|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
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 |
#2
|
|||
|
|||
CCD Image of NEAT's Tail with Fuzzy Stars?
"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 |
#3
|
|||
|
|||
CCD Image of NEAT's Tail with Fuzzy Stars?
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. |
#4
|
|||
|
|||
CCD Image of NEAT's Tail with Fuzzy Stars?
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 |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
CCD Image of NEAT's Tail with Fuzzy Stars? | W. Watson | Amateur Astronomy | 1 | May 21st 04 04:02 PM |
apparent image size | Sarah Whitney | Amateur Astronomy | 63 | March 21st 04 04:20 PM |
Bands of Saturn. How many of them can be counted (really!) with 7" scope? | ValeryD | Amateur Astronomy | 294 | January 26th 04 08:18 PM |
New Image of Comet Halley in the Cold | Ron Baalke | Science | 0 | September 2nd 03 04:31 PM |
Stars rich in heavy metals tend to harbor planets, astronomers report(Forwarded) | Andrew Yee | Astronomy Misc | 0 | July 21st 03 05:45 PM |