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pyrasanth

M27- lets see your pictures.

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64210d1ea3a1b7331c55b5280f544326.1824x0_

That's a seriously deep one, Carole. What was the kit and the exposure?

Olly

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Thanks Olly, 

What was the kit and the exposure?

 
 
Done in two different campsites Olly and two different scopes. 
We don't get a lot of clear skies here and have to get what we can, when we can.
 
Kelling Heath star Party Sept 2014

Ha 2 x 30mins & 2 x 20 mins

RGB 2 x 15mins binned x 2
Atik314L & Skywatcher ED120 on NEQ6
 
Cairds Campsite in West Sussex
Oiii using an ED80 and Focal reducer x 0.8
5 x 900secs binned x 2
 
Carole 
Edited by carastro
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I had to go back a bit to find my last visit to M27 -  the year was 2007  - 6 hours of Ha and Oiii taken over 5 nights. I just caught a hint of the outer shell

which was as deep as I could go with kit back then, would love another try now.  Yes 6 hours over 5 nights., the skies were just as bad back then.

post-111-0-67284700-1437057043.jpg

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Hi,

A bit to late I sow this topic. Here is my Dumbell from August last year.

Aquisition was made with MN190 on EQ6/EQMOD and ATIK 314L+ mono.

Exposure in Ha and OIII - 8x1200 sec + 4x1800 sec Ha and 9x1200 sec in OIII.

post-10239-0-40028000-1437315571_thumb.j

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I'm a bit baffled by the SII photograph. This looks like you have photographed a black hole. I'm photographing in SII at present (I took 30 5 min subs last night) & I see a nice dumbell- did something go wrong in your picture?

I played around with my M27 images (DSLR RGB) and found I could get the best results by splitting them into RGB or CMYK and then recombining. When split to CMYK the cyan channel looks just like the S11 photo above. Which is really counter-intuitive as I would have said the nebula was almost cyan in colour

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Using M27 as a test case to learn how to use the GIMP. With

no guiding or background subtraction, the familiar (to Video

Astronomers) "Mark of Zorro" Hot Pixels / Artifacts remain.

But I do think I am learning something. :p

post-539-0-28588700-1438940655.jpg

FWIW: Standard exposure are 100 x 5.12s integrations on

each of UHC (luminance), Ha (Red), and 2 x OIII (B & G).

"If we knew what we were doing, it wouldn't be research"? ;)

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As a playful question: Does anyone know the VALUES of the

colours associated with H-Alpha and O(III) are in Dec/Hex? ;)

You do see quite a variety of different recipes for splitting the

pallet between RGB depending on the (assumed) "physics".

Do colours add linearly, or in quadrature (to sound clever!) :p

Maybe a "convention" is best. It is probably impossible to be

very quantitative? Just something I have been wondering...

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As a playful question: Does anyone know the VALUES of the

colours associated with H-Alpha and O(III) are in Dec/Hex? ;)

You do see quite a variety of different recipes for splitting the

pallet between RGB depending on the (assumed) "physics".

Do colours add linearly, or in quadrature (to sound clever!) :p

Maybe a "convention" is best. It is probably impossible to be

very quantitative? Just something I have been wondering...

Candidate Convention :

HA  656nm -> Hex: #ff0000

OIII 500.7nm -> Hex: #00ff87

Theory :

But then if you have lets say a 7nm (like the common Baader HA one) filter what does it mean exactly?  You get all wavelengths between 652,5nm and 659,5? I have no clue :D

Usefull links :

http://academo.org/demos/wavelength-to-colour-relationship/

which I think is based on the oldish but somewhat acceptable among physicists FORTRAN code from here

http://www.physics.sfasu.edu/astro/color/spectra.html

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Here goes the M27 with a GSO RC 6" test shots from the light polluted Athens.

RGB 50x120secs no luminance

post-39392-0-94214500-1439032156_thumb.j

Bi color HA+OIII 8x300

post-39392-0-87055600-1439032169_thumb.j

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You could try overlaying the spectral lines of this (spectral response of human eye from WP):

287px-Cones_SMJ2_E.svg.png

And then mix RGB according to the resulting amounts or R, G & B.

HA would be mostly red with a touch of green and a tiny hint of blue.

OIII would be mostly green with a fair bit of red and somewhat less blue.

The main difference is that this assigns a fair bit of red to OIII.

This would then approximate what you would see if you just viewed the filtered light, but I I'm not saying it would make an attractive or informative result.

triggers a fair response from the red cones too, but it seems the brain figures out it is not yellow by the presence of the small blue signal.

(I have found this topic fascinating for years and still haven't found a fully satisfying explanation of why violet looks the ways it does in real life, on film and on screen).

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Thanks (to most recently liked) for the above. Also a subject (colour mixing) that

has interested me ever since I began dabbling... I think mine was "a bit green"! :p

Perhaps we will never arrive at "the truth" . But plenty of food for thought...

Not least (+1), for the inclusion of a bit of venerable FORTRAN code. ;)

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excellent thread everyone! only just come upon this thread now, and i must say everyone's images of M27 are brilliant! not a target i have tried yet, but hopefully one day when i get a CCD i can post my own attempt at M27 :)

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One from 2009 when I actually did some Astrophotography,,,

Baader BCF Modified Canon 1000D on CPC 800 XLT @ approximately f6.3
Hutech IDAS P2 2" filter

33 light frames made up of...

4h 24m @ ISO800 including 3h of 30m subs
4h 45m @ ISO1600 in 15m subs

Master Flats for both ISO800 and ISO1600 Produced from 50+ random selected skyflats from 100+

Master Bias for both ISO800 and ISO1600 Produced from 50* bias frames selected at random from 100+

No Dark Frames

Crop from Full frame...

 

M27-Traditional_800.jpg

Peter...

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Back on M27 this year, here goes my last effort in narrowband bicolor with my mono e tec cooled Canon 550D:

get.jpg

Cheers,

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I have just done a reprocess of my image on page 4 of this thread, but as it's too late to amend it I thought I'd post it again.

dfda7de4eabf24b0c9098e1722ebee61.1824x0_

Edited by carastro
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Another go in h-alpha, one in widefield with the William optics zenithstar 70ED, and the other with the skywatcher 190MN.

post-30428-0-18920400-1440505939_thumb.j

post-30428-0-61610300-1440506020_thumb.j

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First light image from my Moravian Instruments G2-8300 Mono CCD, 8 x 300 Seconds R/G/B from the 12th August. 8.5" Newt on EQ8 mount.

ee0c9ed2eb60aee0cb0fc4ba2022f09d.jpg

2f7b1799bafa05c52232a327a7357c41.jpg

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