Re: [APML] NGC7000 with a false comet ! (and Konica 400)

[Wei-Hao Wang <wang@IfA.Hawaii.Edu>]

Hi,

It's nice to see several NGC7000s from Dominic, Robert, Jason...
I have been looking at the comets for 4 days.  It's so boring.

Let me use my NGC7000 as a reference:
http://www.ifa.hawaii.edu/~wang/gallery/picutres/cygnus_tail.htm
On this page, I wrote Centuria Super 400.  This is wrong.  The
one I used is Centuria 400 (120) Professional.  I believe this 
is identical to Centuria 400 (135) sold in B&H and the word
"Professional" probably only means it's 120 format.  The boxes of 
the above two look identical.   They look different from the 
Super version shown in Dominic's picture (the one made Stuart 
laugh on the floor).  If you belive this (Centuria 400, not
Centuria Super 400) is a good film, you can get it from B&H.

The one I mentioned above is Centuria 400 Professional, which is 
old.  The newest one (120) is called Centuria Pro400.  So don't
be confused.

Now, how about Centuria Super 400?  John compared his M8 taken
with SG100 with Dominic's M8.  Another comparison can also be 
made on my and Dominic's NGC7000.  Dominic had F1.5 and 6 min
of exposure, which is equivalent to F5.1 and 70 min and is quite
comparable to mine.  This means, Dominic should have a density
similar to mine if there is no reciprocity failure and if both 
films (Centuria 400 and Centuria Super 400) are similar.

I agree with John in the sense that the density Dominic got is 
too low.  The possibilities are (1) Centuria Super 400 is not
as good as Centuria 400, or (2) the environment of Dominic's 
(temperature and humidity) caused a stronger reciprocity failure.
Which one is the case?  I don't know.  We definitely need more tests.

Cheers

Wei-Hao

______________________________________________________________________
Wei-Hao Wang  :)

Institute for Astronomy at University of Hawaii

Address:                       Phone: 808-956-9867                  
2680 Woodlawn Drive            Personal Website:
Honolulu, HI 96822             http://www.ifa.hawaii.edu/~wang
______________________________________________________________________



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