June 15/16 and 17/18 Comet McNaught etc

[Totnesdave]

A few notes from this week leading up to observation of C/2009 R1 McNaught from my garden

Date : 15/16 June 2010

Location : Follaton arboretum, good elevation, low light pollution, excellent horizons North and West

Conditions : Skies very clear

Notes : Rushed set up and consequently had issues finding and tracking, especially with some RA slop, and I note that a spirit level placed on accessory tray is *not* parallel with mount !

Bright meteor activity, perhaps six noted between 11pm and 1am, particularly one large one travelling on a line to Vega from Arcturus approx 11pm.

Saturn low on horizon, ring shadow, Titan, Rhea clearly visible, the former about 3 ring widths out, the latter half that distance, also Tethys glimpsed near edge of ring

Excellent views of M13 with resolution of stars some way into the core under magnifications from x37.5 up to x150

Epsilon Lyrae resolved 'double-double' easily at x37.5 and x75 (24mm SWA + Barlow)

Left at 1am, pressures of time, neglected to look for McNaught but it's a heavy haul dragging the gear up and down that hill.

Date 17/18 June 2010

Location : My back garden, bottom of valley, surrounding houses, garages, useable horizons to North and South, and marginal West.

Conditions : Patchy cloud at first, clearing by approx 11pm

Notes : After stripping and correcting RA mechanism earlier, and spending some time setting up fastidiously, using inbuilt CG-5 bubble for level, tracking was spot-on, targets remaining in FOV for half an hour easily

Moon very low at around 10pm, and soon dropped from view behind a tree, but excellent views of terminator, most notably emphasised features were the linked craters Catharina and Cyrilla, with the conjoined Theophilus and its central mountain.

Bright flare observed in area of sky slightly northward of Mars/Moon, possibly around 10:30 (I must learn to timestamp) lasted at most 10 seconds, brightening to a magnitude 'significantly' brighter than Venus before fading quickly over several seconds. I am thinking this was an Iridium flare ?

Mars ruddy yellowish and featureless, unlike recent weeks where a dark patch has been discernible

Saturn, heat haze notable from observing across a roofline, still observed Titan clearly near edge of ring, offset from plane. Rhea glimpsed on opposite side somewhat greater then one ring width.

At this point I looked North and spotted Capella amongst the branches of a tree (!) and I decided to see if there was any chance of viewing Comet C/2009 R1 McNaught from this rather poor location.

This proved difficult with skies plagued by blue twilight in this direction, however I did eventually spot Mirphak which gave me a starting point as I knew the comet is located 'between' them at present. This was awfully low in the sky and I was spotting over fences and using a neighbours England flagpole as a skymarker !

A binocular hunt through the twilight proved fruitless but eventually the sky darkened around midnight and allowed me to start picking out asterisms. The Sky at Night chart showed it to be near c Persei (HIP 19343), and I found a small crossed asterism here to locate, which I did by naked-eye and then binoculars giving me 'scale'.

After a few false ID's in this region using my finder, I finally noted a faint unfocussed 'star' in the line between delta Persei and c Persei which looked like a good candidate. It was ! Picking it up in my finder with the help of aforementioned flagpole, I got it in view with my 24mm SWA. (x37.5). Popping in my barlow (x75) boosted things nicely to where I could see a bright core with significant hazy coma, and a definite elongation to lower left in my FOV.

Pushing to x150 with my 6mm proved to reveal no further detail, too hazy, but a barlowed 20mm plossl (x90) gave what I felt was the clearest view through my 4-inch Apo. I'm rather short on eyepieces, how I wish I had my Hyperion zoom

I could not see a tail but skies were far from perfectly dark and I was sighting low over gardens and houses. I felt that I could discern the green colour cast, but only slightly.

Hooray

I retired at about 12.45 am feeling rather pleased, as I'm still very inexperienced at locating difficult objects and really did not expect to see the comet at all from my garden. I was glad to have taken the time on careful tracking set up which also meant I could hold the comet perfectly in view for plenty long enough to drag my wife out of bed and say "hey look at this fuzzy smudge" )

Hopefully there's a few tips in the above tale !

cheers

Dave.

[jinstan]

Excellent report, Dave. Congratulations for the success.

I could not make out the "greenish" colour as well.

Jinsong