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Old 16-02-2008, 05:45 AM
你B
Its only a column of dust

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Observation report 16/2

Now, Melbourne and Clear sky are not things that go hand in hand. However for once, this morning was an exception. Sort of. I actually cleaned the 10" dob's mirror before going out and while I successfully got rid of most of the crud that was on it, I was left with a smokey haze covering the surface. Now I dont know if its always been there, cloaked by the layer of crud, or if its from some reaction of some substance on the mirror with the washing, I dunno. If you shine a flashlight down the tube its very disturbing. Oh No! But luckily, my fears were unfounded. Aiming the tube at a ceiling light renders the haze basically invisible, you wouldn't know its even there!

Set the scope up at around midnight and left it to cool for a 1am start. So far, that infamous Melbourne low cloud was nowhere to be found. Wow. Transparency was good and seeing was shocking. After collimating, I checked Saturn at 156x and the seeing was horrendous. I couldnt focus. I then swinged over to Regulus and that just confirmed it. Yuck.

Anyway I was keen to see if my mirror clean (or that haze crap ) had any affect on the views.

Scope: 10" GSO dob
Time: 1.30am-3.30am
Seeing: 2/10, 4/10 later
Transparency: 3-4/5

IC2948 Running Chicken Nebula
UHC filter greatly improves visibility of this cloud. Tried it with and without the filter using the 17mm Vixen for 73x. Without filter I spotted a faint band of haze running NW-SE along the northern edge of a chain of stars centered on V871. The filter and the 17mm showed an arch like structure looping around the aformentioned star chain in a SE'ly direction. Using the 22mm LVW and the UHC provided the best view, with a thick cloud surrounding the star chain.

Eta Carina Neb
17mm + UHC = FREAKIN OUTRAGOUS!!! Amazing, detailed complex - infact I'd say it was my best view I've ever had of this in my scope! The two lobes of the Homunculus were resolved at 73x. Even without the filter, the nebula appeared better defined than any view I had previously. Maybe that cleaning job did do the trick...

Homunculus Nebula
During a moment of steady seeing, the 10" at 192x showed an awesome pair of complex lobes. The edges of the lobes appeared somewhat jagged. But the seeing was too shoddy to be able to see this level of resolution often.


GUM 39
Faint but visible with the UHC in the 17mm LVW. Has an elongated E-W form. Its neighbour IC2872 remained invisible.

GUM 15
Suspected nebulosity at 56x with the UHC but uncertain.

Omega Centauri
My 8mm LVW needs a really good clean so I barlowed the 17mm for 147x. Really cool, whole FOV littered with tiny pinpoints, surrounding a huge snowball made of sugar. Saw the "owl eyes".

NGC 3115 Spindle Galaxy
Using the 22mm it looks like a tiny shard of light. Increasing power to 147x via the 13mm LVW and 2x barlow, the 10" showed a stellar nucleus with a central bulge with a shard of light protruding outwards from the core.

NGC 4945
Large almost edge-on spiral galaxy best seen at 96x using the 13mm LVW. Elongated, thick smudge of light. The SW end appears to better defined than the NE end, due to obscuring dust clouds within the latter. Spotted the small elliptical galaxy NGC 4976, it showed a stellar nucleus with a faint surrounding haze. Also tried for nearby NGC 4945A and ESO 219-22. Neither were seen.

NGC 5128 - Centaurus A
Surprised by how large this galaxy appears. A mag of 192x bought out a massively thick dust lane and two "hamburger buns" with 4 stars involved. Some 'nebulosity' visible within the dust lane using averted vision and careful concentration.

Saturn
By now it was 3am and seeing had improved. I barlowed the 17mm for 147x and was rewarded with one of the best views of the planet yet. Even though seeing was still pretty poor, the Cassini Division and the Crepe Ring were so easy, more obvious than daylight. Upping the mag at 192x bought its rewards during those rare moments, the Crepe Ring was a slate grey etched against the black sky with razor sharp definition. The Cassini Division was as well defined as I had ever seen it in this scope. It was visible slightly beyond the ringtips. Atleast 2 cloudbelts were clearly visible on Saturn's globe. Looks like the mirror cleaning really did improve contrast here.

Ok, now I decided to go back to Centaurus and hunt down the Centaurus cluster. When I pull away from the eyepiece to check the starchart, I happen to look up and almost suffer a cardiac arrest. A Melbourne climate cardiac arrrest that is. Lets see, UNFORECASTED LOW CLOUD, you know that crap that occupies Melbourne skies 99.999% of the time was moving in. WTF? Honestly WT bloody F? I thought that when we have northerly airstream like now, this freaking Melbourne cloudy grrrrrr wouldnt be able to spoil YET ANOTHER NIGHT. But YET A-FREAKIN-GAIN this most pathetic of climates has killed another night. Now there wouldve been over 1.5 hours of good viewing left.

Before Melbourne's crap weather ruined the night (again), I can see that my mirror clean made a difference. Never has the Eta Carinae looked so good, the Running Chicken Nebula seemed to be bigger and brighter this time round and as for Saturn, I have NEVER seen a better view in any other scope. Man I love this scope
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Old 16-02-2008, 07:09 AM
Dennis
Dazzled by the Cosmos.

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Nice write up – I enjoyed it immensely, thanks!

I was told once never shine a torch either on a mirror or through the objective of a refractor – what you will see in even a clean instrument will scare you unnecessarily!

Cheers

Dennis
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Old 17-02-2008, 11:21 AM
你B
Its only a column of dust

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Thanks Dennis Today officially marks the end of the new moon season with the thing setting at 3am. Gonna go out tonight and get those last 2 hours in before morning twilight.

So yer, will do some Saturn observing, followed by some roving in Virgo and Centuarus Galaxy fields and then finish off with the Eta Carinae complex and jupiter
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Old 17-02-2008, 12:51 PM
Karlsson
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Interesting report - good stuff!

Quote:
Originally Posted by Dennis View Post
Nice write up I enjoyed it immensely, thanks!

I was told once never shine a torch either on a mirror or through the objective of a refractor what you will see in even a clean instrument will scare you unnecessarily!

Cheers

Dennis
Suiter writes in 'Star Testing Astronomical Telescopes' (p.168): "Don't decide to clean mirrors on the basis of shining a light down the tube at night. All mirrors fail such a harsh inspection"
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Old 17-02-2008, 01:16 PM
你B
Its only a column of dust

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YerI know but when I had it out it was basically covered in dust, hairs and other crud. It needed a clean...I believe Saturn was actually more contrasty now than before the clean.
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Old 17-02-2008, 05:18 PM
你B
Its only a column of dust

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Here's a sketch of NGC 3115 and 5128:
Attached Thumbnails
Click for full-size image (spindl.jpg)
64.2 KB16 views
Click for full-size image (5128.jpg)
65.5 KB19 views
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Old 17-02-2008, 06:51 PM
Dennis
Dazzled by the Cosmos.

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Very nice - these drawings and notes are excellent and seem a terrific way of documenting one’s observations. By comparison, my images are quite lifeless and sterile. LOL!

Cheers

Dennis
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Old 17-02-2008, 08:12 PM
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JethroB76 (Jeff)
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Does anyone have an electronic copy of the observing sketch/log like that one?


**Ok I've found a similar one in the IIS files library**

Last edited by JethroB76; 17-02-2008 at 09:31 PM. Reason: found one..
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Old 18-02-2008, 07:28 AM
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goober (Doug)
No obs, raising Harrison

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Quality sketches, SAB. 5128 - you've picked up the glow within the dust lane as well... I often see the star, but rarely (never?) have seen the nebulosity within the lane.

Good report. Your meteorology is really coming along, too!
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