This imaging season I have been trying to do a few things in a bit different way, and with mixed results. For example, I was quite pleased with my attempt at the Lagoon, but pure 100% narrowband Trifid was a bit of a let down.
While working on my first HaRGB image which is yet to be completed, I thought of making an attempt at revealing a tad more of the Helix. I already had 50 hours of Ha at f4.5 from last year, so I just added another 50, but this time at f6, also with my trusty 4" guidescope.
In spite of making a few attempts at putting the data together, somehow I cannot show more than what I already had last year, and I do not want to overstretch the data because IMO my overstretched Helix always looks plain ugly and flat. Perhaps the subs were too short and I should have gone for 30-minute subs or longer.
Anyway, on top of now accumulated 101 hours of Ha, I already have 30 hours of NII and 20 hours of OIII from last year, so may as well go all the way and try adding some SII to the mix and see what I will manage to cook up with all four
Thank you for looking
Suavi
Last edited by Slawomir; 09-09-2019 at 07:24 AM.
Reason: Clarity
Whilst you may feel that you have not made prof progress Suavi, there is still an incredible amount of detail in that Ha image. I admire your dedication to the task at hand.
I'm not sure that going with longer exposures will make much difference. Going longer will only help if you're not already read noise limited, there is a real chance that you're simply aperture limited at your guide scope just doesn't have the light gathering power to suck up any more faint photons.
At 100 hours of Ha, I think the result is what you're gonna be left with.... Which is EPIC!
That's the best set of outer chevrons we've ever seen. It's interesting to work out the photons per pixel per hour for some of those faintest details, which look quite grit-free in your image.
We agree that it's technically impossible with an 8 bit screen to show both the outer details and the "eye" without making it look flat. The fault is with the manufacturers of computer screens. We need 16 bit OLED screens.
Whilst you may feel that you have not made prof progress Suavi, there is still an incredible amount of detail in that Ha image. I admire your dedication to the task at hand.
Thank you Rodney. Your feedback is much appreciated.
Quote:
Originally Posted by Atmos
I'm not sure that going with longer exposures will make much difference. Going longer will only help if you're not already read noise limited, there is a real chance that you're simply aperture limited at your guide scope just doesn't have the light gathering power to suck up any more faint photons.
At 100 hours of Ha, I think the result is what you're gonna be left with.... Which is EPIC!
Thank you for your encouragement Colin. Yes, I may actually need a larger aperture. One day...
Quote:
Originally Posted by ChrisV
That's really nice. You're getting more than me. I've got 40hours on the Helix with OSC and duo filter and it's not bringing out the detail you have.
I thought your attempt at the Helix is fantastic
Quote:
Originally Posted by dave_galera
I think what you have is enough as the outer shell is showing up very very well, which is something you don't often see
Thank you Dave - I was dreaming of showing those shockwaves a bit more clearly.
Quote:
Originally Posted by Placidus
That's the best set of outer chevrons we've ever seen. It's interesting to work out the photons per pixel per hour for some of those faintest details, which look quite grit-free in your image.
We agree that it's technically impossible with an 8 bit screen to show both the outer details and the "eye" without making it look flat. The fault is with the manufacturers of computer screens. We need 16 bit OLED screens.
Superb.
Thank you Mike and Trish. I use your Ha Helix as a benchmark, as your Helix shows everything so well - data and processing both are top notch.
I think I previously estimated that the outer shockwaves register only one photon per pixel per hour of exposure with my 4" guide scope-camera combo, but will check that estimate later.
Maybe I should chuck in another 50 hours of Ha with longer subs Just as a modification to the original experiment
As mentioned elsewhere, that's an outstanding result Suavi, even deeper than my previous effort and the extra integration time has yielded some wonderful extra details.
Failed. Yes Suavi, it's awful. Terrible. Waste of 100 hours. You should permanently delete all this data. Geez, I wouldn't even show this here at all. Embarrassing.
Please, delete - for the sake of humanity - all the data. NOW!
Wasze biczowanie jest głęboko dramatyczne. Zdjęcie jest niesamowite.
Perhaps I was expecting too much of an improvement in the data with extra 50 hrs.
Well, seeing what you've got at the 100h mark I'm thinking there's bugger all chances to get much more with that rig by even doubling the time. Convinced me that you need a RASA or hyperstar setup to go any deeper and stay practical with integration time. I tried from home but was limited by skyglow after 25h and that was with 7nm. You hit it with 3nm. There's no hope for us all. Next time I try it I'll block 1 week somewhere very dark and keep at it.
That's the best set of outer chevrons we've ever seen. It's interesting to work out the photons per pixel per hour for some of those faintest details, which look quite grit-free in your image.
We agree that it's technically impossible with an 8 bit screen to show both the outer details and the "eye" without making it look flat. The fault is with the manufacturers of computer screens. We need 16 bit OLED screens.
Superb.
Thank you again Mike and Trish.
The faintest distinguishable bits in the long bows/shockwaves are just 1 ADU above the floor (this is an average for a number of pixels on those fainter parts of the long bows).
Since my camera's gain is 0.16e per ADU, therefore one registered photon makes an increase of 6 ADUs, unless I got it the wrong way around.
Since the image is a result of combining 15 and 20-minute subs, it seems that there is one photon per 1.5 to 2 hours of exposure that are being registered by this telescope-camera combo and that we can just notice in the total of 101 hours of integration.
Quite fascinating, given that we are taking amateurs having fun from their backyards. Or my maths is incorrect
Well, seeing what you've got at the 100h mark I'm thinking there's bugger all chances to get much more with that rig by even doubling the time. Convinced me that you need a RASA or hyperstar setup to go any deeper and stay practical with integration time. I tried from home but was limited by skyglow after 25h and that was with 7nm. You hit it with 3nm. There's no hope for us all. Next time I try it I'll block 1 week somewhere very dark and keep at it.
That's a very deep Helix Marc You are now tempting me - I keep dreaming of an F/3 10" quality Newtonian...
over here 
, but more seriously, I was really expecting a more noticeable improvement.
" or "This image failed to render me unconscious....I merely fainted" 
