#1  
Old 30-07-2018, 09:56 PM
assbutt94
Registered User

assbutt94 is offline
 
Join Date: May 2018
Location: Sydney
Posts: 67
Unhappy My struggle with Mars

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.
Reply With Quote
  #2  
Old 30-07-2018, 10:22 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,419
That looks pretty amazing all things considered - isn't there a giant dust storm covering most of mars currently?
Reply With Quote
  #3  
Old 31-07-2018, 06:53 AM
middy's Avatar
middy
Registered User

middy is offline
 
Join Date: Feb 2006
Location: Brisbane
Posts: 614
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
Reply With Quote
  #4  
Old 31-07-2018, 09:53 AM
assbutt94
Registered User

assbutt94 is offline
 
Join Date: May 2018
Location: Sydney
Posts: 67
Quote:
Originally Posted by RobF View Post
That looks pretty amazing all things considered - isn't there a giant dust storm covering most of mars currently?
Thanks, i didnt know that, but after looking at other recent shots of Mars on astrobin im sure I've made some errors.

Quote:
Originally Posted by middy View Post
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
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).
Reply With Quote
  #5  
Old 31-07-2018, 10:47 AM
middy's Avatar
middy
Registered User

middy is offline
 
Join Date: Feb 2006
Location: Brisbane
Posts: 614
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.

cheers,
Andrew
Reply With Quote
  #6  
Old 31-07-2018, 11:58 AM
04Stefan07 (Stefan)
Make it so! - Capt.Picard

04Stefan07 is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 1,982
That is a lot better than my attempt with a very similar scope (see below).

http://www.iceinspace.com.au/forum/s...d.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!
Reply With Quote
  #7  
Old 31-07-2018, 01:38 PM
assbutt94
Registered User

assbutt94 is offline
 
Join Date: May 2018
Location: Sydney
Posts: 67
Quote:
Originally Posted by middy View Post
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.

cheers,
Andrew
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.

Quote:
Originally Posted by 04Stefan07 View Post
That is a lot better than my attempt with a very similar scope (see below).

http://www.iceinspace.com.au/forum/s...d.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!
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.
Reply With Quote
  #8  
Old 31-07-2018, 04:09 PM
sil's Avatar
sil (Steve)
Not even a speck of dust

sil is offline
 
Join Date: Jun 2012
Location: Canberra
Posts: 1,302
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
Reply With Quote
  #9  
Old 31-07-2018, 09:34 PM
assbutt94
Registered User

assbutt94 is offline
 
Join Date: May 2018
Location: Sydney
Posts: 67
Quote:
Originally Posted by sil View Post
dont forget to prey, sacrifice a Prius and cross everything you can as part of your setup ritual
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.

Last edited by assbutt94; 01-08-2018 at 09:30 AM.
Reply With Quote
  #10  
Old 02-08-2018, 09:44 AM
sil's Avatar
sil (Steve)
Not even a speck of dust

sil is offline
 
Join Date: Jun 2012
Location: Canberra
Posts: 1,302
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!
Reply With Quote
  #11  
Old 14-08-2018, 11:24 AM
assbutt94
Registered User

assbutt94 is offline
 
Join Date: May 2018
Location: Sydney
Posts: 67
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

Last edited by assbutt94; 14-08-2018 at 11:36 AM.
Reply With Quote
Reply

Bookmarks

Tags
mars, planet

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 09:42 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
Bintel
Advertisement
Celestron Australia
Advertisement
NexDome Observatories
Advertisement
OzScopes Authorised Dealer
Advertisement
Meade Australia
Advertisement
Lunatico Astronomical
Advertisement
Astronomy and Electronics Centre
Advertisement