Patrick, Acording to Rob Ratkawski's phone call during the imaging session, the air was cold, clear, dry with no wind. What caused the stars to be "L" shaped is beyond me. Rodger ----- Original Message ----- From: "Patrick Wiggins" <paw@wirelessbeehive.com> To: "Utah Astronomy" <utah-astronomy@mailman.xmission.com> Sent: Thursday, January 21, 2010 7:15 PM Subject: Re: [Utah-astronomy] Wow!!! (SLAS Maui imaging session)
Hi Kurt,
Your comment about the tracking errors prompted me to look through images others have made using the 2-meter.
Many have shorter exposures but some were longer. But all had round stars.
I mentioned this to Bruce Grim and he wonders if maybe it was windy that night.
Something was off though as some of the stars were not just elongated but also L-shaped. Hopefully we'll have better luck in that department in future sessions.
On 21 Jan 2010, at 13:38, Canopus56 wrote:
Hola, como te va, Group?
Below are my imaging notes on doing a first pass stack and deconvole on the Faulkes M1 session. The results of these processing steps are in Utah Astro Gallery directory:
http://www.slas.us/gallery2/main.php?g2_itemId=2868
By posting these notes, I am working towards another version of the Crab from the Faulkes session and am simply thinking outloud about the image processing steps for the benefit of anyone how wants to follow along. Kibbutizing is welcome.
The end product objective is an asethetic, not natural observation version. Most of the images are underexposed and have tracking problems. So, don't expect the result to beat or meet a professional telescope equipped with adaptive optics, e.g. - http://antwrp.gsfc.nasa.gov/apod/ap040128.html
The idea here is get what can be teased out of the image and work with it.
The end product of the original pass processing step are the 8-bit images, posted in lossless jpg but available from me as 8-bit fits:
Green Channel http://www.slas.us/gallery2/main.php?g2_itemId=2869 201000115_origgreen_bit8.jpg
Red Channel http://www.slas.us/gallery2/main.php?g2_itemId=2873 201000115_origred_bit8.jpg
OIII Channel 20100115_origOIII_bit8.jpg http://www.slas.us/gallery2/main.php?g2_itemId=2875
Ha Channel 20100115_origHa_bit8.jpg http://www.slas.us/gallery2/main.php?g2_itemId=2877
OIII-Ha Difference image 20100115_origOIIIHaDiff_bit8.jpg http://www.slas.us/gallery2/main.php?g2_itemId=2879
Blue Channel 201000115_origblue_bit8.jpg http://www.slas.us/gallery2/main.php?g2_itemId=2883
Stars Only Channel 201000115_origstarsonly_bit8 http://www.slas.us/gallery2/main.php?g2_itemId=2881
The next imaging step will be to work with these 8-bit images in GIMP, a freeware analogue to Photoshop, and clean up some of the artifacts in each image. Clean up will be done before the individual images are assembled into a layer stack.
Since the nebulosity in the raw images was confined to less than 500 pixel values, there probably won't be any improvement by working with the images in an 8-bit (255 levels) as opposed to 16-bit levels.
By posting my processing notes, I hope I'm not boring the group.
Clear Skies - Kurt
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