VintageBigBlue.org

 

Re: PE report and a new image


Jul 28, 2003

 


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

#16358 Jul 28, 2003

A couple of nights ago, I decided to try swapping RA and DEC worms on

my G11/Gemini to see if I can reduce PE . The result seems to be

positive. The peak-to-peak PE has been reduced from 9 arcsecs to

about 6. Here is a chart of the new PE behavior:



groups.yahoo.com/group/Losmandy_users/files/g11-pe.jpg



Here is an image that was acquired with this new worm arrangement on

the same night:



pk.darkhorizons.org/ngc6995.htm



So far, I'm happy I tried the swap :)



Regards,



-Paul



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

#16365 Jul 29, 2003

Paul,



Nice image as always :)



I was wondering, could you share what kind of image reduction you

apply to your images?



Do you just apply a dark-frame, or do you bother with bias and flat

frames too?



Take Care,



--- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@h...>

wrote: > A couple of nights ago, I decided to try swapping RA and DEC worms

on > my G11/Gemini to see if I can reduce PE . The result seems to be

> positive. The peak-to-peak PE has been reduced from 9 arcsecs to

> about 6. Here is a chart of the new PE behavior:

>

> groups.yahoo.com/group/Losmandy_users/files/g11-pe.jpg

>

> Here is an image that was acquired with this new worm arrangement

on > the same night:

>

> pk.darkhorizons.org/ngc6995.htm

>

> So far, I'm happy I tried the swap :)

>

> Regards,

>

> -Paul



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

#16367 Jul 29, 2003

Oh never mind.



I see you had the information at your website.



No dark frames? I guess you run your CCD really cold then?



Take Care,



--- In Losmandy_users@yahoogroups.com, "cjl023" james.lacey@m...>

wrote: > Paul,

>

> Nice image as always :)

>

> I was wondering, could you share what kind of image reduction you

> apply to your images?

>

> Do you just apply a dark-frame, or do you bother with bias and flat

> frames too?

>

> Take Care,

>

> --- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@h...>

> wrote:

> > A couple of nights ago, I decided to try swapping RA and DEC

worms > on

> > my G11/Gemini to see if I can reduce PE . The result seems to be

> > positive. The peak-to-peak PE has been reduced from 9 arcsecs to

> > about 6. Here is a chart of the new PE behavior:

> >

> > groups.yahoo.com/group/Losmandy_users/files/g11-pe.jpg

> >

> > Here is an image that was acquired with this new worm arrangement

> on

> > the same night:

> >

> > pk.darkhorizons.org/ngc6995.htm

> >

> > So far, I'm happy I tried the swap :)

> >

> > Regards,

> >

> > -Paul



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

#16375 Jul 30, 2003

Thanks James!



Starlight XPress cameras are based on Sony chips that have a very low

dark current, so I almost never use dark frames. I do clean up some

hot pixels in the final image before combining, but there are usually

only 10 to 20 of them, even in a 20 minute exposure. Since I don't

use darks, bias frames are also unnecessary.



I also rarely use flats. These are useful when there's a lot of dust

on the filter or the ccd window, and sometimes I do wish I had taken

one, but there's just too little time :)



Regards,



-Paul



--- In Losmandy_users@yahoogroups.com, "cjl023" james.lacey@m...>

wrote: > Paul,

>

> Nice image as always :)

>

> I was wondering, could you share what kind of image reduction you

> apply to your images?

>

> Do you just apply a dark-frame, or do you bother with bias and flat

> frames too?

>

> Take Care,

>

> --- In Losmandy_users@yahoogroups.com, "Paul K" pkane2001@h...>

> wrote:

> > A couple of nights ago, I decided to try swapping RA and DEC

worms > on

> > my G11/Gemini to see if I can reduce PE . The result seems to be

> > positive. The peak-to-peak PE has been reduced from 9 arcsecs to

> > about 6. Here is a chart of the new PE behavior:

> >

> > groups.yahoo.com/group/Losmandy_users/files/g11-pe.jpg

> >

> > Here is an image that was acquired with this new worm arrangement

> on

> > the same night:

> >

> > pk.darkhorizons.org/ngc6995.htm

> >

> > So far, I'm happy I tried the swap :)

> >

> > Regards,

> >

> > -Paul



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