Category Archives: Globular Clusters

One of those sessions…

Last night was One of Those Sessions where I actually began to regret setting up…I dropped my Telrad (fortunately it didn’t break), stepped in some dog crap that got overlooked earlier (why do they need to go on the path?!) and, when I was wheeling my scope back down the garden later, a large globe thistle caught up in it, then broke free and smacked me in the mouth, which hurt but, although the plant is prickly, at least it didn’t draw blood.
It was also one of those sessions when I couldn’t find half of what I went after but, although I have decent dark skies here, last night’s transparency wasn’t as good as I’d hoped and as I was looking for faint objects that wasn’t really surprising, so I went back to the brighter stuff. Oh and my sister, and her kids plus their hyperactive spaniel, are visiting for a week so the house lights kept going on, as well as the upstairs bedroom and landing lights which she keeps on for her kids who, at ten and twelve years old, surely no longer need lights on at night. She let her boisterous spaniel out at one point, so not only did the garden get blitzed when she put the light on, I also had a suddenly-aggressive/nervous dog, who is in an unfamiliar place, barking his head off at me.

The dew was appalling. Everything was wet and it was like observing in a swimming pool. I persevered but packed in just before 3 am when clouds began to roll in; I dismantled my 18 inch Dob and just shoved it into the shed, uncovered, to give it a chance to dry out, gathered up my by now sodden charts and notebook, which were rapidly turning into paper mache, and went to bed not in the best of moods and regretting the three cups of very strong filter coffee I’d drunk!

Anyway, here’s what I actually DID manage to see:
NGC 6440, 6445, M51 (just for something really nice and bright to look at), Abell 2, NGC 7013, NGC 5832 and NGC 6011. Seven objects in a four-hour period is a pretty poor return but I spent (wasted) a lot of time looking for stuff that was a bit too faint for the conditions.

I am looking into getting some digital setting circles for the 18 inch, which will make finding stuff a lot easier. I’ve been talking to Gary at Wildcard Innovations of Australia who makes the Argo Navis DSCs and, although I can make some modifications to my scope’s mirror and/or rocker boxes to accommodate the encoders, it will be a tight fit. The only problem right now is money, with no job (and, looking like no prospect of actually getting one) I can’t justify spending over £600 – which it will be once I have paid import taxes and VAT – on something like this, especially with my car’s annual inspection due on 20th August. I may have to look for alternatives.

 

Observing 1st August: 8 inch Dob

The 8 inch got its first outing on 1st August, as it was clearer than forecast and I couldn’t be bothered to get the 18 inch out and assembled.

Apart from the substandard 1.25 inch focuser it’s a pretty good little scope. I used my 25mm and 15mm Plossls and my 9mm Nagler with it; I also tried the 22mm Panoptic, which wouldn’t quite come to focus because the travel of the draw tube isn’t enough, and the 12mm Nagler which seriously unbalanced the scope below a 45° angle. A friend of mine from VAS, Richard, has got a Crayford focuser which he will fit to the tube. The Crayford is a lot heavier than the 1.25 inch rack and pinion but we will do something about the balance, whether it’s moving the tube back on the rocker box or using counter weights.
I have already removed the finder, which was located in an awkward place below the focuser and added a Telrad base. The photo shows the base in position and tape put over the holes where I had taken off the finder bracket (to the lower right hand side of the focuser); as you can see, it was in a stupid and awkward place.

8inchfocuser
The stars are nice pin points, once the mirror has cooled, and there is no coma, as you’d expect in an f/6 mirror, totally unlike my 8 inch f/4.

I looked at NGC 6401, M107, NGC 6568, the Veil Nebula, N27 and M57 before it clouded over and thunderstorms moved in.

Observing, 9-10 July 2013

Date: 9/10 July 2013
Conditions: Cooler than previous night (10°C/50°F), 74% humidity with some dew. Astronomical twilight persists all night until mid-July
Seeing: Good; Transparency: Good, but not as good as previous evening.
Instrument: 18″ (457mm) f/4.3 Dobsonian with 22mm TeleVue Panoptic (90x); 12mm TeleVue Nagler (165x); 9mm TeleVue Nagler (219x)

Only a one-hour session due to tiredness and light skies. The objects are all globular clusters, except where stated.

NGC 6402 (M14), Ophiuchus – Easy to find, large and bright. Some stars resolved across face of cluster at 90x. At 165, almost totally resolved. Nice object.

NGC 6535, Ophiuchus – Smaller than M14 and quite faint against a not-quite-dark sky. At 219x it’s a roundish glow with some foreground stars superimposed on it. Slightly granular but mostly nebulous.

NGC 6517, Ophiuchus – Fairly small but easy to find. Quite bright but not helped by light summer sky and low altitude. At 90x, it is a round glow with a slightly brighter centre. At 165x it shows a brighter dense core and some granulation. No real improvement at 219x.

NGC 6426, Ophiuchus – Very easy to find, because it is located between ϒ and ß Ophiuchi, and is a round glow which is not resolved at 90x although it does have a vaguely granular appearance. It doesn’t brighten towards the core.
Granular at 165x but no improvement at higher powers.

NGC 6712, Scutum – Large, partly resolved with many stars on a nebulous background. Not concentrated towards the core. 90x, 165x.

NGC 6664, Scutum – Open cluster. Large, loose group of approx. 30 stars in NW-SE line. Mostly white stars of equal brightness but there are fainter ones scattered in between these. Located 1° from α Scuti.

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Today (10th July) I did some solar observing, as usual, and encountered an unforeseen hazard of day time astronomy – a bird shit on my notebook! Better than on me, I suppose but clothes and hair can at least be washed!

Today’s solar sketch:

sun10july13

Observing, 12th and 13th May 2012

The run of crap weather ended for a brief period over the weekend (but is back to being rubbish today), so I was able to do some observing on Saturday and Sunday night. Saturday night’s session was excellent, but Sunday’s was less so, thanks to some pretty woeful transparency due to some thin high cloud.

I hadn’t used my 18″ since the Isle of Wight Star Party, back in March, so it was nice to get it out of the shed and set it up. The new 2″ Howie Glatter laser collimator worked brilliantly but I will get a TuBlug for use with it, otherwise I have to look in the top of the scope to see the laser and the shadow, then go to the back of the scope to make the necessary adjustments. The collimation was only slightly out, which wasn’t bad, considering the telescope had been disassembled after the star party, driven over shoddily-maintained roads which resemble Afghan goat tracks (at the risk of insulting Afghan goat tracks), carried up the garden and reassembled.

As well as the H2500 I have been doing the AL’s Globular Cluster program. As well as observing 26 of these at TSP last month, I was going to use some ‘ancient’ observations from my 1997 Australia trip but I decided against this, apart from NGC 5139 (Omega Centauri) and NGC 104 (47 Tucanae) which I will keep in the list, as I have enough observations from recent years (2010 to now) I can  use, including some from this weekend. You need 50 observations to complete the program, I now have about 70-odd so I’ll select my best ones to send in, including the Challenge Object (I have Palomar 11, NGC 5466 and 5053 to choose from). One of the good things about these programs is the fact that doing them often takes care of objects on the Herschel lists, as well.

I have loads of observations to type up, from the Isle of Wight Star Party, the Texas Star Party and the past two nights but I’ll save these for the next rainy day – and I don’t think I’ll have long to wait, as the unsettled period goes on.

Galaxy groups and clusters are also among my favourite targets, mainly because find one and you have found half a dozen or more, so I put Abell 1656, the Coma Galaxy Cluster, on my list.

Saturday:

Date: 12th May 2012
Conditions: Clear, very dewy, no Moon (rises at 0200)
Transparency: II-III; Seeing: II; NE Limiting Mag: 6.0
Equipment: 18″ f/4.3 Dob with 22mm TeleVue Panoptic (90x), 15mm TeleVue Plossl (132x), 12mm TeleVue Nagler (165x) and 9mm TeleVue Nagler (219x).

I began with some eye candy (M53), then went on to some fainter stuff before returning to bright objects. Objects observed were M53, a globular cluster in Coma Berenices, NGC 4147, a globular also in Coma B, an attempted observation of NGC 5053 in Coma B, Abell 1656, the Coma Galaxy Cluster, M5, M56 and M3. The Messiers were objects that I hadn’t looked at in about 17 years so it was nice to catch up with them again, besides I wanted them for my Globular Cluster observing progam mentioned above.

I failed to find NGC 5053, a notoriously hard object to observe because of its low surface brightness (I returned to it on Sunday night with more success).

I identified 14 members of Abell 1656 during the course of an hour and a half, plus I saw many others that’ll have to remain nameless until a better night, as the transparency, while ok, wasn’t as good as it could be. The ones I could put names to were NGC 4889, NGC 4874, NGC 4864, NGC 4869, NGC 4865, NGC 4881, NGC 4860, NGC 4848, NGC 4921, NGC 4911, NGC 4923, NGC 4908, IC 4051 and MGC+5-31-46, the latter object only visible with averted vision. I used my new (second-hand) Naglers on these and was pleased with their performance.

I finished with some more Messier globulars, M5, M56 and M3, before packing up.

Sunday:

Date: 13th May 2012
Conditions: Cool, slight dew, breezy.
Transparency: II-III; Seeing: II, NE Limiting Mag: 5.8 to 6.0 later before deteriorating badly.
Equipment: 18″ f/4.3 Dob with 22mm TeleVue Panoptic (90x), 15mm TeleVue Plossl (132x)

The sky was not that good although the transparency did improve slightly later. I ended up just observing three objects, all globular clusters, NGC 6229 in Hercules (another re-visit to something I’d not seen in years), M92 (the last time I looked at this was in 1999) and I had another crack at NGC 5053, this time successfully, despite the less-than-optimal sky conditions. NGC 5053 was faint, very faint and amounted to nothing more than a roundish glow with stellarings in moments of good seeing and no central condensation whatsoever.  As globular clusters go, it is a pretty poor specimen!
I decided to go after some more galaxy clusters but the transparency gave out completely and the sky became extremely milky. When it’s like that, it’s no good for anything, much less faint galaxies which vanish if even the slightest bit of haze appears.

So, it was a couple of good sessions – well, one excellent session and one not-so-hot one. It’s been a mediocre year so far for observing, with not many sessions because ‘life’ has just plain got in the way, although it had been quite clear up until the second week of April when the period of bad weather set in. I’ve done most of my observing at the IoW and Texas SPs.

IoW Star Party

We got some reasonable observing in at the star party, despite poor transparency on Thursday and Friday nights. Sunday night was pretty transparent but hampered by a stiff breeze, which forced Owen Brazell to call it a night at 3am because his 22″ was moving around so much that it was impossible to observe and also becoming dangerous, both to observer and scope. I ended up dismantling mine totally and stowing it beside the chalets, out of the wind. Others, in more sheltered locations, continued for a while longer before also giving up for what was left of the night.

I didn’t get through as much of my lists as I would have liked, due mainly to the poor transparency and to Sunday night/Monday morning’s stiff breeze. I spent a lot of time in Leo, Virgo and even down in Crater and Corvus. I’m not going to post all the observations I made but, suffice to say, it was nearly all galaxies apart from NGC 4361, a planetary nebula in Corvus (and this was a second visit, I’d previously observed this in May 2008, with my 12″ Dob), NGC 5634, a globular cluster in Virgo, plus some eye candy in the form of the best views I have ever had of M42 (come on, it’d be rude not to!), Saturn, Mars and NGC 869/884 (the Double Cluster).

Thursday, 22nd March, was the day of arrival. I arrived late morning, and set up my scope once I’d stowed my other stuff in the chalet and parked the car. Other people were also arriving through the afternoon and the ‘serious visual observers’ area (as designated) soon began to fill with large Dobsonians plus some smaller fry, in the shape of a couple of SCTs and a few refractors.

The visual area, with large Dobs. Mine, minus shroud, is in the foreground.

Thursday night was fairly cloudy, with a lot of high stuff, mist and generally poor transparency so I messed about for a while, looked at one of my favourite galaxies NGC 4565 and its neighbour NGC 4562, as well as NGC 4494 and some bright eye candy. I packed up at 2330 GMT and went to bed. Apparently it cleared a while later but as I was tired I wasn’t that unhappy about missing it. We did see an iridium flare earlier in the evening.

Friday was clearer but, as chairman, I had to go to the VAS meeting in Newport first but I managed to escape at half time because the sky looked promising. I got back to the observing field at around 9.45pm and set up. The transparency still wasn’t the greatest but I got my observing lists out and started hunting for galaxies in Leo before moving on to Virgo.
A lot of the session was spent in and around the Realm of the Galaxies in Virgo, as soon as it was high enough out of the crap in the atmosphere. Here, the 18″ really showed what it can do, especially given the fact it had more than 24 hours to cool down to ambient temperature, something it doesn’t always get to do at home. Galaxies were simply everywhere. Find one and you have found dozens, maybe even hundreds, including some faint little sprites not on my charts (these were evident on the Sunday night when the transparency had improved and the naked eye limiting magnitude was 6.4) and, what’s more, the brighter NGCs and the Messiers showed detail – this is what I bought the 18″ for! Simply put, I got totally blown away by these galaxies!

Saturday evening started off with an ‘eye-candy’ session. The eye candy included M42, which was simply stunning in the 18″, and several people commented on how good my telescope and mirror are which pleased me no end, of course, as it is nice to know your ‘investment’ is as good as the money it cost. It does need a few modifications and what I want to do is get a decent focuser for it (I’d originally ordered it with a bog-standard rack-and-pinion focuser, on grounds of cost, which does the job of course, but could be better) such as a Moonlite Crayford or a Starlite FeatherTouch, adjust my crappy shroud* (easily the one poor thing about the scope is that the shroud is rubbish) so it doesn’t blow about all over the place, plus waterproof it to prevent dew soaking through and dripping onto the mirror, and finally get round to adjusting the position of the Telrad base, which I’ve been meaning to do for ages** (I had a brain-fade when putting it on the scope and put it in the wrong place – it still worked, of course, but meant I needed to walk round the scope to look in the eyepiece). I’d also like to put some sort of light-absorbing material on the truss poles to reduce light scatter and improve contrast.

Most of the session was, again, looking for galaxies. I spent a good amount of time in Corvus and Crater, which meant bending down or kneeling on the ground to look through the eyepiece – it therefore wasn’t surprising when I had severe knee pains and back ache for three days afterwards, but at least I managed to cross a few of the objects off my observing lists.

Sunday was much clearer. After a very interesting visit to St Catherine’s Lighthouse in the afternoon, we spent the evening in the Crown pub at Shorwell, before returning to BHC and a stunning sunset.

The lantern at St Catherine's Lighthouse

Although Sunday night into Monday morning was very transparent, a stiff breeze had arrived, which made observing difficult. I gave up by 3am, fearing my scope would blow over, so I dismantled it and moved it to a more sheltered location, with other people packing up shortly afterwards. As Monday was the day we all went our separate ways, I stowed a few things I didn’t need, such as the truss poles and a few other bits and pieces, in my car. I did, however, manage to observe some more galaxies in and around Virgo, as well as the globular cluster NGC 5634.

It was an excellent star party and I had a good time. This was the 5th IOWSP and the 4th I have attended (I missed 2011); in 2008 and 2009 I could only come for one evening and went home afterwards while in 2010 I came for two nights, camped and nearly died of hypothermia – I have never been so cold in all my life! This year, I was at the star party for all four nights, staying in a chalet, and it was so much nicer and I also felt more part of things.

Next year’s star party is in early March. Unfortunately I think it coincides with OzSky 2013 which I would like to go to, depending on finances.

* I have altered the shroud, using some velcro and I have attempted to waterproof it with some tent waterproofer I bought in Mountain Warehouse – this failed but I’ll get some better stuff from Goodyears in Sandown.
** I have now altered the Telrad position. Much better.

For all the photos from the star party, please click here.

 

Messier 13

Ever since I became interested in deep sky observing and sketching nearly 20 years ago, I have mostly used 6, 8 and 12 inch telescopes for my observations, plus the odd big ones (20, 36 and 48 inches) at star parties such as Texas. My new 18 inch dob has now brought my observing into a Whole New Realm – the magnitude or so difference over my 12 inch means that there is a lot more to see.

The other night, October 15th, as the conditions were a bit lousy (nearly-full Moon plus some mist) I forsook my usually faint galaxy-hunting and decided to sketch M13 instead. I haven’t done a lot of sketching while using the 18 inch yet, as I have spent the time in my six sessions with it so far searching for more detail in objects and things such as faint galaxies in the field of view.
While sketching M13 I found – totally unsurprisingly – that the big and more detailed objects are far more challenging to sketch when viewed in larger apertures. You’re just overwhelmed with the profusion of detail and M13 is a prime example of this; while it isn’t totally resolved in the 18 inch, it is a very large glittering ball of many stars.

Here’s the sketch I made the other evening:

 

And the same sketch inverted for a more natural look:

 

And, for comparison, here’s a sketch I made back in the 1990s with my old 8.75 inch f/4.5 Newtonian:

 

I am looking forward to M42, that will  present an interesting challenge later in the winter – weather permitting…

The 18 inch gets to see the sky

The 18 inch finally got its first look at the sky, as it cleared just before sunset after a day of thundery showers, some of which were torrential. The forecast called for a clear night so I hoped to get at least an hour in. I put the scope together, which at least is getting easier and waited – impatiently it has to be said! – for darkness. Collimation was a breeze as, despite the scope being loaded into a van, driven along 200 miles of motorway network, carried on a ship across a bumpy Solent, driven across the appalling goat tracks that pass for roads on the Isle of Wight, unloaded from the van and bumped across the cratered and uneven back lawn, it was not that far out and even if it had been, the large bolts make it a joy to do and not a boring chore. It took 30 seconds to line up the secondary and then the primary – it was FAR easier than either my 12 inch or my 8″ scopes.

I did discover a slight Telrad fail – I’ve put the base in the wrong position. It’s not a big problem but I could have done with putting it next to the finder. I’ll move it at some point, and I’d like to screw the base to the UTA, rather than have it fixed by means of the adhesive base, but it’s going to be ‘fun’ getting it off to move it. It’s not a big deal, it just means that I have to walk round the scope to the eyepiece once I have located something.

When it got dark, the Milky Way was as good as I have ever seen it, with the Cygnus rift very striking and the rest iridescent. It was very prominent right down into Sagittarius. I forgot the SQM, but the naked eye limiting magnitude was at least 6.2.
The neighbours’ lights were annoying as usual, and I wish they’d adjust their insecurity light as it blitzes everything. Luckily that only seems to be put on when their dogs are out having their late night piddle. I wish they’d move away and a nice elderly couple who go to bed at 8.30 and who don’t have all the house lights on would move in instead!

Date: 18th September 2011
Conditions: Clear at first, clouds moving in later. Very dewy (88% humidity) and wet underfoot.
Seeing: II
Transparency: II-III; IV later when clouds arrived.
NELM: ~6.2
Equipment: 18″ f/4.3 Dob, with 22mm Televue Panoptic (90x), 8mm Televue Radian (247x)

First up, as it wasn’t dark and I was just itching to look at something, was the Alcor-Mizar system.Very nice at 90x, with the jewels blazing brightly. As this is an f/4.3 mirror it was evident that I need a coma corrector, such as a Paracorr but I can live with it for now.
I didn’t take any notes, beyond writing names down, either; this wasn’t a ‘serious session’, it was more a case of getting used to the scope and to the ladder I needed to use with it, rather than a proper serious observing session.

NGC 7006, globular cluster in Delphinus – I’ve seen this on quite a few occasions but never as good as this, and this was with the sky still dark blue. At 247x, it was resolved and the core was very dense. 90x, 247x

NGC 7331, galaxy in Pegasus – This was the best ever view, the galaxy appeared very large and bright, with a bright tiny core. Elongated north-south. 90x, 247x.

I also viewed NGC 7337, NGC 7335, NGC 7336, NGC 7340 and MCG+6-49-44, the ‘Fleas’ in the Deerlick group. The fainter Fleas were quite hard with my 12″ but are easy in the 18″. NGC 7336 was pretty faint and the faintest of the group. 247x

The scope is a bit stiff to move, although not hugely so and I expect the stiffness will wear off in time. Besides, it’s better for it to be slightly too stiff than too easily moved.

I packed up at 2130 just before the moon rose as the clouds had returned (contrary to the weather forecast!). I took the scope to bits and returned it to the shed, after carefully drying it off. The shroud was wet through and that’s now hanging over the landing rail to dry.

In unrelated news, I have decided to get another car. My Citroen is getting a bit old and I’ve never really liked the thing as it’s too small, feels ‘cheap’ and is easily ‘bullied’ off the road, so I have traded it in for a Renault estate. Hopefully I can pick the new one up on the 24th. It has an added bonus in that the big telescope will fit into it, as I decided on the spur of the moment to change my car, I thought I may as well get a bigger one while I was at it. The only downside is that the tax will cost more and it will also cost more to run.

Red sky at night…

The evening of 21st August looked promising, with a few high clouds, so I set up the 8 inch again. I wanted to get the 12 inch out but I’d been out all day, and had got up at 7.30 that morning so I frankly couldn’t be bothered. The clouds made a spectacular red sunset again so their photo was taken. The quality isn’t the best because my wide-angle lens, a basic Canon 18-55 kit lens, is as ropey as hell although a new lens is pretty low on my list of priorities.


My targets were in Sagittarius (Among others, I wanted to see NGC 6822; I’d seen it from Australia in 1997 but not from the UK. It should be relatively easy at -14 dec) and Aquila but, as it got dark, it became apparent that I wasn’t going to do any observing in Sagittarius, as it was completely murked out, so I switched my attention to Aquila, which was still clear. A bit fell off the equatorial mount at one point, but this didn’t affect its performance.
I did an SQM reading before I began, this was 20.80, which corresponds to a NELM of 6.0.

Date: 21st August 2011
Conditions: Some high cloud, 4th quarter Moon not yet risen, humid, warm
Seeing: II – Good
Transparency: III – rather poor
NELM: 6.0 to 6.1
Equipment: 8″ f/4 equatorial Newtonian; Televue 22mm Panoptic (36x), Televue 15mm Plossl (53x), Televue 8mm Radian (100x) and Televue 5mm (160x).

NGC 6760, globular cluster in Aquila – Round, quite large and moderately faint. Found easily at 36x. At 100x it is unresolved. Still unresolved at 160x. Brightens to a compact core. 36x, 100x, 160x.

NGC 6749, globular cluster in Aquila – Very small and quite faint. Not resolved. Lies in a rich area. 36x, 100x, 160x.

At this point I took an reading with the borrowed Sky Quality Meter (I must get myself one of these but, like the wide-angle lens, it’s fairly down my list of priorities) and it was 21.02, which equates to 6.1 on the visual scale. Not bad for a pretty average night and confirms my average naked-eye estimates.

Looked for the planetary nebula NGC 6852, also in Aquila, but failed to find it. I don’t have much success with Aquila planetaries! Will try this again next time.

NGC 6934, globular cluster in Delphinus – Bright, small and round. Unresolved at 100x and 160x. Compact. There is a mag 9 star just to the west of the cluster. 36x, 100x, 160x

I packed up at 2345 as the Moon was rising and my feet hurt after being on them all day! I only managed three objects – my sessions seem to be like that at the moment thanks to a combination of conditions and having to be at work the following morning.

More ‘Glorious Globulars’ – well, two of them

Yesterday, 19th August, was one of the every-other-day warm and sunny ones in this strange mixed bag of a summer. The evening was cloudless and, although the Moon was going to rise before it got astronomically dark and it was forecast to cloud over later, I decided to set up the 8″ Newtonian and catch some low southern globulars. The 8″ is a good scope to get low objects because its tripod is higher than my 12″ scope’s Dobsonian mount and, as such, I can get at the hedgehopper objects, objects that are inaccessible with the bigger scope.

Date: 19th August 2011
Conditions: Clear at first, rising 75% illuminated gibbous Moon, dew.
Transparency: I, deteriorating later on as clouds appeared
Seeing: III
NELM: 5.9 under the gibbous Moon
Equipment: 8″ f/4 equatorial Newtonian. Televue 22mm Panoptic (36x), Televue 15mm Plossl (53x), Televue 8mm Radian (100x), Televue 5mm Radian (166x) and Televue 3mm Radian (267x).

NGC 6642, globular cluster in Sagittarius – Found easily at 36x, it is small, bright and round. Unresolved at 53x and remains unresolved at 100x although it does look slightly granular. Condenses to a bright core. Outlying halo looks granular but not resolved. 36x, 53x, 100x

Palomar 9 (NGC 6717), globular cluster in Sagittarius – You see the word ‘Palomar’ and you think ‘not easy’ but this one is not that hard, even in an 8″. However, it would be easily overlooked if you weren’t actually looking for it. Palomar 9 is right next to Nu 2 Sgr, a 5th magnitude star, and is slightly overwhelmed by it.
Pal 9 is very small round patch with a brighter, tiny, core. Totally unresolved. 100x, 160x, 267x.

I packed up at 2330 because clouds were forming, as forecast, and the Moon was getting higher. I only observed two objects in 50 minutes, as most of my targets were getting too low and had vanished behind the garden hedge.

 

‘Glorious Globulars’ – observing, 30th July 2011

We’ve had quite a spell of cloudy weather just lately here, all a bit depressing really – a friend of mine confessed that it’s the first time he’s ever had SAD (Seasonal Affective Disorder) in July – with only the occasional clear spell at night and only the odd sunbeam poking through during the day. Humans can’t, of course, control the weather or climate (putting aside anthropogenic climate change) – if we did, I’d make sure the UK had an Arizona climate! – but it’s hard not to blame the messengers, in this case the weather presenters and forecasters who smugly, it seems, inform us we’re in for yet another crappy dull summer day or cloudy night.
Last night (30th July) it cleared, sort of, and I decided to track down some globulars in Ophiuchus and Sagittarius.
I had recently dug out an 8″ Celestron scope on a Vixen GP mount, which I was given several years ago but haven’t used for various reasons (mostly because I prefer using my 12″ Dob, as aperture counts in deep sky observing). I didn’t know the focal ratio or focal length of this scope, just that it was ‘pretty short’, so I posted a photo and description on Cloudy Nights and it turns out that my scope is a 7.9″ (20cm) f/4 (800mm focal length) GP-C200 made by Celestron back in the late 90s/early 2000s. 7.9″ is a strange size but it seems that a lot of 8″ mirrors are actually 7.9″ in diameter. I’ll call it 8″ for convenience! Anyway, I decided to give this scope a fair go so I fitted it with my Telrad and collimated it after setting it up in the garden.

20cm f/4 Celestron

 

 

The evening was decidedly unpromising – after a clear late afternoon and early evening, it clouded over again and I thought the session would end before it began. Fortunately, it improved enough to do some observing, at least.

 

 

 

I got off to a slow start for various reasons but, once I’d settled my differences with the equatorial mount (reminding me why I prefer Dobs!), all was ok, apart from the endless procession of cars coming down into the village and sweeping the trees with their beams.

Date: 30th July 2011
Conditions: No Moon (New Moon), partly cloudy, 82% humidity (very dewy), 12° C (53.6° F)
Transparency: III, deteriorating to IV later.
Seeing: Antoniadi II
Equipment: 8″ (20cm) f/4 Newtonian, 22mm Televue Panoptic (36x) and 8mm Televue Radian (100x)

NGC 6426, Ophiuchus – This globular is very faint, not helped by the poor transparency. It is faint at 36x. Putting in the 8mm (100x) is not much of an improvement, so it is not surprising I did not see this with the small scopes or binoculars last week. Very faint and unresolved.

NGC 6333 (M9), Ophiuchus – Round, bright and dense with a very bright and dense core. Granular-looking at 100x but unresolved. One for a better night.

NGC 6342, Ophiuchus – Fairly bright, despite its low altitude (the transparency had improved by this time). Smaller and fainter than M9 and fits into the same field of view at 36x. At 100x, a round halo with a brighter, dense core. Slightly granular but unresolved.

NGC 6356, Ophiuchus – This is close to M9 and NGC 6342 but I didn’t see it, probably because it was too low and had gone behind the shed.

NGC 6626 (M28), Sagittarius – Very bright, quite small and round. Unresolved, although that might be due to the poor transparency. 100x

NGC 6656 (M22), Sagittarius – Large and very bright. Not round, more irregular. Mostly resolved at 100x but with a nebulous background hinting at many more unresolved stars. The overall appearance is almost that of a crab or a spider. There are dark patches within the cluster. Very nice indeed.

NGC 6638, Sagittarius – Small, moderately bright. A round halo surrounds a dense, compact core. The edges are diffuse. Unresolved.

By this time the transparency had got a lot worse, so I called it a night at 0035 BST. As I was packing up, I got to listen to a couple of women prowling up and down the footpath next to the garden. I am not sure what they were doing but I think they were looking for something, especially when I heard ‘Darling! Come to mummy!’ from one of them. Probably a cat or dog, or something. To be honest, no matter who they are or how nice they are, I don’t like people hanging around or being loud outside at night, it makes me nervous – probably a hangover from when I lived in towns and cities where it was noisy and anti-social behaviour was common – and it’s a feeling I can never shake off.
Anyway, the scope performed beautifully and is a real little gem, perfect for those nights when getting the big scope out is too much hassle or the conditions aren’t good enough and I want something more than binoculars and the tiny scopes. The coma isn’t too bad, considering it’s an f/4 mirror, and as a coma corrector won’t fit (it only accepts accessories with 1.25″ barrel size) that’s a bonus. It’s also good for putting into the car and taking somewhere with a better southern horizon. I’ll be using it more from now on.