Re: [APML] Another September Image

["Richard Crisp" <rdcrisp@earthlink.net>]

----- Original Message ----- 
From: "John C. Mirtle" <spampit@shaw.ca>
To: "Richard Crisp" <rdcrisp@earthlink.net>; "Discussion of Film
Astrophotography" <astro-photo@seds.org>
Sent: Tuesday, October 21, 2003 9:54 PM
Subject: Re: [APML] Another September Image


> Richard,
>     I don't think that it really matters which way is up so much, except
for
> the more established fields like the North America nebula. Here, I think
> that you probably want to keep Canada well up north and Mexico at the
> bottom, Pelican on the right. Everyone expects it that way. Putting north
at
> the top of every image would be very tedious, especially for those of us
> using an OAG, where the guide star could put the field orientation in
pretty
> much any direction. For myself - and I think most people on this list -
> "correct" image orientation is important. If nothing else, it makes it
> easier to identify other objects in the field against a star chart. I
don't
> know about other mail lists, but if you post a flipped image on APML,
> generally someone will point it out.

Good, I need the discipline :-)

>     I have been looking at your equipment lists and trying to figure out
how
> you could get a flipped image. This generally implies an odd number of

I am using a Traveller with a 0.75x telecompressor (AP) with my FLI IMG1024S
camera (25 x 25 mm sensor). No diagonal.



> reflections, which is not very common. The Schmidt camera has one
> reflection, so images here are reversed. I must remember to invert the
> negative before scanning. SCT's have two, refractors none. Are you
shooting
> with a diagonal?
>     I once submitted a flipped image to "The Observer's Guide", which was
> published in the Nov/Dec 1990 edition. (by Kepple & Sanner) It was a shot
> with a friend's 5" Schmidt. It has bugged me ever since...... :-)
>
> John Mirtle
> Calgary, Ab. Canada
>
> Oh... I can read music but can't play guitar!
>
> ----- Original Message ----- 
> From: "Richard Crisp" <rdcrisp@earthlink.net>
> To: "John C. Mirtle" <spampit@shaw.ca>; "Discussion of Film
> Astrophotography" <astro-photo@seds.org>
> Sent: Tuesday, October 21, 2003 10:01 PM
> Subject: Re: [APML] Another September Image
>
>
>
> ----- Original Message ----- 
> From: "John C. Mirtle" <spampit@shaw.ca>
> To: "Richard Crisp" <rdcrisp@earthlink.net>; "Discussion of Film
> Astrophotography" <astro-photo@seds.org>
> Sent: Tuesday, October 21, 2003 8:10 PM
> Subject: Re: [APML] Another September Image
>
>
> > Richard,
> >     You are right - the SII, Ha and OIII filters really do bring out
some
> > interesting structure in the nebula. I would like to try this tri-colour
> > using tech pan in my Schmidt, but it would require full aperture
filters.
> > Glass filters in the light path would knock it way out of focus.
> >     Just a minor point, but one of you guys has IC1396 flipped E/W......
>
> that has to be me. I just leave them whatever way they come out. I think
my
> system does a flip and I seldom change it: only in rare occasions like the
> NA nebula, who's name would make no sense if the image were mirrored or
> flipped :-)
>
> That brings up a question I asked about two years ago on a ccd group:
should
> images be presented in a particular orientation? Is it considered bad form
> to have an E/W flip (ie that's what I get with a particular scope, should
I
> correct it before calling it "done"?).
>
> I'm interested in the answer over here. Over in the CCD group the
> predominant answer at the time was "it doesn't matter". Maybe that's
because
> a lot of us are ignorant newbies and don't know the discipline of the real
> art like you film guys do: ie we can play lead guitar but don't read
> music...
>
> Richard
>

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