ATM My first zonal measurement

[Bob Prabowo <BOB@bahana.co.id>]

Hi guys,

Thanks for the responses on my previous post.
And as usual, another question :-) but first...

I took a couple of masurements last night.  I use 5 zone mask, took 2
readings -- I wanted to take at least three readings but when I was
measuring zone 1 for the third reading, I bumped the tester. It was
completely dark, I dark-adapt my eyes for approx. 20 minutes and I used
my red flashlight to read the dial and write down the numbers (is it too
much?).

Prior to this reading (the night before) I decided to try 1/3 COC for 5
minutes after 1.30 minutes of cold press. BTW, my mirror specs is 330 mm
diameter, f.l 1,816.5 mm.  I use a dial gage with 0.01 mm increment

Zone             1              2               3            4
5
Hx              72.86     103.93   128.30    148.295  165.00            
Hm^2/R          0.178      1.065    11.865    2.632    3.377

Here's my result:
k.e position    
#1 reading      916     868     723     602     480     
#2 reading      915     876     741     618     504

I decided to use zone 1 as the reference zone therefore I didn't cut
this zone like the picture in Tex book. To make reading this zone easier
I made a circular hole in this zone about 25 mm diameter. This hole acts
as a separator of the left side of zone 1 and its right side. So, it's
easier for me to determine when the zone is null. This is my
understanding and I'm not really sure whether it's right or wrong.

Since I use zone 1 as the reference zone, the constant is -8.967 (0.183
- 9.15).
#1 reading      0.193   -0.207  -1.557  -2.787  -3.927
#2 reading      0.183   -0.287  -1.732  -2.947  -4.167
average         0.188   -0.247  -1.6445 -2.867  -4.067

Hm^2/R          0.178      1.065    11.865    2.632    3.377
        
That my first result with the Couder mask. Now my question:
1. Did I do it right? Is my measurement right?
2. The constant that I use is -8.967, do I use this same constant
through out the whole process? or do I change the constant for each
readings, because the constant for the second reading will be different,
#2 reading for zone 1 is 9.16 so the constant is -8.977?

3.If I input this measurement to the Fouc program, do I input the
"average" of the readings or do I input each reading to the Fouc? Or, do
I add another constant (in Tex'  it's 0.015") and then input the result
to the Fouc?

Well, I still have a loooong way to go but slowly and painfully I begin
to see the picture clearly. 
Thanks in advance for your advice,
Bob P. Sumitro
Jakarta, Indonesia

visit my still-under-construction astronomy and telescope making page:
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