What to see in the night sky, September 2020

well pete's let's start with mercury the innermost planet uh this is easily done because it's down low with the west to the sky poor altitude after sunset we're not likely to see it are we no not really it's not the best month for mercury we've had some good appearances of it this year so um that's not too bad we can put up with that venus of course completely different story but i'm afraid you'll have to get up early to see venus because it's now in the morning sky it's very well positioned all month long rising about four hours before the sun but it is starting to get quite small now it is so it presents a 19 arc second disc 59 lit at the start of the month but by the end of the month it will have dips a little bit be minus 4.0 magnitude but 15 arc seconds across that is notably smaller so it'll be a bit tougher to see towards the end of the month um personally i tend not to get up and see it in a dark sky i tend to observe it during the daytime uh and that's easily done if you know how to find venus during the day with setting circles you have to be very careful of course but one thing you do have to remember is that if you're following venus if your drive fails it can drift towards the sun when it's in the morning sky so you do it there's a lot of extra cautions you have to take yeah there are and it's it's actually at a reasonably safe position at the moment because it's moved quite a way away from the sun but yeah that's that's good advice i can remember after it passed through uh inferior conjunction in june i was because i'd followed it all the way through may because we had that fantastic run of clear weather right up to the day before inferior conjunction and then there was a clear patch just after inferior conjunction and i thought should i have a look for it now i don't like doing that because there is that danger that if your drive fails on your telescope the telescope stops tracking and the sun drifts into the field of view and you're in trouble and at the end i decided not to do it uh there was a few clouds and things started to appear and i thought no it's not worth worth the um the bother and i'm quite glad i didn't because i actually had a power cut here i drive from a mains transformer so that would have happened yeah actually it could be very very dangerous so yeah you bet you're counting your lucky stars you didn't do it pete slightly yes i've got a camera left which i wouldn't have had otherwise okay well let's um have a look at what is rapidly becoming the best planet on view uh which is the planet mars which is now heading towards opposition it actually reaches opposition on the 13th of october but at the moment it's pretty amazing really to see in the sky it is dominates the night sky i think it's because we're not used to a lot of color in the night sky and something like mars which is almost i would describe as shockingly red it's so overwhelmingly colorful that you you you notice it as soon as you see it especially because it's so bright so it is a very even if just look again at the naked eye it's a very remarkable object in in the night sky uh on the 10th of september the planet's east apparent eastward motion i should say against the background stops uh so mars then reaches what is known as its stationary point yeah so after the 10th of september it appears to be moving to the west um of course in reality it hasn't changed direction at all it's just the consequence of our own orbital motion compared to that of mars but it's actually getting larger through the eyepiece as well so on the the first of september uh telescope will show it to have a disc which is 18 arc seconds across and by the time the end of the month has arrived uh it'll be absolute mars luxury because it'll be about 22 arc seconds across can you imagine that paul 22 arc seconds it's an enormous sight a three-inch refractor or three-inch effect or a telescope that size will show quite a bit of detail uh in in good conditions so uh this is a time when anybody with whatever size telescope you have now's the time to get out and have a look because there'll be some stunning details available uh people with larger telescopes uh really in for a treat uh you you're gonna catch all sorts of fascinating intricate details in the albedo features uh in the ice cap and various other locations you also get mists and fox collecting in the basins and valleys uh such a dynamic planet and as you say peak 22 arc seconds an enormous size to to have well it's also quite good for imaging as well of course because it's bright so there's a big signal there to latch onto at the beginning of the month it'll be magnitude minus 1.8 but by the end of september it will have increased in brightness to magnitude minus 2.5 um that's really bright yeah mid-month it actually overtakes jupiter in brightness so that's how bright it is and i'll tell you what there's an interesting point you mentioned earlier on you said it'll look you know we don't get much color in the night sky and it will look stunningly red but that's that's an astronomer's red isn't it yeah you talk about red stars they tend to be orange yes in color an orange hue and the same with mars mars sort of has that salmon pink appearance it's a salmon pink color rather than a deep deep dark red yes it's a cinnamon pig but at magnitude minus 2.5 it will be shockingly obvious in the sky yeah i agree completely and the ice cap you mentioned it'll be the southern ice cap the southern polar cap which is pointing to what we're not pointing towards us but tilted towards us which we'll be seeing yeah that's right so earlier in the year uh it was sort of springtime on the southern hemisphere of mars and the cap was quite large now it's shrunk right down and it's quite small and what tends to happen is all those volatiles that are released when the caps evaporated all that goes into the air it's the thin martian atmosphere and this is what allows the the fogs uh to to form and collect in the basins so if you look at particularly on the terminator so either the east limb or the west the following label the preceding limb of mars uh it's not uncommon to see these brilliant white clouds collecting over the mountain ranges and you can watch them they're not static they change and evolve over time the ones on the morning terminator tend to dissolve away as the sun rises and heats up the valleys that they're in so it's really quite a dynamic world you can watch from your road back garden like i never tire of it it's going to be amazing i'm really looking forward to that on the evening of the 5th of september mars is joined by an 87 lit waning gibbous moon and at 2300 bst on the fifth both objects appear 3.2 degrees apart measured from the center of the moon's disk over the remainder of that night and into the morning of the 6th of september the separation continues to reduce reaching a minimum value of around half a degree around 0.630 bst under daylight conditions and with mars being so bright at that time it should be easy to follow the pair with binoculars or a telescope despite the sun being up and that's quite close actually half a degree from the center of the moon it is um hopefully if it's clear here i should give that a go uh and it would be interesting to see just how easy mars is to see uh in a telescope during the daytime particularly in the finderscope uh but you just see against the background sky well presumably it should be fairly good in terms of the contrast because it's a reddish coloured planet and the sky is blue yeah so i think that and the brightness means it should be fairly easy to pick out yeah okay well that'll extend your mars observing period then into the day um so the two gas giants jupiter and saturn they remain very low down as seen from the uk but they are quite close together in the sky um being about 7.4 degrees apart on the 30th of september and i think that'll be the highlight for jupiter and saturn over the coming months the fact that they are a pair in the sky yes a pair very low down just scraping the tops of the trees but nonetheless as i always say so it's still worth having a look at these planets because they are beautiful wonderful gas giants and you know you do get in the early hours of the morning 12 1 in the morning you can get periods of stable seeing even when the planets are very low down so you can then try and make the most of it doesn't last very long i find normally about half an hour but long enough to try and catch either image something or get a drawing yeah okay okay well heading out even further to the ice giants let's go with uranus first of all and uranus is actually quite well positioned during september located in the southern part of aries and actually that places it quite close to mars but of course um where whereas mars is in negative magnitudes uranus is shining away at plus 5.7 which although it makes it theoretically visible to the naked eye is a tricky thing to pick out with just your eyes it is i've only ever done it to using the finder scope and setting circles you can start up to it if there's some bright stars nearby you can use that method but i tend to use setting circles and that a low power eyepiece you can normally pick out uranus quite quickly because even a low power there's got this distinctive greenish shoe which is quite unmistakable it's going to be a bit bit trickier this year actually because it's in a part of aries i mean aries is not the best constellation to navigate through that there are the three stars which form the main shaping aries if you like but the rest of it's pretty faint and obscure so you haven't got much as a navigational guide so you're heading to the southern part of aries between pisces and aries to the north of cetus and if you can navigate that without a little bit of assistance good on you yeah it is difficult isn't it but nonetheless worth a try as i say i think most telescopes now certainly all of telescopes on equatorial amounts can be set in circles might be a good idea to give those a try to to tighten up those setting circle skills yeah that's a good idea um and neptune of course is well the key to finding neptune is to look for fire aquarii because neptune will be near fire aquarium for some time now um so neptune reaches opposition this month on the 11th of september but unlike mars uh opposition doesn't make a huge difference to the appearance of neptune uh it'll be shining away at magnitude plus 7.8 so you'll need binoculars to see it and at the moment it's about 2.1 degrees east northeast of mag plus 4.25 so phi is definitely the key to locating neptune in the sky yeah okay well let's move on to some of the specials which are occurring in september and the first one uh picked out is actually a bit of a payback because we hear all this stuff about super moons in the sky which is oh there he goes he's moaning already um a super moon is basically a term introduced by uh an astrologer and it's one of those annoying terms which has caught a bit of traction so everybody describes the super moon and the super moon is uh sort of describes it's a bit vague in its own definition to be honest but it describes when the moon is full near to perigee when the moon's orbit brings it closest to the earth so at that position the moon appears slightly larger and brighter than it would at other times well on the 2nd of september when the moon reaches its full phase it'll be quite close to the opposite of perigee in the moon's orbit a point known as apogee apogee actually takes place on the 6th of september so that means that the full moon you get on this morning of the 2nd of september is one of the smallest in terms of its apparent diameter for 2020 and unofficially that's known as a micro moon so that's the opposite of a super moon [Laughter] yes anyway moving on the 12th the 12th of june we have a photo opportunity don't we pete we do we have ganymede's shadow in transit so if you catch jupiter early enough through a telescope of the evening uh we'll be able to see the end half of uh a ganymede shadow transit uh this happens because as the galilean moons pass in front of jupiter the shadows are cast onto the cloud tops and with ganymede it's really quite an effect because you get a really big black shadow and the ganymede shadow is on the midline of the planet so this is the central meridian at 2100 bst that's 200 ut and the transit itself comes to an end at 2255 bst so quite well timed actually to get out and have a look at that on the morning of the 13th we've got venus again which is hitting the headlines because it'll be a couple of degrees south of the beehive cluster m44 so that's a good photo opportunity there and on the following morning on the 14th venus and m44 the beehive cluster are joined by a 14 lit waning crescent moon so that'll be a really photogenic scene to try and get a shot of so if you are up about four o'clock bst the center of the moon sits one and a half degrees north of m44 and 3.8 degrees north of venus so good meeting there yeah that'll be a nice a nice one to choose uh dice want to catch if it's clear okay well the moon is also quite useful over the 16th through to the 18th so on the 16th uh in the morning sky there's a chance to spot a very thin waning crescent moon which could be seen rising above the east northeast horizon about 0 5 15 bst that's time by the way is correct for the centre of the uk so if you lift it live in other locations there'll be a few minutes difference there but if you do manage to spot that moon you'll be looking at a two percent lit crescent which is quite good it is quite it's also uh it's not something you see very often uh it's at two percent like crescent it's especially a waning that's right quite early for that and it does actually look quite different to the other when the other side's lit it is notable the the other side the crescent of the moon is is not as got as many features as as you see it in the evening sky that's a really good point it looks quite odd it looks almost as if somebody's taking a scraper and scraped off all the detail of the moon because you've got the large oceanis procellarum which is the the main sort of sea which runs around that bit and it just creates quite um a smooth looking moon really it's quite an odd thing it is odd and not not many people actually have seen that joking apart because you do have to get up early in the morning to see it so you have to make an effort for that one but if you can't be bothered getting up early in the morning there is a thin waxing crescent moon which may be visible potentially 20 minutes after the sun is set on the evening of the 18th of september for a very short space of time so you've got to have a good flat western horizon and you've got to look after the sun has gone below the horizon make sure the sun has properly set before you do look for it um but here quite interestingly the moon is at perigee so it's close to its closest point to the earth so that prison will be slightly larger and brighter than it would normally be so actually in this position perigee actually does work for you because it might make that crescent a bit easier to see but it is going to be quite a thin one that you're looking for there i mean what are we going to call this a super crescent if you want is that yeah look for the super present super crescent moon okay well also let's finish off with the moon on the evening of the 25th there's a chance to see another interesting clear obscure effect that's a shadow and light effect on the moon called the eyes of clavius which is what happens when the the morning light floods into the crater it doesn't actually illuminate the crater's floor but just the tops of two of the large cratolets inside clavius so it makes it look as if you've got two eyes inside the dark oval shape of the crater have you ever seen that i haven't i should look out for the eyes of clavius though it sounds like a 1950s slasher sci-fi film the eyes of clavius i'll look out for a piece i'm going to see it now it's quite dramatic actually it's quite something uh to see but you have to catch it at the right time because of course it doesn't take long for the moon's light to flood into the crater and then it completely wipes out the eyes but no well worth looking out for okay well let's move out to the stars uh the northern hemisphere's autumn equinox actually occurs at 1431 bst that's 1331 ut on the 22nd of september and this represents the date when the length of the northern hemisphere night is growing at its fastest rate of the year common misnomer that people think is that equinox marks the time when all places on the earth have equal day and equal night and that's not really the case is it no it isn't the precise term for such a day is called an equilux and that occurs a few days before the spring equinox and a few days after the autumn one and awkwardly well i suppose that's why people don't mention it that much the precise date of an equilux varies with latitude so you can't specify it as an absolute for any um a general country it actually varies slightly with your position where you live but it's splitting hairs really because the um yeah the actual difference isn't isn't great in the uh the day and night time length they are almost balanced at that time of year but i think the big thing we have to take away from that is the fact that it creates a dramatic effect because as the length of night is change is increasing in size at its fastest rate around the autumn equinox for the northern hemisphere i should say that means that the spectacular constellations that we associate with autumn and winter are get get a bit of a boost they come into view uh in a much more dramatic way yes it is uh it's a reminder as well isn't it that the longer colder lights are on the way yes uh so this this means the area of the sky which is sort of rich with the summer triangle and the milky way continues to be visible during september in fact i think it's always surprising to me just how long the summer triangle hangs around it hangs around long long after summer you can see it in december can't you you can yes or the northern part of it yeah but the well i suppose let's take a look at the southernmost style then while it's still visible to us and that's um alter or alpha aquili and that's easily identifiable because it has two fainter stars either side of it uh yes and they're not particularly brilliant uh in fact the constellation of aquila represents an eagle i've never been able to see that myself its stars form a sort of distorted x pattern at the southern end there's a little small group a small curve of stars that are formed by lambda and 12 equilibe together with eta scuti and not far here from here is this beautiful open cluster m11 no wild that's one of my favorite open clusters of the night sky it does actually look like a flock of wild ducks in flight you've got a good imagination there then but they i think it does it's it's well it's supposed to be yeah it's the v in the cluster isn't it it's a it's a line of stars which forms a v which is supposed to look like that that weird pattern you get when ducks are flying across the sky together and um it's an immensely rich open cluster it's just it's quite a stunning open cluster to look at through a telescope especially a large one i have to say if you look at us with a smaller one you may just see it sort of as a misty a mistiness there but with a larger or mid-sized to a large one it's just incredible it is the amount of stars in it it is a it is a stunning object uh the wild duck will sits close the clusters itself sits close to the top of a diamond-shaped constellation of scutum the shield and the northern end of this little narrow diamond is marked by beta scuti and the southern end is marked by gamma skutai okay well and if you locate gamma there are a number of interesting objects uh to the west and south of that star including m16 the eagle nebula which is always a bit of a disappointment through a telescope i find it it's i think it's because it's got a low brightness isn't it it's it's not got a very high brightness and there isn't a lot of structure to it at least a few times i've seen it anyway you can see the cluster but it's really difficult to see the nebulosity and of course you've got m17 which is the opposite because m17 is quite bright and quite impressive and that's that's got loads of different names m17 it's called the swan nebula or the lobster nebula the amiga nebula you name it it's got loads of them um you've got the rich open cluster which is m25 and it's quite an odd feature actually this this is um an object especially when you consider that messier was supposed to be hunting comics and recording objects which looked like comets he recorded the star cloud m24 which has also got a name it's called del corstice and that's huge and quite an impressive region to look at but does it look like a comet no need but then neither does m44 so there's uh there's quite a few things at the catalog that i don't think could ever ever be confused with comets but nonetheless there it's nice to have a catalogue of these objects i guess okay well the m24 star cloud is large and impressive and it's it's good to scan it with binoculars or telescope i guess and there's a similarly interesting region at the top of scutum which is quite close to the wild duck cluster which is called the scutum star cloud and that's so bright if you've got dark skies that it's been known to trigger astronomic panic and you think i think there are clouds appearing and you start to pack up because they're drifting in but it's actually the scutum star cloud you've been fooled by a uh by by a star cloud thinking that the uh the clouds were coming in it's got it's got me a couple of times i have to say ah you're obviously observing them darker skies or skies that aren't obstructed because it's never got makes i've never seen it okay well there are lots of interesting things up there the region north of aquila is populated by small constellations some well-defined and others which are frankly pretty obscure but uh one of them is the constellation of vulpecula the fox oh yes which is pretty obscure and uh it used to be called vulpecular answer which is the fox and the goose that's not the name of a pub it doesn't sound like the name of patrick describing this actually he said i don't know where the goose has gone he said maybe the fox has eaten him but you've got broccoli's cluster in valpecula which is colander 399 and that's a lovely thing to look at it's called the coat hanger because it looks a bit like a coat hanger uh well it looks exactly like a coat hanger actually but it's not a cluster at all it's um an asterism right and we also have shouldn't forget the beautiful planetary nebula m27 the dumbbell nebula appears to the east northeast of colander 399 visible in binoculars but through a telescope even a small telescope actually because it seems to have quite high surface brightness it is quite well structured and it kind of looks like an apple core that's just been tossed aside yeah it does so quite a quite a nice object to look out for in this sort of remote area of the sky yeah well um m27 is is a glorious thing to see um and you've also what other constellations you've got there you've got sagittar the arrow um which has a better definition than vulpecular really doesn't it and uh and it kind of does look like an arrow that you know does look like an hour ahead in flight to me yeah okay uh you've also got delphinus the dolphin which is supposed to represent the head of a bottlenose dolphin does it right no well i kind of i guess you could if you really put your mind to it you could see a a leaping dolphin there maybe okay and then of course the uh the one which is furthest to the east of that little group of constellations is um equilius the foal which yes yeah let's just leave it there cooler's got nothing has it at all it's very difficult to see it's quite a tough constellation because there's not much in this no but as we're sort of heading towards that direction we're heading into the stars of autumn so um i think we'll leave it there and leave those for another time so thank you very much paul as usual thanks pete

Channel: BBC Sky at Night Magazine

Views: 86,875

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Keywords: astronomy, stargazing, what, see, night, sky, bbc, magazine, science, how, to, space

Id: HBbPC9DeF28

Length: 26min 36sec (1596 seconds)

Published: Sun Aug 30 2020