3.58
#...
·
 |
|---|
|
I took this image of FlameNebula and Alnitak, but can't get rid of the incredible blodge around Alnitak, which stems from the filters used. Any idea how to get rid of this artefact in Pixinsight? Image was taken on an 11" EdgeHD with L-Enhance OH and Askar OS dualband filters on an ASI2600mc OSC. Integration time 2h15, flats taken that night. https://www.astrobin.com/8869xz/  |
0.00
#...
·
|
|---|
|
The Askar NB filter is most likely causing that, much more than the Lpro. I had a filter that had similarly severe haloing and returned it. Here’s a link to a tutorial of how to eliminate halos in PixInsight. https://digitalstars.wordpress.com/2019/10/27/tutorial-how-to-eliminate-star-halos-in-pixinsight/ If you have PixInsight and StarXterminator, you can try StarXterminator and use the "unscreen" stars option. You might be able to use clone stamp and some other tools to clear it up after that. Searching for, “how to remove halos in PixInsight” or “…from Astrophotos.” Etc should turn up addition info in forums and YouTube. I’ve never tried to remove a halo that severe so I’m not sure how well any of those methods will work. |
|
3.58
#...
·
|
|---|
|
Thanks a lot for the tipp - and the insight that the Askar might have caused it. Its somehow escalated during GHS stretching and was too tough to fix it with clonestamp process or colormod script. StarXTerminator also is already in use - so I might be scratching the barrel :-) BTW: Do you understand, why some filter create stronger blodges than others? Arny |
7.56
#...
·
·
2
likes
|
|---|
|
That tutorial isn't going to help you. I described how to in another thread. Here: https://www.astrobin.com/forum/c/astrophotography/deep-sky/help-with-new-light-areas-in-narrow-band-subs/ |
|
0.00
#...
·
·
1
like
|
|---|
Arny: https://www.researchgate.net/publication/377357274_Understanding_Filter_Induced_Star_Halos Thinis the most detailed explanation I’ve come across. Filter off band blocking performance, reflections within the filter, filter thickness Andrea posted a link to their tutorial. That’s probably going to be you’re best solution. I’m not aware of anything that will work better. |
2.11
#...
·
|
|---|
Arny: Despite what everyone else is saying about filters, ontop of those, that's just the internal reflections from the EdgeHD optical design. To get rid of these from this point on, you'll need to either flock the telescope with flocking paper, or buy some vantablack paint to coat the insides of the tube & the T-Adapter/baffle with. This is an issue with all SCT's when dealing with bright stars, that reflections can occur. Alternatively (wouldn't be my pick) you can sell the 11 and go for a similar optical system that does not use a Schmidt Corrector Plate. |
|
0.00
#...
·
·
2
likes
|
|---|
V.M Legary:Arny: I definitely agree that the Edge HD optical system can be prone to those issues. I have had them with my Edge 11 myself with running the Hyperstar config (my understanding is that faster optics are also going to have a greater impact) with an Antila highspeed filter which was absolute trash. Not only did it have harsh haloing, but also caused internal reflections. This issue was eliminated by swapping it out for an IDAS UHS filter and haloing was minimal. Results may vary. |
|
2.11
#...
·
|
|---|
| Precisely, IDAS UHS is a really good filter. I'm wanting to get one myself, but I don't really see the benefit in Bortle 3. |
|
0.00
#...
·
|
|---|
V.M Legary: If you have a Hyperstar / OSC, then the IDAS UHS would be my goto recommendation. If you’re imaging at f7 or f10 then I’d look at a mono camera and 3nm bandpass NB filters. (I use a OSC and Optolong Extreme.) I believe the extreme in 5-7nm but don’t remember. I’m in a Bortle 7 | SQM about 18+. Although the IDAS isn’t going to be as effective as a 3nm it should be drastically better than nothing or a standard LP broadband filter when used on emission nebulae. On the lower end, I think Optolong recently came out with the l-ultimates that have a 3nm bandpass in Ha an Oiii. They claim that it has virtually no haloing on 52 Cyg / Witches broom, but I don’t have any 1st hand experience. Ideally we’d all have Chroma filters. |
|
2.11
#...
·
|
|---|
|
Ah, I'm shooting off the ASI2400MC Pro at F/10, easy peasy to be honest, 5.94um pixels are a perfect match with my HD8. Don't really care about mono too much yet due to a lack of a mono sensor that is at true parity with the 410 chip (6200 doesn't even come close to the numbers the 2400 puts out despite being very impressive in its own right.) I'll wait for my SCA260 and an IMX544DQ C/M Astrocam to release unless APS-C NIR-SWIR cameras become available under 10 grand. I'll buy one of those instead  |
|
0.00
#...
·
|
|---|
|
I use the same OSC. Great pixel matching at f10/7 imo. Looking at 6200MC or MM for Hyperstar and my ES 152 APO. What do you mean by, 6200 doesn’t some close to the numbers…? I thought that the 6200 would be better for lower FLs, has higher resolution and bit depth. It has lower full well than the 100k e, but that’s due to pixel size. I thought the only downsides were price, large file size, and fullwell depth. |
|
2.11
#...
·
·
1
like
|
|---|
I use the same OSC. Great pixel matching at f10/7 imo. Looking at 6200MC or MM for Hyperstar and my ES 152 APO. Yes, it is better for lower FL, but the ADC is the 16 bit part, the sensor output is still 14 bit. The resulting effect is similar in value to the overall system as stacking drizzle 2x on bin 2x data is to SNR. Superficial. Until you get a sensor with a 16 bit dynamic range output a 16 bit ADC does you no good. The 2400's sensor should've used a 16 bit ADC since its DR is electronically limited by the ADC. |
3.61
#...
·
·
2
likes
|
|---|
|
Hi, A very efficient way to limit the blodge is to use the Ha layer as luminence. Halos are much more sever in the Oiii band pass than they are in the Ha band pass. Besides, as the Ha provides nice details when used as luminence. You want to linear fit Ha and Oiii to get nice colours. However, Ha a luminence is incredible for emission targets, simply because the signal is stronger. See my own image of the same object: https://www.astrobin.com/144eyd/ Clear skies, Patrice |
