[Aavso-photometry] Rope Light Illumination for Flats

[Donn Starkey]

Steve:

I took 5 B band flats using twilight illumination and 5 B band flats using the
light ring illumination on the dome screen.  I averaged each set of flats and
then created a new frame that was composed of one set of flats divided by the
other.  The brighter of the two flats was scaled down to equal the average
pixel intensity of the darker of the two flat before creating the new frame.
This action offsets the differences in inherent brightness of the two frames.
Each frame was in the 17,000 range for average pixel brightness.

The new differential frame had the following values:
Maximum	     1.142
Minimum	     0.763
Average	     0.938
Std Dev	     0.005

The two averaged frames are available at:
http://starkey.ws/FTP%20Page/Bu%20Flat%20Frame%20Set.ZIP

On the Blanc Fixe coating, my company can supply it in quart containers.
Anyone that wants to purchase it should contact me off-list for details.

"Talent", to paraphrase Rush Limbaugh, "is only on load from God."

Donn

==============================================
The price of freedom is constant vigilance.
Donn Starkey
starkey73 at mchsi.com
http://www.starkey.ws
AAVSO Observer SDB  -  CBA Indiana
VSNET Observing Team  -  MPC Code H63
==============================================

~ -----Original Message-----
~ From: Brady, Steve [mailto:sbrady at kerkmotion.com]
~ Sent: Thursday, January 13, 2005 10:07 AM
~ To: starkey73 at mchsi.com; aavso-photometry at mira.aavso.org
~ Subject: RE: [Aavso-photometry] Rope Light Illumination for Flats
~
~
~ Donn--
~
~ Thank you for your description - I am stimulated to duplicate your
~ setup!! I can check with Lumetron on availability of the coating
~ but wonder if this is something that could be purchased through you
~ / your company in quantities (cost??) that are appropriate for an
~ amateur needs. Out of curiosity, have you compared your domes flats
~ to twilight flats?
~
~ I very much enjoyed browsing your web site - your a man of many talents.
~
~ Clear skies,
~
~ Steve
~
~