Re: [MaxImDL] Re: Question about bias frames for SXV-H9


Sep 18, 2003

 


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#8346 Sep 18, 2003

When I take bias frames for my SXV-H9 using MaxImDL 3.20 for camera

control it automatically applies a dark frame. Maybe I don't

understand the math behind a bias frame, but why is it subtracting a

dark frame? What's the difference between a zero duration bias frame

and a zero duration dark frame if the scope is covered for both?

Terry Platt recommends that you do not apply dark frames to SXV-H9

images, only bias frames. What I've been doing is a luminosity of

zero duration with the camera covered. Can someone help set me

straight?

Nick



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#8347 Sep 18, 2003

nickbtx wrote:

> When I take bias frames for my SXV-H9 using MaxImDL 3.20 for camera

> control it automatically applies a dark frame. Maybe I don't

> understand the math behind a bias frame, but why is it subtracting a

> dark frame? What's the difference between a zero duration bias frame

> and a zero duration dark frame if the scope is covered for both?

> Terry Platt recommends that you do not apply dark frames to SXV-H9

> images, only bias frames. What I've been doing is a luminosity of

> zero duration with the camera covered. Can someone help set me

> straight?



If it's subtracting a dark frame, it's because you turned on auto-dark

subtraction. Turn it off (Settings tab).



Doug



---------------



Doug George

dgeorge@...



Diffraction Limited

Makers of Cyanogen Imaging Products

www.cyanogen.com



100 Craig Henry Drive, Unit 106,

Ottawa, Ontario, Canada, K2G 5W3



Phone: (613) 225-2732

Fax: (613) 225-9688



---------------



----------------------------

#8348 Sep 18, 2003

Doug,

Thank you for the fast response. I don't have "autodark" selected

(the box is not checked). That was the first thing I looked at. Any

other ideas?

Nick





--- In MaxImDL@yahoogroups.com, "Douglas B. George" dgeorge@c...>

wrote: > nickbtx wrote:

>

> > When I take bias frames for my SXV-H9 using MaxImDL 3.20 for

camera > > control it automatically applies a dark frame. Maybe I don't

> > understand the math behind a bias frame, but why is it

subtracting a > > dark frame? What's the difference between a zero duration bias

frame > > and a zero duration dark frame if the scope is covered for both?

> > Terry Platt recommends that you do not apply dark frames to SXV-

H9 > > images, only bias frames. What I've been doing is a luminosity

of > > zero duration with the camera covered. Can someone help set me

> > straight?

>

> If it's subtracting a dark frame, it's because you turned on auto-

dark > subtraction. Turn it off (Settings tab).

>

> Doug

>

---------------

>

> Doug George

> dgeorge@c...

>

> Diffraction Limited

> Makers of Cyanogen Imaging Products

> www.cyanogen.com

>

> 100 Craig Henry Drive, Unit 106,

> Ottawa, Ontario, Canada, K2G 5W3

>

> Phone: (613) 225-2732

> Fax: (613) 225-9688

>

---------------



----------------------------

#8349 Sep 18, 2003

nickbtx wrote:

> Doug,

> Thank you for the fast response. I don't have "autodark" selected

> (the box is not checked). That was the first thing I looked at. Any

> other ideas?



On the Settings tab, there is a radio button, not a check box. Make

sure it is set to "None", not "Simple Auto Dark" or "Full Calibration".

If it is on None, then it will not subtract a dark frame when you use

the Expose tab.



There is a seperate control on the Focus Tab; that is a check box. It

only affects the Focust tab.



Doug



---------------



Doug George

dgeorge@...



Diffraction Limited

Makers of Cyanogen Imaging Products

www.cyanogen.com



100 Craig Henry Drive, Unit 106,

Ottawa, Ontario, Canada, K2G 5W3



Phone: (613) 225-2732

Fax: (613) 225-9688



---------------



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