Hi Steve,
Great image.
I am a lot late to this thread as I wasn't aware anyone on IIS had imaged it. I only stubbled on this thread while searching for another thread on IIS re Murrell 1.
Just some info which you may or may not wish to correct in the notations on your website re this target.
This planetary nebula was only discovered in 2004 by Andrew Murrell of the Astronomical Society of New South Wales. The diameter is 105" x 100" and the magnitude of the central star is about 18. Apparently it has been seen in a 25" scope at TSP.
I think you have confused its visual observation at the real TSP with it's visual observation in a 25" telescope at the Deepest South Texas Star Safari, which is an event hosted by 3RF Australia and held at Coonabarabran every year. Andrew, myself and a few of our US visitors have observed Murrell 1 visually over the past 8 years at different times in the 25"/F5 Obsessions and 30"/F4.5 SDM
For those interested here is some more information on Murrell 1 and its discovery and verification.
Murrell 1
Type : PN
Co-ordinates : RA: 15 06 17.13 Dec -41 45 18.4 J2000.0
Central star mag: approx 18
Image link: http://stdatu.stsci.edu/cgi-bin/dss_...e&fov=NONE&v3=
Discoverer : Andrew Murrell, Mount Kaputar 21-Feb-2004
Verified: Brian Skiff, Lowell Observatory 22-Feb-2004
Verification image: Steve Lee, Coonabarabran 3-Mar-2004
Reported not in MASH database: David Frew, Department of Physics, Macquarie University 5-Mar-2004
Verification spectroscopy: David Frew, 2.3m telescope, Coonabarabran, circa 22-Jul-2004
Second to Andrew I have probably observed this target visually more than anyone else. I had previously only ever been able to observe it visually in telescopes of 25" aperture and larger. I had tried a couple of times in Andrew's 20"/F5 and while he was able to see it, I wasn't. I have also tried a few times in my own 18"/F4.5 without success. I have an ability to see deeper than most but I think Andrew must have a 20mm pupil dilation to see as deep as he does. Regardless of telescope size and observer skill, it requires good optics, good eyepieces, clear transparent skies, very dark skies, excellent dark adaption and high target altitude above the horizon.
At the most recent Ozsky event which finished last Friday (formerly Deepest South Texas Star Safari) I was able to observe it last Wednesday evening in James Pierces 16"/F4 SDM. The skies were very good and transparent and the target was located at zenith. Andrew, myself and James Pierce all observed it in the 16" scope. Several others on the field were able to observe it in one of the 25"/F5 Obsessions. Visually, it appears more triangular in shape than circular due to the lower brightness of a couple of the outer sections.
Irrespective of the telescope size it is a very dim difficult visual target. Notwithstanding that it may be above the horizon, I believe it is to far South to be successfully seen from locations as far North as Texas. Here is an account of our Texan friends Van Robinson and Jimi Lowrey's attempt to observe it visually in Jimi's 48"/F4 Newtonian. Jimi is located at Limpia Crossing Fort Davis Texas which is less than 10km from the Prude Ranch, which is the site of TSP
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Even though it is down near the dirt, we decided to give Murrell 1 a go through Jimi Lowrey's 48", here in the frozen hinterlands of the far North.
We had to lie in the cacti and kick the rattlesnakes out of the way to get to the eyepiece.
Using a 17mm Ethos which gave 330X, and a UHC filter, we squinted through the haze.
Nada.
--van
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Cheers
John B
