Archive for November, 2012

I’m Mooning again

Blog for Friday November 23rd 2012

 

This will be just a short note describing a long overdue return to some lunar observing and sketching.

A clear and bright day had me discussing with a fellow astronomer at work how we were going to take a look at the moon that night. So I was keyed up, gee’d up call in what you like. The day deteriorated weather wise the wind got up and cloud started to scud around the skies but I managed to get out and make a sketch. I settled upon Clavius the 3rd largest crater on the visible side of the moon. Seeing was horrible everything doubling up almost all of the time. I used the 6” triplet refractor, plugged in my Watec 120N+ deep sky camera, added a barlow lens to give a bit of ‘image scale’ and sketched the crater from the b&w CRT monitor in my warm cosy office, how bad is that?

I used all the pencils, paints, pastels, brushes and blending stumps that I had to hand to create this sketch:

Magnificent Clavius

Wow there is still a universe out there!

Blog Wed 21st November 2012

 

Despite a 63% Moon a clear night sky during a season when they had been very scarce was an opportunity too good to be passed by. With my quest for Hickson groups all but stalled due to the year of the poorest skies since I started in astronomy in 1999!

So I was going for Hickson’s at the top of my list, this started with HCG 1 and was followed with HCG8 both in Andromeda. I admit to seeing if HCG 90 & 91 might be possible in Piscis Austrinus, I can on occasions see Fomalhaut at -30?, this wasn’t visible tonight however and I feel my chance of getting these 2 groups maybe missed for another year from my 52? North location for another 12 months.

I did have success with HCG 1 though, after half a dozen star hops and ‘re-sync’s’ between scope park and its residence to the left of the square of Peg! I should add at this point that a 63% Moon as in the sky and not so very far to the west either. Notwithstanding, I got a view and a sketch. This is a very small & close group of 4 galaxies in Andromeda, 2 are easily identified, being larger & brighter UGC 248 & UGC 248a, mag 15.1 & 15.6 respectively, show a hint of spiral structure going on, a nice pair.PGC 1614 C & PGC1618 D members to the west were diminutive, no detail at and may 16.0 and 17.1 respectively. Nice catch considering a 63% moon 20deg away! Taking the Hickson tally to 71

HCG 8 is pretty close by but was a much harder nut to crack! I couldn’t find any identifiers in my software or literature, subsequently Sue French has kindly provided me with that information, but on the night I had to find the group by RA & DEC coordinates. The 4 members were only seen as the faintest of smudges, all members appeared elongated especially (a) which was most westerly which showed a bright core; another faint galaxy was spotted out to the east. A real challenge even for the 505mm mirror and Watec video camera! I’m not sure if it was down to sky conditions with the moon, haze and strong wind, but on this occasion this was a very difficult observation.

Mega Star screen print from Sue French showing HCG 8 region

OK with these 2 pleasingly in the bag taking the Hickson total up to 72, I moved to take a look at some brighter objects that were local to the point I was at. I decided upon a pair of interesting looking galaxies in Aries NGC 678 & 680. NGC 678 is an edge on to the NW in my sketch and sports a rather striking dust lane in its western extension, NGC 680 to the south is large round, with hints of spiral goings on, this pair actually turned out to be a triplet with IC 1730 to the NE, this is also an edge on but considerably smaller and fainter than NGC 678. I highly recommend this trio to owners of larger scopes and CCD cameras.

A fine triplet in Aries

My closing observation of the night was a large face on spiral again in Aries NGC 691, very interesting in CCD images but less so as a live video on a poor moon lit night. There was some arm detail that I was able to catch in my sketch, the triple star to the NE set a nice scene, the primary and secondary components being equal and bright the third just to the south of the western most star and apparently touching it was considerably smaller and dimmer. Due east of 691 appears a smaller and fainter galaxy again kindly identified for me by Sue French as Mac-0150+2145, again I had an unexpected bonus.

NGC 691 & MAC-0150+2145

And so to bed, not a bad night all considered, Dale

Mixing the 19th C with the 21st C

Blog Sunday 11th November

 

Simon Kidd called over to have a rough try out on the Calver relector to see if it would be possible for him to obtain an image of Jupiter through the historic beast of a telescope. Aubrey my youngest son and I had spent sometime during the cooling afternoon preparing the observatory, playing a fan onto the 12.5” mirror and running a power cable out to run the RA drive. Simon arrived about 19.30 and after a brew we got out doors under a poor and hazy sky. It quickly became apparent that we could achieve focus with the basic web came that Simon was using for the experiment, which is positive as Victorian telescopes weren’t necessarily designed with planetary imaging in mind!

What wasn’t so positive was the fact that the draw tube of the focuser is a push fit affair there is no locking screw and ring, the eyepiece is held in place by friction, however that friction won’t hold a barlow lens, web cam and filter wheel in place against gravity! We overcame this matter by rotating the superbly engineered secondary cage so the focuser was facing down wards from on top of the tube so gravity worked in our favour by pushing in and not pulling out. This position however made visual observation to get the planet on the camera chip a little more interesting!

Now this telescope was originally powered with drive in the RA by clockwork it is most likely that the star of stage and screen Will Hay upgraded this during his spell of ownership in the 1930’s to electrical drive via an early gramophone motor and belt/pulley system. The motor has recently been fully rebuilt. Adjustments to the RA & DEC position are done manually by means of large palm knobs attached to the axis via steel rods and gears. A web cam CCD chip is small, the scale of Jupiter barlowed and through a long focal length telescope is pretty large, the drive visually looks fine but under such testing it requires constant tweaking to keep the planet and camera chip aligned. We managed x4 1 minute runs, the later being the best as I became more practiced at the knob twisting role. What Simon was impressed with was the rock steadiness of the system when the filter wheel was rotated, the image barely moved, evidently this is not the case with modern telescope even on expensive and substantial equatorial mounts! Testament to Mr Calver’s design and no compromise build.

To me the image on the lap top panel looked poor and wobbly; Simon had hoped that with processing he could pull something half reasonable from the run, this wasn’t to be the case as you can see from the processed image below. We are unsure at this stage if quality is due to poor seeing, tube currents which a prevalent with the iron tube’d scope or collimation?

Any how this is a work in progress, it was fun and a great delight for Simon, Aubrey and I to be working together with the venerable old telescope.

I hope that when I write again on imaging Jupiter with the HST Calver that the result will be more impressive.

 

Dale

 

Before the Moon does show!

Blog Friday Nov 2nd 2012

 

A brief window to observe the deeper sky was taken tonight as it was clear, dark early and with the moon not due to interfere until around 20.30ut.

As has become the norm, I was intent to grab another of the 100 Hickson groups, but before I did this and as Altair (Alpha Aquilae) was a stop off on my hopping progress up into Pegasus I took a look into Mark Bratton’s excellent Guide to the Herschel Objects to see what was local. I picked up on NGC 6781 which is a beautiful mag 11.8 planetary in Aquila with plenty of exquisite detail to enjoy.  Compared to M57 the Ring Nebula in Lyra it is relatively large and faint, yet not so faint that it isn’t visible in smaller, say 8” telescopes, I feel it is more akin to the Helix nebula, though considerably smaller at 2.0′ diameter.

 At 16.8 magnitude, the central star (a white dwarf) is clearly seen just off centre in my sketch, made using the 500mm mirror, Watec 120N+ video camera of course! Sketched in pencil on white and then inverted on the computer.

No time to spare, one sketch in the bag, yeeha!, with the Moon getting ever closer to the horizon, I pushed onto Hickson 99  there are 5 members in this group which is located just SW of Alpha Andromedae (Alpheratz) in the square of Pegasus.

(A) member UGC12897 mag 14.8 is extended N-S with a star on its southern tip. (B) UGC12899 is round fairly bright at mag 14.7 with a brighter nucleus. I find (C) PGC 58 to be the most interesting, it is a barred spiral and despite being only mag 15.6 I was able to see and capture arm structure in my sketch, amazing J (D) & (E) members PGC 60 & PGC 57 respectively at mag 17.1 & 17.6 are merely tiny smudges to the south of the 3 main members.

Hickson 99

I was very pleased with this short and productive observing session, time to close up and return to the family & gardeners world indoors!

Dale

Return top