#1  
Old 11-02-2019, 02:51 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Thor's Helmet

Thor's Helmet taken with an ASI071 OSC using my new toy an STC-duo filter. So fake HOO? Using an 8"F5 GSO newt on CGEM mount. 40x 6min subs over 2 nights. Processed in PI as an OSC image.

I probably should have taken longer subs as I wasn't swamping read noise. But was nervous enough about 6min subs - I've never had to go this long before on my OSC camera before.

Comments please, thanks for looking.
Attached Thumbnails
Click for full-size image (NGC2359_integration_2019_02_DBE-4_final.jpg)
237.6 KB207 views
Reply With Quote
  #2  
Old 11-02-2019, 04:08 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 7,033
Looks great Chris. Certainly looks like narrowband, and sub lengths are right. Your still going to be Moon affected though, if it is allowing Oiii through. At least it stops sky glow pretty well. I am curious as to how you process to allow Orange stars to show up, which should be blocked, did you colour rebalance?
Reply With Quote
  #3  
Old 11-02-2019, 06:27 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Thanks Glenn. I was blown away by the low background level and even more so - the lower noise associated with it.

I didn't do any color balancing. The filter lets through HO and the O hits G+B on the Bayer matrix, so looks like enough to maintain star colors. But I have to check what colors the stars in this image are actually supposed to be.

I'm doing tarantula and ngc3324 tonight to see what something with more Halpha looks like.
Reply With Quote
  #4  
Old 11-02-2019, 10:06 PM
Rigel003's Avatar
Rigel003 (Graeme)
Registered User

Rigel003 is offline
 
Join Date: May 2006
Location: Adelaide, South Australia
Posts: 1,079
Lovely image. Just did some reading about the filter. Sounds intriguing.
Reply With Quote
  #5  
Old 12-02-2019, 07:58 AM
AstroBogan's Avatar
AstroBogan (Jacob)
Jacob

AstroBogan is offline
 
Join Date: Mar 2018
Location: Sydney
Posts: 175
Stunning image, by far my favourite DSO.
Reply With Quote
  #6  
Old 12-02-2019, 08:55 PM
traveller's Avatar
traveller (Bo)
Not enough time and money

traveller is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 2,133
Nice one Chris, the duo filter certainly making it look like a HOO image.
I'd be tempted to bring out the red a bit more, but that's personal preference.
A good image.
Bo
Reply With Quote
  #7  
Old 12-02-2019, 09:00 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Looks great! Very sharp and deep. Beautiful.
Reply With Quote
  #8  
Old 15-02-2019, 11:14 AM
Geoff45's Avatar
Geoff45 (Geoff)
PI rules

Geoff45 is offline
 
Join Date: Jul 2006
Location: Sydney
Posts: 2,631
Looks good Chris. Nice wide field but still keeps a good size for the helmet.
Maybe needs a bit more of the Ha to show through.
Reply With Quote
  #9  
Old 15-02-2019, 04:36 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Thanks Graeme, Jacob, Bo Marc & Geoff.

No, the image doesn't have much H-alpha. I tried to push the H-alpha but it didn't improve it. Maybe I'll try and separate the colour channels and redo it - I'll have to read that bit of the pixinsight book as I have onyl done OSC processing before. I've tried other regions with more intense H-alpha (NGC3324, NGC2070) and they have much stronger reds. Or maybe I just need more/longer subs.
Reply With Quote
  #10  
Old 17-02-2019, 11:25 AM
Stevec35 (Steve)
Registered User

Stevec35 is offline
 
Join Date: Aug 2010
Location: Canberra
Posts: 3,654
That's a nice sharp wide field image Chris. As others have said maybe there should be a bit more red but I would still be pretty happy with it.

Cheers

Steve
Reply With Quote
  #11  
Old 06-03-2019, 04:54 PM
nevfaith (Nev)
Registered User

nevfaith is offline
 
Join Date: Jun 2015
Location: Gold Coast, Australia
Posts: 6
Looks great. Very sharp
Reply With Quote
  #12  
Old 07-03-2019, 04:18 PM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Thanks Nev. Now updated to 8 hours of 6min subs. Got some red in it now.
Attached Thumbnails
Click for full-size image (NGC2359_integration_2019_03_19_DBE_DBE-8_final-bin2.jpg)
235.1 KB26 views
Reply With Quote
  #13  
Old 07-03-2019, 04:49 PM
JA
.....

JA is offline
 
Join Date: Oct 2016
Location: Melbourne, Australia
Posts: 2,945
Quote:
Originally Posted by ChrisV View Post
Thanks Nev. Now updated to 8 hours of 6min subs. Got some red in it now.
That's a great image Chris

In as much as needing more red, I'd have to agree. Based on the fact that you're using the STC filter and a OSC camera, you could (should?) consider doubling the red intensity/saturation in processing, since the OIII band is represented by 3 times as many pixels as the Ha band (Bayer Matrix: 1Red, 2 Green, 1 Blue), albeit at slightly lower camera relative sensitivity around the OIII band (approx 55%) versus approx. 80% for the Ha band.

Given that it's bicolour image, that works out that the red channel should be pumped up 2.06 times its existing value to represent "reality" and correct for the differences in number of representing pixels ([Ha] RED vs [OIII] BLUE +GREEN) as well as the differences in the camera's sensitivity in the OIII area of around 500nm and Ha area around 650nm as can be seen in the Relative Sensitivity Curve for the ASI071 below.

It would be interesting to see the change to the image. The only penalty may be that it might bring out some background noise, but given the exposure time you might be OK with that.

Best
JA
Attached Thumbnails
Click for full-size image (ASI071-Relative Sensitivity.jpg)
81.9 KB6 views

Last edited by JA; 08-03-2019 at 10:50 AM. Reason: corrected sensitivity to 55% (was 65%)
Reply With Quote
  #14  
Old 08-03-2019, 08:31 AM
Atmos's Avatar
Atmos (Colin)
Ultimate Noob

Atmos is offline
 
Join Date: Aug 2011
Location: Melbourne
Posts: 6,980
I've been curious to see how this filter performs and it looks to do quite a good job. A few months ago I received an ASI094 that I'd be interested in being able to use in Melbourne and this does appear to be a possible way of fighting the light pollution with an OSC.

The colour balance may not yet be perfect but it's certainly nothing to scoff at considering what you can now do from light polluted suburbs.
Reply With Quote
  #15  
Old 08-03-2019, 11:13 AM
ChrisV's Avatar
ChrisV (Chris)
Registered User

ChrisV is offline
 
Join Date: Aug 2015
Location: Sydney
Posts: 1,737
Its worth a go. I'm 15km from Sydney CBD, so there's a reasonable amount of light pollution.
Reply With Quote
Reply

Bookmarks

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 10:05 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Testar
Advertisement
Bintel
Advertisement