This image capture came out fairly nice. Of course, I had to throw away some subs after my ASIAir suddenly stopped working a third of the way though (after 21, 5-minute subs) one of the most solid tracking runs I've ever had! Of course. Why should I expect things to go smoothly -- ever? 🤣 After I went back to square one and started up the run again, the tracking wasn't as solid, but it wasn't bad.
I find it odd that this nebula doesn't have a name! I think a lot of people (on YouTube, anyway) refer to it as the Flaming Skull Nebula, which is actually different and is designated Sh2-68 and located in the tail of Serpens (Serpens Cauda) rather than Cepheus. When NGC 7822 is imaged together with a small round nebulosity designated Sh2-170, it makes what some refer to as the Question Mark Nebula. (I was going to try getting the question mark but I would have been forced to use my manually focused 200mm lens. I've gotten VERY spoiled by my electronic auto-focuser!)
Does anyone else see an image of a calf in the center of NGC 7822, just above the bright star-forming region? Maybe it's just me...
This was my first test of an Antlia ALP-T dual narrowband filter and with an 82% illuminated moon it did very well, indeed!
AT60ED w/ field flattener (360mm fL)
ASI2600MC Pro (OSC camera)
SkyGuider Pro with guiding via ASIAir Plus using an ASI120mm mini and a 30mm F4 guide scope
Antlia ALP-T dual-narrowband filter (H-alpha, O-III)
First run -- 300 second exposures x 21; Second run -- 300 second exposures x 30: [Total exposure time: 4:00 after tossing out a few subs]; with dark, flat, and dark-flat frames
Stacked in Siril (as an RGB image, not as narrowband) and post-processed in Photoshop
Greg
Nice. I do see the calf, though I had to go back and read your description of where it is. It's facing to the upper left and show only the head, front shoulder and part of a front leg. There is also a hummingbird with a crooked beak to the upper right of the calf which you have to view with the image magnified.
I see that there is some fine detail in some of the higher contrast features. It would be interesting to see the results with less noise suppression. A matter of personal preference of course. I don't mind seeing a little graininess in a nebula, it tends to keep the overall contrast a little higher in the low contrast areas.
Nice. I do see the calf, though I had to go back and read your description of where it is. It's facing to the upper left and show only the head, front shoulder and part of a front leg. There is also a hummingbird with a crooked beak to the upper right of the calf which you have to view with the image magnified.
I see that there is some fine detail in some of the higher contrast features. It would be interesting to see the results with less noise suppression. A matter of personal preference of course. I don't mind seeing a little graininess in a nebula, it tends to keep the overall contrast a little higher in the low contrast areas.
Thanks for your input, Paul. I tried again, this time reducing the denoise to a bare minimum. The image brightness is a little dimmer than the first one. I thought I brightened it enough, but I guess not.
Can you see any additional features?
Greg
Nice. I do see the calf, though I had to go back and read your description of where it is. It's facing to the upper left and show only the head, front shoulder and part of a front leg. There is also a hummingbird with a crooked beak to the upper right of the calf which you have to view with the image magnified.
I see that there is some fine detail in some of the higher contrast features. It would be interesting to see the results with less noise suppression. A matter of personal preference of course. I don't mind seeing a little graininess in a nebula, it tends to keep the overall contrast a little higher in the low contrast areas.
I think this one is on par with the brightness in the overly smoothed one. I tried...
Greg
Hum, more noise reduction please. I am thinking a little less than the first one, with maybe the same sharpening though you may have to back off a little on the sharping as well. No right way, just different ways. Some imagers like very smooth nebula. Everything is a tradeoff. With the 2 band narrow band filter and f/6 optical system your image brightness will be fairly low so you may need more total time. Your color imager with its built-in color filters further reduces the light. To top it off I think this is probably one of those rather dim objects. Terri or one of the other imagers who may have tried this object may have an idea of how dim it is. It may be your first rendering will be the best : )
Hum, more noise reduction please. I am thinking a little less than the first one, with maybe the same sharpening though you may have to back off a little on the sharping as well. No right way, just different ways. Some imagers like very smooth nebula. Everything is a tradeoff. With the 2 band narrow band filter and f/6 optical system your image brightness will be fairly low so you may need more total time. Your color imager with its built-in color filters further reduces the light. To top it off I think this is probably one of those rather dim objects. Terri or one of the other imagers who may have tried this object may have an idea of how dim it is. It may be your first rendering will be the best : )
Yes, I only have 4 hours of data, which is why there is so much noise I tried to smooth out. Definitely more time is needed to have inherently less noise in the image to be removed. And yes again -- much better if you can image without a Bayer filter in front of the sensor if you can afford the camera, filter wheel, and filters and you have the time you'll need to image using a mono setup. Maybe someday! 😊
Thanks again for the input, Paul.
Greg
This image capture came out fairly nice. Of course, I had to throw away some subs after my ASIAir suddenly stopped working a third of the way though (after 21, 5-minute subs) one of the most solid tracking runs I've ever had! Of course. Why should I expect things to go smoothly -- ever? 🤣 After I went back to square one and started up the run again, the tracking wasn't as solid, but it wasn't bad.
I find it odd that this nebula doesn't have a name! I think a lot of people (on YouTube, anyway) refer to it as the Flaming Skull Nebula, which is actually different and is designated Sh2-68 and located in the tail of Serpens (Serpens Cauda) rather than Cepheus. When NGC 7822 is imaged together with a small round nebulosity designated Sh2-170, it makes what some refer to as the Question Mark Nebula. (I was going to try getting the question mark but I would have been forced to use my manually focused 200mm lens. I've gotten VERY spoiled by my electronic auto-focuser!)
Does anyone else see an image of a calf in the center of NGC 7822, just above the bright star-forming region? Maybe it's just me...
This was my first test of an Antlia ALP-T dual narrowband filter and with an 82% illuminated moon it did very well, indeed!
AT60ED w/ field flattener (360mm fL)
ASI2600MC Pro (OSC camera)
SkyGuider Pro with guiding via ASIAir Plus using an ASI120mm mini and a 30mm F4 guide scope
Antlia ALP-T dual-narrowband filter (H-alpha, O-III)
First run -- 300 second exposures x 21; Second run -- 300 second exposures x 30: [Total exposure time: 4:00 after tossing out a few subs]; with dark, flat, and dark-flat frames
Stacked in Siril (as an RGB image, not as narrowband) and post-processed in PhotoshopGreg
Hi Greg, Beautiful image. I see the front half of a calf (head, front leg). I love looking at clouds and making associations as well. The first image is nicer than the second.. maybe a blend of the two 80% of 1 and 20% of 2 or something like that is easy to do in photoshop. The first overly smoothed maybe a little... the second very noisy. There is color noise as well which you may get rid of by desaturating the background. Great image for 4 hours!
Terri
Hi Greg, Beautiful image. I see the front half of a calf (head, front leg). I love looking at clouds and making associations as well. The first image is nicer than the second.. maybe a blend of the two 80% of 1 and 20% of 2 or something like that is easy to do in photoshop. The first overly smoothed maybe a little... the second very noisy. There is color noise as well which you may get rid of by desaturating the background. Great image for 4 hours!
Terri
Thanks, Terri! I agree with you and Paul so I tried to get a happy medium between smoothing and not. (I'm getting bleary-eyed, though, so I can't guarantee a good result!)
Greg
Hi Greg, getting bleary eyed myself but I think that looks pretty darn good.
terri
Hi Greg, getting bleary eyed myself but I think that looks pretty darn good.
terri
I agree, Terri -- it's better! In spite of cluttering up the Forum with numerous posts of the same thing, I have to say this is very helpful for me to have these critiques and revisions. It gives me a much better sense for what final results should look like.
Thanks again to you and Paul for the extra pairs of experienced eyes - and your willingness to take time to comment! Very valuable.
Greg
