It’s been a while hasn’t it, so I’ve decided that a short update on my progress with the Herschel 400 – or 281 since I can’t see anything below 0º declination – is in order now that the season’s drawn to a close with the approach of Summer Solstice.
Sadly it seems that I’m down to only fifteen more open clusters, three globular clusters, a pair of emission nebulae and a solitary planetary nebula to observe. That’s just twenty-one more of my favoured celestial deep-sky objects. I say sadly because that means there a colossal one hundred and sixty more galaxies to hunt down and this is bad news for a couple of reasons.
I’ve discovered galaxy hunting isn’t as much fun as you might suppose.
Don’t get me wrong, there’s nothing intrinsically wrong with galaxies; I live in one and many of my favourite observations have been made of objects in it; also there are some fantastic galaxies to observe, it just turns out that many of the H400 galaxies aren’t.
And mostly it’s my observing location: bright suburban skies in a very damp climate.
No doubt the weather this observing season has been bad, and even on the few ‘clear’ nights I’ve experienced this Spring (prime time for galaxy hunting) I’ve noticed very poor transparency.
The problem is moisture in the atmosphere which is never helpful, but I’ve learned that for the galaxies it’s terrible. The extra scattered light strips them of any contrast against an already bright background sky, and on the worst occasion I spent four hours barely observing just three galaxies!
May be next season will be galaxy season…
I’m hoping for better skies next season. I found from my notes that some of the galaxies I could see reasonably well in my six inch newtonian a year ago were much worse in my new ten inch this time. That shouldn’t be, and yes, I have checked the new scope on other targets and there’s nothing wrong with it.
So whilst I’m now 100 for 281 in my Herschel quest it’s safe to say that I’m not very excited about most of the rest of it. I’ll do it damn it! Just don’t expect me to be happy about it 😉
Previously most of my lunar observing had been limited to the spectacular array of impact craters. Yet most of these contain details that passed me by until I was told to really look, and they only scratch the surface (so to speak) of what the Moon has to offer. Now I’ve surveyed 90% of the sights listed in the Lunar 100 list, what were the highlights?
Discovering Lunar domes and dark halo craters has lead me to consider lunar vulcanism more closely. The latter were completely new to me despite being easily visible under bright illumination. These are long extinct volcanoes or vents and probably a result of the impacts in the early life of the Moon.
Which leads me to the lunar rilles (rimae). I love trying to resolve those thins dark or bright lines, depending on the direction of the sunlight. They’re a real observing challenge though they range enormously in both complexity and size, some being much more easily spotted than others. Faults lines or collapsed lava tubes? They have different origins to investigate.
Likewise I’ve developed quite a soft spot for crater chains (catenae). The Davy Crater Chain is listed amongst the 100, but I’d never noticed it before attempting the list. I’ve discovered that there are several more of these structures which are the result of the Earth tearing a passing asteroid or comet apart. Remember Shoemaker/Levy? That’s what we’re talking about, albeit on a smaller scale.
This is the small scale detail so far and as much as I love this the Moon isn’t the Moon without those vast impact basins that for the Maria. They’re not hard to see, even with the naked eye they’re obvious, so what’s to learn?
Firstly I certainly know where to find more impact basins than before. I also enjoy trying to trace the multiple rings of mountains (I think of them as ripples) around many of them. The area around the Mare Vaporum is a favourite now because of its variety. Evidence of volcanism and the deep scouring by debris from the Imbrim impact, one of the biggest, is really obvious.
With a telescope and the right illumination the Imbrium lavas are covered in dorsa (wrinkle ridges). Initially I thought these were evidence of cooling lava flows. By working out the direction of slope as the illumination changed I hoped I could trace their origin. But I couldn’t because these are genuine ridges and not sloping ways from any centre. This is what happens when the marial lava cools and the impact basin sinks under its weight: the surface really wrinkles! The detail at modest magnification can be impressive, especially since it all disappears when the Sun is high.
This project started out as another observing list to tick off, but I’ve come to realise that misses the point of the Lunar 100. To get the most out of it you have to observe the features and then think about what they’re telling you about the geology and history of the Moon. More than any previous casual sessions, this project has lead me to identify features from continuing observation and research. I have a far better feel for the complexity of our nearest celestial neighbour.
When we imagine early astronomy from ancient times to the medieval we assume that lacking optical devices they would see only pinpoints of light fixed in their place all eternity. Sure they would have noticed that the Sun and Moon moved across that backdrop, and these stars would make interesting patterns, but that’s about all the naked eye could show you, after all we wouldn’t see much more today.
Then I realised that until relatively recently the skies were really dark. Consequently the night sky would have been far more dramatic and dynamic to the ancient eye than it is to our own. Modern skies are so bright that it’s easy to fail to notice there’s anything up there at all, and most don’t even bother to look.
The Sun and Moon are bright enough to be seen in the most light polluted sky, but the planets all the way out to Saturn are bright enough to be easily visible to your eyes, and although their true nature might not have been known they were named and their strange paths commented upon: these were not normal stars!
The rugged bright band of the Milky Way moves across the sky with the seasons being right overhead in the late summer and autumn at mid-northern latitudes. In the dark it casts a shadow so I’m told and is a mosaic of dense starlight and dark dust clouds.
They certainly noticed that the patterns of stars that give rise to the constellations also move throughout the year and gave many of them names. The fact they managed to pick these stars out of the dazzling background shows that they were really observing. Several stars were singled out as having special significance in connection with seasons.
To cap it all some of the “unchanging stars” were seen to vary in brightness, such as Algol (beta Persei), and new stars would very occasionally appear in a dazzling flash that would become known as Novae or Supernovae, such as that which created the Crab Nebula.
Comets would have been more noticeable and invested with the power of victory or doom. I can only imagine how spectacular the regular meteor showers would have appeared.
I would love to experience those skies, but I really don’t like to travel and few places in the World remain where you can see what the ancients might have. All the same much of what I’ve mentioned is available in a diluted version to modern unaided eyes (well perhaps with glasses).
I’d urge you to try really observing the Moon and see what you notice; have a go at making brightness estimates for variable stars like Algol; try splitting some wide double stars and see what’s the closest you can manage; and examine the large scale structure of the Milky Way. You don’t need any equipment to be an amateur astronomer.
I think it’s fair to say that I was more active on the blogging front in 2017. Unfortunately I appear to have fallen off the wagon again, so I’ll try to get things rolling with my traditional summary of the last year. I’ve a few more ideas after that so who knows?
The results for 2017
Going back over the diary for 2017 shows about a third of the nights to be observable based on my loose definition.
I feel that the duration of those “clear” skies opportunities have declined, especially in the autumn, a point born out by notes in the diary. There’s no doubt that the quality of my home skies have been in decline for some time due to atmospheric moisture and the rising light pollution from the nearby industrial estates.
Many of those months make great use of the fact that the Moon is quite observable in even relatively cloudy conditions, and the light pollution doesn’t matter one bit. In fact I normally observe the Moon with a bright white light to illuminate my atlas and journal.
I have indeed started lunar sketching in the last year… but not well enough to share yet. At the close of the year I’m down to the final ten sights in the Lunar 100, and some of those will need just the right libration.
The Herschel 400 (H400) list is actually the Herschel 281 for me since I’m limited to objects above the celestial equator. It’s gone reasonably well since I started it last year with 92 objects observed despite the poor deep-sky conditions.
I have pretty much run out of Binocular Messiers to observe from my garden and started on the low altitude Summer Messiers. I’m about a third of the way through this project and progress has been very slow.
Variable star observations topped 1300 at the end of the year and I did receive my certificate from the AAVSO for my first 1000. I was aiming for 1500 in 2018, but that’s going to have to be revised… I hope.
What about Solar?
I’ve been just as active as in 2016 but with a lot more sketching in both Hα and white light using the Herschel wedge… and cheap binoviewers which are excellent for white light in my Starwave achromat.
OK, not quite as many sessions as a packed 2016, but I felt that the quality of the work I was doing was much higher. Most sessions had a sketch and detailed notes.
My plans for 2018
To be frank it’s not started well. Lots of poor weather and a prolonged illness have made it impossible for me to get any scope time for the last month.
Unfortunately I’ve now observed many of the fun objects in the H400 and there are a lot of galaxies remaining. I’ll admit that I’m not a big fan of galaxies. This is partly being limited to 150mm of aperture, which I may able to do something about, but also the poor quality of my sky: any haze and glare makes galaxies invisible.
I’ve kicked off a couple of new programmes focused on objects visible from my home site to make up for a galaxy infested H400.
The resurrected and revised version of the Astronomical League basic open clusters programme containing 88 clusters.
A programme to observe 56 bright planetary nebulae.
I have another that may prove to be insane from my garden: 34 objects from the Sharpless HII Regions catalogue. They’re the ones that Stewart Sharpless gave a ‘3’ for Bright, though I suspect that to be a relative term. We’ll see how that goes, I may have for travel far afield to complete it, or leave the Country.
I want to finish off the Binocular Messiers but I need to find a better horizon. I have a few ideas that are considerably more local than those for the Sharpless project and at least binoculars are nothing if not portable. The majority of the outstanding Messiers are spring and summer objects, so I’ll need to get started soon.
Lunar observing is guaranteed to continue. The final few Lunar 100 sights may be a question of waiting for the right opportunity, but I’ve identified a few features of special interest to pursue, research and perhaps even sketch well in the process.
I’d like to try and observe Venus a again this year, but the apparition isn’t very favourable, just better than for all the others. I caught a brief glimpse in binoculars last night at only 5º above the horizon: no chance of getting a scope on it. The planets are mostly hopeless this year I’m afraid.
We march towards solar minimum in the next couple of years, and despite some fireworks last year the beginning of this one hasn’t been promising. The Sun is very quiet. Is this the right time to start learning how to do sun spot counts? I hope for better by the summer.
As it turned out it was cloudy most of the time, so very few meteors were seen, but during the early part of the night, before the Moon rose, I stuck my 10×50 binoculars on their monopod and pointed them low to the South in the direction of Sagittarius.
As you can clearly see there’s a lot to go at here! Unfortunately, even from this site trees obscured anything below the star Kaus Borealis marking the tip of the lid of the Sagittarius teapot.
I could get pretty close and that star was a nice bright marker, so I decided to begin with M22. It was immediately obvious to the East of Kaus Borealis and well clear of the trees. A large round fuzzy patch with no sign of resolving into stars. Just what you’d expect from a globular cluster in a pair of binoculars, or in fact in a small telescope. I panned to the West, but as expected M28 was not seen. It was obscured by the tips of those trees.
I was keen to bag the lowest of the objects on view, and typically enough the next target isn’t marked in the image above. I chose M8 (the Lagoon Nebula) which is that box below M20 and to the West of the last targets.
M8 was seen amidst a collection of brighter stars aligned east-west as a patch of nebulosity in direct vision. It’s nothing but a fuzzy patch which was about 7’x3’ in size when compared to the separation between the adjacent stars 7 Sgr and 9 Sgr. Truthfully, I suspect that I was primarily seeing the open clusters NGC6530/6523 forming within this emission nebula as they match the position of this patch.
M24 is an interesting target, and one made for binoculars. That’s because it’s the Sagittarius Star Cloud: a view through an interstellar dust cloud of the neighbouring galactic spiral arms. It’s a large and very obvious grouping of stars of various magnitudes, there’s nothing nebulous about this one! It spanned about ¼ of the binocular field of view, or about 75 arc-minutes, in its length and perhaps ⅓ of that in width (25 arc-minutes). It’s aligned roughly northeast-southwest.
I wondered whether I could find the open clusters in Scutum. Being the brightest M11 was the first on the list using the stars of Aquila as a signpost (Scutum isn’t very bright). To my surprise there it was as a modest sized, but bright condensation of stars. It was immediately obvious, but I couldn’t resolve an stars with the binoculars. I’ve managed to get a telescope on M11 from Home since and it’s a spectacular open cluster!
Down and to the West I sought and found M26 which was much smaller and fainter than M11. Definitely no stars to be seen in this one, and I haven’t viewed it telescopically yet.
I’d taken to starting my star hopping at M24 because it’s so obvious in binoculars, and fabulous to look at too. This time I noticed two more fuzzy patches to the northeast as the transparency improved.
The first spherical patch of nebulosity appeared above a convenient asterism allowing me to identify it as M18. Nebulous and unresolved I estimated it to be about 8 arc-minutes in diameter by comparison to the local stars separations.
Further to the North is a much more irregular patch in the right place to be M17 (the Swan Nebula). Again this was nebulous and unresolved. M16 (the Eagle Nebula) spotted as a nebulous patch around a coarse cluster of stars that formed a suitable pattern for a positive identification. No detail seen, but it’s clearly visible whilst not resolved. I estimated it to be 5 arc-minutes in size.
These two objects are star forming in that dust cloud mentioned earlier. Without it the whole area would be as star filled as M24! On the other hand we wouldn’t have objects like M16 to look at, even if it didn’t look like that in my 10x50s.
Finally for the night I found M25 easily spotted to the East of M24 as a coarse and sparse open cluster that did resolve fairly easily. A range of magnitudes leads me to assess it as a Trumpler class II2m open cluster.
And that was the end of a very good night’s work with the binoculars. Nothing I viewed that night was particularly taxing, many other Messier objects are much trickier. It’s a lovely part of the night sky and there are more to capture here, but I think that’ll have to wait for next year as time and the weather have not been kind.
Considering that we’re near solar minimum there’s been a surprising amount of activity to be seen around the end of March and the beginning of April. The most dramatic events have been in Hα, but even white light views have been impressive. The cause of the excitement has been a pair of large Active Regions (ARs).
The first of these (AR12644) produced some large eruptive prominences as it exited the face of the solar disc on 3 April. I was lucky enough to be observing then with the PST with a Baader Zoom eyepiece, and the events were fabulous.
I don’t image, and was too busy observing to sketch, but fortunately NASA does image almost continuously with the Solar Dynamics Observatory (SDO) from orbit. This is what they came up with, and despite their use of the ultraviolet part of the spectrum it’s not too far from the PST view in the red of Hα (656.3nm).
It is just a little more detailed and has a larger image scale. They also have some movies of this solar eruption, and trust me, you could see that big prominence changing before your eyes!
I checked out the white light view too, but there was no indication of the violent events to be seen. The clusters of sunspots and surrounding faculae were plain to see in all their intricate detail despite sitting right on the limb in the image below. It was taken by the SDO HMI instrument, but is very similar to my white light view.
In its wake followed the equally large AR12645 in the lower left of the image below. If anything it was more impressively detailed in the wedge, and I found it to be naked eye visible through some Baader solar film (another method for safely viewing the Sun). It didn’t produce any Hα fireworks, but the sharp filaments and swirling patterns in the spicule and fibril background of the solar chromosphere were beautiful to observe.
These ARs were great to view throughout their transit across the face of the Sun, but will they survive to reappear for another transit?
And now I’ve forgotten to post through March… which is a shame because it was a huge improvement over February. Not only a big uptick in the quantity of observing opportunities, but lots of variety in my observing diet too.
Both this month and the last have started with some Lunar observing. I’m starting to take this increasingly seriously just as the Moon is due to sink lower in my sky until it disappears behind the house until Autumn… still you have to start sometime, and I’ve decided now with the Charles Wood’s Lunar 100.
Which is why I’m very happy to welcome the return of solar observing. As the Moon sinks, the Sun is getting higher in our northern hemisphere skies, so it’s around now that I start to swap lunar for solar observing. Despite being around solar minimum, with relatively few sunspots to be seen, I’ve been rewarded with some Hα fireworks and spectacular white light sunspots in the last few weeks. Few in number perhaps, but the quality was undiminished.
Planetary observing wasn’t left out as I followed the sliver of Venus up to the last possible moment. For me that was the point it fell behind the houses and trees to the west at sunset on 15 March 2017, but it was a very thin crescent by then: I estimated 5% and Stellarium claims 4.4% illumination. I’ve caught a glimpse of Mercury at sunset too.
There were several Jovian sessions, even though it’s a bit too low to see well from my back garden. I can observe Jupiter low to the SE over the top of my garage for about 30 minutes before it goes behind the house. No moon transits yet, but a look at a slightly washed out Great Red Spot (GRS) was possible in my 60mm refractor. Why the small scope? To have any view I have to pick my position carefully, and you try manhandling a large telescope into the garden undergrowth.
I’ve tried to spot the comets 45P/Honda and C/2015 V2 (Johnson) with my binoculars, but with no success. At first they were too faint or low, then the Moon arrived and I haven’t bothered again. Once the Moon disappears I’ll certainly try again for the latter of the two at least.
March witnessed the arrival of British Summer Time (BST) which heralds the rapid shortening of night in these parts. Naturally in astronomical circles this is never well received, and Deep-Sky observing isn’t going to be easy! By the end of May there’s no astronomical darkness for a couple of months, but in the meantime there can be some lovely transparent skies for the patient.
After a rather wet period in the middle of March, during which the Moon got out of the way, clear skies returned just before BST inflicted itself upon us. I’ve started working on the Herschel 400 list again. This spread of several nights gave me the chance to start on the faint and fuzzy galaxies of Spring, as well as polishing off some surprisingly faint open clusters from late Winter.
Finally, I’ve collected a few more variable star observations thus clearing the backlog a bit and responding to an AAVSO alert on AG Dra (one I regularly follow). The conditions haven’t been great for it: patchy cloud doesn’t kill a lunar session, but it makes reliable binocular variable estimates pretty tricky. Still it’s nice to be logging some data again.
So a March was a much better month and April has started in stunning style with observing sessions on each of the first seven days!
Since I last posted the rest of February 2017 has happened… there’s not a whole lot more to say than that.
Last month wasn’t quite as bad as last June, but it came perilously close for a while. It’s been cloudy and wet most of the time, but I’ve managed to grab a handful of brief sessions with my smaller scopes.
The fact that the Moon is lovely and high at this time of year has been helpful, though many of the best opportunities have been around New Moon ironically. I say that because there’s a theory that it’s only ever clear when the Moon is in the sky. Admittedly it’s a theory of Deep-Sky observers, but we couldn’t complain about that too much this February.
Still the skies weren’t Deep-Sky clear: the Transparency has been poor due to the high levels of humidity. I believe that the unseasonable warmth is a problem since the moisture hasn’t been forced out of the local atmosphere by sustained freezing temperatures. I’ve often been out observing at midnight at temperatures around 10ºC this winter, and that isn’t normal from a long term historical perspective.
The beautiful twinkling stars are a really bad sign for the observational astronomer. They’re symptomatic of poor Seeing and I suspect the polar Jet stream has been a frequent visitor overhead. When this happens everything is blurred like you’re viewing it at the bottom of a swimming pool. So seeing small features on the Moon or planets is out, and so is splitting tighter double stars.
So I’ve spent February as a bit of an astronomical tourist, just visiting the brighter Messier and NGC objects, the Moon and even Venus as the conditions allowed a half hour of clearish sky. No time for notes or sketches, I’ve considered myself lucky to get the telescope set up before the clouds reappeared.
That’s been OK, though rarely as relaxing as a quick tourist session should be, but it’s also frustrating when my Herschel 400 project has stall, the remaining binocular Messiers are a no-go, and my Variable stars are nearly a month overdue.
Let’s hope for kinder weather in the coming Spring before British Summer Time (BST) arrives and the Solar season is upon us.
I’m still working to my usual leisurely pace, but I’ve collected good observations of 60 of them now. This year would be a great time to finish this project since it’s the 200th anniversary of Charles’ death. The BAA are encouraging observers to complete a Messier Marathon, or at least view all the objects this year. Perhaps I will.
I’m basing my work on the Astronomical League’s Binocular Messiers Program that rate 102 of the 110 to be observable with binoculars. I’ve set the additional challenge to observe as many as possible from my north-west facing back garden. This is one reason why it’s taking so long to complete the project: some objects have a very short window of opportunity. That said, I seem to have managed a couple they don’t think I should be able to see, but I stand by my observations ;-), and having observed 58 from their list have 44 left to go.
Unfortunately most of those are pretty low in the sky from the UK. For example, I snagged M41 in Canis Major a few nights ago as it briefly appeared from behind the row of houses before falling into the trees, and all whilst standing on top of a wall peering through the undergrowth. On the other hand I couldn’t have done that with a telescope! I’m very glad that M41 is big and bright or the Industrial Estate light pollution would have rendered it invisible.
The upcoming galaxies of Virgo and Coma Berenices may cause some problems. I’ve observed all the brighter ones and have the trickiest to collect on a night of really good transparency. I’ll have another go at M108 and M109 in Ursa Major on that night too.
Then I’m down to the horizon huggers of Scorpio and Sagittarius below 25° altitude. I can’t think of anywhere around my house that they’re possible. Not the street outside, our front bedroom window, they’d probably be difficult from the roof. So I’ll have to start being mobile to mop the rest up, and perhaps that’s the time for a marathon?
I started variable star observing about four years ago with the naked eye and the 10-Star tutorial. I soon moved on to binocular variables, to which I’ve added a smattering of telescopic Mira variables now.
As you can see below, fuelled with enthusiasm soon clocked up 200, receiving a certificate from the AAVSO for my first 100, which was unexpected. Then the observation rate started to drop for various reasons including the appalling weather, British summer time (these two are often linked), and the pursuit of other astronomical interests. It stalled drastically after the first 600.
Well at the end of 2016, I decided it was time to pick up the slack and at least push through the 1000 observations barrier, which I did on 5 October 2016. At the time I generated the chart for this post I was handful short of the 1100 observation mark, but another clear night has put me well over the top.
Choosing my variable stars
I’ve got a telescopic aperture limit of 6 inches and a relatively light polluted site so those exciting, but faint, cataclysmic variables are off the menu for me. Eclipsing binaries are fine, but the most valuable observations of these are CCD photometric these days: visual observers need not apply. Most of my efforts are aimed at Long Period Variables (LPVs) with a few other types thrown in for variety, and delta Cephei for nostalgia.
I choose variables to suit the magnitude range of my equipment and by constellation. The latter allows me to concentrate my effort in a smaller area of the sky: it’s an efficiency thing. I also have favourite constellations: it’s a personal thing, and possibly pragmatic too 😉
My back garden has a terrible horizon for an amateur astronomer. Houses block most of the lower 30 degrees of the sky to the south and east, there’s heavy light pollution to the west now from an industrial estate, but I’ve a much better northern horizon.
For that reason I tend to favour circumpolar constellations that are accessible all year round, providing an unbroken record of observations. I’m concentrating on Cassiopeia, Cepheus, Draco, Ursa Minor and Ursa Major.
There are currently 49 variable stars on my observing list of which I have to admit only 30 get regular attention at the moment, and all of those are in the constellations mentioned above.
I use a combination of instruments depending on the brightness of the star and the sky conditions.
I can monitor variables with magnitude brighter than 5 with my naked eye (as long as I’ve got my glasses on!). A pair of 2.1x binoculars extends this to 7, but from around there down to magnitude 9 can be handled by a 10×50 binocular on a good night, and 15×70 binoculars for the fainter end on a night of poor transparency.
These can be pushed to magnitude 10, but around that I fall back on my first telescope: a Skywatcher 130P (130mm F5) newtonian. With the right eyepieces it provides good 1 and 2 degree field of view, which is plenty of room for the variable and comparison stars near the centre.
My final limit is about magnitude 12–13 depending mostly on altitude and transparency.
A good example is the recent CTA 102 quasar which reached around magnitude 11.5 and should have been possible. But by the time I had a clear sky – bad weather – CTA 102 was low in the western sky glow and had faded to magnitude 12.7. With the Moon right on its doorstep it proved just too faint for any of my telescopes. I suspected as much, but its not every day you get the chance to see something eight billion light years away with your own eyes, so I had to have a go! I found the field stars, but no quasar. I could have filed a “fainter than” observation, but it didn’t seem worth it when I was limited to 11.4.
I try to observe these rare opportunities – the Nova V339 Delphini and SN2014J in M82 spring to mind – as they’re not often within my range of magnitudes or a part of the sky I can see.
Making regular observations of selected stars really has its benefits though, quite apart from the fun of following their progress. Practice makes perfect and with the comparison stars fresh in my mind I can manage one observation every three minutes, which is quick by my meagre standards, and maintain this rate for a couple of hours.