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

Visual and Imaging Spectroscopy on Ealing
by Canopus56 03 Jun '08

03 Jun '08

Last weekend, I did some initial probing into amateur visual and imaging spectroscopy using the Ealing on Arcturus with a Rainbow Optics grating. Preliminary results and preliminary setups for visual and spectrograph imaging are shown in the following Utah Astro Gallery pics: I. Spectrum imaging: Arcturus Spectrograph - 1st attempt - image http://gallery.utahastronomy.com/main.php?g2_itemId=11453 Arcturus Spectrograph - raw Vspec plot http://gallery.utahastronomy.com/main.php?g2_itemId=11455 Ealing Spectrograph imaging setup - Rainbow Optics grating with targeting http://gallery.utahastronomy.com/main.php?g2_itemId=11445 Ealing Spectrograph - Rainbow Optics, extension tubes and Meade DSI http://gallery.utahastronomy.com/main.php?g2_itemId=11447 The imaging setup will be changed in future versions to aid in spectrograph calibration by the filter method. A filter wheel needs to be added in front of the flip mirror to accomodate a set of Johnson BVRI cut off filters. This allows taking a picture of the spectrum several times, using the JOhnson cut-off filters to mark the spectrograph with calibration lines. Buhl's filter method - order cut-off calibration http://astrosurf.com/buil/us/loris/loris.htm Another option that I am considering for light lamp calibration is simply a halogen hiker's headlamp flashed down the targeting e.p. tube. I understand that a halogen desk lamp also can be used on down the telescope down. Any experience comments on using an inexpensive halogen desklamp for making a calibration spectrum would be appreciated. How do you image both the faint target's spectrum and the desklamp spectrum in the same exposure? II. Visual spectrum observing: Ealing Visual Spectrometry - Rainbow Optics setup with parafocal targeting http://gallery.utahastronomy.com/main.php?g2_itemId=11449 Ealing Visual Spectrometry - Rainbow Optics grating and extension tubes http://gallery.utahastronomy.com/main.php?g2_itemId=11451 The visual spectral observing setup works but left me scratching my head about what visual spectrometery was all about. After rereading my Rainbow Optics Grating manual, I noticed that I missed a small comment that for visual observing, the grating had to be slightly defocused _infocus_ to bring out of the spectral lines visually. Otherwise, only the most prominent broad lines can be seen with no detail. Depending the results of the second visual observing test with infocus defocusing, I'll probably also use a lower focal lenght ep. A 20mm ep would only allow observing part of the spectrum at a time. I'll probably go to 32mm ep. The Forum for Amateur AstroSpectroscopy has a good set of recommendations for a beginning observing list for amateur visual spectroscopy with notes on what the most prominent visual lines are in each spectral class. FAAS Visual Observing Guide to Spectra http://users.erols.com/njastro/faas/pages/starcat.htm FAAS Spectroscopic Grating Visual Observing FOrm http://users.erols.com/njastro/faas/pages/workgrat.htm FAAS Spectroscopic Certification page with visual observing spectral forms http://users.erols.com/njastro/faas/pages/winter-g.htm FAAS website http://users.erols.com/njastro/faas/ III. Lessons learned As an initial imaging spectroscopy session, the weekend was more of a lesson learned experience than one of results. Part of the general outline of the Arcturus spectrum was imaged but could not be accurately calibrated and normalized. Some goofs, gafs and lessons learned included: 1) The Meade DSI was left with the autocontrast mode on. Autocontrast must be off. This meant that the multiple spectrum images (see above http://gallery.utahastronomy.com/main.php?g2_itemId=11453 ) could not be calibrated to each other. The spectrum turned into the graph above covers the green through red visual region. 2) To make a drift spectrum image, the grating has to be fixed to project a N-S spectrum before the session begins. Drift spectrum images help make the spectra lines easier to see. After the grating's position is fixed, the grating cannot be moved. During setup, a reticule is placed where the camera appears in the spectral imaging setup. A star is used to align grating along the meridian line in the eyepiece. Then the star's spectra is rotated into view and the grating is so it projects a N-S spectrum. The camera is reinstalled and the process is repeated, aligning the camera so the star moves N-S along the long-axis of the camera's frame. If the camera is inadvertently rotated during the session, it can be realigned at any time using a bright star. One expert amateur recommends imaging the single pencil line of the spectrum. The image is then cropped and stretched. This creates a "digital" drift scan in which it is easier to see the spectral lines. I tried it and it seems to work well. 3) A lot of time was lost getting the newest version of installed and learning VSpec. Vspec is the leading amateur software for spectroscopy. There is an option in the VSpec manual to "Import dat file" that did not appear in the software. I had a number of problems getting the software to run properly on Windows XP. The fix was to rename the current version from "vspec.exe" to "vspec3_51.exe". Leave the old version (3.30) under the executable name of "vspec.exe". Instead of using the raw pixel intensities, it was easier to identify element lines in Vspec if a reference copy of the raw image is first stretched to the full 65,000 pixel range of a 16-bit fits image. In the stretched reference copy, the corresponding x-axis pixel to be paired with a calibration line can be located and written down. The calibration is then actually performed on the unstretched image. 4) Calibration, Calibration, Calibration Initially, I was hoping to calibrate the spectrum image using a reference spectrum of Arcturus - something built-into Vspec. That proved more difficult than expected. Taking the time to make a calibration image using the light pencil or filter-cut off methods seems like it will be much more time efficient and will provide a higher confidence in the calibrated spectral plot. 5) For visual observing the grating can be placed considerably in focus. The Rainbow Optics manual and another expert amateur spectrum imager both noted that the grating, for maximum dispersion, can be placed as far infocus of a Newt or Cassegrain, e.g. 100mm, as is practical. Secondary mirror or tube interference is the practical limitation. I am not sure how that works in terms of diffraction theory (placing the grating at other than prime focus), but it seemed to work on the Ealing. 6) The Rainbow Optics grating needs to be defocused infocus for visual observing. As noted above. Please feel free to drop me a line if any other club member is interested in adding visual spectral observing to their observing program for this season. Peace - Kurt

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Spitzer Telescope study proposes revision to Milky Way galaxy structure
by Canopus56 03 Jun '08

03 Jun '08

Two of the Milky Way's Spiral Arms go Missing NASA Press Release 6-3-2008 http://www.nasa.gov/mission_pages/spitzer/news/spitzer-20080603-10am.html Revised structural map http://www.nasa.gov/images/content/236084main_MilkyWay-full-annotated.jpg Basically they are proposing (reminiscent of the Pluto planetary debate) to downgrade the Orion-Cygnus Arm from a "major arm" to a just a "minor arm". Peace - Kurt P.S. - This was released at a press conference at the current AAS meeting in St. Louis - no published journal paper. The focus of this year's meeting is preparing for public education for next year's 400th Galileo anniversary. See - "Preparing for the Internationl Year of Astronomy Workshops" in the meeting schedule at http://www.aas.org/meetings/aas212/schedule.php

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Re: [Utah-astronomy] Phoenix
by Canopus56 02 Jun '08

02 Jun '08

Today's NASA-JPL-UofAz 6/2/2008 telephonic conference: Press release http://www.nasa.gov/mission_pages/phoenix/news/phoenix-20080602.html Recording http://www.nasa.gov/235822main_phx_media_telecon-6-2-08.MP3 Slides discussed in recording http://phoenix.lpl.arizona.edu/images.php?gID=0&cID=36 Peace - Kurt

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PM for Ann Blanchard
by Chuck Hards 02 Jun '08

02 Jun '08

Ann, I tried to reply to your private email, but it was rejected at your end. C.

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Re: [Utah-astronomy] Oxygen III filers
by Chuck Hards 02 Jun '08

02 Jun '08

I'm fairly sure that the Orion interference filters are not made by the same maker as their color filters. I have Lumicon broadband in 2", Celestron narrowband in 1.25", and O3 in both 1.25" and 2", although I can't recall the brand of the O3 filters at the moment. All work very well; I have to say that the O3 is probably the one that now gets used the most- there are a lot of planetary nebulae out there... My Lumicon 2" broadband is old, dating from Marling's ownership (they are now owned by Parks, IIRC). On Mon, Jun 2, 2008 at 1:03 PM, Rob Ratkowski Photography < ratkwski(a)hawaii.rr.com> wrote: > Hi Ann > > > Buy the Baader !! I bought their 2" Continuum filter and the quality > is fantastic. I had purchased an Orion 2" polarizer and after a few > months, the polarization element fell out from the Chinese aluminum > cell. Lumicon makes nice products also but I don't have any of their > filters. AND if the filter is $98, it's a great price >

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Porrima split - documentation pic 20080531 Ealing
by Canopus56 02 Jun '08

02 Jun '08

Posted a small documentary image showing the newly enlarging split of Porrima A-B (gam Vir) now at around 1". After being unseparable for a couple of years at perigee, Porrima B is now again becoming accessible by small telescopes. This binary split is discussed in Alan MacRobert's S&T note on page 68 of the June 2008 issue. http://gallery.utahastronomy.com/main.php?g2_itemId=11377 Porrima was only at 38 degs alt at my op and seeing was Pickering 1 or 2. Because of this, an asthetic image was not possible. 83 short 0.125" exposures where taken of the atmospheric speckle pattern. The two best images showing the split and the two components are included in the posted image. Visually, at 564x with a 16" apeture, Porrima AB, in moments of still air, appeared as figure-8 pattern or a just-touching kiss split, using Haas's 2006 split nomenclature. My computed split of 1.4" has a high degree of uncertainty and, due to observation error, is not in consistent with the S&T article predicted separations of 1.0" on April 20th, 2008, increasing to 1.1" on Sept. 15th. It is not consistent with the 6th Orbit Catalogue ephemeris split (rho) values of 0.91" for 2008 increasing to 1.168" in 2009. The WDS 6th Orbital Catalogue ephemeris plot of observations for Porrima can be viewed at: http://ad.usno.navy.mil/wds/orb6/PNG/wds12417-0127r.png The entry for Porrima in the WDS 6th Orbital Catalogue references neither the ids gam Vir or Porrima. Search the catalogue using the alternative id STF1670AB. Alternate designations for Porrima include: gam Vir 29 Vir WDS12417-0127 STF1670AB ADS8630 HD110379 Peace - Kurt WDS 6th Orbit Catalogue: http://ad.usno.navy.mil/wds/orb6/orb6frames.html

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Shuttle station
by Patrick Wiggins 02 Jun '08

02 Jun '08

Just watched the shuttle and station fly over. The much brighter station came over first with the shuttle (much fainter and noticeably whiter) about 75 seconds later. Possibly an optical illusion but both to the eye and through 7x35 binoculars the station appeared larger than the shuttle. The shuttle appeared much more starlike. Both NASA ( http://spaceflight.nasa.gov/realdata/sightings ) and Heavens Above ( http://www.heavens-above.com ) are calling for much better passes for northern Utah Wednesday and Friday nights and a very nice pass for southern Utah (Cindy, Jerry, Debbie?) Saturday night. patrick p.s. to "Mr. Anonymous", nice try but, no this is not me earlier in life <grin>: http://www.gamesfather.com/video/BestFQay-kz67NI.htm

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Pluck foam adhesive
by Canopus56 02 Jun '08

02 Jun '08

In pulling pluck foam for a new solar scope hardcase I made a one row of pluck square error. Is there an appropriate adhesive to make stick back in place? - Kurt

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My first exo-planet
by Patrick Wiggins 01 Jun '08

01 Jun '08

Thanks to the suggestion, assistance and encouragement of UA list members Cindy and Jerry Foote I nabbed my first exo-planet transit early last month. http://gallery.utahastronomy.com/main.php?g2_itemId=11354 While the graph may not be all that exciting to look at, it is kind of fun to look at it and know that the tiny dip in light was caused by a planet transiting another star some 1,500 light years away. Carpe Noctem! patrick

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Misc nature pic - Iridescent cloud 2008-05-31
by Canopus56 01 Jun '08

01 Jun '08

Posted to gallery. Not much to look at; just a documentation example. Typically, these can be seen in July and August when hiking in the Wasatch and Unita Mtns - usually around 1-4pm. Visually, a finer division and range of the rainbow colors was seen that was not captured by the camera. - Kurt http://gallery.utahastronomy.com/main.php?g2_itemId=11362

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