June 2008 - Utah-Astronomy - mailman.xmission.com

Re: [Utah-astronomy] RE spectrometer links
by Canopus56 06 Jun '08

06 Jun '08

Jerry and Chuck, After thinking it through some more, it looks like the way to go is Jerry's original neon light suggestion. I was trying to avoid another Radio Shack electrical hobby box project, but guess it will have to be part of the fun on this observing skill. - Kurt http://www.radioshack.com/product/index.jsp?productId=3014501 http://www.radioshack.com/product/index.jsp?productId=2102794

1 0

Re: [Utah-astronomy] RE spectrometer links
by Canopus56 06 Jun '08

06 Jun '08

Jerry, Thanks for the tips. For pen lamps, I was thinking professional calibration lights - http://uvp.com/penraylightsources.html which cost several hundred dollars. >From other newsgroups, it looks like the low-cost solution is a garden variety compact flourescent bulb, some of which have distinct spectral lines (spectral graphs are below the screen fold) - http://ledmuseum.home.att.net/spectra7.htm Since I am using a slitless stellar grating, such extended sources cannot be used directly. One suggestion was to put the light in a box with a low-cost slit installed in one end. Then the light source should produce a specturm when held in front of telescope equipped with a slitless stellar grating. Thanks again, Kurt

1 0

RE spectrometer links
by Jerry Foote 06 Jun '08

06 Jun '08

Hi Kurt, A pen light would give a continuous spectrum (actually a black body distribution) and not show calibration lines. A good source for calibration lines is a neon bulb running on AC current as might be found on many kitchen appliances to indicate that they are on. There are many lines in the red portion and a few dim ones toward the green. As you want the source to be as stellar as possible mounting it a ways away on a nearby wall will reduce the "glow" size. Picking a bright hot star with plenty of emission lines will also serve as a rough calibration. I have many times thought of an objective prism for the telescope ala, Henrietta Leavitt and Anne Jump-Cannon. Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-216-5450 jfoote(a)scopecraft.com

2 1

Color imaging CCD camera for the Northridge HS telescope
by Wayne Sumner 05 Jun '08

05 Jun '08

Hi all, At long last the foundation and telescope base for the Northridge observatory has been poured, and work is progressing. I am looking very seriously at the brand new 6 Megapixel, TEC cooled CCD color imaging camera just put on the market by Orion. At $1300, it's only slightly more expensive than the 1.4 Megapixel units already out there, and considerably cheaper than the other comparably sized units available. This unit uses the Sony 23.4 mm by 15.6 mm CCD chip with a 3032 by 2016 pixel array. Pixel size is 7.8 by 7.8 microns. I realize I would be an early adopter since it's new on the market, but Orion has been very good to me in the past with support and exchange of defective products. Any advice from you experienced users of CCD imagers would be carefully considered and gratefully accepted. This device is featured on the Orion web site, www.telescope.com if you'd like full details. On a different subject, I have 20 Orion model #05690 Lasermate Deluxe Collimators and 20 Orion model # 07212 9x50 mm erect image, right angle finders that I would like to sell or exchange for 20 15mm wide angle eyepieces. I just finished this year's 3-day teacher workshop where each of the 20 participants received an Orion XT8 telescope. I replaced the finders with telrads, and kept the laser collimators since I've learned that most teachers don't know how to use them anyway. Last year the Clark Planetarium was willing to work with us on this, but since they still have unsold product from last year, they don't want to deal this year. I've called Orion, and they also have refused. Their list prices on these two items are $64.95 and $79.95 respectively, for a total retail value of $2900. If I could get even half retail value, that would pay for the color CCD imager! I've thought about Craig's List or ebay, but wonder what you guys (and girls) think. Thanks in advance for your always kind and useful advice. I learn a lot reading your exchanges, even though I don't often have time to get involved in the discussions. Wayne A. Sumner Math/Physics/Astronomy/Engineering Boy's Tennis Coach Northridge High School Davis School District (801) 402-8610

2 1

Spectroscopy links
by Canopus56 05 Jun '08

05 Jun '08

Thanks, Jerry. Those all look like great links. I'll put them to good use. On another note, since I'm using a siltless stellar grating setup, can I calibrate with a pen light source, e.g. a halogen desklamp? Or is that kind of calibration limited to slit spectrometers? - Kurt

1 0

Spectroscopy links
by Jerry Foote 05 Jun '08

05 Jun '08

I have had an interest in Spectroscopy for many years and even went so far as to build a grating spectrograph for my telescope. It was in the early days of CCD's and all I had was a linear CCD. The alignment proved to be almost impossible so I abandoned the project. The interest still remained. Here is my collection of URL's on spectroscopy: http://www.fiz.uni-lj.si/astro/as_mon_1/iraf.html http://www.eso.org/projects/caos/ http://www.astrosurf.com/buil/ http://www.fiberguide.com/ http://www.jobinyvon.com/SiteResources/Data/Templates/1main.asp?DocID=2&v1ID =&lang= http://users.erols.com/njastro/faas/ http://astrosurf.com/thizy/lhires3/index-en.html http://www.shelyak.com/ http://mais-ccd-spectroscopy.com/ http://www.astroimagem.com/Espectro/spectroscope.htm http://astrosurf.com/vdesnoux/sas/sas.html http://tech.groups.yahoo.com/group/spectro-l/ http://www.astrosurf.com/buil/us/book2.htm http://astrosurf.com/vdesnoux/ http://www.spectrashift.com/ http://www.astroman.fsnet.co.uk/index.htm Enjoy. Jerry Foote ScopeCraft, Inc. 4175 E. Red Cliffs Dr. Kanab, UT 84741 435-216-5450 jfoote(a)scopecraft.com

1 0

Field trip rep - Clark Planetarium Science-on-a-Sphere projection globe
by Canopus56 05 Jun '08

05 Jun '08

Last Friday (5/31), I went to Clark Planetarium ( http://www.clarkplanetarium.org/ ) to look at their new acquisition - a Science-on-a-Sphere - display globe. In summary, the SAOS sphere is sufficiently interesting that the club might want consider asking for a special presentation of the sphere with an astronomical theme as a field trip for one of our summer monthly meetings. This is one of 20 nationwide deployments of the NOAA's Science-on-Sphere initiative. http://sos.noaa.gov/ NOAA's Science-on-Sphere is a 6 or 7 foot diameter movie screen that is shaped as a sphere. http://gallery.utahastronomy.com/main.php?g2_itemId=11467 The globe screen is surrounded by four ceiling equilaterally mounted computer room-light computer projectors. These are computer projectors with sufficient power to display in ambient room lighting. http://gallery.utahastronomy.com/main.php?g2_itemId=11471 The result is that any three-dimensional globular object can be projected on the sphere in 3D, such as: Earth http://gallery.utahastronomy.com/main.php?g2_itemId=11473 Jupiter http://gallery.utahastronomy.com/main.php?g2_itemId=11475 Mars http://gallery.utahastronomy.com/main.php?g2_itemId=11477 or the Moon - http://gallery.utahastronomy.com/main.php?g2_itemId=11479 The project sphere's educational strength is to display animations, e.g. - rotating planets, weather patterns and geologic processes. A hint of the sphere in animation mode can be seen in the following two low-resolution videos that I captured last Friday: members.csolutions.net/fisherka/astronote/photos/EarthWeather.avi 2.75Megs low res members.csolutions.net/fisherka/astronote/photos/MarsRotation.avi 1.6Megs low res Higher resolution example videos of currently available projections can be seen at the NOAA Science-on-a-Sphere website: SOAS demo movies webpage http://sos.noaa.gov/gallery/index.html Consistent with NOAAs Earth science focus, most of the 150 available animations deal with the weather. For example, 24 hours of near real time weather satellite imagery can be displayed, a 400 year history of Earth's magnetic lines or a topographic Earth. Topographic Earth http://gallery.utahastronomy.com/main.php?g2_itemId=11481 For astronomy, they also a great set of planetary and solar animations that allows you to look the planets in large size and in animated rotation. You are probably asking yourself, as I did, with a big shrug, "So what? I can already see 3D animations in my computer. I've seen Damain Peach's Jupiter rotation movie." A few minutes with the sphere quickly changed my ideas about it. There is a quantitative learning difference in having a 3D 6 foot dynamic model to walk around as opposed to flat images. I have studied the Moon for some years and never really appreciated the relative sizes of the South Polar Atiken and Australe impact basins - although I've seen numerous maps, images and Google Earth simulations of the same. Similarly, the rotating animation of Mars really started to fix in my mind the relative geography of the major features in ways I had not previously experienced. South-Polar Atiken Basin http://gallery.utahastronomy.com/main.php?g2_itemId=11483 Australe Basin http://gallery.utahastronomy.com/main.php?g2_itemId=11479 Damian Peach Mars and Jupiter rotation movies http://damianpeach.com/index2.htm This Soas projection globle appears to be a beta deployment of a new product. As such, there is alot of room for new projections to be added and more potential to be developed. For example, while near real time satellite weather imaging is available; near real time Soho is not. Similarly, the NASA JPL Horizon system could be a feed source for near real time simulations of current phases of each planet in the solar system. Expert amateurs in a particular areas will probably note datasets for any one focus area missing. For example, there are four or five USGS lunar datasets on geology and topography that are not included in the available datasets. In that it is a beta deployment, there were a number of problems and areas for potential improvement in the current system. First, is that it is deployed in "push" education mode with heavy commercialization, consistent with the Clark movie business model. The sphere display pushes passive content, which bored about 90 percent of the groups that walked by the sphere. The first 20 minutes that I watched the sphere consisted of commercial advertisements projected over planets. This was followed by a cheerful voice proclaiming "These science animations have been brought to you by NOAA." For example, although I was there almost a full hour, it was not possible to take a picture of the Moon without the logo "Brought to you by Zions Bank" plastered over the globe. After a first 1/2 hour of commercials, _then_ the NOAA science demo really started playing. Unlike an Exploratorium science education model, the sphere is deployed in push mode. About 80 percent of passerbys watched it like it was a big screen tv, became bored within 60 seconds and walked on. Maybe 10 percent stayed 2-3 minutes and another 10 percent for 5 minutes. The sphere would be a far more engaging display if the sphere was deployed in Exploratorium "pull" learning mode. E.g. - allowing the Information Desk employees or the sales desk employees to start any animation on request. A "whack-a-mole" console or a public terminal that allowed the public to select an animation would far more engaging then a scripted TV presentation. Even scheduled lecture-demo times would be an improvement. To a docent's credit, he offered track down the education director to see if they would do a special demo for me. Finally, as an idea for product improvement, the whole sphere projector seems to have been conceputalized as a projection _surface_ when it can display a 3D _volume_. Perhaps there is some technical reason for this limitation; maybe the projectors will not display a realistic 3D volume. But imagine a 3 inch glass sphere that contains a leaf and five or six grazing ants surrounding by four microscope cameras. Then imagine 18 inch long projected ants crawling around in 3D on the inside of the sphere! Or how about a two foot tall amobae crawling across a virtual microscope slide, diatoms swimming in a glass sphere of pond water, that National Computing Center animation the 3D Milky Way you see in the NOAA opening credits, glob cluster M3 in 3D, or Tully's 3D simulation of galaxies within 40 megaparsecs. Sorry for the overlength post - and the string of recent long posts. Must be my inner-geek escaping again. Again, the sphere is that the club might want consider asking for a special demo of the sphere with an astronomical theme as a field trip for one of our summer monthly meetings. Peace - Kurt

2 1

Re: [Utah-astronomy] Visual and Imaging Spectroscopy on Ealing
by Canopus56 04 Jun '08

04 Jun '08

Chuck asked: > Kurt, what's the ruling on the Rainbow optics grating? > I have a number of ruled gratings; perhaps one or > more might be suitable for a home-brewed spectroscope. It is a 200 lp mm blazed grizm. That's not alot by today's standards. The spectroscopy newsgroups told me that in practice you can get 40 to 60 angstrom low precision slitless spectrographs of stars with it. The blazing is nice for inline transmission gratings since it keeps the specturm traveling about 5-10 degrees down the optical center, instead of the 30-40 degs for unblazed standard gratings. In December, I ordered some parts with the idea of using the grating to make an alternative slit tranmission grating spectrograph, so I could use the grating on extended objects like the Sun, comets and clusters. I have a Surplus Shed D1570 adjustable slit and some tubing. Then I set the project aside for other things. Last night's post inspired me to order a couple of aco lens from Surplus Shed - the last parts that I needed. A reflection grating is beyond my construction skills. - Kurt

1 0

Re: [Utah-astronomy] Visual and Imaging Spectroscopy on Ealing
by Canopus56 04 Jun '08

04 Jun '08

Patrick, > Hi Kurt, As far as I know you are the first to ever > do anything at SPOC that could be considered research. > Kudos! Thanks, Patrick. I don't view it as research. Amateur spectroscopy, like aesthetic imaging or asteroid hunting, has just come into its own in the last 15 years because of the prevalence of CCD cameras and cheap advanced image analysis software. Frankly, I've always been confused when reading about apectroscopy - either amateur or text books. The books always present a confusing array of advanced Balmer series physics coupled with information overloaded black and white images of high-dispersion spectra. The high-dispersion spectra illustrate stellar classification in terms of spectral segments that you cannot see in the eyepiece or high-dispersion spectral lines that requires a $5,000 spectrometer to render. It all seemed to be so disconnected from the visual observing roots of the thing - going back to Pickering's day when all you had was a prism, bad film plates and a hand-lens. In the early Harvard days, they figured the stellar classification thing out without alot of, relative to today, high end gear. Now that I've made a start in stargrazing through a grating, it has given me some experiential grounding that makes the spectroscopy books real. Yes, there really are blue distinct blue, green and red parts of a star's spectra - that's why Johnson and Bessel filters are labeled B,V and R. That B-V color index whe read in star catalogues is a ratio that expresses a real physical thing - the relative apparent intensities of those purple-blue and green segements of the spectra. Most books on amateur spectroscopy focus on absorption lines and ignore that the most telling visual difference between O and M stars - the emission spectra intensity between the B and far I segments. Many of the blue segment absorption lines in F through M class stars shown in books can only be seen with a camera. I've found it very difficult to find good articles and books that really layout - a la a Messier Marathon guide for amateur spectroscopy - what are the prominent features that can be seen visually in a simple diffraction spectrometer for various classes of the stars. A few sources, like the FAAS site and Tonkin's recent book (from the Patrick Moore series) have some good figures and tables. I recently found a good figure in an Oct 1996 S&T article by Alan McRoberts. Today, I figured out that the Vspec software - the MaximDL or Photoshop of amateur spectroscopy - can be used to generate good synthetic images of the visual observing experience that include both visual absorption lines and relative intensity of the emission spectrum. (Again, many "prominent" absorption lines visually are invisible because they lie on a segment of the spectrum that is too dim.) I'm hoping to cobble a chart together that will, for visual observing, be an improvement over McRoberts' 1996 version. Hopefully, armed with that chart, I'll really know what to look for and what I'm looking at when using the Rainbow Optics grating at the eyepiece. Turns out it is not that difficult once you know what to look for. - Kurt P.S. - An asterism note: Most of us are familiar with the winter "G" asterim - the letter G traced out by Castor and Pollux, Betelguese, Sirius and running back up and ending in Orion's Belt. It is one of those major finding asterism like the Summer Triangle. The FAAS website's winter observing program calls that asterism the "Spectral G". Running through the major bright stars of the letter G asterism with a spectrometer will cover most of the major stellar classes.

2 1

Oxygen III filers
by Ann Blanchard 04 Jun '08

04 Jun '08

Any opinions on which Oxygen III filters are best (for the money)? We have an Orion 1.25, but after Craig bought some larger eyepieces, he now wants a 2" for them. We were out in Rush Valley Saturday night, and either we went to the wrong place, or no one else chose to go, but just the two of us were looking at various nebula in Sagittarius between midnight and 1:00 (the Lagoon was sooo lovely) and that got us in the 2" filter wish mode. I've been told that Lumicon is better, but not necessarily enough better for the $. A Lumicon costs about $200, and Orion about $150. A salesperson at OPT claimed that the Baader filter at $98 for a 2" is better than the Orion. There are also filters by Teleview or Thousand Oaks. Any suggestions from you pros? Thanks! Ann M. Blanchard Executive Assistant to the Associate VP Undergraduate Studies 110 Sill University of Utah (801) 581-3188 a.blanchard(a)ugs.utah.edu

6 6