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Space_Plane

The Moon - 18/11 - First Light new camera

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Hi all,

Just a quick post after spending an hour the other night experimenting with my new zwo178mc-cool.

I'm new to cmos cameras, new to pipp and debayering, new to autostakkert etc lol

The following is 5 x 10ms images, 0 gain, 25 offset, roughly (and badly) focused by eye on an unbalanced 72ED-R / AZ-GTI

I've a lot to learn but it was a fun first outing.  Tips & criticism welcome ? Enjoy!

Thanks

Chris

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Bump up the gain - in short exposures typically used for planetary imaging, read noise is dominant component (compared to LP, dark current) and you want lower levels of read noise if possible.

It is possible, fortunately, by using higher gain values. Select gain around 250. Record in SER format, and do quite a bit more frames. 10ms is good exposure length, but you can try even shorter - like 5-8ms range (image might look dim but that can be fixed after stacking). Take darks and if you can flats (and flat darks) and include those in Pipp when calibrating. Leave bayer matrix (don't debayer) and use Bayer Drizzle in AS3!

After you complete stacking - try Registax sharpening via wavelets (just don't over do it :D ).

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Thank you both for your comments and suggestions, its greatly appreciated!

I must have slid the gain and exposure sliders up...and down....and up lol over and over, it mostly looked very blown out on screen, so just took a guess ?

I'll try higher gain and lower exposure as you suggest, and certainly more frames, sounds good.  Is there a benefit to .ser?  I haven't tried it before.

The initial images I took had loads of squares all over them at different zoom levels, which led me to debayering & pipp after some research.  I'll look into bayer drizzle instead.

Lots to experiment with!

Thanks again!

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18 minutes ago, Space_Plane said:

Thank you both for your comments and suggestions, its greatly appreciated!

I must have slid the gain and exposure sliders up...and down....and up lol over and over, it mostly looked very blown out on screen, so just took a guess ?

I'll try higher gain and lower exposure as you suggest, and certainly more frames, sounds good.  Is there a benefit to .ser?  I haven't tried it before.

The initial images I took had loads of squares all over them at different zoom levels, which led me to debayering & pipp after some research.  I'll look into bayer drizzle instead.

Lots to experiment with!

Thanks again!

Benefit of .ser is that it records video, or sequence of frames in single file. It is better than avi as it can store 16bit frames / images - which you should use. This way, when you process there is single file to copy / work with - and it can contain very large number of single frames / images that will be stacked - I often end up with 10000+ subs on planetary imaging.

Yes, there is bayer patter in your images until you debayer - process which "makes up" some pixel values (creates a bit of blur along the way - but also creates colorful image out of black and white sensor data). If you leave bayer matrix in your images (skip debayering and tell pipp to preserve bayer pattern when cropping/calibrating) then stacking algorithm can use it - use only existing pixel values across multiple frames (without making anything up - you can't do this in single image, but you can do it if you have hundreds of frames and your target moves between frames tiny amount - some frames will contain information from green pixels, some from red, some from blue - AS3! can use this and create color for each pixel in final stack out of individual pixel colors). Trick with bayer drizzle is to take a lot of frames, and also let target do slight drift across the screen, few pixels is enough - on high zoom target tends to "wobble" and jump around due to seeing anyway - this is needed so that successive frames don't end up on exactly the same spot (you will not get mix of colors this way - some pixels might end up missing some color components).

Point in increased gain is just to reduce read noise. You may end up with over exposed target this way - this is not good. You want your target to be either properly exposed, or under exposed. Stacking makes up for this - under exposed image can be processed with levels to proper exposure. With over exposure you can't recover clipped information / detail. Another benefit of lowering your exposure time is that you are "freezing" your seeing. Seeing distorts image in two ways. First is "bending" it, and second is motion blur. This bending effect is really fast and if your exposure is long enough so that atmosphere bends image one way then the other way - you will get blur / smear effect - not good. It is ok for image to be distorted/bent by seeing - software can account for this. Blur is not good. Atmospheric distortion changes in milliseconds, depending on conditions this is usually in range of 3-8ms (in very good seeing it can be slower than this even 20-30ms, but such conditions are rare) - you want your exposures to be at least this quick to freeze the "action".

So higher gain and lower exposure work for you (one reduces read noise, other improves freezing of atmospheric "action").

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Wow Vlaiv, that's an incredible amount of helpful and useful info, thanks for taking the time to go into so much detail!

I'm really rather looking forward to getting to try all these things out, especially the .ser files and gain/exposure settings.  Sounds like it'll make a lot of difference.

Just need some clear nights lol ?

Thanks again

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