspective on Saturn and the rings, uh, those rings seem to, uh, change their, uh, angle, at least their angle towards the sun. And that inclination changes how bright the pattern appears or how bright the planet appears.

34:37Uh, when tilted open, the reflected sunlight comes off the rings and boosts that brightness, uh, quite dramatically, um, compared to when they're edge on. So this year, and I have noticed this, is that Saturn does look, in fact, appreciably brighter to the unaided eye, um, than it did last year when they were edge on. And, uh, and like you were saying with the unaided eye, you can see that, uh, it's a bit of a creamy yellowish color. Um, and in binoculars, you'll still see it as a point of light, although, I think in some of the higher power binoculars, Shane, I can start to pull out those rings.

35:16They're not overly difficult in the larger and higher power binoculars. Yeah, for sure. Like there's, uh, you're not going to see a lot of detail, but you can certainly tell that there's something more than just a point of light, like around a point of light. Mm-hmm. And you can start to see a few of the moons. Typically, you can see the brightest moon, Titan, um, in, uh, in your binoculars as well. But honestly, for me, Saturn really comes into its own when you start looking at it through like a 60 millimeter to like a four inch, 100 millimeter telescope.

35:49And once you get those magnifications in and around like that, 100, 150 kind of magnification, uh, zone is really, uh, where you start to be able to see details. About 100 or 160 X is about max for a 60 mil and, uh, probably about 200 magnification issues is where you're going to run up against the maximum for the 100 mil. Although in my Takahashi DC 100, I've certainly run up to into the mid to high 350s power. And, um, certainly I've had some good views of Saturn using some very, very high power on these instruments.

36:24Yeah, that's awesome.

Ring structure and gaps

36:26Some of the things you can see are clear gaps between the rings and the planet. And, uh, that's one of the things that I always like to look for because when, when you follow those rings around the backside of the plane, you look for those dark gaps between the ring and the planet or the rings and the planet. Um, it really gives you that three dimensional view. And with larger apertures, you can really start to pick apart that ring structure. Uh, you can see like the A and the B, the big rings. One of the things I like to do is try to see some tonal differences between those rings.

36:58One of them looks almost like a rusty red color to me, while the other one looks, uh, almost like a, uh, a buttery color. And the rings are not solid sheets. They consist of billions of individual particles ranging from microscopic pieces of ice to house size ice and rock boulders. Um, and they're not very thick. The, uh, the rings are about, uh, 30 feet in thickness, Shane.

37:28Yeah, that always blows my mind. Like you, I would just expect there to be more given how large, you know, the, the, the structure is and how much light it reflects. But, um, you know, it, it, it's quite dense with all of that material in there. Yeah. Cause about 282 kilometers, uh, across, like as, as far as, uh, you know, their, their full aperture goes 175,000 miles. Uh, so you think, well, maybe they're going to be like some thousands of miles across or a thousand miles across or some hundreds, but they're not, they're on average, uh, very, very thin.

38:08Uh, the main ring divisions are the B ring. That's the central ring, which is the widest, brightest, and most massive. I think that's one that I see as more of a, uh, buttery color. The A ring is the outer ring separated by the B ring and the prominent Cassini division. And the C ring is the inner ring, the Krepp ring, uh, which is much fainter and semi-transparent. That one is a little tougher to see and definitely need a four inch or larger telescope. And see it, my five inch, okay. Four inch, not as much. Um, then you get the gaps, the Cassini division and the ENC gap.

38:42Uh, these are gravitational resonances, uh, resonances, uh, created by embedded Shepard moons that keep, uh, large, clear areas in and amongst the rings. Uh, the Cassini division is 4,800 kilometers across and that's between the A and the B. And the ENC gap is near the outer edges of the A ring. For me, uh, only on the very best nights have I seen that ENC gap and that is way out at the edge of the rings. I, I have seen it through larger, like 10 inch and larger telescopes kind of running a little bit further, but in the smaller apertures, I find that I can only see it at the very sort of outer edge of the ring points.

39:25Yeah, the, the, the ink gap is quite challenging. Um, similar to you, I've, I've only seen it on the best of nights and I can't remember what telescopes I were using. I was using at that time, but they were not small ones.

Atmospheric bands and storms

39:38The atmosphere is comprised of bands and belts, uh, not unlike Jupiter, but I have to say it's not quite as striking to my eye as Jupiter, Shane. Yeah, it's far more subtle, far less, you know, different colors and contrast. Um, it's, it's like to start to see structure. Like I usually see some stuff in the Southern hemisphere. Um, but again, it's just real subtle tone differences. And, um, sometimes you just have to like look at the planet for quite a while to start to pull out some of those subtleties.

40:12It's, it's, uh, it'll test your observing a little bit. Yeah. And the, uh, the, the clouds exist as the result of, uh, rising and sinking, uh, uh, warmer and cooler air. And also are, are forged by, uh, high jet streams, uh, winds that are driven up to 1800 kilometers now over a thousand miles per hour, uh, which are much faster than Jupiter winds. Jupiter's winds. Um, they're more washed out though.

40:43Um, and this is a result of a, uh, a thick upper level haze of ammonia ice that, uh, and mist that sits higher up in the atmosphere. And that, uh, obscures the colorful chemical layers, uh, below. So it's not that the rings aren't as colorful, uh, as on Jupiter. It's just that, uh, there's a bit of fog in the upper atmosphere you see. Okay. Uh, visual observing highlights include seeing the equatorial band, the equatorial zone.

41:14These are the most prominent features, uh, kind of look like, as we're saying, subtle cream tones, yellowish brown variations, um, and polar hoods, uh, in the high latitude areas appear as like a dusky gray, maybe with a bit of a green tint. Um, and I, uh, I have seen these, uh, I don't find those, uh, bands too difficult to see, uh, in the seven inch, uh, they've been showing quite well. And that's one of the reasons why I, uh, I thought maybe we would, uh, uh, do a focused episode on the opposition of Saturn this year.

41:53Uh, because, uh, those, uh, larger bands, uh, on the planet surface itself seem to be standing out, uh, quite nicely on good evenings. Mm-hmm. For sure. You can get some white spots there, periodic megastorms. Um, these seem to come around every, uh, 20 to 30 years. Um, there's none currently happening. The, the big historical ones occurred in 1876. If you want to read more about those ones, uh, Asif Hall, who was, uh, I think he was the discoverer of the moons of Mars.

42:26If I'm recalling that off the top of my head, um, he, uh, he wrote about them in 1903. Barnard, E.E. Barnard wrote about them, uh, as well. And in 1933, uh, Will Hay, a British amateur astronomer and comedian. Uh, people should look up Will Hay if they want, uh, uh, an interesting astronomer figure. In fact, Asif Hall, E.E. Barnard, and Will Hay are all pretty interesting, uh, characters. And, uh, 1990, that was the last, uh, big one that was, uh, observed visually, um, by amateur astronomers before, uh, before the Hubble.

42:59Uh, then we had in 2004, this one I did see, uh, was the dragon storm, which was this giant flared shape, uh, that, that, that came across, uh, Southern, Southern hemisphere, uh, in what is termed the storm alley. But, uh, you really could see this, uh, this giant, uh, obstruction, uh, on the cloud tops. Not sure if you were able to see that one, Shane. No, no, I've never heard of that one actually. But the, the great white spots, wasn't there some photographs of that recently?

43:34Like within the last two or three years, I want to say? Or am I, am I not thinking of, uh, the same thing? Well, we've had some white spots on Jupiter, but, uh, I'm not sure about that on Saturn. In 2010 and 2011, there was a super storm, um, that arrived early, ahead of that 30-year cycle. And, uh, we had a giant white spot that appeared at, at that time, expanded rapidly, rapidly, and then, uh, kind of came, like, and wrapped around the planet and left behind, like, some, uh, atmospheric disturbances.

44:11Um, yeah, I think I'm, I'm just looking here. It says, uh, Cassini, uh, like that space probe that went out, uh, uh, looks like it photographed a bunch in 2010, 2011. Yeah, that's, yeah, the 2010, 2011 one. That was the, the last, uh, big, uh, white spot that was, uh, that was there. Okay. Cool. Uh, to see those, you want to get into, like, eight-inch scopes and larger, though, I think.

Moons of Saturn

44:40Um, when it comes to the moon, Titan is, uh, magnitude 8.4. So, um, you can see it in, uh, good binoculars or small telescopes. It's the largest moon in the solar system. And they sent that probe down in the Cassini, uh, first one. I remember watching that to send through the, uh, liquid methane, ethane, uh, lake. And then, um, Rhea, which is a, uh, a smaller one. You need a good three- or four-inch telescope to, to pick that one up. Uh, it's the second-largest moon and made out of solid, uh, water ice.

45:14Then we have, uh, Tethys, uh, again, a good three- or four-inch telescope. Uh, it's got a giant, uh, impact crater. Of course, you can't see that with your telescope, but you might, in, uh, larger telescopes, be able to pick up some, uh, variations in the tonality of, uh, uh, of Tethys. Um, Dione, which is, uh, again, uh, three- or four-inch telescope minimum. Um, it's got these, uh, two Trojan moons that are around it, uh, Helene and, uh, Polydeusis.

45:45And, uh, they, uh, they trail after, uh, the moon. Iapetus, uh, you can see it in a three-inch scope, but really a six-inch is where you start to be able to, uh, pick it apart pretty good. Uh, Iapetus has, uh, a coal-black hemisphere and then a snowy-white hemisphere, so it varies quite a bit, but you can see it really well in a three-inch sometimes, and, and then sometimes you need, like, a larger six-inch telescope to see it because it varies between about 10th and 12th magnitude.

46:16And I have noticed that on night-to-night, and there was a night recently when I was looking at it, and I couldn't, I was having trouble even picking up that moon in the seven-inch with the moon up. Uh, my favorite moon is Enceladus, which is almost a 12th magnitude moon as well. I'll need about a six- or seven-inch telescope to see it well, and it's got a cryovolcanic geyser in the center. Last one is MIMIS, uh, about 13th magnitude, really getting into that, uh, six-inch-plus instrument under reasonably dark skies to be able to see.

46:48And, um, the cool thing about MIMIS is that it looks like the Death Star. Yeah, if, if people aren't familiar with it, definitely just do an internet search for this because it just, it doesn't seem real. Um, like, that impact must have been quite the show if you were anywhere near that when it happened. Yeah, yeah. And so that's kind of our opposition of Saturn episode. Shane, not sure if you have anything further to add.

47:18Um, just if anybody's observing Saturn, please send us your observing notes. We always love reading that stuff. And, um, you know, we're, we're getting into peak season for Saturn. So it'd be great to hear, um, how people are viewing it and what they're using to, uh, to check it out. Yeah, I'm kind of getting myself tuned in for it. I was hoping to get this ComaCore working so I can do some better planetary observations, but, uh, we will see how that goes, Shane. Mm-hmm. All right. Thanks everybody for listening. Please subscribe, share the show with other stargazers, you know, as Shane mentioned,

47:51please send us your observing notes about Saturn to actual astronomy at gmail.com. You are listening to the 365 Days of Astronomy podcast.

48:02The 365 Days of Astronomy podcast is produced by the Planetary Science Institute. Audio post-production is by me, Richard Drumm. Project management is by Aviva Yamani. And hosting is donated by LibSyn.com. This content is released under a Creative Commons attribution, non-commercial 4.0 international license.

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49:13With every new discovery from ground-based and space-based observatories and each milestone in space exploration, we come closer to understanding the cosmos and our place within it. Until next time, let the stars guide your curiosity. Transcription by ESO. Transcription by ESO. Translation by —