Hodgson Observatory

Yesterday the south-wall drop-down feature in the Wide-Sky Observatory was completed so that the 203mm (8-inch) reflector and 80mm (3.15-inch) guide refractor can now look all the way to the southern horizon (horizontal).  To verify this the telescopes were swung down so they could view the base of the hills to the south with their full aperture without obstruction by the building wall or the corn crop, now cut. Now we will be able to go after objects at the hill tops, about minus 45 degrees southern declination. The building design works very well!

Northern Phoenix, northern Horologium, northern Centaurus, and all of Columba, Pyxis, and Antlia, here we come! What a joy it will be next spring to glimpse the super-galaxy NGC 5128  (Centaurus A) from southern South Dakota!   (It is about 43 degrees south declination.)

Dick

Boo!  (It’s Hallowe’en!)

Solar disk observed at Wide-Sky facility at Hodgson Observatory with 203mm reflector and 38.5x, at 2007 Oct. 31, 15h 35 to 41m UT (10:35 to 10:41 a.m. CDT). NO SUNSPOTS WERE OBSERVED after a careful  six-minute search of the disk. Negative observations are dull to read, but may be important. Active observers might wish to know.

On Monday evening, Oct. 29 (UT Oct. 30, 00h 25m to 01h 07m) Comet 17 P/Holmes was viewed in Perseus, a follow-up to the observation of last Thursday evening. The Wide-Sky facility at Hodgson Observatory was used. This time the sky was dark, the bright full Moon at perigee absent. Seeing was fair (6 to 7/10); transparency was ~ 5.5 based on UMi sequence, with a little harvest dust present. Used a 9x50mm finder refractor which showed the comet well, the 80mm (3.15-inch) f/11/4 guide refractor at 23x, and the 203mm (8-inch) f/4.9 Newtonian reflector at 38.5x and 100x. The best views generally tonight were with the 203mm at 38.5x. Seeing was not good enough for the 100x view to be superior. The 80mm refractor gave good views too, but tonight the 203mm was better.

Compared with last Thursday, the coma appeared larger, but that may have been due to much darker sky. I was surprised the comet had not moved much in the past 4 days — it is the slowest moving comet I have ever seen when it comes to its apparent proper motion.

The very bright nucleus was a single star-like point image; no signs of elongation were seen. The bright region of the coma lay entirely to the left side of the nucleus and tangent to it. This differed from last Thursday evening when the nucleus was in front of the bright coma, although distinctly asymmetrically placed toward the right side. (Orientations here are as seen with classical refractor and Newtonian reflectors:  images are reversed and inverted from naked eye views.)

Overall the brightness of the comet was not much changed from last Thursday, possibly a little fainter, but still approximately magnitude 3.5. (I did not carry on detailed observations to verify this value.).

I hope this observing note is of interest and help to others. Your observing notes are welcome!

– Dick Hodgson

Comet 17 P / Holmes suddenly brightened in late Oct. 2007 (24th). Watching it over several days showed that it was expanding and in motion towards Mirfak, in the constellation Perseus. I imaged it on a couple of nights and have the results here.

This image was taken on 10/25/07 with a 120mm F 8.3 Orion refractor. Afocal through a 17mm plossel eyepiece and a Fugi Fine Pix camera, zoom at maximum.

This next image was taken on 10/28/07 from same location and equipment. Time was 11:30 pm local. In this case the zoom on the camera was set at minimum for a wider angle shot. Notice a magnitude 9.03 star designated SAO24247, in the background of the coma. I watched this star move from beside the nucleus to the outer edge of the coma over a period of 3 hours.

I will continue to try and post images as long as the comet remains bright enough.

JJ

Latest Image from comet 17 P / Holmes shows the comet is now getting more diffuse and starting to dim. All images are with the same equipment and settings as from above. Image was taken from the Hodgson Observatory on 10/31/07 at 10:20 pm local time. The nucleus and inner coma remain very visible, and is expanding, however the outer coma has expanded so much that it is becoming very diffuse.

I had a chance to see the comet P/Holmes in Perseus last night with the 203mm (8-inch) f/4.9 reflector & the 80mm (3.15-inch) f/11.4 refractor in our new “Wide-Sky Observatory”  at Hodgson Observatory in rural Beresford, South Dakota. The temperature was in the low 50′s F. and falling; the wind calm; the very bright nearly full Moon near perigee.

Observation began 2007 Oct 26 at 01h 30m (UT), or October 25 at 8:30 p.m. (CDT) using a 9x50mm Orion finder scope. In this the comet was found without difficulty, looking oversize for a star, and more like the tiny disc of Uranus. In the 80mm refractor the comet was observed at both 23x and 91x. Then a switch was made to the 203mm reflector at 38.5x and 100x. The image was better in the latter telescope, but not by much of a margin.  (Don’t underrate longer focus refractors when it comes to observing objects in the Solar System!)

In both telescopes the comet displayed a bright, broad nucleus, nearly round with slight limb irregularities. The coma was slightly asymmetrical. No tail was seen, but given the very bright Moon in the eastern sky destroying the observer’s ability to acquire any darkness adaptation, and brightening the whole sky, a tail, if present, would probably be impossible to see.

I am sure many of you have and will be observing this comet with superior equipment to mine, but I would urge its continued observation, particularly after the bright Moon is no longer dominating the night sky. The dramatic rise in brightness of this object suggests strongly that the nucleus has sustained a major impact. Monitoring it may reveal brightness variations due to the nucleus’ rotation. It is also possible that a major impact (if that is the cause) might soon lead to a brake-up of the nucleus into two or more pieces. Such an event, should it happen, should be promptly reported.

I would also strongly recommend that observations of high quality be reported promptly to Sky & Telescope and to the IAU Minor Planet Center at the Smithsonian Astrophysical Observatory in Cambridge, Massachusetts.

I want to thank James Hoefelmeyer, John Johnson, and Doug Allen for their excellent reports of their comet observations. Let’s continue to share them!

Dick Hodgson

On Wednesday night, October 10, John Johnson (“JJ”), Paul Daugaard, and Leon Lewis  joined Dick Hodgson for a memorable night at Hodgson Observatory. While the two previous nights had been very calm, very dark and very clear, this night was to be the best, probably the best night of 2007, at least so far!

Participants all rated transparency excellent — with darkness adaptation one could see stars almost to 7th magnitude. Seeing was above average to good, a 7 or 8 out of 10 in my opinion.

JJ warded off dew and later light frost from his equipment with several ingenious heating devices. I observed in the Wide-Sky Observatory first with the 203mm reflector for two hours until dew began to be a problem, enjoying good views of Jupiter, M31 (the Great Andromeda Galaxy), M45 (the Pleiades star cluster), and M92, (a fine globular cluster in Hercules). The Wide-Sky Observatory was then closed down, and I opened the Main Observatory roof which had been previously prepared for opening. The big Obsession gave superior views of several of these Messier objects until frost forced closing the roof at 3 a.m. Sometimes two observatories can be better than one — although a lot can be said for JJ’s mini-heaters, and they cost less.

For sheer productivity, JJ’s Obsession had a terrific night. Highlights included superb views of M31,  M33 (the Pinwheel Galaxy in Triangulum), M13 (the Great Globular Cluster in Hercules), NGC 6173 in the remote Hercules Galaxy Super-cluster (~ 450 million light years distant), fine details of the Veil Nebula in Cygnus never seen by us before, excellent detail of the Trapezium mini-cluster in Orion, among many others. The icing on the cake for all of us was our first clear observation of the Horsehead Nebula in Orion, a famous dark nebula, using a Hydrogen Beta filter!  Thanks, JJ!

Observing continued until about 3:45 a.m. when clouds arrived.

On the evening of October 9 (2007 Oct. 10 UT date) observing conditions were quite similar to the previous night:  no Moon, no wind, and remarkably transparent skies. The 203mm (8-inch) f/4.9 reflector and 80mm (3.15-inch) f/11.4 guide refractor were both used to observe Jupiter & 4 satellites, and selected Messier objects.

The primary task was to test the Orion Sirius GoTo drive system, and to get more acquainted with its command functions. Messier objects 22, 11, 74, 31, 110, 45, and the star Kohab in Ursa Minor were all visited in that order. The positioning of Polaris was found almost “spot-on” from the previous night, but was given a slight “tweak.”  One-star alignment was used (Vega), but was done imperfectly, but objects were found with help of the 9 x 50mm finder scope, and then centered. All things considered, it was a satisfactory performance for the Orion Sirius GoTo system, but it is not as convenient as the Argo Navis system in my view. (Observing was done between 00h 35m and 02h 20m UT.)

What a joy it was to observe in the new observatory!  The roof opens very quickly and sufficiently to permit horizon to horizon observing for the southern half of the sky — and there is a lot of the northern sky visible as well. You can go from objects low in the SW sky like Jupiter and M22 right now to the Pleiades rising in the ENE in less than one minute if I wish without having to reposition heavy ladders and climb them. Wow! This Wide-Sky Observatory is a delight, particularly when available time is short, but you want to check on two or three targets.

If SEAC members have a special observing project that could make good use of the equipment in the new Wide-Sky Observatory, we would be glad to discuss the project with them, and make the necessary arrangements. We are always eager to promote small-observatory research projects of value, and to assist those involved in astronomy education.

After this evening’s observing experience, I was once more filled with appreciation for the insight and help received from family and friends whose wisdom and hard work refined the designed and constructed this new observatory: Dick January, for design refinements, my wife Nancy for design advice, lengthy discussions, and construction assistance, and the SEAC officers John Johnson, Jim Morris, and Fernando Nino, who. amid terrible summer heat, set up the walls, constructed the roof, made the electrical connections, and brought it all together. Thank you all!

The exiting new 8 x 10 foot mini-observatory at Hodgson Observatory swung into action last night. The new building is being called “the Wide-Sky Observatory” because it affords views from the eastern horizon through the southern horizon (when the corn is cut) to the western horizon. It also has some fairly good views in the northern half of the sky. (The older (2003) larger observatory, housing the 635mm (25-inch) Obsession, will generally be referred to as “the Main Observatory” if one needs to be specific.)

The Wide-Sky Observatory houses an Orion 203mm (8-inch) f/4.9 Newtonian reflector on a Sirius GoTo mount, and an 80mm (3.15-inch) f/11.4 Orion refractor riding on the same mount. The Wide-Observatory’s clamshell-type roof, now properly counterweighted, opens and closes quickly and easily.

Last evening was the first full-evening observing session in the new Wide-Sky Observatory. Here is a report of that session:

Observing began 2007 Oct. 9 at 00h 54m UT and ceased at 02h 45m UT. The sky was clear, dark (no Moon)s, and quite transparent, cleansed by recent rains. Astronomical seeing was ~ 6/10 (average). There was no wind, and no dewing until near the end of the session. RGH observed alone. Targets were as follows:

1. JUPITER and three satellites in the SW sky (observed from 00h54m to ~ 01h 14m) was best seen through the new 80mm f/11.4 guide refractor at 91x with a Sirius 10mm eyepiece. The larger reflector’s mirror had perhaps not adjusted to the early-evening temperature changes, but it was not happy at that point with higher magnification than ~38x. Also the refractor’s long focal ratio is regarded as an important asset in planetary observing.

2. MESSIER OBJECT # 22. Viewed from 01h 16m to 01h 35m, this magnificent globular star cluster in Sagittarius in the SW sky was best seen at 38x in the 203mm reflector, as its larger aperture gave an advantage over the 80mm refractor. The 80mm scope showed M22 well, even at 23x, its low power, but could not resolve any of the individual stars in M22. Careful examination with the 203mm scope allowed a count of 8 to 10 of the brightest of M22′s stars to be clearly resolved at the best moments of seeing.

3. MESSIER OBJECTS 31, 32, and 110 — THE GREAT GALAXY IN ANDROMEDA and two of its satellite galaxies — were viewed from 01h 38m to 01h 55m UT. These were examined with the 80mm refractor most of the time to see how the new telescope would perform. It did well at low power (23x), but for really low power I prefer the wide-field view (9.4 degrees) achieved with Nancy’s 8x40mm binoculars which showed the whole outer arms better (when seen at the 2007 SD Star Party). Before leaving M31 the satellite galaxies M32 was searched for and found with the 80mm at 23x. M110 was also seen briefly with that scope, but the view was marginal.

3a. While in Andromeda, a quick search for NGC 404, a small spiral galaxy near star Beta Andromedae was made next. (NGC 404 is easily visible in the 635mm Dob.)  At one moment I thought I saw this galaxy in the 80mm, but it was not seen with any certainty, so this is a negative observation.

4. MESSIER 33 in Triangulum was next faintly viewed ~ 02h 00m UT with the 9x50mm finder and the 80mm refractor. The very low surface brightness of M33, even at 23x in the refractor, was a problem. It was there, but not very exciting. I like the view in the 635mm Obsession far better!

5. THE PERSEUS DOUBLE OPEN CLUSTER (NGC 869 & 884, Caldwell Object # 14) was breath-taking in the 9x50mm finder, the 80mm refractor at 23x, and the 203mm reflector at 38x. A fairly wide field helps on this beautiful part of the northern Milky Way. Both telescopes gave very good views.

6. THE PLEIADES, (Messier 45) had risen in the NE when viewed ~ 02h 20m UT. Both telescopes gave excellent views, considering the low altitude of the target.

7. MESSIER OBJECT # 13, the Great Globular Cluster in Hercules, was the next target. It was impressive in both scopes, but neither gave any resolution of individual stars in this cluster, unlike M22.

8. MIZAR, the famous binary star in Ursa Major, was just split, but cleanly split, by the 80mm refractor at 23x. Wow! The split was wider when seen with the 203mm reflector at 38x. Time ~ 02h34m U.T.

9. GAZED AT THE MILKY WAY ABOVE AND TO THE
SOUTHWEST IN THE SKY. Naked eye is sometimes best!  I could see Messier 11. It was all magnificent, billions of stars in one glance! It is worth taking the time to look up!  Time: ~ 02h40m UT.   RGH