Go Back   IceInSpace > Images > Deep Space

Reply
 
Thread Tools Rate Thread
  #1  
Old 28-07-2022, 08:49 PM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
NGC55 - An (now HaRGB) Irregular Whale

Here's my take on NGC55 (The Whale) - an irregular galaxy in Sculptor, and one of the closest of our local group neighbours. At a measly 6.5Mly away, there's plenty of lovely detail to observe, with pockets of Ha, dusty tendrils and a plethora of new bright blue stars.

My shot from the Sydney suburbs is over 2 nights, over 2 new moons, to end with a total of 5hrs of data in somewhat below-average seeing conditions. Taken with the asi2600mc, I haven't added any additional narrowband data at this point, so the Ha regions are not as pronounced as some of the excellent deeper shots by others.

Still pretty happy with how things have come out, and maybe might invest in a Ha filter down the track to enhance things further. As always, happy for your constructive criticism too!

300x 60sec subs (no moon)
C14 non edge @f7
EQ8 pro
Asi2600mc pro (no filter)
Asi290mm / celestron OAG
ASIAIR pro / APP / PS

Bigger version here

Thanks for taking a peek!
Attached Thumbnails
Click for full-size image (IMG_8858.jpg)
188.9 KB232 views

Last edited by Dave882; 11-08-2022 at 10:08 AM.
Reply With Quote
  #2  
Old 28-07-2022, 11:36 PM
PKay's Avatar
PKay (Peter)
Registered User

PKay is offline
 
Join Date: May 2017
Location: DEPOT BEACH
Posts: 1,643
Hi David

Not a bad peek at this beautiful galaxy.
Your processing is good and the detail is starting to appear.
Using a Ha filter on a OSC is hard going so probably not worth the effort IMO.

Well done
Reply With Quote
  #3  
Old 29-07-2022, 07:12 AM
Startrek (Martin)
Registered User

Startrek is offline
 
Join Date: Dec 2017
Location: Sydney and South Coast NSW
Posts: 5,990
Dave,
Lovely Galaxy image of the Whale
Colour and detail are a pleasure to view
I agree with PK , a Ha filter on that 2600MC probably won’t improve the image , it might even detract from detail and colour as you would be imaging with a Ha filter over that internal UV/ IR cut or Lum filter and Ive read on CN that there’s no advantage when imaging galaxies under that scenario with the 2600MC , the 2600MM is a different story.
I think more data under stable conditions would improve it ( only my opinion though )
Well done !!
Tonight , Saturday night and Monday / Tuesday nights in Sydney are looking promising

Cheers
Martin
Reply With Quote
  #4  
Old 29-07-2022, 08:39 AM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
Thanks Peter/Martin. Yeah I think you’re right, trying to work out how to combine narrowband into osc (and make it look good!) is going to be quite difficult. I usually get quite good Ha pickup with the 2600mc on galaxies but it’s in reeeaally deep on this target so already at 5hrs the whole thing was looking very very bright blue!! I had to do some colour correction already to reveal the core detail. Another 5hrs would be absolutely lovely and the target will benefit greatly if I can get it! It’s very hard to get good conditions at the moment (I had to cull several hours of soft subs from my data already).

You’ll notice I’ve started doing 60sec subs instead of my normal 120sec which has helped keep things a bit tighter in poor seeing but perhaps made it harder to go “deeper” in the red??
Reply With Quote
  #5  
Old 29-07-2022, 12:38 PM
Anth10's Avatar
Anth10 (Anthony M)
When its late stay awake

Anth10 is offline
 
Join Date: Jan 2016
Location: Briar Hill
Posts: 784
Dave,
I find it's a compromise with the sub lengths using my Newt (by the way haven't taking in out for quite a while lately). Yes, the longer exposure naturally the more enhanced the detail but I see your point with shorter subs being a bit more forgiving in regards to keeping things looking sharp. Perfect polar alignment is the key in trying to meet halfway I recon. I'm tipping with your C14's light capacity coupled with your OSC is doing a fine enough job anyhow (nice shot!).
Have a look at some posts in the past in this section where large numbers of subs at short exposure produce very good results (Kevin will vouch for this I'm sure).
Regards,
Anthony
Reply With Quote
  #6  
Old 29-07-2022, 09:41 PM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
Thanks Anthony- I know there’s a formula somewhere that determines the minimum sub length to overcome the noise floor…can’t for the life of me find it now though.
Reply With Quote
  #7  
Old 30-07-2022, 03:07 PM
Addos (Adam)
Registered User

Addos is offline
 
Join Date: Apr 2021
Location: Brisbane
Posts: 291
very nice! great colours with no filtering from anywhere in sydney is impressive! also gotta love that c14 fl!

re the narrowband, with a osc definitely look into one of the dual nb filters like l-extreme or that new antlia one. not too challenging to pull out a synthetic Ha layer from that data, plus you get additional utility from the oiii on other targets.
Reply With Quote
  #8  
Old 30-07-2022, 08:46 PM
AdamJL
Registered User

AdamJL is offline
 
Join Date: Sep 2010
Posts: 2,100
Really good! Great level of detail and natural processing works well. I will buck the trend and say an Ha layer might actually be a good idea, depending on how much this object has (I don't really recall looking at it too much)
Reply With Quote
  #9  
Old 30-07-2022, 10:54 PM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
Thanks Adam(s) - yeah it might be worth a crack with my IDAS nbz (would love to geth the 5nm Antila but a bit out of my budget just now) and probably need a bit more rgb as well tbh. There’s a couple of brilliant shots in RGBHa on IIS so there’s certainly something there. Just whether I can do it justice at the processing stage… let’s see how the weather goes this week!
Reply With Quote
  #10  
Old 11-08-2022, 09:36 AM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
With some added Ha data...

I had a go adding approx 3hrs Ha data to my previous NGC55 attempt (along with an extra 3hrs RGB as well). All completed with the same asi2600mc OSC setup but using the IDAS NBZ dual band filter to extract Ha via APP Ha extract tool.

The data was pretty terrible and I have since discovered this is probably due to the fact I'm getting dew forming on my filter inside the filter drawer in the early hours of the morning while on autorun- how the heck am i going to sort that out for future imaging I have no idea yet... I'll post a screen grab of the background noise profile just so you can feel pity for me

But as a proof-of-concept, I thought I'd have a go putting it all together. Pleasantly surprised by the result - and yes I did a comparison with just the extra RGB data and there was a big difference in the Ha areas. Still getting the hang of the combine RGB function in APP, but the data didn't warrant a super amount of time spent here.

My only main complaint (other than the woeful stars/background after all that noise reduction) is I lost detail in the bright core after adding the Ha data.

Bigger version

Let me know what you think...
Attached Thumbnails
Click for full-size image (IMG_8925.jpg)
210.7 KB93 views
Click for full-size image (Screen Shot 2022-08-11 at 10.22.13 am.jpg)
84.7 KB63 views
Reply With Quote
  #11  
Old 11-08-2022, 12:51 PM
Startrek (Martin)
Registered User

Startrek is offline
 
Join Date: Dec 2017
Location: Sydney and South Coast NSW
Posts: 5,990
Dave,
To be honest I think the original presented image looks much better , cleaner , sharper and more detail. Colours more natural ( only my opinion)
I just shoot galaxies without a filter on the 2600MC ( internal IR Cut ) and end up getting better colour and detail at my puny focal length let alone +2000mm
Unfortunately you have to be patient and score clear nights during the new moon period of 10 days or so ( a small window of opportunity)

As far as dew goes , I’m not fully automated at both sites and don’t want to be as I find the worst atmospheric conditions are between 1am and dawn at both imaging locations. It’s worse down the coast as I’m located 150m from the beach up on a hill and we often get sea mist rolling in through the wee hours ( unless wind is around through the night )
I always get my best subs early on to just past midnight
Ive learnt to wrap up a session no later than 1am to 2am or thereabouts ( dependent on the targets position)

Maybe shorten your sessions to automatically finish around 1 to 2am ??
Just a suggestion ?

Also I check Weatherzone and CFN for humidity and dew point data through the night , if the humidity is above 85% early on , I don’t bother imaging as sure enough, I go outside at 8pm and the scopes cloak and workstation weather cover is dripping wet. I have dew heaters but they can only do so much on a Open tube Newt.
Cheers
Martin
Reply With Quote
  #12  
Old 11-08-2022, 06:16 PM
gregbradley's Avatar
gregbradley
Registered User

gregbradley is offline
 
Join Date: Feb 2006
Location: Sydney
Posts: 17,877
That's a very good NGC55.

Greg.
Reply With Quote
  #13  
Old 11-08-2022, 09:00 PM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
Thanks Greg!

Thanks Martin I appreciate your input there. There is no doubt that the original image is cleaner and more detailed- I reckon the quality of that Ha data set has got a lot to do with that tho. That and I think I could do better with the colour mix- It was really just an experiment to see if I could combine the data…The take-away for me was that it’s possible to combine the sets to boost the Ha regions, but that it’s also a more complex process that I’d only do for targets that would really benefit from it. I’ll also need to work out how to do good star masks etc otherwise the rest of the image suffers even if the target benefits.

Good point about the humidity in the early hours. I’ll keep an eye on that tho it is nice to wake up in the morning with a few extra hours of data, even if some needs to be culled. Plus my focus remains much more stable after midnight too.
I do confess that my impatience has had me imaging on nights with poor conditions because we’ve had so few clear nights in the last 12months
Reply With Quote
  #14  
Old 15-08-2022, 01:52 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Sydney
Posts: 22,060
Nice going Dave. Lots of details.
Reply With Quote
  #15  
Old 15-08-2022, 05:07 PM
Mickoid (Michael)
Registered User

Mickoid is offline
 
Join Date: Feb 2016
Location: Melbourne, Australia
Posts: 1,439
David, I find that with a OSC Ha narrow band captures always seem very noisy/grainy and maybe dithering would help but it also might be inherent in using the colour sensor. Why not swap cameras just for your Ha data capture. Guide with the 2600 and capture with the 290. I think there will be less noise and if your image scale is not too big for the 290, then all you do is register the Ha data into your RGB capture. I guess it depends on your processing skills and how effective it will be but the grainy Ha is probably reducing the quality of your OSC data capture by trying to reduce its noise in post processing.
Reply With Quote
  #16  
Old 15-08-2022, 08:18 PM
Dave882 (David)
Registered User

Dave882 is offline
 
Join Date: Nov 2020
Location: PADSTOW
Posts: 2,056
Thanks Marc and Michael. For some reason I had thought Ha data would be a bit cleaner than broadband but from what you’re saying I may well need to try a new approach. It’d be a really good idea using the mono guide camera, except for the slight hitch that the fov would necessitate a mosaic! I really can’t squeeze much sky into the fov at 2700mm lol! I do truely think I can get better data which will give a better result, but the way things are going, maybe not this season…
Attached Thumbnails
Click for full-size image (C690851F-3CCB-4A9E-8225-305CF1906F8F.jpg)
161.6 KB31 views
Reply With Quote
  #17  
Old 15-08-2022, 08:37 PM
Mickoid (Michael)
Registered User

Mickoid is offline
 
Join Date: Feb 2016
Location: Melbourne, Australia
Posts: 1,439
Yes, well at 2700mm my idea would not be an option for using the ASI290mm and I can see by where it would frame your shot that it would, in fact, be useless! I had not realised you were using the native focal length of your scope. Chuck a focal reducer on your C14, take your Ha data with the 290 and enlarge it to fit your OSC data in post processing. There's always a way!
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 01:15 AM.

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