Help with M42?
Posted 28 January 2013 - 01:07 PM
I'm in a white zone with no filters, this was during full moon, and my alignment was not perfect, so certainly not best conditions
Calibrated and stacked Tif file is linked on that site, if someone wants to have a quick go at processing it. I'd really like ot knwo what the data is capable of so I can work on my processing. Thanks!
Posted 28 January 2013 - 01:36 PM
Posted 28 January 2013 - 01:52 PM
I'll give it a go..., with your consent.
I'd appreciate it, thanks!
Posted 28 January 2013 - 01:58 PM
Posted 28 January 2013 - 02:26 PM
Posted 28 January 2013 - 02:34 PM
I'm bored with nothing but clouds
That's exactly why I set up during full moon, bad seeing, and 20 degrees out Been so long since there's been a decent clear night
Posted 28 January 2013 - 07:39 PM
that's about 15 minutes in pixinsight 1.7
did you use flats? there's kind of a weird, square gradient in the picture that i was not able to remove. i have seen this before but i'm not sure what causes it.
Posted 28 January 2013 - 08:25 PM
Yes, I used Flats, Darks, Dark Flats, and even Bias frames. I noticed that gradient too, I don't know what it is. It's the first time I have seen it in any of my pictures. It may have to do with the stacking. My alignment was a bit off. The stars didn't really trail, but the frame moved considerably over the imaging session. I had to crop out a wide margin after stacking.
There's obviously a lot of room for improvment in my raw data, but I'd like to get my processing skills up to a higher level too.
If anyone else wants to have a go at it, feel free!
Posted 28 January 2013 - 09:19 PM
You have captured a lot of detail in such short subs. Good going!
Posted 28 January 2013 - 09:44 PM
It was hard to tell whether there was a square gradient in the picture, or there was dust that surrounded the nebula. I think there's a lot of potential to get a great picture, possibly by creating a mosaic. Once I had this round gradient in my pictures, and I traced it back to my flats - I use a box with white paper in the middle, and white paper on the end where I shine the light. The white paper in the middle ended up having a circle shape from where the telescope rested, which caused a circular gradient in the flats. Maybe there was something like that going on in the creation of the flats, or maybe it's nebula dust, hard to tell.
Posted 28 January 2013 - 10:20 PM
As for the gradient, I am pretty sure its artificial. If you over-stretch the image it is very pronounced, and very linear along the bottom of the frame. As they say, nature never produces perfectly straight lines. I'll try to play around and see if I can figure out what caused it.
Posted 28 January 2013 - 10:54 PM
You can still do pretty much all the same stuff in PS just takes some work.
Posted 28 January 2013 - 10:59 PM
Posted 28 January 2013 - 11:24 PM
1. It is written specifically with astro processing in mind. It takes me from raw images from the camera, calibration, stacking and all the way through processing. This really simplified my workflow
2. It has a great community of contributors. They are constantly writing new scripts that aid in processing, plate solving, etc.
3. It costs a lot less than PS (cost was a big factor for me)
4. Also, once I tried the demo and followed Harry's tutorials I saw how easy it was to use. I was confused at first (coming from GIMP), but the many videos really show how powerful the program is (and easy - once the lightbulb goes off).
5. Lastly, I looked at lots of pictures here and on Astrobin and focused on the one's that really spoke to me, then tried to use similar tools/approaches.
I guess the only thing I can't do in PI is acquisition - but that is where BYE comes in :-) another really great piece of software.
This is not to say you can't do all of this in PS, some people are really good at it. My above points just made me gravitate to PI. Basically an end-to-end solution with a record of good results that was in my price point.
I hope this helps,
Posted 29 January 2013 - 12:17 AM
Posted 29 January 2013 - 01:43 AM
anyway it's possible this is a stacking artifact but those usually look more discrete rather than smooth. but then again i didn't realize you cropped the image.
i use pixinsight for the same reasons as cclark mentioned above. it's great to use dedicated software. i use a mac so that was also a big factor - it was either nebulosity or PI and PI just appealed to me more.
Posted 29 January 2013 - 10:04 AM
BYE really is great. Some of the best money I ever spent. I'll have to check out PixInsight too. Can't really afford it right now, but maybe in the future, if it makes things that much easier. I had thought the majority of people used Photoshop, but maybe I'm wrong.
Back to that gradient... I stacked without bias and dark-flats (still used darks and flats) and the gradient was still there. I tried again with darks only (no flats or anything else) and it may be gone, but it is hard to tell because without flats there is a pretty harsh vignette. I stretched one of the flats out and didnt see anything weird with it. So, I'm not sure. Let me clarify on the crop. In the tiff I uploaded, I had DSS stack in "intersect" mode, meaning it should have cropped out the border artifacts itself. I originally (and normally) stack in default mode and I crop off the edges myself. I figured it was some sort of stacking artifact which is why I tried it in "intersect" mode.
Posted 29 January 2013 - 12:40 PM
There are also some great processing instructions and techniques on Jerry Lodriguss's website: http://www.astropix....GIT/TOC_DIG.HTM
Fortunately, there is no one way to process astrophotos in photoshop. I would recommend trying out different techniques to see what works and what doesn't.
Posted 29 January 2013 - 10:52 PM
Posted 29 January 2013 - 11:56 PM
there's kind of a weird, square gradient in the picture that i was not able to remove. i have seen this before but i'm not sure what causes it.
If you're talking about an artifact that presents as almost a frame; more prominent on the left and bottom... I've experienced this on my Canon XS. it's there with or without flats, with or without darks. I've not spent much time trying to solve it because the rare clear sky has been to valuable to waste troubleshooting. I never used to encounter this issue so troubleshooting will entail eliminating software and just using a timer/remote shutter. It could be related to controling via USB?, maybe a bad USB:thinking:? shutter shadow?
Posted 30 January 2013 - 09:42 AM