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#91
Astrophotography / Re: M51
Last post by Hugh - Apr 06, 2025, 18:05:07Very nice John ~ the larger cropped image looks a bit like a jewelled brooch 
Good to keep the smaller galaxy as well.
~ Hugh
Good to keep the smaller galaxy as well.
~ Hugh
#92
Astrophotography / Re: Lambda Orionis (little dat...
Last post by Carole - Apr 05, 2025, 15:38:40Thanks Dave, yes latterly during all these clear nights, I was imaging for less and less each night, until the last night I only managed 20 minutes before the trees encroached. Didn't want to wait another year to complete it if I could get something out of it. Obviously in an ideal world I would have got much more data.
#93
Astrophotography / Re: Lambda Orionis (little dat...
Last post by Dave A - Apr 05, 2025, 14:35:29Well done Carole
Nice image considering all the difficulties- I have trees in the way too
Nice image considering all the difficulties- I have trees in the way too
#94
Astrophotography / Lambda Orionis (little data)
Last post by Carole - Apr 03, 2025, 16:00:39Taken with my Samyang Lens 135mm and Atik460EX in HaRGB.
Been a bit of a mission as:
a) Next door's tree is in the way for half the night.
b) I get a small window between it re-emerging and then disappearing behind the final clump of trees
c) Late in the season was disappearing earlier and earlier each night.
d) Managed very little data what with it being a mosaic (as huge) and it disappearing early.
e) The ICE sftware (image composite Editor) I use for making mosaics seems to have disappeared from the internet, so had to make the mosaic manually in Photoshop.
So only 1 hour each panel (little RGB) = 2 hours.
Been a bit of a mission as:
a) Next door's tree is in the way for half the night.
b) I get a small window between it re-emerging and then disappearing behind the final clump of trees
c) Late in the season was disappearing earlier and earlier each night.
d) Managed very little data what with it being a mosaic (as huge) and it disappearing early.
e) The ICE sftware (image composite Editor) I use for making mosaics seems to have disappeared from the internet, so had to make the mosaic manually in Photoshop.
So only 1 hour each panel (little RGB) = 2 hours.
#95
Astrophotography / Re: M51
Last post by The Thing - Apr 03, 2025, 13:43:52Very. Very. Nice.
Lovely detail and colours,
Lovely detail and colours,
#96
Astrophotography / Re: M51
Last post by JohnH - Apr 02, 2025, 11:29:57
I have further cropped the image. I wanted to keep the small galaxy on the left.
(Edit) I have de-noised the tails.
#97
Astrophotography / Re: M51
Last post by JohnH - Apr 02, 2025, 11:19:13Thanks Carole,
My working theory is that simply using a Dual Band filter for Luminance would mean that some areas with detail might be completely missing because there would only be data from the narrow Ha and OIII bands. That is why I have added an arbitrary 25% of my RGB data.
For chrominance I use RGB data and a "Photometric Continuum" subtracted Ha layer. Again, my working theory is that Blue/Green data will be picked out by the OIII Luminance and the Ha/Red data will be picked out by the Ha Luminance.
For both layers I use a Masked Stretch followed by a Generalised Hyperbolic Stretch to pull as much detail as possible. I the use the Pixinsight Multiscale Linear Transform process to further sharpen the Luminance layer.
Starexterminator then gives me the subject layer and star only layer which I process separately in Affinity Photo 2 before recombining.
Obviously, some or most of this may be wrong or unnecessary
but I think that my images are considerably improved.
My working theory is that simply using a Dual Band filter for Luminance would mean that some areas with detail might be completely missing because there would only be data from the narrow Ha and OIII bands. That is why I have added an arbitrary 25% of my RGB data.
For chrominance I use RGB data and a "Photometric Continuum" subtracted Ha layer. Again, my working theory is that Blue/Green data will be picked out by the OIII Luminance and the Ha/Red data will be picked out by the Ha Luminance.
For both layers I use a Masked Stretch followed by a Generalised Hyperbolic Stretch to pull as much detail as possible. I the use the Pixinsight Multiscale Linear Transform process to further sharpen the Luminance layer.
Starexterminator then gives me the subject layer and star only layer which I process separately in Affinity Photo 2 before recombining.
Obviously, some or most of this may be wrong or unnecessary
but I think that my images are considerably improved. #98
Astrophotography / Re: M51
Last post by Carole - Apr 01, 2025, 21:19:56With the genuine tidal tails, and without the miscreant tidal tails. Well done for your perseverance. Nice image. I'd be inclined to do a separate Crop as well.
Can you explain what Chrominance is compared to Luminance and why you need both?
Can you explain what Chrominance is compared to Luminance and why you need both?
#99
Astrophotography / M51
Last post by JohnH - Apr 01, 2025, 19:02:11A fairly wide field image of M51
Approximately 7 hours 30 mins of imaging.
Luminance HaO + R + G + B
Chrominance Ha + R + G + B
Sharpstar 15028 HNT 150mm f2.8
ZWO ASI1600MM Pro
Approximately 7 hours 30 mins of imaging.
Luminance HaO + R + G + B
Chrominance Ha + R + G + B
Sharpstar 15028 HNT 150mm f2.8
ZWO ASI1600MM Pro
#100
Astrophotography / Re: IC 443
Last post by Carole - Mar 28, 2025, 14:05:39Yes, I always use a PNG on Astrobin.
Just having try to post your image from Astrobin
Just having try to post your image from Astrobin