My struggle with Mars

[assbutt94]

After much planning and reading for an attempt to capture Mars, I feel my efforts have been wasted so far.

I've been trying to process with both AutoStakkert! 2.6.8 and Registax6.
So far this has been of the more detailed stacks.

https://i.imgur.com/yiWR6R2.png

Celestron 8SE
3x TV barlow
ZWO ASI120MC
2 min capture, 2ms shutter
10231 frame captured
Gain 100%
Stacked best 5%
RGB align off
Sharpened w/ 20%raw blended in
Used various sized Alignpoints but 24 seemed to give the most detail, set via AP Grid
Seeing was rated 8 on SkippySky for that night, 1300m Altitude too
I've spend a couple hours trying different settings in AS2.6 but I cant seem to end up with a result much better than this



Is this quality to be expected? Surely I should be able to do better with my equipment (and if I can, I'd like to before we move much further from opposition!).

I look forward to any input, I'll continue to try get a better result.

[RobF]

That looks pretty amazing all things considered - isn't there a giant dust storm covering most of mars currently?

[middy]

My first thought when I saw the picture was “That’s dim”. Your exposure setting is way too fast. As a starting point, I’d reduce the gain to 50% and increase the exposure until it looks reasonably bright without saturating the image.

Cheers,
Andew

[assbutt94]

Thanks, i didnt know that, but after looking at other recent shots of Mars on astrobin im sure I've made some errors.



Thanks for the tips, I was trying to get the fastest exposure i could while maintaining about 50-60% on the histogram as I thought from what I've read, that it would lead to decent reaults.

I havent processed further than either stacking program (just rebuilt my computer and haven't put Photoslop back on yet).

[middy]

Keeping the histogram away from the right side is correct, to avoid saturating the bright parts of the image. I usually aim for around 70% across for the histogram.

The problem with using the fastest exposure is that you are capturing very little signal in each frame (the histogram would be well over to the left). You are then cranking the gain right up to the max to shift the histogram accross to the right. Using the gain to amplify the signal also amplifies the noise. Mars is a nice bright target so you can crank the gain right down (maybe even down to 30%, experiment a bit) and use a longer exposure time to catch more signal. Use longer exposure time to shift the histogram right and avoid amplifying the noise unnecessarily. The only time I needed to use 100% gain was when I was trying to image Neptune and Uranus, which are much harder to image.

I look forward to seeing your next attempt. :thumbsup:

cheers,
Andrew

[04Stefan07]

That is a lot better than my attempt with a very similar scope (see below).

http://www.iceinspace.com.au/forum/showthread.php?t=168739

I have been waiting for someone who captured Mars with the same or similar setup to me so I can compare and see if I am doing anything wrong. I felt that I had trouble focusing as mine looks really blurry.

- Did you let your scope cool down to the outside temp before imaging?
- Did you use any dew straps or shield?

I noticed you are in Sydney so maybe the atmospheric conditions were different from Melbourne.

Thanks!

[assbutt94]

Thanks for the tips. I was under the impression the ASI120MC performs better at higher gain, and having a faster shutter speed would help freeze the movements in the atmosphere. Ill try again this coming weekend hopefully.



I need to make up a thing to attach to my focuser to increase the knobs diameter and make focusing a bit easier. I also find it very touchy.

I shot the video from near Oberon at a camp ground, the scope had cooled down as i set up at 9pm and captured at midnight. Skippysky rated seeing as an 8.
I had to use my dew strap (dew-not) and a dew controller, everything other than my optics were frosting up by 930. I also have a dew shield and a good EQ Mount.
It was a bad night to forget my thermal pants, trackies and boots.
My re-attempt will be from home in Penrith.

[sil]

set gain to 0%, 100% is way too noisy on 120mc and exposure to 20ms for a good frame rate, now set a region of interest around mars, allowing room for whatever drift you get, just do not capture at full resolution as its reducing frame rate and all wasted pixels anyway.get your log histogram up above 50 and maybe into 70s but no higher, it fluctuates so why waste capturing bad data you have to throw away?! 3min is good limit per capture

Capture 16bit SER format
install PIPP (free) and chuck in the SER file, click on planetary target at bottom and you can tweaak settings, basically use pipp to debayer, find and centre your planet in each frame and crop the output to throw away all the blackness around the planet you definitely dont need
set pipp output to SER again

throw this ser into autostakkert, enable sharpen and normalise to 75% and other things you want and let it go, Generally i just output to png and its sharp enough i find. up to you.

PS mine right now are brighter than yours but no clearer so don't panic.
all this will greatly improve your result.

and yes Mars is blurry still, has been for weeks very featureless due to dust storms. but its clearing no i think. so keep at it. take care focusing. I tend to do a couple of captures then use the focus helper to refocus completely then do a couple more and again so hopefully one of the focusing times I got it as close to perfect as I could and caught seeing conditions at a favourable patch too I process each set and can choose which I consider the best of the bunch.

dont forget to prey, sacrifice a Prius and cross everything you can as part of your setup ritual :)

[assbutt94]

Once I got to this part I realised you definitely know what you are talking about.

After some more playing around with Autostakkert! some more I enabled nomralize stack (to 75%).
Sharpened with a 30% RAW blend.
RGB Allign
AP size 48
Pretty sure I stacked 10% of frames
Adjusted curves and levels and in photoshop
Dont remember if this was the same file as the last, I think this one was captured a few minutes apart.
https://i.imgur.com/xlMAi1D.png

EDIT: Still cant work out why my image wont display in the forum :(

EDIT2:
I also use firecapture to capture. I recorded at like 240x240 giving about 25 pix around mars (approx. 188pix diameter iirc). My tracking wasnt perfect but i connected the cam via st4 to mount and ensured its axis' were aligned so firecap could send corrections to the mount. Once set up mars never reached the edge of my capture area.

[sil]

I drop AP size to 16, and tick multisize and close to edge options then autopopulate APs in autoStakkert.

you'll have a 10 in a box for 10% frames and probably all other boxes still red, you can output other stacks too, I put 25, 50 & 75 in three boxes so it gives me outputs stacked using 25%, 50% and 75% of the frames. I can quickly look at those and decide in that instance which looks best to my eyes as PNG and then decide which value would be good for a FITS output.

240x240 is awesome, i'm usually 3x that and manual adjust during my capture to catch it before it drifts off an edge. with 240x240 though you should be able to get your exposure rate down very low and keep a good histogram with gain close to zero.

I dont have much on my astrobin page yet for mars this season. My focus has been to get captures so I only do quick processing in AS2! and dont upload anywhere. been grabbing jupiter saturn and venus too while i can. Pretty sure in the passed two months Ive got my best shots yet of those planets and happy with what i get. Each session I get my gear out, I make time adjustments to my setup and settings and how I work. I'm not so paniced now about what I'm getting, I trust I can get a good image in processing and I can be up and capturing faster now than two months ago. So it really pays to just get out there, its all practice and enjoy it most of all!

[assbutt94]

Here is an update.
Taken on 8/8 from Penrith NSW.
Seeing 5-6/9 according to Skippysky
Altitude above 70 degrees
http://imgur.com/p0hW0lO


Processed with registax 6.
I might try reprocess my original shots the way I processed this as I did the wavelets differently.

Also on the weekend I shot jupiter at around 50 or 60 degrees altitude. I did this to compare with my shots of mars. I checked my collimation prior to shots and as far as I can tell it's not the issue but I could still be wrong. I'm yet to process the Videos of Mars from this weekend but I should be able to this afternoon.

http://imgur.com/clCvdRJ
Seeing 4-5/9

I think this is pretty blurry still, surely I should be able to capture sharper images with my equipment?

Edit : my resolution of 240x240 is not correct, it was off the top of my head but it's probably closer to 320 or 420.
I'm at 6096mm f/30 with 3.75micron pixels