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  #21  
Old 12-08-2017, 07:42 PM
Tropo-Bob (Bob)
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I viewed this with my Vixen 140mm refractor and tonight and did not see any starlike point. This tends to confirm my opinion from yesterday's observation that the point, which I saw was just a background star. I used 25, 18 and 14mm EPs.

The Comet was in the same field as the bright star Omicron Centaurus. However, as misfortune would have it, I became confused with my star hopping and it took me about 20 minutes to find the comet. If anything, having the bright star in the field also made peripheral viewing more difficult.
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  #22  
Old 12-08-2017, 08:09 PM
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I am following and enjoying your reports Bob.
I have the location maps ready for star hopping but am completely frustrated by the lack of clear skies. Tonight was looking promising but scudding cloud and fine driving rain appearing from no where has put and end to that. We have had fresh snow on the nearby mountains.
I hope I can log one last observation before it dims out of sight.
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  #23  
Old 13-08-2017, 02:27 PM
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Quote:
Originally Posted by Tinderboxsky View Post
I am following and enjoying your reports Bob.
I have the location maps ready for star hopping but am completely frustrated by the lack of clear skies...
Thanks Steve. Before joining this forum, I thought it was only me that suffered from terrible skies!

I see from the predictions tonight that the comet will pass very close to Omnicon Centaurus during the later part of this evening.

See: https://theskylive.com/comets
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  #24  
Old 13-08-2017, 03:07 PM
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Yes, I had noticed the predicted close encounter. It is currently clear here, so we will see what tonight brings. Hopefully Omnicon Centaurus is not too bright to drown out the faint coma.

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Originally Posted by Tropo-Bob View Post
Thanks Steve. Before joining this forum, I thought it was only me that suffered from terrible skies!

I see from the predictions tonight that the comet will pass very close to Omnicon Centaurus during the later part of this evening.

See: https://theskylive.com/comets
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  #25  
Old 13-08-2017, 06:34 PM
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Viewed tonight with my 115mm Vixen with 15mm EP.

Hard to see of course, but was outside of and on the northern side of the 'haze' around Omnicon Centaurius.
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  #26  
Old 15-08-2017, 08:25 PM
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OK, I have to admit to being a little confused here. Comet Johnson passes no closer than 35 degrees from omicron Cen. On 13/8, it more or less passed in front of 4.0 mag SAO 205839 - is this the star you mean?

Please forgive if I'm being dim.
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  #27  
Old 15-08-2017, 09:17 PM
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Hi Patrick
Yes, 205839 was the star that Comet Johnson passed very close to on the 13th. I think your reference to a 35 degree separation from Omnicon Centaurus should probably have been 3.5 arc minutes or less.
I have just come in from observing the comet - it is now very close to 8.63 mag star SOA 205900. It will pass in front of this star later this morning, our time.

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Originally Posted by DeepSkyBagger View Post
OK, I have to admit to being a little confused here. Comet Johnson passes no closer than 35 degrees from omicron Cen. On 13/8, it more or less passed in front of 4.0 mag SAO 205839 - is this the star you mean?

Please forgive if I'm being dim.
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  #28  
Old 15-08-2017, 09:29 PM
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At last, a night, without other commitments, and clear skies except for some high cloud low to the north.
Comet Johnson was clearly visible as a broad, very faint, diffuse glow. Moments of better seeing revealed a slight brightening in the central area, but no central bright spot. It is now close to 8.63 mag star SOA 205900. It looks as though itís path will take it directly in front of this star early tomorrow morning.
True to form the high cloud to the north had been growing as I searched for and observed the comet. Within 30 minutes of my observation, the sky was completely covered by thin high cloud! The same fate stopped me in my tracks for the last 3 nights - clear at dusk but clouded out be the time I had my scope out ready to search for the comet.
Well, at least I have caught a final glimpse of Comet Johnson before it fades from view.
Vixen NA140SS and LVW 13 giving 62X gave the best view.Seeing and transparency were only average.
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  #29  
Old 16-08-2017, 10:11 AM
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Quote:
Originally Posted by Tinderboxsky View Post
Hi Patrick
Yes, 205839 was the star that Comet Johnson passed very close to on the 13th. I think your reference to a 35 degree separation from Omnicon Centaurus should probably have been 3.5 arc minutes or less.
I have just come in from observing the comet - it is now very close to 8.63 mag star SOA 205900. It will pass in front of this star later this morning, our time.
Hi Steve. You keep typing 'omnicon' is that a misspelling of 'omicron', or another star altogether? Comet Johnson passed only 35 degrees (no mistype, I don't mean 3.5') from omicron Centauri. My charting software puts Johnson on top of SAO 205900 as well, so we're talking about the same comet at least!

Patrick
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  #30  
Old 16-08-2017, 11:05 AM
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Quote:
Originally Posted by DeepSkyBagger View Post
Hi Steve. You keep typing 'omnicon' is that a misspelling of 'omicron', or another star altogether? Comet Johnson passed only 35 degrees (no mistype, I don't mean 3.5') from omicron Centauri. My charting software puts Johnson on top of SAO 205900 as well, so we're talking about the same comet at least!

Patrick
Originally my bad with the spelling of Omicron. Also, I took the symbol from my "Bright Star Atlas" to be Omicron, but again, I may be mistaken.
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  #31  
Old 16-08-2017, 03:08 PM
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Originally my bad with the spelling of Omicron. Also, I took the symbol from my "Bright Star Atlas" to be Omicron, but again, I may be mistaken.
Yep, I am mistaken, as the bright star that Comet Johnson passed a few days ago was not Omicron. When I look more carefully, the star has "b" marked against it in the charts. There are many bright stars in Centaurus, so I can only assume that all the Greek letters were used before this star was designated.
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  #32  
Old 16-08-2017, 06:49 PM
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Ah! Right, thank you Bob. I thought I was going daft for a bit.

Patrick
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  #33  
Old 18-08-2017, 01:41 AM
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For what it's worth, here's an observation I made of the comet back in May, when it was above my horizon!

Located just over 2į from ε Boo at the time of the observation, it was washed out in the twilight. The head was fairly large and round. It grew gradually and then sharply brighter towards the centre. A twinkly stellar nucleus was occasionally visible. There was a persistent suggestion of a tail, long and thin, heading away from the head towards the south-east.

Cheers,
Patrick
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  #34  
Old 18-08-2017, 09:14 AM
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Thatís great Patrick. By the time of my first observation on 1 June here, Comet Johnson had moved well past and to the south of ε Boo.

I like your drawing. As they say ďa picture paints a thousand wordsĒ. How long did it take you to complete the drawing? I have wanted to try a couple of times but just have not made a start.

Quote:
Originally Posted by DeepSkyBagger View Post
For what it's worth, here's an observation I made of the comet back in May, when it was above my horizon!

Located just over 2į from ε Boo at the time of the observation, it was washed out in the twilight. The head was fairly large and round. It grew gradually and then sharply brighter towards the centre. A twinkly stellar nucleus was occasionally visible. There was a persistent suggestion of a tail, long and thin, heading away from the head towards the south-east.

Cheers,
Patrick
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  #35  
Old 18-08-2017, 06:35 PM
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I make a rough sketch at the eyepiece. That would take 5 minutes or so, then usually on the following day I'll make the full drawing. It's pencil on white paper then inverted using an image processing package.

I've been sketching deep-sky objects for over 40 years. In fact, I've sketched just about every DSO I've ever seen, apart from open clusters. I just write descriptions of those, usually. The same techniques apply to comets. I've only made a dozen or so observations of comets though, as opposed to something over 1300 DSOs.

Last edited by DeepSkyBagger; 21-08-2017 at 05:03 AM.
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  #36  
Old 22-08-2017, 02:53 PM
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Last night was clear with above average seeing and good transparency, so thought I would check in on Comet Johnson.
It was projected to be just next to a near 10th mag star HD 131186.
To my surprise I could just make out a very faint smudge of light surrounding the star with it being slightly more distinct with averted vision.
Tonight the comet is predicted to be between the two close stars HD 131488 (8th mag) and HD 131435 (7.15 mag), which is a very easy star hop from Kappa Centauri.
Iíll have look tonight if it is clear, but I suspect that the glare from these two stars may be too much for the very faint comet.
Vixen NA140SS with LVW13 giving 62X and 2.26 exit pupil.
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  #37  
Old 24-08-2017, 12:30 PM
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A final glimpse

Last night was clear with average seeing but quite good transparency So, I thought why not give Comet Johnson one last try.
The comet had moved between and past the two close stars HD 131488 (8th mag) and HD 131435 (7.15 mag) and was residing in a very faint star field with the relatively bright Kappa Centaurus lurking nearby and in its path.
The comet was visible with averted vision as the faintest broad smudge of light using a Panoptic 24 (33X and 4.25 exit pupil) but very difficult to retain sight of when looking directly at it. Kappa Centaurus needed to be kept out of the FOV.
Switched to an LVW13 (62X and 2.26 exit pupil) and the comet was easier to spot with averted vision and I could just hold sight of it looking directly at it.
I think this will be my final glimpse of Comet Johnson. It is forecast to be another clear night tonight, but the comet will be swamped by Kappa Centaurus. After that I think it will be beyond my scope as it fades further, some poor weather and an emerging Moon interferes.
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