Posts Made By: Dmitri Kulginov

Where can I buy pure (preferrably spectral grade) acetone in Florida?

Dmitri

Yesterday I looked in my 80mm refractor at some artificial stars and also at Vega at hight power >= 200x. With my Televue dielectric 1.25" diagonal the Airy discs looked like figures of eight! The effect disappeared with another diagonal and straight through. Is anything wrong with the diagonal?

Dmitri

Finally I have time to write a report from Rio de Janeiro where I have my 80mm refractor with me. In Rio there is a lot of light pollution, nevertheless I observed from the hotel roof a couple of times. Proxima Centauri was hard to see because it was low above the horizon, and hard to find because it is just a small star among other small stars - but I saw it. Seeing is not too good either, so Jupiter (albeit high in the sky), Alpha Centauri and Alpha Crucis looked not too impressive 8) Much more interesting were the bright open clusters with striking shapes and coloured stars - NGC 3766 and both Jewel Boxes, 6231 and 4755.

But last weekend I visited my friends in a small town in the state of Sao Paulo. We first went to a dark place on Saturday, but the weather was bad, and my friends had most fun with my green laser pointer. However, at sunset on Sunday I went to their back yard to check the seeing - and found it excellent. We looked at Jupiter where GRS was right in the middle, and then I noticed that Milky Way with Sagittarius in zenith was well seen already in the dusk! While it was getting dark, we looked at Alpha Centauri and Alpha Crucis - they were magnificent, with steady diffraction rings and brilliant Airy discs. Alpha Crucis is beyond any doubt the most beautiful multiple star in the sky. Antares was very close to zenith and I could see the companion as a tiny whitish knot on the outer edge of the diffraction ring.

After that we looked at Milky Way, first with the naked eye (I used the laser pointer a lot), and then with the telescope. M7 was the brightest knot of light easily seen without optical aid. M8 and M24 were almost as easy to see, M6 was a little dimmer. I finally got to know what Large Sagittarius Star Cloud and Scutum Star Cloud were - they looked like star clouds and showed uncountable stars in chains and other patterns at low power. I could see the galactic bulge and the great dark nebulosity in front of it, with winding dark rifts on the Cygnus side where Milky Way was well seen down to the horizon.

The Messier objects in Sagittarius and Scorpius looked like I had never seen them before. There was a lot of detail in M8 with UHC filter at 70x. I could finally see the dark lanes dividing the Trifid unfiltered at 90x. What is the ID of the double star in the middle of it? M16 looked like a sack of nebulosity with a ball of stars of equal brightness in it. (Did I see some dark lanes?) M11 withstood all magnifications from 20x to 140x. The galaxies, M83 and Centaurus A, were disappointing because of the city lights in the West, but no galaxy can compete with Milky Way! The Sculptor/Fornax galaxies would rise in the dark part of the sky later, but I had to go back to Rio. I concluded the night by observing the Helix Nebula where I could easily see the hole in the middle at low power.

Dmitri

The summer-like warmth is over in West Sweden, a cold front has passed. Before going to bed, I noticed there were holes between the slowly running clouds, grabbed my 80mm refractor, eyepieces and the chair and went to the back yard. The sky was really transparent, for the first time after two weeks of constant haze.

Last Monday I tried to find the Footprint nebula, first with the help of Pocket Star Atlas, then Uranometria 2000.0, then Millennium Star Atlas - all in vain. All I could see was a double star. Today I studied some photos, including DSS plates, and knew exactly where to look. At 190x with Nagler zoom I could see a 'third' star where the nebula should be, but only at times. Barlowed 4mm Burgess planetary (280x) provided a stable view plus, at times, I could see the 'Draco head' asterism that confirmed the find. I was surprised how the extra high power showed much dimmer stars - I could see up to 30 stars in M29 and steadily hold the 13m star next to M57.

Dmitri

Does anyone know a source of a good 50mm finder - straight through, correct image?

Dmitri

I have recently counted how much I spent on my astro gear. To my surprise, I spent almost exactly the same amount on telescope OTAs and mounting. The cost of accessories was 20% higher which I see as a disbalance. I think I must buy a new telescope with mount.

Dmitri

Steve,

Diffraction rings outside of focus are extra blurred by atmosphere. It sounds like you have got a decent lens. You should not expect from an achromat a text-book-star-test-for-a-Newtonian a la Suiter. You should only star test to discover collimation problems like coma.

Pay attention to images of the planets and the Moon in focus, try splitting some tight doubles - that's what matters.

Dmitri

. . . are they? What kind of glass do they use, how prone to misalignment are they, and what level of colour correction to expect?

Dmitri

The evening was clear (more clouds are coming), and I felt that I would go mad if I don't see some starlight after two weeks of cloudy weather, so I had a quick session with 80mm in my backyard.

I spent some time (more than I would like to) on two planetary nebulae, NGC 6886 and 6905 in Delphinus/Vulpecula. I don't think I've found 6886 which is very small, but I could see 6905 as a small dim cottonball building a small triangle with two stars. NGC 7006 followed; it is a very special feeling to look at a globular cluster on the other end of our galaxy, some 140,000 light years away! It was small and dim but distinctive at high power.

In spite of the street lights behind the house I decided to give the Veil a try. I saw both parts pretty easily with UHC filter and 24mm Panoptic, they almost fit in the same FOV. 9mm Nagler with filter gave a hint of detail in both parts.

I finished with NGC 7331, looking forward to the autumn galaxies and cursing the first cold (ah, observing in Florida with Ivan!).

Dmitri

Do they exist? Does anyone have one?

Dmitri