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Observation Report: 7 January 2007
Location: Melbourne
Time: 10pm - 12:40am
Seeing: 4/10 early, 7/10 late
Transparency: 7/10
Conditions: breezy early, still late, cloud in the south and west.
I received my 6:1 fine focuser device today, and installed it onto the scope. Mid year I found the F5 scope to have a very narrow cone of focus, which was tricky to nail, especially on Jupiter and the Moon. My cheap and nasty solution was to bolt a focus lever onto the focuser - it worked, but on a balanced alt-azimuth mount it was too easy to move the scope tweaking the focus lever. Hopefully the fine focuser will help here.
I continued to work through my list of summer objects - Messier clusters, doubles, a few old favorites, and a curly one SAB threw in yesterday (one of the reasons I love reading other observation reports - gives me new targets to chase).
The focuser worked a treat. It's a chunky beast that looks rather odd, but who sees that in the dark.
Unfortunately I forgot to take my pen outside, and didn't want to ruin my dark adaption - so this is from memory and five hours sleep.
Double Stars in Orion - I did a quick tour through the Orion double stars I'd been observing lately, to check the seeing. Early on, it wasn't great, and the scope wasn't cooled yet. Lambda Orionis - nice easy multiple star system - four stars seen, all looking rather white. Rigel - the faint companion seen at 105x, but not the best view I'd had of it. Eta Orionis - a poor, but resolved split at 270x. Alnitak - this always looks very similar to Eta Orionis - again split at 270x, but poor seeing. 32 Orionis - tight double, could tell it was a double at 270x, but touching in a figure "8" pattern. Couldn't be bothered going back in for the 3.5mm eyepiece to see what 385x would do.
Sirius - hey, it's bright and right there. No sign of Sirius B.
Beta Tucanae - nice easy double at 22x. A white pair of stars of almost the exact same magnitude. A really nice view through the eyepiece.
Lambda Tucanae - listed as a double in the Pocket Sky Atlas, but I was a bit confused by this one. Seemed to be a triple star - two bright wide stars, with a much fainter companion tight against one of the bright stars.
Kappa Tucanae - a tight white/gold pair cleanly split at 105x.
Gamma Volans - easy naked eye star - gold stars split at 77x
NGC 1261 - globular cluster in Horolgium. Took a bit of locating, as there was no naked eye stars nearby. It's tricky to star hop with a 1x finder and viewing through the 3 degree eyepiece (the star images are flipped with respect to the atlas). I usually print off corrected finder charts for targets I expect to struggle with, but had forgot to here. Still, after 5 minutes I had it - quite easy even from suburban Melbourne - bright smudge next to an 8th magnitude star. Best views at 77x and 105x, but nothing resolved in it. The light from the cluster appeared lumpy and uneven, and after a while it appeared to be an almost triangular shape to the core. I also spent a bit of time racking the focuser out until the cluster and nearby star were the same size - they appeared to be identical, so I expect this cluster is around magnitude 8-9.
M93 - open cluster in Puppis. Bright cluster, almost layered in appearance. Gave me the impression you could up the magnification and drill into it, finding more clusters of stars inside - weird effect. Nice arcs of stars branching off it.
M46 and M47 - viewed in same field at 22x. Contrasting open clusters - M46 is a lot larger and made up of much fainter stars. M47 seems to be around half the size, and has around six quite bright stars accompanied by fainter stars.
M48 - open cluster in Hydra. I'm writing this from memory and I don't remember much about this one. Unremarkable smattering of stars. I think this is Messier's "missing" cluster - and this was the best solution to the mystery. I'll revisit with my pen and record a better impression of it.
M50 - open cluster in Monoceros. More compressed and more pleasing than M48. Nice cluster.
NGC 2440 - planetary nebula in Puppis. SAB reported on this yesterday, so I printed off a finder chart and went after it. I found it much easier than I was expecting - I should have more faith in my 4" from Melbourne. It's only a few hops away from M46/M47 - bright and obviously non-stellar even at 22x. It took power really well - 49x and 77x showed a planet-like misty disk. 105x and things started to look rather lop-sided. I popped the DGM narrowband filter in, and viewed at 270x. The view was impressive - the nebula held its brightness - obviously elongated, with slightly uneven brightness across the object. Slight tinge of blue to the predominately grey colour.
Mars - it was past midnight and the seeing had settled down nicely. With the scope balanced at 270x, I swung down to Mars for my usual disappointing view. Wow! Rather nice, with Mars looking red and ruddy. Lunar eclipse ruddy. Obvious large dark triangular marking over the surface of the planet. I couldn't work out why the sudden and dramatic improved view of the planet, compared with all the washed out pale pink views I'd had over the past month. I then remembered I still had the narrowband filter in place! I'm not sure in terms of the physics exactly what I was doing, but I was impressed with the planetary detail I was seeing through the filter at 270x. I whipped the filter out and sure enough - pale pink Mars was back, but I could see the triangular feature albeit with much less contrast. I need to research this happy accident.
Sirius - returned to Sirius with the much better seeing. Rock steady star at 270x, but no sign of the Pup.
Castor - double star in Gemini. Nice bright double that required 105x to split.
Omega Centauri - I was dragging the scope back inside and noticed that Centaurus was up and the king should be in view. I still had the 5mm in so did a rough sighting and swept it up quickly, low in the south east. I was impressed, even low down I resolved stars right across the face of it. Amazing object, even in 4". I swept north for Centaurus A, but couldn't find it.
Saturn - just heading inside when I noticed a bright star out of place near Regulus. Had a quick look at 105x and it was Saturn. Okay, I should have known that, but Saturn had been under my radar. Even just clearing a neighbour's house, it was a nice view. Rings are closing right up, no sign of Cassini. Pleasing first view of the season.
Good session, lots of boxes ticked. The fine focuser is a vast improvement on the focus lever.
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Let's hope we have seeing to match. Should be good as there's no jetstream anywhere near Victoria.
