Re: Solar Imaging with PST and ToUCam
- From: "canopus56" <canopus56@xxxxxxxxx>
- Date: 30 Oct 2005 16:46:53 -0800
Mij Adyaw wrote:
> Does anyone have any experience solar imaging with a PST and ToUCam? I am
> using a ToUCam that I purchased from Scopetronix with the eyepiece adapter
> so that you can insert the webcam into the diagonal. I cannot get the PST to
> focus in this configuration. The CCD device needs to be inserted farther in
> the diagonal in order to reach focus. Has anyone experienced this problem?
> Are there any adapters specifically for this configuration?
I am a beginner at this but, this is what I have found out so far.
The best web site on this topic that I know on is Paul Hyndman's
Astro-Nut website and his articles on "In Search of Solor Nirvana."
http://www.astro-nut.com/tips.html
Paul Hyndman's pages will show you what can be accomplished.
Basically, the PST has a fixed prime focus plane that you have no room
to play with in negative projection. So, you do an odd from of positive
or "afocal" projection. I has able to focus on a Meade DSI and on a
film camera using a 9mm to 12mm eyepiece. Then you have to directly
couple the camera to the eyepiece trying to place the imaging plane as
close to the eye relief distance as possible. With what play you can
get out of the PST focuser, you can get a kind of positive projection
on to the chip or camera's image plane. I was unable to focus using
longer focal length eyepieces, like 20mm, 25mm, or 32mm. Caution and
measurements with a ruler had to be used in positioning the cameras to
avoid running the eyepiece into the film camera focusing plane or the
CCD's chip.
Hyndman recommends using a TeleVue direct-connection adapter. See -
http://www.astro-nut.com/adapters.jpg
in http://www.astro-nut.com/sun.html
I believe Meade also makes a similar attachment.
I jury-rigged a coupler out of a 2" inch direct camera adapter. I cut
a foam block. The outside diameter fit inside the 2" camera adapter and
an inside donut hole cut went around the eyepiece and the PST focuser
housing. Then I could position the camera's imaging plane at or near
the eye relief distance.
Hyndman's Ha image processing pages are a must read. In my images, the
raw images of the solar disk were nearly featureless. Most of the
information on the solar disk is either in the grayscale image or, in
my case, the red channel. Hyndman's web pages show more detail in the
blue and green channels.
http://www.astro-nut.com/solar-nirvana2.html
The point is, don't look at the raw color image alone. Check each color
channel separately and make a grayscale.
Good tracking on a solid equatorial mount is also essential. Although
the exposure time is short, the linear height of the details in the
disk and the prominences are small.
Here's a sample of my beginner attempts on a day with a quiet Sun and
no sunspots. Not much to look at - but it was a start.
http://members.csolutions.net/fisherka/astronote/photos/20051023PSTHafullsun.jpg
http://members.csolutions.net/fisherka/astronote/photos/20051023PSTHamagnified.JPG
None of these pictures bring out the detail in the prominences that can
be seen with the naked-eye at the PST's eyepiece. For example, in my
photos, the southern prominence consisted of about 8 individual strands
of gas, while the photo only shows a single area.
See also Maurice Gavins's website, Maurice frequently posts his solar
Ha pictures taken with a PST and Canon digital camera.
http://home.freeuk.com/m.gavin/pstmg.htm
There's also a yahoo PST group.
- Canopus56
.
- References:
- Solar Imaging with PST and ToUCam
- From: Mij Adyaw
- Solar Imaging with PST and ToUCam
- Prev by Date: Re: Ebay scope
- Next by Date: Re: buytelescopes.com trustworthy?
- Previous by thread: Solar Imaging with PST and ToUCam
- Next by thread: Re: Solar Imaging with PST and ToUCam
- Index(es):
Relevant Pages
|
