Username:

Password:

Altair AstroDIO DehumidifiersAtik CamerasModern AstronomyDavid HindsNe3 Filters

Author Topic: 2244 not very good  (Read 540 times)

0 Members and 1 Guest are viewing this topic.

Offline clive

  • Poster God
  • *****
  • Posts: 989
2244 not very good
« on: 23:21:36, 23 January, 2017 »
ngc 2244 not very good one hour 12 minute of  two minute 50 second subs eso 6d  iso1600  transperancy went bad high clouds  after an hour  pluss clouds came ill wait for a better nite to do rosset again

Offline chris.bailey

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 9520
  • If at last you do succeed, don't try again
    • Rosemount Observatory
Re: 2244 not very good
« Reply #1 on: 08:52:35, 24 January, 2017 »
Clive

Thats pretty good for a DSLR. If I were you I would try and increase the sub-exposure length. If you can guide for 3 minutes you can guide for 6 or 8. You would get a lot more signal in each frame and I reckon you would start to loose some of the artefacts you are struggling with.

Chris
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Online Nimbus

  • Poster God
  • *****
  • Posts: 1856
Re: 2244 not very good
« Reply #2 on: 10:04:17, 24 January, 2017 »
Clive as Chris says that is not bad for. DSLR certainly nothing to be ashamed of so well done you. ATB Jim
EQ8 Pro
TAK FSQ 106 EDX4
ATIK 16200 Mono & Lodestar OAG, EFW2 2" Filters
Focusmax4, Robofocus
Maxim DL6.13, CdC & Photoshop CS3E,

Offline clive

  • Poster God
  • *****
  • Posts: 989
Re: 2244 not very good
« Reply #3 on: 14:05:01, 24 January, 2017 »
Ok thanks lads  will take longer exposures and i wont image when transperancy is bad  again thor

Offline PaulB

  • Galactic Poster
  • ******
  • Posts: 6262
  • Canis Major
    • Paul's Astronomy Pages
Re: 2244 not very good
« Reply #4 on: 17:43:17, 24 January, 2017 »
I agree with Chris and Jim.
Darks will help as well as flats.

I use my Canon 1000d  that has been modified, and tend to use 180 seconds (3 min) with ISO 800. I get very good results with that exposure time from my semi- suburban backyard. I usually take 40 or more when imaging with the DSLR.
Paul.
"Whirlpool Observatory"
Losmandy G11-Gemini L4.
Celestron C9.25.
Megrez 80 ED II Triplet.
Orion OMC 140
Altair 115ED F7
Coronado PST
Atik 428EX
Atik EFW 2
QHY5L-II.
Modded Canon 1000D.
IOptron Mini Tower II
CCD Images
http://www.flickr.com/photos/paulabrierley/

Offline clive

  • Poster God
  • *****
  • Posts: 989
Re: 2244 not very good
« Reply #5 on: 18:19:24, 24 January, 2017 »
Cheers paul with my lumicon deep sky filter i cant expose longer  6 minutes iso 800  but ill use my h alpha filter next time i image ha targits  i can do longer exposures then

Offline chris.bailey

  • Administrator
  • Galactic Poster
  • *****
  • Posts: 9520
  • If at last you do succeed, don't try again
    • Rosemount Observatory
Re: 2244 not very good
« Reply #6 on: 10:34:33, 25 January, 2017 »
Clive

You "ideally" want to expose long enough so when you view the histogram of the unstretched stack in PS, the peak is detached from the left hand side. That is a reasonable indication that you are in the 'sky limited exposure' zone rather than the 'read noise dominated' zone. If the peak of the histogram is hard up against the left hand side then read noise dominates the image and stacking will not be as effective. That is much harder to achieve with narrowband filters and one of the reasons why they have to be exposed for a lot longer. Ha exposures in particular are hard to get to the sky limited point.

DSLR's and OSC' CCD's are much less efficient in turning photons into usable signal than a Mono CCD (for red and blue only one pixel in four is truly recoding signal) so you tend to have to expose for much longer. On my Atik 460 OSC, I started off being very disappointed with normal 4 or 6 minute exposures BUT giving it a much longer 'soaking' i.e. 12 or 15 minutes, the results are significantly better BUT you have exposed for 3 times the length and hence the assertion that OSC imaging is actually no quicker than doing RGB with a mono CCD.

Chris
LX200|ZS70|FSQ85|FLT110|Altair DF250RC|EQ6 Pro(Rowan Belt Mod)|ParamountMX
ATIK383L+/EFW2/OAG|Lodestar|Baader 36mm LRGBHaSIIOIII
Starlight Express SXVRH16/ONAG/FW|Lodestar X2|Baader 2" Filters
Starlight Express SXVRH814/ONAG/FW|LodestarX2|Baader 2" Filters
Lunt LS60PTBF1200|DMK41|Quark Chromo
Samyang 135mm f1.8

Offline clive

  • Poster God
  • *****
  • Posts: 989
Re: 2244 not very good
« Reply #7 on: 12:26:23, 25 January, 2017 »
Ok thanks chris  for that ill take longer exposures specialy with my h alpha 12 filterwhen i did rosesett some of my subs were exposed all most to the far right side of my lcd histogram  that image was with a lunmicon deep sky filter to much lite polution for faint things i can just get away with id say  6 minutes at iso 800 with that filter so ill use my ha filter now

 

ukbuysellRemote Imaging from AustraliaSharpSkyblank APTUKAI on Facebook
Powered by SMF 2.0.13 | SMF © 2006, Simple Machines LLC
DarkBreak by DzinerStudio. Theme modified by The UKAI Team

Page created in 0.157 seconds with 37 queries.
TinyPortal © 2005-2012