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Comets, Galaxies, Meteors And NLC's

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18 years 8 months ago #14397 by martinastro
Comets, Galaxies, Meteors And NLC's was created by martinastro
Hi all

I had a fantastic observing session last night. The clouds fizzled out at dusk revealing a lovely crystal clear sky! I went outside and uncovered the 16" to let it cool down, Arcturus was dominant in the bright twlight so i choose it as my guide star to align the telrad with the telescopic FOV and waited for darkness to arrive.

I Spent over 2 hours comet hunting very close to the sun and then into regions of increasing solar elonagtion within the S,SW,W,NW,N and NE sky. I swept up M10, M12, M14, M11, NGC4750 and a host of open clusters and binary systems from the NGC catalogue. I paused to examine the glorious sky tonight...yip, this is the best sky i have seen for months, so dark and clean with excellent trans (10/10). With the naked eye M31 looked at me..not the other way around!. The milkyway was beyond words as it stretched from the N horizon, arching overhead and into the S horizon like a bright well defined cloud complete with obscuring dark clouds, the mliky band then divided into two bright sections like an upside down 'Y' in the regions of Aquila and Serpens Cauda. Telescopically the star fields where utterly outstanding particularily in Scutum and Sagittarius. i could see stars to mag 6.5 with ease using the naked eye.

I took a break from comet hunting and decided to try and find comet 161P/ Hartley- Iras which has eluded me on many previous nights. I began a very slow vertical sweep in the NW sky in Draco moving through the comets location when i got my first suprise of the night. I found a new galaxy i had never seen before called NGC3735 which is a nice edge on mag 11.8 spiral that looked like a ghostly streak with sharp edges and bright galactic equatorial region. It was barley visible and could only be seen with averted vision...a nice find.

I continued on when i stumbled over 2 more brand new galaxies that had eluded me before. NGC4589 and NGC4648 (mag11.7 and mag12.6) where located close to each other within the same FOV and had the appearance of two elliptical grey patches of light with well defined edges, 4648 was slightly larger than its companion. I sketched all these objects and was about to move on when i spotted another fuzzy at the corner of my eye, it looked like another galaxy so i checked SA2000 which showed me that there was no DSO's in that area, then it dawned on me that i was looking at comet Hartley-Iras!! It was located in the same FOV as these 2 galaxies and slightly to the NW. I estimated it to be mag 11 and 2.5' in diameter, the coma was a grey elliptical patch with a very faint starlike false nucleus and a DC of 3/ It was very faint and to be honest it looked more like a galaxy than a comet, i heard the comet is very diffuse visually so perhaps i was looking at the inner coma? which itself had easy to see edges. The comet and 2 galaxies where a treat in the same field!

However one thing bothered me..the location of the comet was way of the BAA Ephemerides position by a considerable amount...confusing I would be grateful if someone could post a naked eye map of the comets location last night (31/1) from SNP as i have a few unanswered questions.

I resummed comet hunting, this time in Ophiuchus when i found a genuine comet suspect. The suspect was located in the N of that constellation at the midpoint of an imaginary line connecting Alpha and Sigma. I had searched through this area repeatedly for over 5 years and had never seen anything at this position before....my adrenaline started pumping fast and my hands began to shake a little. The suspect was a large circular patch of lively grey light hidden in a moderatley dense star field. It was VERY diffuse and had a very low surface brightness and got just slightly brighter towards the centre. At that moment i was convinced that i had discovered a new comet! i made a sketch but i was scared that my faint red light would make the object vanish as it was so delicate, just a little brighter than the back ground sky. I checked SA2000 again and oh oh it was another galaxy called NGC6384, a mag 10.8 barred spiral, if it had of been a comet i would rate it a DC of 1. I was actually over the moon because i had a bagged a very nice trophy, it was only on an exceptional night like this that i could see it so i felt very satisfied with my own personnal discovery I have uploaded a CCD image of this suspect below. Have a look at it yourself with your telescope and see how cometary it looks.

During the session i happened to spot 17 meteors, 11 Perseids and 6 Delta Aquarids. I also seen distant lightning flashes 3 times in quick succession. At this time Conor arrived back just as i was rounding up the night.

We spotted a growing NLC display low down in the NE sky. it was so low that it could have been easily missed. We raced out to the pitch but the view was not good due to lights from houses so we decided to head out to the country before dawn beat us to it. We ran with tripod and camera in hand until we found a perfect spot on a dark country road over looking the horizon. We got our camera out and started imaging. I was completely knackered from the run! The NLC was visible from 03.15 - 04.00LT and was a white/green colour with delicate curves. The display was of type 3 brightness and of type IVb structure reaching 5* high and a maximum of 20* wide. It was obvious and nice with the naked eye but difficult to pick up with the camera. i was shocked at just how qucikly they appeared then vanished before dawn. This had been my 7th display of the season.

The wanning crescent moon with earthshine was striking in the horns of Taurus and to its west was Aldebaran. In the SE i could see Fomalhaut and in the N Castor and Pollux had arrived onto the scene.! What a night this has been for me.....4 new galaxies to my collection, Comet Harltey-Iras found, lightning flashes and zipping meteors finished of by an NLC display. That comet suspect was very exciting for a time i can tell you

Below is a few images from the night....

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tinypic.com/9sfjmp.jpg

Martin Mc Kenna

coruscations attending the whole length of the luminosity, giving to the phenomena the aspect of a wrathful messenger, and not that of a tranquil body pursuing a harmless course..comet of 1680

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18 years 8 months ago #14398 by albertw
Replied by albertw on topic Re: Comets, Galaxies, Meteors And NLC's
try www.irishastronomy.org/user_resources/fi...7028-161phartley.pdf

The stars are only down to mag 7 or so, I can generate a better chart tomorrow if you like.

Albert White MSc FRAS
Chairperson, International Dark Sky Association - Irish Section
www.darksky.ie/

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  • martinastro
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18 years 8 months ago #14433 by martinastro
Replied by martinastro on topic Re: Comets, Galaxies, Meteors And NLC's
Thankyou very much albert.

That was just what i needed. :D

Martin Mc Kenna

coruscations attending the whole length of the luminosity, giving to the phenomena the aspect of a wrathful messenger, and not that of a tranquil body pursuing a harmless course..comet of 1680

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