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Re: (IAAC) Obj: NGC2903 - Inst: 30cm f/10 MEADE LX200




>(After dark adaptation I covered the observing eye for a minute or two, then
>quickly looked at the galaxy and the spiral structure is visable for a moment
>then fades into a featurless oval with a brighter nucleus, this can be repeated
>several times before fatigue overcomes the detail)

Jim, I wanted to thank you for contributing your fine, detailed logs with your
30cm SCT... Also, I was intrigued by the above comment, regarding loss of low
light sensitivity *while* looking through the eyepiece! What do you think were
the causes of that effect in this particular case? Was it that stray light at
your observing location was seeping into your eye during the observation? Or
perhaps light being scatter down the tube of the SCT from some distant light
trespass source? If it was either of these, then shielding may help you to see
more detail in future! (Adding a longish dew shield to the front of your tube,
to avoid light scatter; or covering your whole head with a black photographer's
cloth, if light seepage was a problem.)

Or is it possible that the effect you describe was actually due to a bright
field star, or true sky brightness in the field of view? If this is the case,
I'll have to confess that I've never noticed this effect! But your solution
of applying the eyepatch for a while, then quickly looking through the eye-
piece to capture glimpses of detail sounds like a good approach.

Clear skies, Jim, and thanks again for the logs!
Lew Gramer <owner-meteorobs@jovian.com>


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