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I scrapped all the Oiii and Sii data I previously took during a full moon (about 15 hours worth) and retook it all when the moon was a bit smaller at 76%. Ha was taken during 98% and 67% moon. All the lights were taken on the following nights: 12th, 19th and 20th September 2019.
Integration times, all in 600s subs unbinned:
Ha = 28.33 hours
Oiii= = 5.67 hours
Sii = 5.67 hours
The Ha data is really nice, and unsurprisingly the Oiii and Sii is not as strong (or nice).
I'm missing that (vital) step in my processing routine of getting the Sii and Oiii properly stretched to match the Ha, before combining. I dont really know how to deal with the weaker data properly. Any pointers would be appreciated.
What I do currently:
All the data is loaded into APP into separate channels/sessions.
The data is stacked and registered against the best Ha sub
This produces individual stacks of Ha, Sii and Oiii that are all registered
Each channel is processed with DPP in APP and then saved as a 16bit TIFF
Each is opened in PS
Stars removed with AA and any remnants removed and tidied up
I then open a blank RGB document in PS
I paste Ha into Green, Sii into Red and Oiii into Blue
Adjust the selective colour settings to get 'Hubble palette'
Adjust levels, curves, saturation until looks ok
All the Ha Sii Oiii data is then combined together in a single 'super' stack in APP using quality weighted algorithm to create a 'luminance'
That luminance layer is adjusted using levels, curves, and NC tools such as local contrast enhancement and deep space noise reduction (using masks to apply as required)
The luminance is pasted onto the above colour layer, and incrementally added using gaussian blur
Cropped and saved.
Here it is anyway I haven't intended on any more exposure time for this one, but will consider it, if the expert opinion dictates otherwise!
I own a Vixen ED-80 refractor which is used with a custom focuser by Telescope Service.
A Celestron f/6 SCT reducer corrector did not provide decent images either because it is not appropriate or because I did not maintain the correct distance.
I am thinking of buying the Sky-Watcher .85x Reducer/Flattener instead, as it is made for similar ED80 telescopes.
I do not know what is the correct distance of the SkyWatcher reducer for my setup and more important, I do not know if it will focus with the custom TS focuser.
Do you have any similar setup that you have used successfully?
i seem to have a dirty lens on the telescope side of the lens.
Anyone disasemble this before ?
I already checked the camera, filter, and focal reducer seperatly, the "staines" are from the telescope-side of the lens (already cleaned the outside of the lens to)
So then, just as i thought the DSO season was well and truly over for me until late August/early September, as it turned out last Saturday night (May 5th) was mostly clear, so i set about trying to finish the NAN image i had captured in Ha a while back (see thread below):
So all i needed was some OIII. It's obviously not the ideal time of year to capture this i know, as it's so low on the horizon, but beggar's can't be choosers so i tried my best to make the most of the small amount of astro dark time available and just make the best of it.
In the end i managed 9 subs, two of which were sub-standard due to passing clouds, but as is my want these days i still asked APP to stack them (using the Quality setting) and it didn't seem to affect things. So in total this is:
Ha: 7 x 480s, 6 x 1200, 13 x 1200 (a little over 7 Hrs)
OIII: 9 x 1200s (3 Hrs)
RGB (with IDAS-D1 filter): 20 x 60s
The usual Flats & Bias, stacked in APP and processed in PS.
Gear used: Nikon D5300 (modded); SW 80ED (510mm FL); HEQ5-Pro; SGPro and PHD2.
The RGB subs were used solely for the stars. I still need to get better at merging them with the NB channels, i'm not as good as i'd like to be at controlling them. Although in this instance, i did mask the stretching of them, and it definitely helped, but i need to practice this to get better at it. I think the fact that the RGB stack (even at just 20 mins) contained some nebulosity didn't help things. When it's just stars and nothing else, it's so much simpler to combine them.
So this is just a Version 1 for now (i'll try an sSHO next). I used Ha for Red, OIII for Blue, and used one of Carboni's Actions to synthesize the Green channel. Then went round and round in circles trying to find a colour balance to my liking (on my rubbish monitor!) so i'd love to hear what you guys think. Too dark? Too much saturation? (i tend to do that, lol). I also couldn't decide on orientation, so have included two different ones. Which do you guys prefer?
All C&C welcome. Don't hold back! I'm always looking for ways to improve.
Already spent my Christmas money, and then some. Ordered a William Optics GT81 APO triplet f/5.9 with field flattener/reducer that makes it f/4.7. It has a 2" 1:10 Crayford 2-speed focuser. Now, I'll be able to image at f/4.7, f/5.9, f/6.3, f/7, and f/10, depending on what I want to shoot at.