Old 17-05-2016, 09:11 PM
Rob Hamlin
Registered User

Rob Hamlin is offline
Join Date: Nov 2009
Location: sydney
Posts: 25
Help diagnosing lines in Flats

Hi All

Im running an Sbig STF8300M.

Am finding my HA, SII and LRGB flats have a grid pattern running through them.

OIII flats quite oddly, seem far smoother and dont have the issue. Somewhat baffled about this.

The image ive attached below shows what I see on-screen.

The grid pattern seems quite clear and im not entirely sure how big a problem this actually is.

Any feedback thoroughly appreciated

With thanks

Rob Hamlin
Attached Thumbnails
Click for full-size image (HA Screenshot Stacked Flats.jpg)
176.4 KB33 views
Reply With Quote
Old 17-05-2016, 09:44 PM
glend (Glen)
Registered User

glend is offline
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 6,253
How are you shooting your flats? Looks like a cloth weave pattern.
Reply With Quote
Old 18-05-2016, 06:57 AM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 20,191
Could be a reflection of the micro lensing on the chip when the light source for the flat is too bright and the exposure too short. Try to dim the light and lengthen the exposure see if it looks better.
Reply With Quote
Old 18-05-2016, 07:49 AM
RickS's Avatar
RickS (Rick)
PI cult recruiter

RickS is offline
Join Date: Apr 2010
Location: Brisbane
Posts: 10,584
What ADU levels are you getting in the Ha and Oiii flats?
Reply With Quote
Old 18-05-2016, 08:01 AM
gregbradley's Avatar
Registered User

gregbradley is offline
Join Date: Feb 2006
Location: Sydney
Posts: 16,702
Did you subtract a bias or flat dark from the flat? Its fixed pattern noise.

Reply With Quote


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 04:35 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Limpet Controller
NexDome Observatories
Astronomy and Electronics Centre