Go Back   IceInSpace > Equipment > Astrophotography and Imaging Equipment and Discussions

Poll: What approach to use in long-exposure images [Multiple selection possible]
Poll Options
What approach to use in long-exposure images [Multiple selection possible]
You can only choose 2 options to vote on.

Reply
 
Thread Tools Rate Thread
  #1  
Old 26-08-2014, 02:37 PM
Meru's Avatar
Meru (Michael)
More stars please!

Meru is offline
 
Join Date: Jan 2012
Location: Vic
Posts: 560
Question Advice for my first mega-exposure image

Hi everyone,

I finally got around to getting my pier installed and plan to do my first mega-data image this week (>16 hours) Widefield of NGC6188 + NGC6164. I need advice about the following two topics (Image Capturing + Hardware):

  1. Get mega data in Ha and use it as L, with OIII & S2 binned 2x2 for colour only. This is my normal routine and find it works very well.
  2. Go for a true Hubble Palette image i.e. Use SHO as RGB directly. Never done this before.
I am leaning towards 1) as it will give me oodles of Luminance data in that channel that will be rich with data, rather than spending 6 hours on each channel.

  1. Use 80ED with Flattener. This gives a very well-corrected image but only @ f/7.5 d)
  2. Use 120ED with my 0.67x reducer @ f/5. Edge performance isnt very good (though tolerable) but gives me a full stop extra of light.
I am leaning towards 2) as an extra full stop of light (i.e. double the amount) over 16 hours. I've shot an image with the 0.67x reducer (see here) and dont think I will have too many issues processing the coma out in Startools.


Thanks for reading, and what would you recommend? I have a poll to make it easier

Last edited by Meru; 26-08-2014 at 03:12 PM.
Reply With Quote
  #2  
Old 26-08-2014, 02:50 PM
Amaranthus's Avatar
Amaranthus (Barry)
Thylacinus stargazoculus

Amaranthus is offline
 
Join Date: Jan 2014
Location: Judbury, Tasmania
Posts: 1,203
Depends a lot on your target What are you aiming for?
Reply With Quote
  #3  
Old 26-08-2014, 02:53 PM
Meru's Avatar
Meru (Michael)
More stars please!

Meru is offline
 
Join Date: Jan 2012
Location: Vic
Posts: 560
Sorry probably should have mentioned that! Widefield of NGC6188 + NGC6164 (Elephant's Trunk Nebula)

[Original post updated]
Reply With Quote
  #4  
Old 26-08-2014, 03:04 PM
RickS's Avatar
RickS (Rick)
PI cult recruiter

RickS is offline
 
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
I've never heard that called the Elephant's Trunk before? That name is usually reserved for IC1396.

Since you're unlikely to be getting any significant benefit from hardware binning on a QHY9 I'd go for unbinned data in all three filters and decide what to do once you've collected a couple of hours in each. You can still software bin OIII and SII if you want.

You won't see the OIII halo around NGC6164 very well if you use Ha for Lum, but even if you don't it is pretty faint...

Cheers,
Rick.
Reply With Quote
  #5  
Old 26-08-2014, 03:13 PM
Meru's Avatar
Meru (Michael)
More stars please!

Meru is offline
 
Join Date: Jan 2012
Location: Vic
Posts: 560
Sorry, 3.30itis finally kicking in


Hmmm that's a good point, I can always bin in software. So maybe spend the first night getting a few subs of each and then see what the data looks like? And when you say not much benefit are you referring to the shallow well depth and not much gain in quality of data when binning on the 8300? Or something else?

And yes I was thinking about that, I might see if I can get some O3 on the weekend if all goes well
Reply With Quote
  #6  
Old 26-08-2014, 03:34 PM
RickS's Avatar
RickS (Rick)
PI cult recruiter

RickS is offline
 
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
Quote:
Originally Posted by Meru View Post
Hmmm that's a good point, I can always bin in software. So maybe spend the first night getting a few subs of each and then see what the data looks like? And when you say not much benefit are you referring to the shallow well depth and not much gain in quality of data when binning on the 8300? Or something else?
The only benefit of hardware binning is reduced read noise. In a perfect world you'd get the same read noise for a 2x2 superpixel as you get for a single pixel read. The KAF-8300 sensor doesn't do as well as some others. There's probably some benefit but it's only small and if you're doing decent length subs so that read noise isn't overwhelming then it will be even smaller. Better to do unbinned and have the extra flexibility.

Cheers,
Rick.
Reply With Quote
  #7  
Old 26-08-2014, 04:39 PM
alistairsam's Avatar
alistairsam
Registered User

alistairsam is offline
 
Join Date: Nov 2009
Location: Box Hill North, Vic
Posts: 1,837
hi,

There is the other issue with horizontal blooming on the kaf8300.

qhy recommend software binning for horizontal and hardware for vertical (in a forum).
no idea how this'll be done but the horizontal blooming when binned 2x2 is a pain. I now bin 1x1 for all. it can quite easily be fixed in Maxim as it doesn't affect target data, just saturated stars.

As for the 2 options, I'd go with the larger aperture.


Cheers
Alistair
Reply With Quote
  #8  
Old 27-08-2014, 12:34 PM
Meru's Avatar
Meru (Michael)
More stars please!

Meru is offline
 
Join Date: Jan 2012
Location: Vic
Posts: 560
Ah ok, thanks for the advice Rick & Alistair. Yes I think going unbinned will be the way forward for the flexibility.

Last night I tried the 120ED + reducer combo and with 20min subs got an unbelievable amount data in Ha. However I was faced with some issues with my new pier setup, field rotation + dew killed the imaging session. Hopefully I can sort this out tonight and give it another shot
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 03:31 AM.

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