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M20 Trifid Nebula in LRGBHa

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Posts Made By: Dmitri Kulginov

November 16, 2005 10:22 PM Forum: Solar System Observing

Mars sketch 16 November 2005

Posted By Dmitri Kulginov

C8, Nagler 9mm T6, UT about 21:00, rather bad seeing.

Dmitri

November 22, 2005 08:49 AM Forum: Deep Sky Observing

What to look for in the Magellanic Clouds

Posted By Dmitri Kulginov

I might soon have a chance of looking at the two with 80mm. What should I look for? Any maps/guides/reports to recommend?

Dmitri

November 29, 2005 07:16 PM Forum: Deep Sky Observing

Help me to justify 4"

Posted By Dmitri Kulginov

A thought of having a 4" achromat has been visiting my mind lately. What good can 4" refractor be along with C8 and ST80 - specifically for deep sky? Can it add anything that I don't already have?

Dmitri

December 5, 2005 01:48 PM Forum: Deep Sky Observing

Rio

Posted By Dmitri Kulginov

Here comes my first report from Rio de Janeiro. The weather is bad, the only clear evening yesterday. Transparency was bad. Unfortunately they didn't let me to observe from the roof of Sheraton (I'm not staying there) that overlooks the dark South over the ocean, so I had a short session in the rather brightly lit yard of my hotel. I didn't just go to the beach because I want to keep my scope for myself. . . No trace of SMC, but I looked at some showpieces nevertheless.

Globular clusters:
47 Tucanae, 100x - Huge, a bright cirular concentration (that looks grainy) is surrounded by a fading halo of outlying stars. Definitely better framed in my 80mm than Omega Centauri! Diameter with outlyers at least 9'.

NGC362 - concentrated with bright but not star-like core; grainy at 100x. It was put there to make a contrast to 47 Tuc.

Galaxies:
NGC1316 - detected at 22x, small at 40x, rather bright; a stellar core.

NGC55 - detected at 40x - no more than lumpy darkness...

NGC253- seen at 22x, worse at 40x. Huge!! Seems mottled. An outstanding galaxy; should be a killer sight given dark skies. In a way, it's better than M31. [ Thomas, I know you would have loved the view! ]

January 18, 2006 03:38 PM Forum: Deep Sky Observing

High level of folk astronomy in Norway

Posted By Dmitri Kulginov

We recently went to ski in Norway (much criticised by Inge for its observing conditions). When there was no Moon, the Milky Way was obvious and I enjoyed good binocular views of the big galaxies M31/32/110/33.

One evening we went to a local stable to look at the horses. Unexpectedly, I had an astronomy chat with the old lady who runs the place. She mentioned some constellations, and I showed her a new one - the Swan. Then she told me how they predict extreme cold: it will be freezing if there is a lot of lumps (klumpar) in the Milky Way. That is, when they see a lot of open clusters with their naked eyes!

Finally, the Milky Way is called The Milky Way in Norway, not The Winter Street like in Sweden.

Dmitri

January 24, 2006 12:57 PM Forum: Refractors

Longitudinal CA -> focal shift

Posted By Dmitri Kulginov

Is it possible to extract focal shift values from a longitudinal chromatic aberration graph? I guess one crude possibility will be to make a section at 70% of aperture. How good is this rule and where does it come from?

Dmitri

February 11, 2006 09:58 AM Forum: Refractors

WO fluorite doublet design

Posted By Dmitri Kulginov

I've just shone a green laser into the objective glass of my ZenithStar FD. The laser light scatters in both lenses, which means that neither of them is made of fluorite crystal (to my relief). I can also see that the front lens is negative and the second one is positive, and there is a rather wide, a few mm, air gap.

The colour correction is very good, I can see a small (5-7 Airy disc diameters) weak violet halo on bright sun reflexions and also on very distant luminiscent lamps, but I cannot see any colour on Moon or Vega.

Would anyone care to comment on the design?

Dmitri

March 2, 2006 09:38 AM Forum: Deep Sky Observing

Re: DSO details with a Celestron 8i

Posted By Dmitri Kulginov

Mike,

You will see A LOT of details in all kinds of DSO. Bright cores of different shapes, dust lanes and sometimes spiral structure in galaxies, plenty of stars in open and globular clusters, detail in planetary nebulae. 8" is always better than 5" on DSO, even if the 5" is a very expensive APO [ ducking ].

Dmitri

March 24, 2006 09:57 PM Forum: Deep Sky Observing

Me too, me too...

Posted By Dmitri Kulginov

Thomas, Inge,

Thanks for very inspiring reports!

As a matter of fact, I was also out to my dark place on March 20/21. I observed with my C8 with F6.3 reducer. GOTO let me to look at some 30 galaxies (plus the Ghost of Jupiter) and also spend some, sometimes considerable, time with each of them. To the question of seeing details in galaxies with 8 inches: For the first time, I saw the spiral structure in M51 - an awesome sight! (Took me perhaps 25 minutes to soak in all the details.)

The second amazing observation was of NGC 2403, a galaxy in Camelopardalis. I looked at it for a rather long time trying to understand what I saw. The effect was at the limit of my vision, and in the end I logged: There seem to be curved dark lines [ in the fabric of the galaxy ] between the two stars [ a couple of 10m stars in the foreground ]. I was hugely surprised when I saw tightly wound dark lanes on the photo of this galaxy in NSOG!

I finished the session with panning slowly along the Markarian chain - a totally mind-blowing sight! One of the strongest experiences a man can get.

Dmitri

April 5, 2006 11:48 AM Forum: Deep Sky Observing

Mexico City

Posted By Dmitri Kulginov

Here is my report from Mexico City.

Contrary to my expectations, I found the skies rather clear and not very light-polluted, at least to the South proper. This is because my hotel was on the elevated Southern rim of the city whose boul filled with smog could be seen in the North. I observed from the hotel terrace that featured a grotesque 10m high chair installed on it for advertising (of what?). Because of the time difference I woke up every morning at 3 to 4am and went to the terrace, which gave me access to Scorpius/Sagittarius area and Jupiter. I observed four mornings for one to two hours. All mornings were clear, and all evenings were cloudy, so I hadn't looked at Sirius - I was too sleepy after 6pm anyway. Seeing was worse than I expected, but one morning it was around 8. I used my 80mm APO on a light Bogen tripod with geared head, a bit shaky but light and good for travel. My faithful Karkoschka, red lamp, MP3 player or mobile phone for logging, Ultima 30 and 18mm and 2x Barlow and Burgess TMB planetary 4 and 6mm completed my setup (I wisely left Naglers and Panoptics at home).

My primary targers were Jupiter and Antares (I hope Inge will not delete my post because of that). Jupiter was high up and stunning. I saw a lot of small details in NEB, long oblique white ovals and blue festoons in NEZ, thin interrupted EB, bright STZ sharply defined against SPR. Once I saw Ganymede transit - its bright dot was very obvious against darker NPR. Later GRS rotated into view, with a hint of detail inside it.

I could not resolve Antares on the first night. The second night the seeing improved, but I still could not see the companion. At dawn I gave it another try at 300x - and there it was, a small white star on or just outside the pale orange diffraction ring, preceding. It was easier than Eta Geminorum. I knew the position angle, but I managed to ignore the separation, so I didn't known what to expect. I could see the companion the next night as well; to check that I was not fooling myself I looked at Epsilon Bootis that was in zenith - and I saw a fat blue star sitting on the diffraction ring!

At this point I realised that I could run the Southern leg of my Messier survey. Scorpius was stunning, I've never seen it so high before. The views of globular clusters were much better than I had from Italy in ST80. M4 was extremely beautiful - resolved at 90x except for the central vertical bar with its vertical chain of stars on the nebulous background. It took half of FOV at 140x. M80 showed a star-like core, grainy halo and some outliers. I had an impression of total resolution in M22; there was a dark intrusion from beneath on the following side. The other globulars showed not much resolution but a huge variety in size, brightness and concentration. M30 was most difficult to find at dawn; I could only detect it at high power.

80mm of aperture shines on open clusters, and there is a lot of them in Scorpius. M7 could be seen by naked eye as a large nebulous spot. At 20x it was a fabulous sight - widely thrown brilliant apochromatic white-blue stars arranged in groups. The Northern Jewel Box was a tight group of six bright stars with a lot of smaller stars around them. M6 really looked like a butterfly, but I find it more interesting to try to imagine its 3D structure instead of joining dots.

The second night was most transparent of all, and I had very good views of the diffuse nebulae M8 and M17. I only made two mistakes here - forgot my UHC filter at home and missed M16 on the map in the dark. I could see bright nebulosity in Trifid, but no detail. At last I had a good view of M24 - it was really a could of bright, small and very small stars at low power. High power showed a nebulous background behind them, all cut by dark lanes of galactic dust. At one point I was scared by coming clouds - only to realise that it was Milky Way in Sagittarius!

I spent a lot of time with the single galaxy of the trip, M83, and its neighbour M68. 3am was really a little too late for them, and I didn't have good views. M83 was more like lumpy darkness, very mottled and rather large. At high power I could clearly see a round nebulous core forming an obtuse triangle with two stars at its sides. M68 was grainy and only weakly concentrated.

My last target at the dawn of the last day was Venus, sharp and brilliant. The lit side had two small horns - refraction of light in planet's atmosphere.

All in all, it was my best astro-travel so far (even though the views of Eta Carinae from Brazil make a good competition). The food was very good, and the Mexican people are very helpful and honest - I got back my back pack with my passport, computer, camera, MP3 player and other stuff that I left in the taxi after 18 hours on the road.

Dmitri