All posts by James

Observing in 2016

I guess it’s obvious that I wasn’t blogging much in 2016, but I have been writing for my local astronomy society newsletter which has obviously drained my creative well… that’s my excuse anyway.

I have be observing and probably more intensively than ever. Having posted a real article I thought I’d do a round up of my rough and ready observing statistics for 2016.

If you haven’t seen 2015’s and feel you need some context then “Observing Patterns” is the place to go.

How did 2016 stack up?

I keep a diary in which I note the weather conditions at night, whether I got out there, and if not what stopped me. Summarised here is the number of observable nights – remember my loose definition – and the number I actually observed.

My observing record for 2016

Not unlike the one from 2015. I averaged about 7 observing sessions per month last year too, and took advantage of 78% of opportunities presented.

The stand out month has to be June with one single session.

In my defence, the month of June isn’t ever dark here in the UK and the weather last year was miserable. As you can see there were only 5 nights available and they weren’t very good. In fact June 2016 was by far the worst astronomy month I’ve experience to date, so I at least have decided to cut me some slack 😉

So how was the Solar?

I think this chart tells the story very nicely.

My Solar observing record for 2016

I did a lot more Solar work in 2016 than in the previous year: 2016 had 67 sessions, whilst 2015 saw only 28. I also stretched the solar season a little too.

These are both white light, which increased, and hydrogen alpha observing sessions. I’m pretty happy with my solar progress last year and hope for more of the same. It’s been great fun.

Was 2016 what I expected?

For once I think things turned out much as I’d hoped… which can’t be said for many other aspects of 2016.

I’ve completed some solar sketching of both white light and hydrogen alpha features. I plan to carry on in much the same vein this year.

I concentrated on learning my lunar geography and geology over the last year, the result of which is that I’ve spotted some regions of particular interest for close study this year.

I revitalised my variable star observing towards the end of last year as I targeted 1000 submitted observations. I’m becoming even more stellar obsessed, so much more variable and double star action to come in 2017.

I’ve advanced my deep-sky observing skills whilst furthering my binocular census of the Messier objects, starting the Herschel 400 with small scopes and getting better observations of the Veil nebula using an even smaller scope (another story).

On a sad note, I soaked up the last of the planetary goodness for a while, observing Jupiter whenever it was visible. The gas giants are sinking way too low for me for the next few years. So despite recently observing the last of the major planets to escape me – Neptune – and last year spotting Titan in the C90, planetary observing isn’t likely to feature in 2017.

And of course, I expect to remain aperture challenged 😉

An Unexpected Moon

It was the 8th January 2017. The morning had been lovely with sunshine in place of the predicted fog! It didn’t last. As the afternoon wore on the clouds gathered and by nightfall not only covered the sky but had delivered a persistent drizzle.

So I didn’t expect much when I stuck my head out of the back door at around 22:20 UT. The first thing that struck me was how warm (6°C) it felt despite being dressed in a T-shirt and lightweight fleece pullover. Then I noticed how damp it felt: our local humidity was nearing 100% it seems.

Not expecting much I looked up to the south west and I noticed something bright. The Moon was punching through the rapidly moving clouds well enough to be quite observable!

The Moon at 10.7 days into its lunation
The Moon at 10.7 days into its lunation in Virtual Moon Atlas
Continue reading An Unexpected Moon

Observing Patterns

I’m alive, well and still observing… I’m just not writing about it much.

We’re halfway through the observing season and the weather in the UK hasn’t been helpful. I’ve still managed to clock some hours under the night sky, and I’m finding it useful to keep a record.

Keeping track of observing data.

In February last year I decided to start keeping track of my observing activities and the weather that sometimes kept me from doing so. At the end of the year I added up the totals and here they are.

Chart of my astronomical observing record for 2015

I should mention that my definition of clear is pretty generous. If there’s a half hour spell between the clouds, that’s a clear night; if it’s cloudy enough to make the constellations hard to see, but the Moon is about, it’s clear.

On the other hand, there will be times when it’s been clear but I haven’t noticed it. I have to admit that I don’t constantly watch the weather outside for a chance, and I do sleep too.

So caveat aside, what does this tell me?

Firstly it tells me that I took 77% of the opportunities to observe that the weather chose to present me.

It was a good start to the year, in fact so good that it enabled me to work out that other activities enforce a practical observing limit somewhere in the mid-teens. I’ve not been too far from that at times, which I’m satisfied with, and considering my other obligations and a couple of prolonged bouts of illness it’s been a good year overall.

Summertime blues

Unfortunately, the observing cliff in the middle of the year was partially due to the aforementioned illnesses, but more particularly two issues of orbital mechanics.

The first is that it doesn’t get properly dark until nearly midnight around the summer solstice, and only stays that way for a couple of hours. It never reaches astronomical darkness at that time of year, so some objects are very tricky for the analogue observer without GoTo as signposts can be few and far between. There are many of my deep-sky friends that completely close down for the summer: kind of inverse hibernation.

That said the skies weren’t bad. I experienced some lovely transparency and managed to find the Veil and North American Nebulae for the first time with a little help from my new Astronomik UHC filter. Little did I know that I’d come to miss those skies.

And then the solar system picks on me in particular because I do almost all of my observing from home, I don’t own a car, and I don’t like driving much anyway.

Having found joy in lunar observing early last year I discovered that the Moon never strays high enough in the summer to be visible over the top of the houses from my garden. The planets are rather low in the ecliptic at the moment too, and intend to stay that way for a few years! I couldn’t see Saturn from my garden at all… which was upsetting. I wasn’t pleased, but the Universe didn’t seem to care about that much, so I’ve had to make different plans. It did reduce the options to fill observing time in those bright summer evenings though.

My ST-80 on a photo-tripod provides a grab-and-go facility, but it’s not ideal for either planetary nor lunar observing. In an attempt to remedy this problem I’ve resorted to retail therapy and bought a Celestron C90 in the hope that greater mobility will help in 2016. I like this scope already: it’s compact and as easy to mount as the ST-80.

So what did I do instead? I found that the Sun puts in more of an appearance as the Moon plays hard to get, which is shown in by the number of solar sessions below.

Chart of my solar observing sessions in 2015

These seasons pick up the slack nicely and mean I don’t have to wait for it to get dark. I intend to do more white light and hydrogen alpha observing, and sketching, in 2016. Oh, and more nebulae too. They’re addictive.

Autumn!

Don’t worry, the dark nights are on their way I thought. Frankly what constituted a clear night in autumn (fall) 2015 had to be very broadminded.

We’ve had unusually warm and wet weather from the south-west which has produced the night time temperatures of summer, which never seem to happen in summer! It’s also brought lots of cloud.

What’s worse is that the moisture in the air has made even cloudless nights appear milky: washing out most deep-sky objects and many constellations. I was pleased to see the return of the Moon this winter, since the poor transparency has frequency made it the only game in town.

On occasion the Seeing has been a compensation: there have been really good spells. This has been perfect for observing lunar and double stars with a small refractor, which I do as much as possible.

Observing in 2016

Winter has yet to arrive at the time of writing, but the next few weeks look hopeful: forecast is for it to get cold and clear. I hope they’re right.

Tracking my observing through the last year’s varying conditions has caused me to consider my choice of equipment more carefully, and perhaps more importantly, diversify my observing goals. I’ve been asking myself, what gets me out there?

It’s one of those times that I’m glad I don’t own a big scope. My small scopes, with their rapid cooling time, can be in action in a few minutes without the need for an observatory. Perfect for the conditions I’ve been experiencing. I’ve decided to stick with them, so the 10–14 inch dobsonian mounted scope is shelved for the moment, since many of my autumn sessions have been a sequence of half hours between rain showers. It’s an interesting challenge to see what you can do with limited aperture.

I expect 2016 to contain much more lunar and solar sketching, the former for the winter and the latter in the summer. Double and variable star observing remains unchanged because I love it. The biggest change is that in addition to open clusters I’ve become obsessed with planetary nebulae. They’re an interesting test of your observing skills and many are accessible to small scopes from light polluted locations.

Partial Eclipse

The morning of the solar eclipse and looking to the East it’s not a pretty picture. I can see the location of the Sun, which is a major advance on yesterday, but it’s not even bright enough to show up through the solar filter… not good.

Optimism wins out, and I decide to set up the solar telescopes – white light and hydrogen alpha (Hα) – before having breakfast in the hope that luck will be with me today. It owes me a break since the night time trend is for me to get cloud when others get pristine skies.

Breakfast out of the way I’m asking myself whether it’s clearing. It looks like it is, but which way are the clouds going? I’ll take a look with the Herschel wedge on my ST-80. I can see the whole solar disk and think that the remaining light clouds lend an atmospheric touch as the sunlight bounces off them. But wait, is that a notch appearing in the circular face of the Sun? Yes! The game is on.

I watched the Moon slip across the face of the Sun, pausing to make notes and quick sketches of what I could see. The Sun is very active in Hα and some of the prominences became divorced from the Sun – detached isn’t the word, these were in limbo, now above the Lunar limb! I noted the time of first and fourth contact, and when a lonely sunspot group was occulted and later reappeared.

At maximum the temperature dropped, the sky took on a twilight feel, but the colour was different. Imagine a blue sky that’s fallen in luminance, a bit like that, purple for me and my dodgy colour vision. The birds actually clammed up, they’d been active until that point.

I noticed the temperature drop caught out the relative humidity. It had been dropping too as the morning progressed, but water was suddenly unhappy being vapour and my breath sent plumes across the garden. Weird would be a good word for it.

I could have imagined it, but it looked like there was some spillover of light onto the northeastern limb of the occulting Moon. In Hα I thought I could see some detail there. Very faint if it was real at all and not a product of the optics.

The house started to get in the way, so I had to be creative with the repositioning of my equipment around the garden to watch the next phase of the drama. But it was all there – much to my surprise – from beginning to end, first contact to the last.

An evening with the Pleiades

For those nights when you don’t want to spend an eternity tracking your target down it’s nice to have a plan that involves one of the brightest objects in the night sky. The Pleiades (M45) is handy for just this reason, and armed with a map and some doubles from the Washington Double Star catalogue (WDS) that’s what I decided to do on the night of the 6th January 2015.

A reversed image of the Pleiades from the Digital Sky Survey

Continue reading An evening with the Pleiades

M103 in Cassiopeia

It’s time for another open cluster, and in truth I’ve built myself a bit of a backlog. The issue is that I’m too lazy to scan my drawings in a timely fashion. That’s my excuse and I’m sticking to it.

This time I’ve chosen to turn my telescope, with pencil in hand, on M103 (one of Charles Messier’s objects) in the constellation of Cassiopeia for the second time this season. The first was with my ST-80, but I felt that 44x magnification didn’t to it justice. So on the night of 4/5 October I returned with the Vixen A80MF and 7mm Nirvana eye piece for a higher powered attempt (130x).

If you know what you’re looking for M103 isn’t hard to find being about 1 degree from the 2.5 magnitude star, delta Cassiopeiae. It’s not one of the “obvious” clusters, in fact I’m not sure why Messier found this one and not the nearby NGC 663, perhaps it looks more “cometary”.

My Observation

So once again, here’s a scan from my logbook. I’ve tidied up the notes on the computer, but the sketch has just had the contrast increased as the scanner leaves it a bit faint. My field of view is about 38 arcminutes with this telescope and eye piece combination.

Sketch of M103 in Cassiopeia

You’ll get to see the scan with handmade notes if you click on the sketch. And this is what the Deep-Sky Survey makes of M103.

DSS view of M103 in Cassiopeia

I don’t think I’ve done too badly.

Classification

To my eye, and telescope, M103 isn’t rich with stars. I’ve drawn pretty much all I could see, and some of those weren’t constantly visible. Yet there weren’t many more than a dozen stars in the cluster. So I classed this cluster as p (poor) using the Trumpler system.

There aren’t any really bright stars in M103, but there are obviously very faint ones (I estimate that I could see down to about 11.3 magnitude). This led me to settle on a brightness range of 2.

This cluster is clearly detached from the Milky Way background – quite a feat that was contested for some time after it’s discovery – and there’s concentration of the brightest stars, but its not highly condensed to my inexperienced eye.

So to reach my final Trumpler classification for M103 I threaded these components together estimating M103 to be a II2p open cluster of about 10 arcminutes angular diameter.

How does this compare with the official data? My estimate of the angular diameter is a little above the 6 arcminutes in the literature which also thinks that M103 is a bit richer giving it a rating of m rather than p.

I can live with that comparing my sketch with the DSS image.

Splitting the Double-Double

A couple of nights ago I got the chance to set my Vixen A80MF telescope up for a session under the stars. It’s been a while since I last used it, I’ve been using a newtonian and binoculars recently, but the it’s reminded me why I like refractors so much.

This isn’t an instrument for wide field views normally, it’s my double star scope, but with a 16mm Skywatcher Nirvana eye piece (82 degree AFOV) the view of the double cluster was fantastic.

It’s so easy to get the focus just right on these ‘slow’ scopes, and it tends to stay right whatever the sky condition… almost. Lovely sharp stars with a hint of the circular diffraction pattern.

This is a great scope for general use – in the same mold as the Skywatcher Evostar range – but I’m not entirely satisfied with it’s performance at high magnification on double stars. So decided to try it out on the double-double (epsilon Lyrae) which has become a standard for testing optics and handy at the moment near the zenith.

Finder map of the double-double (epsilon Lyrae)

There’s a very widely spaced pair – eps01 and eps02 – that can be seen with binoculars and even the naked eye, but each of these is a double pair too, and that’s the test.

With my 7mm SW Nirvana in the diagonal, giving angular magnification of 130 times and about 38 arcmins TFOV, I could cleanly split both pairs.

What I found interesting is that the southerly eps02, comprising the C and D components of the double-double, was much easier to split even though it’s the closer of the two.

True, it’s components are separated by 2.3 arcseconds whilst the components of eps01 (A and B) are 2.4 arcseconds apart, but the visible difference was huge. I was using a 2x barlow on the 7mm eye piece to get a clean split between A and B with an angular magnification of 260 times.

The difference was clearly down to the apparent magnitudes of the component stars. The CD pair are very even in magnitude at about 5.5, whilst the AB pair have a difference of about a magnitude (A at 5.2 and B at 6.1).

It’s impressive how much difference that makes to splitting a double star, and what it says about the limiting performance of telescopes given the traditional methods of calculating angular resolution. These are based on even pairs.

Sissy Haas has a project to empirically derive a correlation for telescope performance on uneven double stars. It’s open to, reliant in fact on, contributions from the amateur public, so why not have a go.

Stephenson 1

I’ve finally made a start on the open cluster observing programme I talked about in… February this year! It seemed sensible to start with an easy one because I was determined not just to observe and classify, but to produce a sketch too.

The chosen target was Stephenson 1, which is also known as the Delta Lyra Cluster. As you’ve probably guessed, the delta Lyrae visual double – and many would say that is enough reason to take a look – plays a key role in the structure of this open cluster.

The delta02 Lyrae component lies right at its heart, and makes finding this cluster pretty straight forward with nothing more than a red dot finder.

The instrument I chose was my Skywatcher 150PDS (a recent addition) furnished with a 16mm Skywatcher Nirvana eye piece (also a new addition). This combination provided a field of view of about 1.75 degrees, or 105 arcminutes, at an angular magnification of 47x.

My observation

And so, for your enjoyment, here’s the sketch drawn at the eye piece and later scanned from my logbook.

My original sketch of Stephenson 1 open cluster

Ok, there are two sketches really, one with the field stop, and another drawn larger with more detail. It might be a little messy, but I think it’s a good representation of the cluster.

I’ve also tried using digital means to clean it up a bit. The image below was produced by tracing the original scan using a paintbrush tool to make round stars. I wouldn’t need to do this if I’d been more careful. A lesson for next time.

Digitised version of the original sketch

Using the field stop as a guide, I’d estimate that the cluster spans about a third of the field which gives it an angular width of about 35 arcminutes.

Classification

Now to the matter of classification. I’m supposed to classify each of the open clusters I observe using the Trumpler system (which is explained in this nice article.

It’s clearly not rich with stars, I could count no more than 20 actually in the cluster. I suspect larger apertures would find more. So the rating for the number of stars in the cluster would have to be p (poor).

By virtue of fourth magnitude del02 Lyrae and many stars I’d estimate at magnitude 8 to 12, it’s got both bright and faint stars alright. This yields a range of brightness rating of 3.

Finally there’s the question of concentration, and I have to admit to struggling with this one. I’m not clear on what constitutes a cluster being deattached, or not.

Stephenson 1 certainly lacks any central concentration. This leaves me with a rating of III or IV, but which one? I guess I’d have to say that it’s more of an increase in the density of stars than a clear concentration, so perhaps IV, but it could have gone either way for my money. I guess I’ll get better at this with practice.

Piecing together my work, I’d classify Stephenson 1 as a IV3p open cluster of about 35 arcminutes angular diameter.

According to the professional data del02 Lyrae isn’t likely to be part of the cluster as it’s nearly 100 parsecs closer to us. It’s still a pretty yellow coloured star though.

Digitally inverted detailed sketch of Stephenson 1

I really enjoyed doing this, and I’m looking forward to the next one. But which will it be?

Charles Messier’s objects

Charles Messier

Charles Messier was born in 1730, in France, and grew up to be a comet obsessed astronomer working in Paris. To be fair to Messier, most 18th century astronomers were obsessed with comets since discovery could bring fame and riches.

Whilst hunting for these bringers of wealth, Messier kept finding himself confounded by other objects that appear non-stellar, but lacked one of a comet’s defining features: they weren’t moving. Whatever they were, they weren’t what Charles was devoted to.

It’s curious then that Charles’s lasting claim to fame is the Messier catalogue in which he listed 103 ‘nebulae’ – a definition that included almost anything that wasn’t a comet or clearly stellar – with 7 more being added after his death.

The binocular observer.

The thing about these 110 objects that might look like comets, but aren’t comets, is that they were objects not to confuse with a comet and as such, in binoculars they’re generally not impressive. The main exceptions tend to open clusters due to their looser stellar nature. Even so, many fail to break the fuzzy blob mould even with the benefit of modern optics.

Perhaps binocular astronomers are getting a good impression of what Charles Messier saw when we’re looking at globular clusters in the 15x70s. They’re little more than faint fuzzy object with a brighter core… perhaps.

It’s noticeable that many of the best binocular astronomy targets were ignored by Messier completely, but perhaps it’s not a surprise.

The Double Cluster

With his goals in mind, he was hardly going to mistake the double cluster (NGC 869 and NGC 884) above for a comet. They neither display background nebulosity, nor appear as a nebulous object as so many globular clusters have a tendency to do in antique telescopes and binoculars.

So what’s the interest in Messier’s catalogue?

Observing the Messier catalogue with binoculars is mostly an exercise in finding things. Most of these objects stand out well from the stellar background with a reasonably dark sky; that’s why they’re on the list in the first place.

Finally, a pair of binoculars is very compatible with this activity. Many of the Messier objects are near the horizon from the UK as Messier was working further south. Additionally, dark skies can be hard to come by to finish off those faint galaxies. So to locate the lot you’ll probably need to move around, which is home turf for binoculars.

I might sound disparaging about Messier’s objects. He certainly had no interest in them, however some of them are really beautiful, even in binoculars, take M45 Pleiades for example. But to see many of them at their best you need a telescope.

Which is your favourite binocular Messier?