#1  
Old 24-08-2018, 09:59 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Ha filter + SGP autofocus = no likey...

Hi all,
Having such an odd issue.
Using HA with my 1600 for the first time, the autofocus is just not having it!
40 seconds or 10 seconds, no Difference...
Gain 139, using ZWO 7nm filter with SGP
Issue here is that the graph is just all over the place regardless of what happens, i think because it is just too dim. but 40 secs?!
Reply With Quote
  #2  
Old 24-08-2018, 10:46 PM
DJT (David)
Registered User

DJT is offline
 
Join Date: Nov 2011
Location: Sydney
Posts: 1,452
What Mag star? 40 secs seems a tad excessive..
Reply With Quote
  #3  
Old 25-08-2018, 06:51 AM
peter_4059's Avatar
peter_4059 (Peter)
Big Scopes are Cool

peter_4059 is offline
 
Join Date: Jun 2007
Location: SE Tasmania
Posts: 4,532
Have you considered autofocusing using just the Lum filter and then applying filter offsets for the other filters? You can manually focus each filter using a Bahtinov mask to work out what offsets you need for your filters. That's how I have set up SGP and I think if you look on the SGP forum you will find this is quite a common approach for people using narrow band filters.
Reply With Quote
  #4  
Old 25-08-2018, 07:12 AM
Slawomir's Avatar
Slawomir (Suavi)
Registered User

Slawomir is offline
 
Join Date: Sep 2014
Location: North Queensland
Posts: 3,240
Hi Logan,

I also had to initially fine-tune settings to get reliable autofocus with SGP and narrowband filters. What works for my 3nm and CCD with small pixels is binning 2x2 for autofocus and 30-second images, plus min star size is at 4. Step size for the motor should stay the same as you had with LRGB filters.

These settings work reliably for me for both bright nebulae and also for star fields without any nebulosity.

Focusing with Lum and applying offsets would be faster though due to shorter exposures for a Lum as opposed to narrowband.
Reply With Quote
  #5  
Old 25-08-2018, 08:39 AM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Maybe that's my problem, min star size was 10
Reply With Quote
  #6  
Old 25-08-2018, 12:02 PM
Lognic04's Avatar
Lognic04 (Logan)
Registered User

Lognic04 is offline
 
Join Date: Mar 2016
Location: Melbourne, VIC
Posts: 889
Doh! Was imaging in 8 bit last night...
The frames are usuable anyway, good thing it's clear tonight!
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 09:32 PM.

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