Re: [ap-ug] Re: [ap-gto] M86 and the Realm of Galaxies


May 3, 2016

 


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#72975 May 3, 2016

Hello Roland,

Amazing image !

Just curious, do you have the SQM value for the "heavy local light pollution" sky that you refer to?

 -Kai

On May 3, 2016, at 15:09, chris1011@... [ap-gto] ap-gto@yahoogroups.com> wrote:



 

Hi All, Testing scopes and mounts in our observatory. Image centered on M86. Taken with AP 167mm aperture imaging refractor, 1000mm focal length. 20 x 10 minute exposures with QSI 683 WSG camera, scope mounted on AP 1600 mount.



www.buytelescopes.com/content/images/thumbs/4a9afac94223efb814b161350d76610db1875af4_realm-of-galaxies.jpg



Despite heavy local light pollution, the image shows dozens upon dozens of faint background galaxies down to mag 19.6. Rolando



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#72980 May 4, 2016

Thanks. No I have not measured the sky pollution. We have a lot of light from industrial and shopping corridor just down the road. Summer Milky Way not visible at all, only a few bright stars can be seen with unaided eye. We do get cold Canadian air coming thru periodically which reduces the atmospheric moisture and allows imaging of faint stuff. What is the best way to measure SQM? Rolando  -----Original Message-----

From: Kai Yang gugidon@... [ap-ug] ap-ug@yahoogroups.com>

To: ap-gto ap-gto@yahoogroups.com>

Cc: ap-ug ap-ug@yahoogroups.com>

Sent: Tue, May 3, 2016 8:55 pm

Subject: [ap-ug] Re: [ap-gto] M86 and the Realm of Galaxies





Hello Roland,

Amazing image !

Just curious, do you have the SQM value for the "heavy local light pollution" sky that you refer to?



 -Kai

On May 3, 2016, at 15:09, chris1011@... [ap-gto] ap-gto@yahoogroups.com> wrote:





 

Hi All,

 Testing scopes and mounts in our observatory. Image centered on M86. Taken with AP 167mm aperture imaging refractor, 1000mm focal length. 20 x 10 minute exposures with QSI 683 WSG camera, scope mounted on AP 1600 mount.

www.buytelescopes.com/content/images/thumbs/4a9afac94223efb814b161350d76610db1875af4_realm-of-galaxies.jpg

Despite heavy local light pollution, the image shows dozens upon dozens of faint background galaxies down to mag 19.6. Rolando



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#72996 May 5, 2016

The SQM refers to the Sky Quality Meter made by Unihedron. Their basic unit costs about 100 bucks, with more expensive models that provide USB and Ethernet interfaces (some observatories use those for continuous sky brightness tracking).



Readout is in mag/arcsec2 of course. They are supposed to be accurate to 0.1 mag/arcsec2.



There is also an app for the iPhone called DSM (Dark Sky Meter). The Pro version can be calibrated and they suggest using a Unihedron (the "gold standard").



Robert


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