CCD Image of NEAT's Tail with Fuzzy Stars?

I had a brief opportunity to shoot NEAT last night with my ST-7E CCD camera. It was a
one minute exposure and the focus seemed good. Some of the brighter stars were round
and well lit. However, several in the tail appeared fuzzy and frazzled. Is this a
result of looking through the tail or maybe too short an exposure? I was using 1x
binning. You can see the details at
http://home.earthlink.net/~mtnv95959a/misc3.html. I adjusted the brightness and
contrast to make the fuzzy stars more obvious. The dark subtracted image produced an
image that was pleasing but hid the details of the image. Possibly it was the
conversion to jpg that did this.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

Your mother was right. Wear your hat and sunglasses in the summer sun.
This is especially true if you're older. -- NYT Science Section, May 2004

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html

"W. Watson" wrote in message ink.net...
I had a brief opportunity to shoot NEAT last night with my ST-7E CCD camera. It was a
one minute exposure and the focus seemed good. Some of the brighter stars were round
and well lit. However, several in the tail appeared fuzzy and frazzled. Is this a
result of looking through the tail or maybe too short an exposure? I was using 1x
binning. You can see the details at
http://home.earthlink.net/~mtnv95959a/misc3.html. I adjusted the brightness and
contrast to make the fuzzy stars more obvious. The dark subtracted image produced an
image that was pleasing but hid the details of the image. Possibly it was the
conversion to jpg that did this.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

Your mother was right. Wear your hat and sunglasses in the summer sun.
This is especially true if you're older. -- NYT Science Section, May 2004

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html

Hi Wayne,

The stars are trailed, which I’d attribute to your mount’s
tracking. Trailing always shows up first in the little stars. What
was the focal length of the scope and what is the mount?

If the dark didn’t improve the image, the dark was scaled
improperly. If you put in a scaling factor less than 1.0 the dark
subtraction should improve the image.

Clear skies,

Dennis Persyk
Igloo Observatory Home Page http://dpersyk.home.att.net
Hampshire, IL

New Images http://home.att.net/~dpersyk/new.htm

Dennis Persyk wrote:

"W. Watson" wrote in message ink.net...

I had a brief opportunity to shoot NEAT last night with my ST-7E CCD camera. It was a
one minute exposure and the focus seemed good. Some of the brighter stars were round
and well lit. However, several in the tail appeared fuzzy and frazzled. Is this a
result of looking through the tail or maybe too short an exposure? I was using 1x
binning. You can see the details at
http://home.earthlink.net/~mtnv95959a/misc3.html. I adjusted the brightness and
contrast to make the fuzzy stars more obvious. The dark subtracted image produced an
image that was pleasing but hid the details of the image. Possibly it was the
conversion to jpg that did this.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

Your mother was right. Wear your hat and sunglasses in the summer sun.
This is especially true if you're older. -- NYT Science Section, May 2004

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html


Hi Wayne,

The stars are trailed, which I’d attribute to your mount’s
tracking. Trailing always shows up first in the little stars. What
was the focal length of the scope and what is the mount?

If the dark didn’t improve the image, the dark was scaled
improperly. If you put in a scaling factor less than 1.0 the dark
subtraction should improve the image.

Clear skies,
Thanks. The scope is a C11 f/10, but I've got a 6.3 focal reducer on it. Could be
tracking. I was using the mount raw, since my autotracking facility (Parmount ME) is
out of order (using a laptop with no tracking data for the mount. my computer with
tracking corrections is broken). Odd though, 2x2 binning of other objects (m81,82)
for four minutes gave me some very good images. The bright star in the corner looks
reasonably round. Maybe the tracking is just off enough to give little wiggles that
dim stars magnify but bright stars smear nicely in the larger disks they produce.

Just sending the broken computer in today, so it'll be a week before I get it back
into operation. I'll probably do a small tpoint run to get some reasonable tracking data.

W. Watson wrote:

Dennis Persyk wrote:

"W. Watson" wrote in message
ink.net...

I had a brief opportunity to shoot NEAT last night with my ST-7E CCD
camera. It was a one minute exposure and the focus seemed good. Some
of the brighter stars were round and well lit. However, several in
the tail appeared fuzzy and frazzled. Is this a result of looking
through the tail or maybe too short an exposure? I was using 1x
binning. You can see the details at
http://home.earthlink.net/~mtnv95959a/misc3.html. I adjusted the
brightness and contrast to make the fuzzy stars more obvious. The
dark subtracted image produced an image that was pleasing but hid the
details of the image. Possibly it was the conversion to jpg that did
this.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet,
Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N,
121° 1' 0" W

Your mother was right. Wear your hat and sunglasses in
the summer sun.
This is especially true if you're older. -- NYT Science
Section, May 2004

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum:
home.earthlink.net/~mtnviews/imaginarium.html



Hi Wayne,

The stars are trailed, which I’d attribute to your mount’s
tracking. Trailing always shows up first in the little stars. What
was the focal length of the scope and what is the mount?

If the dark didn’t improve the image, the dark was scaled
improperly. If you put in a scaling factor less than 1.0 the dark
subtraction should improve the image.

Clear skies,

Thanks. The scope is a C11 f/10, but I've got a 6.3 focal reducer on it.
Could be tracking. I was using the mount raw, since my autotracking
facility (Parmount ME) is out of order (using a laptop with no tracking
data for the mount. my computer with tracking corrections is broken).
Odd though, 2x2 binning of other objects (m81,82) for four minutes gave
me some very good images. The bright star in the corner looks reasonably
round. Maybe the tracking is just off enough to give little wiggles that
dim stars magnify but bright stars smear nicely in the larger disks they
produce.

Just sending the broken computer in today, so it'll be a week before I
get it back into operation. I'll probably do a small tpoint run to get
some reasonable tracking data.

Some more imaging this weekend does suggest it's tracking, as you say. It looks like
the present mount arrangement gives better results the closer to the poles I get and
worse as I get to the equatorial. With my previous mount, I never quite had this
problem. It had so many other idiosyncracies I never noticed the dim star tracking
effect. Well, in a week or so I'll have my other computer back that has lots more
Tpoint data than I'm currently using.
--
Wayne T. Watson (121.015 Deg. W, 39.262 Deg. N, 2,701 feet, Nevada City, CA)
-- GMT-8 hr std. time, RJ Rcvr 39° 8' 0" N, 121° 1' 0" W

Your mother was right. Wear your hat and sunglasses in the summer sun.
This is especially true if you're older. -- NYT Science Section, May 2004

Web Page: home.earthlink.net/~mtnviews
sierra_mtnview -at- earthlink -dot- net
Imaginarium Museum: home.earthlink.net/~mtnviews/imaginarium.html