OSC - Quad Band Filter
Stacking program, astrometric (plate) solver, fits file viewer
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Han - First off, awesome product and customer service. Brilliant.
Am using a OSC qhy 168c with the Altair Quad Band Filter. https://www.altairastro.com/altair-quadband-osc-ccd-2-inch-filter-321-p.asp
Asking for your assistance/recommendation in how to pre-process it. I typically calibrate and stack in ASTAP, then monkey about in PI & Photoshop. But this a quad band filter and would like to get HA, O3, S3, HB, extracted or something so that I can post process. I'm not sticky just any recommendations from you to best use your product in this case.
Thank you.
PS - just downloaded ASTAP version that came up a few hours ago. 0.9.377
tchalla
Hello Tchalla,
Yes those new filters are interesting.
You could split the red, green, green, blue channel in batch processing in the tools menu of the viewer.
Viewer:
Tools,
Extract one Bayer matrix pixel position from raw OSC images
select 11, 12, 21 or 22.
Two of the four exported series will be for green since there are 2 green pixels in the 2x2=4 bayer matrix. The program doesn't use your debayer setting for splitting. It just split the 2x2 bayer matrix and indentify them as 11,12,21,22.
I assume you could also just stack them as normal colour images. Probably debayer method Simple (=AstroSimple) would work best. You should switch off option "Autolevels" since it will be impossible to get white stars and gray background. Also switch off "Colour smooth". See attached image. Probably binning the result 2x2 will improve the result.
I you provide me with a test set, it could use them for futher experimenting with ASTAP.
Clear skies, Han
If the nebula only contains red so H-alpha then colour stacking doesn't make sense. The green and blue channel will only add noise. Then stacking the red channel only is the best option. With some experimenting you will find out which one is the red channnel having signal. Either 11, 12, 21 or 22.
Han
cool. lemme attached 1 file
this is a light no flats or darks.
I got the image. This is a reflection nebula. I'm surpriced it comes through the filter. Will have a look tomorrow.
I will remove the image from the forum. Takes too much space.
Han
awesome. looking forward to your results and recommendations.
Matthew
On Fri, Jun 19, 2020 at 12:51 PM han.k han59@users.sourceforge.net wrote:
Till my surprice it is possible to create typical normal colours. Have you tried the filter on typical h-alpha emitting nebula?
Last edit: han.k 2020-06-20
Am new. Still learning which DSOs emit stuff that I cna pick up. Is there a list of H-alpha or O3 or anything like that I can use to then determine which targets to shoot with this quad band filter?
Oh, I've got a master dark, master flat, and more lights if you want to process it some? If so, do you have a recommendation where I can send it/store it for you?
Han - Here is the link for Master Flat, Master Dark, & Lights. Am
interested, very very interested, to see what you come up with and
especially your explanation of your process.
https://drive.google.com/drive/folders/16d71czDh7L2TtAGMrtbkmPe4X-q6GZ54?usp=sharing
Matthew
On Sat, Jun 20, 2020 at 7:35 AM matthew tchallaaoc@users.sourceforge.net
wrote:
I'm experimenting with the data. Have an unexptected run time error I can't explain at the moment. I will work on it.
It's a pity it's a reflection nebula. They are blue tintend. Only maybe a few percent of the nebula. Therefore the nebual will be faint. You better try something with H-alpha (red) or OIII (greenish) E.g NGC7000 or NGC6960, NGC 6992. The Sharpless-2 catalog is a good list but even that contains a few reflection nebula
Han
Fixed the runtime error and will upload an update.
Attached the stacked result. The nebula doesn't contain really H-alpha or OIII so I assume it is displayed faint.
The background was equalised using pixelmath 1, equalise background tool.
As soon you have a series made of a nebula with strong H-alpha signal and OIII, I'm interested to test the series. Maybe M27 is ideal since it has both. Or NGC6960, NGC6992 have both.
Han
2 or 3 stars shapes are not ideal . I didn't try to fix that. Probablly shorter exposing will help.
Han
Looks good! I'll checkout sharpless 2 catalog and find better suited
objects. Once done, I'll send you data again.
May I ask what the steps you took to get the jpeg you sent?
Matthew
On Sat, Jun 20, 2020 at 1:17 PM han.k han59@users.sourceforge.net wrote:
I just used the standard stacking to colour
Method: "sigma clip average"
pattern RGGB
debayer method: AstroSimple
"Convert OSC image to colour" checked
Auto levels" checked
"Colour smooth" checked
Cropped the resulting image a little with viewer popup tool "Remove borders"
A part of the background was red polluted by light pollution. Applied from pixel math 1 "equalise background tool. " In that process step 2, I removed some background by the viewer popup tool "copy paste tool".
Saved the result to jpeg, compression 70%
All standard, I use this workflow for most images except that my own camera is monochrome.
Han
Last edit: han.k 2020-06-21
Thanks Han!
On Sun, Jun 21, 2020 at 1:52 AM han.k han59@users.sourceforge.net wrote:
Am curious whicj camera you own
On Sun, Jun 21, 2020, 11:20 matthew, tchallaaoc@users.sourceforge.net
wrote:
I have an ASI1600MM-Cool from 2016.
Last edit: han.k 2020-06-29
That 1600mm pro seems to be in use by alot of ppl
On Sun, Jun 28, 2020, 23:28 han.k, han59@users.sourceforge.net wrote: