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M103

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#1 Mentor

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Posted 28 November 2010 - 11:39 PM

My sketch of M103 as seen through my 102mm refractor has been uploaded. Finally a clear night, but humidity was high and transparency was abysmal, I rated it 1/5. Powers less than 100x showed very few stars, it was in fact quite hard to locate this cluster despite its proximity to bright stars.

M103 reminded me quite a bit of a 1/10 scaled-down version of M39. Both clusters have a distinct triangular shape framed by brighter stars. It had an attractive sparkle to it caused by a number of members that were just outside of vision. I did not depict this in the sketch, concentrating instead on the members that I could locate with certainty. One of the brighter stars was distinctly red-orange at low power, the colour in the sketch was lost when I compressed it for posting. The bright star at the northern end was a double.

Only a few field stars are plotted for context. The field was clearly richer to the NE, to the S and W was inky blackness interspersed with only a few lonely dim stars.

#2 frank5817

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Posted 29 November 2010 - 01:29 AM

Ian,

Nice report and very fine sketch.
Any night you can view and sketch the night sky is a bonus night.

Frank :)

#3 CarlosEH

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Posted 29 November 2010 - 04:45 AM

Ian,

An excellent observation and report of M103 in Cassiopeia. It is an attractive small open cluster. Thank you for sharing it with us all.

Links;
http://www.hawastsoc...ps/cas/cas1.gif
http://www.astrostev...sters_M103.aspx

Carlos

#4 Jef De Wit

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Posted 29 November 2010 - 05:02 AM

:waytogo:

#5 FrenchStar

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Posted 29 November 2010 - 07:56 AM

Well, nice sketch and nice choice of target! It's next on my target list but weather has been really bad here for the last 20 days... :(

#6 rolandlinda3

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Posted 29 November 2010 - 10:04 AM

Nice work. It is a pretty one to go after.

#7 Mentor

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Posted 29 November 2010 - 11:25 AM

Thanks for all the nice comments, but looking at this now I need to touch this sketch up.

I need to work on my scanning / compression techniques. Scans of my observing log pages range from 5-10 MB (I scan at 720 dpi). After cropping and processing the picture is 1-5 MB. I then compress this picture down to <200 kb for posting here. In the course of doing so the quality of the sketch degrades significantly. The colour of the red/orange cluster member has faded to almost nothing, and the other stars look grey to me rather than white.

Am I scanning in at too high of a resolution to begin with? How do others deal with compression? Do you compress then add colour and touch-up?

#8 lunar

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Posted 29 November 2010 - 02:03 PM

It's a great sketch! I haven't spent much time viewing it because my lists of objects are starting to pile up on my desk, this being around #50 - still a long way away, and probably not again this year unless I just take a quick glance here and there. However, you did a really nice job on plotting the positions!

#9 proud uncle

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Posted 29 November 2010 - 03:20 PM

Good sketch, IMO. Too bad the red-orange star did not come through. Otherwise, this is very similar to how I see it (except different orientation).

I need to work on my scanning / compression techniques. Scans of my observing log pages range from 5-10 MB (I scan at 720 dpi). After cropping and processing the picture is 1-5 MB. I then compress this picture down to <200 kb for posting here. In the course of doing so the quality of the sketch degrades significantly. The colour of the red/orange cluster member has faded to almost nothing, and the other stars look grey to me rather than white.

Am I scanning in at too high of a resolution to begin with? How do others deal with compression? Do you compress then add colour and touch-up?


Good questions, Ian. Once I get my scanner working, I want to start posting a few sketches here. So, I am very interested in the reply of others to these questions. M103 is a high priority target for me, and that red-orange star, in color, would be an important detail in my sketch.

#10 Mentor

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Posted 30 November 2010 - 10:23 PM

OK, I have corrected the colour of the red star. The other members are still to grey in my opinion. This is because the resolution has been dropped so much. Not sure how to fix that, or even it it is necessary at all.

Perhaps I should just make the stars bigger to begin with.

#11 JayinUT

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Posted 30 November 2010 - 11:19 PM

Wonderful capture of M103 Ian, great star placement and I like the varying magnitudes your sketch provides.

I hope you don't mind, I wanted to do some playing with your image so I downloaded your image and in GIMP played with the curves and the contrast, added some color and this is what I got. You could play with the opacity I guess, but the result here I think turned out ok. It lightened your background outside the eyepiece but I think it made the stars a little brighter.

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#12 Mentor

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Posted 01 December 2010 - 12:49 PM

That's much better Jay! I tried using curves to modify some of my earliest scans, and did not like the way that it created some artefacts with the sky background. I think the adjustments I made were not subtle enough. Your modification of my sketch looks much more like my original 5 MB image, prior to comression. From now on following compression I'll go back and play with the curves a bit to optimize the appearance of the picture.

:waytogo:






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