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Sky Atlas-project sketches 2009 - Part 2

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#1 JakeSaloranta

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Posted 08 September 2009 - 09:09 AM

Obs. place: Koivukylä, Vantaa, Finland
Date: 15./16.8.2009
Bortle class: Class 5 (suburban sky)
NE Lim.mag: 5.9 (east)
Background sky: 4-5
Seeing: 2
Transparency: 4
Weather: +9.0°C, humidity ~79%, air pressure 1011 HPa, NW wind 3.0 m/s. 27% moon low in Taurus.

Session length: 3.5 hours

I started with Collinder 463 as it was still twilight. The cluster stands fairly poorly from the background and it can be difficult not to mix it with at least one obvious asterism (HD 11704-Group with a size of 24') in the region. Collinder 463 contains 12 stars brighter than magnitude 10 and roughly 50 stars brighter than 12th magnitude. A good, easy cluster for small apertures that is. The most obvious feature in the cluster I noticed was a long chain of stars to the NE. The 40mm Celestron Omni (2° 23' field) worked wonders on this cluster.
Posted Image
Cr 463 with 4.7" Sky-Watcher @ 30x

On the previous night I was unable to (properly) spot NGC 1245 in Perseus. This night was clearly better than the last one so I gave it a try. Finding it is easy - just find your way to HD 20023 and look north. There's the cluster. Suffering from clear case of low surface brightness NGC 1245 is not always easy to see. With averted vision I managed to spot about a dozen members and a faint background glow. What I found interesting was this: http://arxiv.org/abs/astro-ph/0312083. According to the 2003 paper, the actual size of the cluster is 40'! Over four times the common value!
Posted Image
NGC 1245 with 4.7" Sky-Watcher @ 60x

Stock 23 was looking good. The brightest star is 7.5 magnitude and the shape of the cluster is very unique. This might also be visible with the naked eye under good conditions. Something to try later on surely.
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Stock 23 with 4.7" Sky-Watcher @ 48x

It was time for a re-sketch. NGC 281 was high up in the sky and showed quite much detail. On a previous night I only managed to spot a haze surrounding the 8th magnitude star in the center. It was round yet somewhat crescent-shaped. Tonight the shape was much more obvious and size larger. Without filter the nebula was only marginally visible. With O-III and UHC filters it came quite obvious. I used both for the sketch and did my best to show all the detail. The faint extension to the SE was extremely difficult. It does look like a Pac-man a bit or like a comma.
Posted Image
NGC 281 with 4.7" Sky-Watcher @ 60x + O-III

/Jake

#2 JakeSaloranta

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Posted 08 September 2009 - 09:18 AM

Obs. place: Hindsby, Sipoo, Finland
Date: 19./20.8.2009
Bortle class: Class 4 (rural / suburban transition)
NE Lim.mag: 6.6m (east)
Background sky: 3
Seeing: 2
Transparency: 2
Weather: +9.0°C, humidity ~90%, air pressure 1022 HPa, no wind

Session length: 2 hours (+ 1.5 hours of travel)

Nver do squats at the gym before going for a 45 minute (one way) bicycle ride with 25 kg weights in your back. The journey to the observing site was quite something.

The most rewarding object of the night was IC 342 - a faint, somewhat famous galaxy in Camelopardalis. Wolfgang Steinicke's NGC/IC data lists this galaxy as visual magnitude of 8.4 - yammy! How about surface brightness? It is listed as 14.9 mag which makes it very faint. Compare it to some other galaxies with low surface brightness: M33 (14.0), NGC 6822 (14.4) and IC 1613 (15.1). So it is faint and when you go after it, use very low magnification. Without all of the galactic gas and dust between us and the galaxy, IC 342 would shine whooping 3 magnitudes brighter! It would surely be a rival of M33 in the northern hemisphere.

My first confrontation with the galaxy was back in 2001, on a dark night (~6.6m in Taurus) in August the 15th. I was observing from the family cabin of my good friend Eero Holmström in Pernaja. With my new 80mm (3") refractor I managed to spot IC 342 @ 32x: "A faint blob, just like described in the book by Skiff and Luginbuhl. Visible also with 40mm. Even brightness, diffuse disk. No nucleus spotted. Totally round. In a rich field. Fainter and more difficult with 8" dobson."

I was in the region again on the 10th of October 2004. I wanted to try if I could spot the galaxy from my suburban backyard with my 8" telescope. The weather was excellent: -0°C, cold breeze from north and naked eye limiting magnitude 5.9 in Perseus. My description was: "Extremely faint. Only the very core is visible, being almost stellar about 1' in size @ 76x. The halo is nearly impossible, 10' gradually fainter, slightly elliptical halo around the nucleus. A line of stars mags 11...12 visible W from the nucleus. 11th magnitude star N from the nucleus. In a rich field. Very challenging."

Tonight I was out with the 4.7". I wrote: "Tasty little galaxy. Spotted @ 23x (2° 13') as a very faint, round glow. 60x displays a nearly stellar nucleus surrounded by a bright, round halo. Galaxy slightly elliptical in E-W direction. Several 11-13 magnitude stars can be spied inside the halo - only the brightest sketched. Details very difficult and annoying. Occasionally some mottling discerned and faint spiral arms suspected.
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IC 342 with 4.7" Sky-Watcher @ 60x

Next were NGC 957 and NGC 1027. Both are good objects but did not show up well enough for my taste from my backyard. From the dark skies of Sipoo, a good amount of fainter stars can be seen in these two.

NGC 957 - 4.7" Sky-Watcher 120x: W-E elongated group of 30* mags 10-14. Two 8th magnitude stars S side of the group. Stars evenly scattered.
Posted Image

NGC 1027 - 4.7" Sky-Watcher 80x: Bright and obvious cluster of 60* N-E from a bright 7th magnitude star. Area without stars in NW. Size 15'
Posted Image

The last object of the night was G1 in Andromeda. This globular cluster is actually fairly easy to see once you know the exact position. I've previously observed it with 8" and 10" telescopes. Now it was time for my little 4.7" to do the same. Using 4mm Celestron Omni eyepiece (180x) the cluster showed up only as a stellar object.
Posted Image

/Jake

PS. Index of all sketched objects (so far) can be seen here:
http://www.kolumbus....s/Observed.html

#3 JimPie

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Posted 08 September 2009 - 11:51 AM

Very nice sketches. :bow: I like seeing those often overlooked objects (Collinder & Stock ) Your sketches of NGC 281 & IC342 show excellent detail.
Does your project include any of the Trumpler clusters? Ive found some of those are very interesting.

#4 JakeSaloranta

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Posted 08 September 2009 - 12:10 PM

Does your project include any of the Trumpler clusters? Ive found some of those are very interesting.


Jim, yes the Sky Atlas 2000.0 does contain some Trumpler clusters (I'm not sure how many exactly). I've only sketched 4 so far. Trumpler 2 and 3 are the best I've seen this season.

/Jake

#5 frank5817

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Posted 08 September 2009 - 09:44 PM

Nice work on these fine targets. Your drawings are carefully done and match the targets beautifully. :bow: :cool:

Frank :)

#6 CarlosEH

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Posted 10 September 2009 - 05:29 AM

Jake,

Thank you once again for your excellent deep sky observations and reports. The objects that you have recorded very nicely are very interesting. Thank you for sharing them with us all.

Carlos






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