Hodgson Observatory

The 2007 South Dakota Star Party (the “SDSP”) was a great success with a total attendance of at least 45 people. Conducted by the Sioux Empire Astronomy Club (SEAC) here at Hodgson Observatory, the program began on Friday, September 7 with set-up and solar observations. Unfortunately the solar disc was blank, but the skies were clear, and a lot of discussion filled the air. After supper Friday night, we had beautiful views of the Milky Way, although well after midnight the dew began to accumulate on telescope optics.Our newly completed 8 x 10 foot Wide-Sky Observatory, its roof opening and closing problems solved by additional and improved counter weighting, was ready for inspection. Unfortunately, amid the many preparations for the SDSP, we did not have time to get the 8-inch telescope’s GoTo drive up and running. It is wonderful, however, to be able to see from horizon to horizon along the celestial equator in the night sky!

Saturday, September 8, mid-morning clouds moved upon us (although we got some good views of the rising crescent moon and Venus at dawn). The SDSP continued buoyed by a weather forecast promising some clearing about sundown.

We had a lot of informal discussions on astronomy through the day, and excellent meals together. As the Sun set, the skies cleared as promised. Two vans of astronomy students from Dordt College joined us, and everyone got busy looking at deep sky objects with a variety of telescopes ranging up to 25-inch aperture. For about two hours we had clear sky until suddenly, without warning, a low blanket of cloud cut off all photons from space. We all wondered what had happened. Cloud remained all night, but we all enjoyed a great “Astronomer’s Breakfast” on Sunday morning.  While we would have enjoyed more hours of clear night sky, the 2007 South Dakota Star Party was a great experience, and many friendships were deepened. We all look forward to next year!

Three of us observed on 2007 Sept. 15/16 from 8 p.m. to 12:33 AM (CDT) under clear skies and a light wind (until it increased late in the session). Astronomical seeing was fair to good (~ 7 on a 10 scale).

Brief observations of the crescent Moon and Jupiter were made at our new “Wide-Sky Observatory” — as we may wind up calling it — with the 203mm reflector (at 38x) and 80mm guide refractor (at 23x). Both were beautiful to behold. Probably a Barlow should be employed in the future to increase magnification, especially for the reflector.

Several physical problems need attention. The 8x50mm finder scope hindered tube rotation when positioned near the reflector’s eyepiece holder. This could be solved by moving the finder to the top of the 80mm refractor which has provision for it. There is also balance problem. When the reflector tube rotates it also changes the telescopes balance around the polar axis. Moving the 8×50 finder to a fixed location on the 80mm refractor should reduce, but not eliminate the balance problem. It was decided to work on these problems tomorrow in daylight, close the “Wide-Sky Observatory” and move the night’s activities to the Main Observatory.

Main Observatory operations with the 635mm aperture Dobsonian telescope began with a view of M75 on the eastern border of Sagittarius, first at 85x and then at 201x. Even at the latter power this globular star cluster was not resolved into stars, probably because of its considerable 59,300 LY distance.

Next the closer globular cluster M30 in Capricornus was observed with 85x and 201x. It is beautiful indeed! It was we resolved into stars almost to its core, aided by distance of “only” 26,000 LY.

Observations followed of two planetary nebulae in Delphinus that were new to all of us in the SEAC. The first was NGC 6891. At 85x it almost looked like a star, being bright and round, like the tiny disc of Neptune. When seen at 201x however, it was clearly the cloud of a violent stellar explosion which happened a few thousand years ago. It appears relatively featureless now.

The second planetary nebula was NGC 6905, a somewhat larger, semi-diffuse swirl of ejected material. Two brighter stars flank it. It was seen only for a few seconds at 85x in the 635mm Dob when strong southern winds hindered observation. John Johnson obligingly located NGC 6905 with his 510mm Dob, and provided a fine view at 200x. This planetary has some definite character to it.

After a coffee break, observations with the 635mm Dob resumed about 11:50 p.m. M31, the Great Galaxy in Andromeda was the next target. It was fairly well seen at 85x, although there have been better nights. The last target was M33, the Pinwheel Galaxy in Triangulum, 2.7 million light years distant, and its astonishing super-globular cluster NGC 604. What superluminous stars that stellar nursery must have to be readily seen at such a huge distance! Both were well seen at 85x.

Also present were Jim Morris and John Johnson who were very helpful, and hunted down a variety of celestial targets. They were particularly delighted to test the quality of an f/8 6-inch Meade reflector recently given to the SEAC. It turns out that its optics are excellent when used with high quality ED type eyepieces. Jim used many binary stars as tests, and its view of M27, the Dumbbell Nebula, was truly outstanding — it seemed as good as a 12 or 14-inch scope! Probably the longer f/8 focal ratio (compared with most f/4.5 and f/5 reflectors now made) had much to do with its performance on these narrow-field objects. All present had a great time!

On Friday evening, 2007 September 14, six SEAC members and friends gathered at Hodgson Observatory under a cold, dark night sky to observe the Milky Way and beyond. (By about 11 o’clock (CDT) the evening dew began to freeze, forming thin ice on the surfaces upon which it had landed, the first freeze of the season. That’s what we get for complaining of 100 degree heat a few weeks ago!)

Initial observing was done briefly in the newly completed observatory, looking at the crescent waxing Moon and Jupiter with the 203mm (8-inch) Newtonian reflector at 38x,  and its new 80mm f/11guide refractor telescope at 23x. The views of both objects were very satisfactory, but the GoTo drive was giving some difficulty, probably because of operator error, so we soon moved on to the 635mm (25-inch) Dobsonian telescope in the Main Observatory. (More practice with that GoTo drive system will be given in the near
future.)

The Main Observatory roof was all ready to be opened, and in just about five minutes observations began there. Using a 38mm eyepiece at 85x throughout the evening, a series of splendid Messier objects were enjoyed. First came M22, a large, well-resolved globular star cluster in Sagittarius. Next, farther north in the Milky Way came the famous open star cluster M11, “the Wild Duck” in Scutum.  In both cases these Messier objects appeared in the exact center of the field of view, the Argo Navis / ServoCAT drive system working at its best!

Following this, still farther north in the Milky Way M27, the famous “Dumbbell Nebula,”  a planetary nebula (i.e. a star that violently exploded a few thousand years ago), was viewed in Vulpecula. It appeared initially near the western edge of the eyepiece’s field of view — not the center — but its location was soon adjusted. We searched for evidence of a central star in this nebula, but none was seen.

We then left the Milky Way region of the sky, moving eastward to the well-known M15 globular cluster in Pegasus. Conditions were very good, and the cluster was fairly well resolved into stars. After a break for refreshments, we returned to view M31, the Great Galaxy in Andromeda, 2.7 million light years distant, and its dwarf satellite galaxies, M32 and M110. As we observed M31 we noted that the light dew that had been falling was turning to thin ice on the surfaces it had coated. Winter is coming.

At this point the group observing ended; Dick continued working by himself a few minutes to improve the collimation of the 120mm refractor on top of the big Dobsonian telescope with moderately good success. (Reported by RGH)

On Saturday 9/1/07, SEAC members met at the Hodgson Observatory to do the finishing touches to the new Observatory for the 8″ EQ telescope.

Here they are trenching for the data and power cables:

Here they are laying in the data cables and Power:

Fernando hard at work wiring the Observatory:

Anita filling in the Trench:

Jim Tamping the trench: