Regulusastro Blog

The spectrograph has seen first light: Altair in Aquila was the willing donor of photons in this case, and what a donor it was! In 180 seconds a very respectable spectrum was obtained and then calibrated with the eShel system. Guiding was not automatic: instead we opted to let the Paramount track as it normally does with slight guide fixes once using the hand controlled joy stick. The results? Well, pretty good! Here are the images for you to enjoy:

The full spectrum is below. Note Ha and Hb lines are pretty prominent. You’ll also see a couple high-spiking emission-like lines. They are not emission lines, but hot pixels. We’ll have to do something about that later. Now, this is a pretty compressed image. There is a lot of data you’re not able to see here, so….

Here is a magnified area around the Ha line. Look at that detail! This is pretty seriously full of information. Absorption lines can be seen within the absorption lines! Yeah!

For those who like the textbook spectra, and to better help you get a perspective on the colors of this object, here is a synthetic color spectrum of Altair. Note that the system doesn’t “see” color so much as it more simply records intensity at a slew of wavelengths. The software used for analysis made this spectrum from the data collected. It’s a synthetic spectrum.

It is pretty, isn’t it?

I spent this morning installing the fiber fed spectrograph in one of the school observatory domes. I have discovered that this device will be a true lesson in cable management. Power, optical fiber and data cables are all over the place. I have also found that local hardware stores are one’s best pal for such pleasures. Pipe hangers, the type used to secure pipes and tubes to joists, make excellent cable management tools. I bought 4. They now secure the two fiber cables and the data and power cables to the guide camera.

I am using an older C-11 telescope. In the light path is an f/6.3 reducer/flattener, a Van Slyke Engineering slide-mirror (2”) and then the optical head for the spectrograph. The head accepts:

• Fiber optic cable for the starlight being studied. This heads down 20m of cable to the spectrograph.
• Fiber optic cable for injecting flat field and calibration spectra.
• Power cable to activate and deactivate the solenoid for the internal flip mirror.
• Power cable for the video guide camera.
• Control cable and hand unit for the video guide camera.

That is a lot of stuff hanging off the end of the C-11!

Images:

Above you see the cables hanging on the wall using those handy pipe-hooks. The spectrograph, power supply and thorium lamp units are on the shelf.

This is the optical head on the telescope. Just look at all the stuff attached to the back there! It’s a dream of mechanical, optical and electronic components. I have to admit, I am really impressed with how small that video camera is!

Below, another look at the cable and spectrograph assemblies. The top two cable coils (silver) are the optical fiber feeds. One is 200 microns (flat field and calibration lamp injector cable), the other is 50 microns (for capturing starlight). The coils underneath are the power supply for the flip mirror solenoid and the video coax cable feed back to the PC.

Now it is time for first starlight!

Quite an experience. The last time I was out there was to visit my mom in Denver shortly after her move there… that was when I got my first US driver’s license! Wow – things have changed. There are more people, the town is built up, and there is more public transportation. There are freedoms and support for a variety of life styles that we do not really have so much of here in New Hampshire. Visit Boulder, and you will see.

The conference was splendid: the combination of the EPO and the Cosmos in the Classroom meetings really was a huge success for me and many others in attendance. The regular ASP annual meeting/s, Cosmos and EPO meetings were well meshed with each other. Posters and presentations rounded out the week and made for excellent discussions, meetings-of-minds, and collaboration. I hope in all sincerity that the ASP decides to do this combined meeting event again each time. The savings in time and money are great, and the plusses are too many to mention.

The opening sessions were held at the Fiske Planetarium right on the campus in Boulder. We were given a simply ridiculous sample of the new Sky-Skan projection and animation systems under the dome. I can say that we DID use binoculars in the planetarium, and we DID see the fainter Messier and NGC objects with them…. and no pixels. You do have to see it to believe it.

A really cool display in the planetarium was an 10’ diameter fiberglass sphere, onto which 4 high definition projectors shone images of various subjects without any visible breakup or overlap: Mars, Earth, all the planets, the celestial sphere and more. The whole thing was computer controlled (Linux) and seamless. The globe looked to rotate, but it was a splendid illusion. Just look at the image below. Incredible.

Got to meet up with a slew of friends including Katy Garmany (NOAO), Chris Martin (Howenstine High Magnet School, Tucson), Connie Walker (NOAO/NASA Globe), Travis Rector (U Alaska/NOAO), Steve Pompea (NOAO), Ian Otto (PEA grad) and many others. Here we see Chris Martin and Katy Garmany with their poster about the AstroBITS project. Check it out, as it is a very worthy project.

Was able to finally meet Steve Bisque of Software Bisque and Paramount fame, to whose company I have sent many thousands of dollars. They have a new “mini-paramount” which is definitely worth checking out. Just look at it below. Features: Polar alignment scope, more portable (holds less optics but still carries a C14 easily), PC controlled and is wired for all your needs.

The banquet was as wonderful and fun as banquets are. I had the pleasure of being at the head table with the other award winners for the year including Alex Filippenko (Berkeley), Marcia Bartusiak (author), and Allan Rahill (Clear Sky Chart). The dinner was delicious, the humor fun, and the award talks excellent. I had my minutes of fame talking to the 400+ audience, giving them my thanks for their support and the award, and also talking a little about my methods.

Afterwards: a reception at the Sommers Bausch Observatory on the Univsersity of Colorado’s Boulder campus. Unfortunately the skies were, well, thunderstorming. No stars. We did get the tour of the roll-off roof section and the domed observatory itself. It’s a fine school observatory with a lot of open space, modern gear and all. After this reception there was reportedly another post-party-party in which (yes you are reading this) team tricycle races were to be had. I missed that. It was beyond my bedtime. I settled for an Avery Brewing Company local IPA. It was just fine.

Frigid (the family penguin) and Polly (not Polycyclic Aromatic Hydrocarbon who is our other cat) also enjoyed the journey. They had a tour of the Southwest 737-700 series cockpit, enjoyed travelling through and around Denver, and had a blast seeking out air at 14,000’ on Pikes Peak. We found a few geocaches on the peak and around Denver as well.

Other exciting/fun/enjoyable opportunities which we did not pass up included a trip to the local Johnny Rockets (fries, shakes and burgers of better quality than most). Wish I could gather $700,000 to think of owning a piece of that franchise. We toured through the Museum of Science & Nature and saw their IMAX Hubble show as well as the fabulous gem collection. On our last full day we checked into the Denver Botanic Gardens and marveled at their collection.

So, all in all, a great trip at the higher altitudes. We’re back in Exeter now, getting ready for the last few weeks of summer break before heading into a new school year.

I am at the Astronomical Society of the Pacific’s annual meeting and conference for Cosmos in the Classroom and (AND!) the Education and Public Outreach group. This year the two are combined, and the result is wonderful. We are at the U of C Boulder campus: a lovely site with the Rockies in the near distance, warm days and drizzly nights, it being monsoon season now. Posters and presentations from both sides of the conference have been quite productive. Enjoyed a planetarium show by Sky-Skan with their latest technology with pixels so fine that (seriously) one can bring binoculars into the dome and use them to view Messier Objects!  I enjoyed talks about Globe at Night and Astro-101 demonstrations for the classroom. Today more and more. Alex Filippenko gave a neat talk about dark matter, energy, etc last night. Today lunch with NASA with a round table and open discussion.

The real joy is the collaboration between educators and administrators who are trying to get the good word out there about astronomy: a capstone course, an all-encompassing science, a fine intro to research and lab work, you name it. The appeal is huge. Time to take over the world!

Getting ready for the trip to Boulder for the annual meeting of the Astronomical Society of the Pacific (ASP), the awards banquet and visiting a slew of friends out there. Many people from the astronomical community and some family friends are going to be in the area: here’s to meeting up with as many of you as possible!

We will be bringing our beloved penguin, Frigid, of course. Paws maybe coming as well. Either way, you can expect to see the posts come in as they visit such places as the Boulder campus, the various museums and planetariums, as well as Pikes Peak and some geocaches as well! I hope the penguin can handle the high altitude.   Those now quite sure they understand who (what?) Frigid and Paws are, please jump here and enjoy.

Fiddling around with the spectrograph again today… the goal: to install the software, drivers and hardware for the guiding camera. The unit is a little, tiny, compact (did I say small?) video camera made by Watek and a USB video grabber. The AudeLA software has a built in module which can see the video from the camera as a webcam device. It then can connect to and control the telescope as any autoguider can. I like the idea: live video with autoguiding built in! This reminds me a lot of the webcam used in the Coude Feed Spectrograph at Kitt Peak, though I think their guide camera is an older TV-style imager. The systems pretty much works the same way: the video camera is focused on a mirror in the guide/imaging head attached to the telescope using a small lens system. The mirror has a 50 micron hole it it. The idea is to place your target (to be spectra’ed –> I know, it’s not a real verb) on that hole. The mirror then feeds an image of that star/planet/whatever, the hole and the surrounding star field for the guide camera to see. It’s pretty slick. This allows real time focusing, real time pointing, and a secure knowledge that you are grabbing spectra of the target of interest. No more trying to get that star on the invisible slit!

While I was playing with all that, I wanted also to try attaching a camera to the spectrograph to see the spectra in color. Why not? The lens used to bring the spectra to a focus on the CCD is made by Canon, and is an EOS standard lens. Sure enough, the Canon camera was able to bring the images to a focus. Here is a colorful sample.

Above is an image of the flat field lamp used to generate flats for later calibration. Nice looking rainbow there. You now get the idea of an echelle spectrograph: the orders at the top are the long wavelengths while the shorter ones are at the bottom.

Still playing a bit, the above is a spectra of the basement lights where I have this all setup. You can see the tell tale emission lines from the fluorescent lights used down there.

The above is my favorite: this is the calibration lamp spectra of thorium-argon. All those little lines have very well known wavelengths and allow each order to be precisely calibrated. Such fun!

To calibrate a spectrograph in terms of wavelength is one thing: get a lamp with known emission line wavelengths and use it to calibrate on a pixel-by-pixel basis the wavelengths of light coming out of the instrument. Ok – done. Thorium has been a good help here.  How to get the instrument’s response in terms of sensitivity to different wavelengths is a whole different ballgame, one that has proven interesting for some not-so-expected reasons.

Generally, the process is to take spectra of some radiator (a lamp) that has a well known spectral output in terms of intensities across all the wavelengths the instrument is designed to handle. This usually means taking some incandescent lamp and getting spectra of it. This lamp must have a continuous spectrum and be as close to an ideal blackbody radiator as possible. Tungsten lamps work well for this, as do some halogen bulbs. The key to blackbody radiators is that one can tell you their theoretical spectral curve if you know their temperature…. Planck and Wien were helpful here.

Trip to the hardware and home supply store: Lightbulbs. Incan-what? Descent? Incan – descent? Wha…?? All these places have gone UBER-green making it darned near impossible to find a well documented incandescent light bulb! I bought several types from several makers in the hope that at least one major company would have an available spec sheet for me to get the color temperature information that I needed. Sure enough: SYLVANIA soft white halogen bulbs have a convenient spec sheet available if you call their tech support. 2850K color temperature for their 28 Watt model. Awesome. I was out to win the race after all.

I took the spectrum of this little glowing heat-maker and got the instrumental response to what should have been a perfect blackbody curve. Now, CCDs are not the nicest of instruments. They are quirky. Mine like blue and far red. Green… not so much.

1. Take spectrum of lamp with the CCD at a known temp (-10C in my case for now).
2. Take a bunch more.
3. Average them.
4. Divide that spectral curve across the whole wavelength domain by the expected Planck curve for a 2850K blackbody radiator.
5. Spline this result to smooth out the rough features of the spectrum. The result is the instrumental response for the spectrograph at that temp across those wavelengths.
6. Use this newly created response curve to correct the recorded spectra of astronomical objects.
7. DONE!

And you thought that using biases, darks, and flat fields was bad!  The file maintenance here is a real game. So here are a couple of spectra for you to enjoy…. and yes, that have been calibrated for wavelength and spectral response of the instrument. Joy! Mission complete.

The above is the Hydrogen-Alpha region. Below is the Sodium Doublet. Look! Lines between the doublet of sodium. Cool resolution!  I am liking this instrument a lot. Note the rough area below around 5760: instrumental noise caused by a not-so-perfect-fit in the modeling of the field curvature for that particular spectral order. Tuning time!

The eShel spectrograph from Shelyak Instruments in France has arrived, and with it a lot of excitement about all the possibilities of projects for the future! The unit came into the country and stopped for a brief stint at an airport customs office before making its way here to Exeter. The box was about 45 pounds in weight and had a ton of individually wrapped goodies inside, all in excellent condition. Packaging was perfect and survived the trip from France without any issues.

Unpacking the unit is best done with a checklist and table nearby in a clean area. I have a very clean basement, dry too. The job was carried out there. Some serious time was spent learning the proper id of all the connecting pieces, some of which are not all that obvious at first glance. The majority were easy to identify: CCD camera and power supply, the optical head which attaches to the telescope, the fiber optic and power cables, the spectrograph and its lens… all easy enough. How to connect them? That is the fun part!

Here is the system completely hooked up and ready to go… with everything but a telescope for the little optical head. If you get one of these: note the use of the correct fiber cables for the starlight going into the spectrograph and the feed for the calibration lamps. The calibration lamp cable is larger than the 50 micrometer diameter cable for the starlight. Also note that the AC power goes into the calibration light box first, then is jumpered to the power supply for the thorium lamp which feeds a 10mA supply back to the calibration box. It is a little confusing, but the insides of the calibration box need power to handle logical switching directions fed into it via a com port. This brings up some interesting points: you need a PC with com ports.

The supplied software is an extension of the AudeLA package. The whole systems runs on top of that. It will manage your CCD imager (power and temperature), a guiding video camera, telescope guide control, the automatic on/off of the calibration lamps (yes, two: one is thorium for wavelength calibration, the other a white LED for flat fields! Cool!), the flip mirror in the guide head which allows either object spectra or imaging the calibration lamps, and the processing of all the final images automatically. It is pretty amazing. The setup is a bit tricky, but not bad. Make note: the software initially expects you to have already taken and formed an instrumental response FITS file… but you can’t do that until you have taken spectra of some standard star or blackbody radiator with a known temperature like a tungsten lamp. There is a checkbox to turn that feature off until you are ready. None of your object spectra will be calibrated automatically until you take care of this.

The spectrograph uses a Canon EOS lens to focus unto a QSI CCD imager (blue above). Focus is achieved by focusing the lens as you would any camera. No, it does not autofocus! The beauty of this design is that the spectrograph can reside 20m away from the telescope in a vibration free temperature controlled environment which makes for very sharp spectra and excellent calibration. Finding exoplanets using radial velocity measurements will be pretty easy with this!

The system is an Echelle spectrograph using an Echelle grating to make a merged spectrum first then is spread out using a secondary prism to break the orders of spectra apart for imaging. The result is an interesting and complicated field of many curved spectral orders. All this must be sorted out! Here is the spectrum of the sun (blue clouds actually) for example.

How to make sense of that!? Well, the software can take the calibration lamp spectrum of thorium and use it to identify the field curvature, the angle of the curves, and the wavelengths across the field: automatically. It then provides both individual spectra for each order and for the whole spectra combined.

Above are the spectra of the sun near H-alpha and then the combined spectra of the orders from about 500nm to 670nm. Note that the true blackbody curve of the sun is not evident here, because the unit has not been calibrated (YET) for instrumental response. We’re almost there! Once that is done, the wavelengths AND the flux values will be calibrated and the curves shall be accurate.

I have been working hard this week to accomplish those goals that need doing while classes are out and time is somewhat abundant. One of my summer goals was to get the robotic observatory mount to accept autoguiding signals from the STL-6303 imager. The mount, a wonderful (and I can’t stress that enough) 2001 vintage Astro-Physics AP1200, can go for 10 minutes without guiding, but after that, a guidestar is needed to keep stars round.

Here’s the kicker. The STL-6303 will guide the mount with the regular cable and such, BUT the hand control unit must be plugged into the mount. The mount needs that control unit to remind it of the guide correction speed (0.25x siderial). That makes it interesting: autostarting and parking become, well a more difficult and not remotely doable task with that unit plugged in. I have no idea why. So I have been playing with that a lot, much to my skin’s dismay as even 100% DEET makes no dent in protecting me from the Exeter River Mosquito Ranch (ERMR).

Last night I went out again, soaked in DEET (and with 50+ bites on the back of my bod from the night before) to see if things had mysteriously changes or if I had missed something. Interestingly, Astro-Physics (did I tell you how good that mount is?) keeps all their legacy manuals online for astronomers to access. Thank you, Astro-Physics. There Astro-Physics Website should you want it. In the manual for our mount, there is mention of a cool feature that other mounts have: the ability to park, shut off completely, then at a later time, reboot and the mount remembers everything: site, time, position, current siderial position, etc, etc. Hmmm, is that turned on? No. NO! Wow – funny how that was missed. I turned it on. No more parking problems. That is one hurdle down.

Now the second hurdle and the final one: how to get the mount to remember its guide correction speed? Funny: it started working of its own accord without ever having worked before! Well, fine. No idea why. Fine. Maybe (and this is not in the manual) the mount remembers this stuff when the “remember everything else feature” is turned on. Well, lucky me either way.

Now, I walk in, turn the mount and everything else on, and away we go! Night time is a better place thanks to all this….. and all this just to allow longer than 10 minute integrations! Sometimes I wonder why we go through all the pains. Because we want to! 

Summer is here and with it the opportunity to catch you all up with a few topics that have been going on and off again throughout the blog.

Fish: The two tanks are doing well. The monster tank with the new hunk of mopani wood has really shown marked improvement this past week. The wood has lost 95% of the hazy gooey mold-like fuzz that I was apprehensive about earlier. The Synodontis has been eating it. I like it, if he likes it. The other tank occupants are happy, too. pH is at a nominal 7. I am running about 4tbl of peat pellets in the canister, so the system is pretty stable and has taken on a lovely dark tan color of black water Amazon. My favorite occupants now are the aggressive and lively black tetras which eat voraciously and like lightning.

The smaller tank with the angels is also fine. It’s a bit more acidic at 6.8 with a new piece of mopani and a lovely tan color as well. Plants in there are growing well, and the Amazon Sword has overstepped its bounds and is trying to do what it always does: leave. No way. I like that plant. It’s staying.

I have been making large progress on my astronomy text. Today I finished the section on spectroscopic parallax. I have been fining the largest difficulty to be the illustrations: I either have to find open source and uncopyrighted works, ask for permission to reprint with modifications and my own copyright, or make my own. I have been making a lot on my own and have become quite the whiz at technical drawing using Adobe Illustrator. This dog can and does learn new tricks.

Biking: Time to BBQ and relax a bit. I have been getting on the road bike between uber hot and wet days. My normal jaunts are about 15 miles, and I average that in about an hour or a little less. There is one good hilly section which keeps my breath going. I hope my heart keeps it up! The bike has been treating me well with the saddle change and stem change last summer. I do not feel all that cramped any more and the saddle is, well, a huge improvement. No more sore…. you get the picture.

Playing at the Domes: I am embarking on a journey into radio astronomy… again. I had initially gotten into this a long time ago (1988) with a friend, Steve Choate, while living in Amherst, MA. We built a simple tube type dipole for 10m with a chicken wire reflector. The project suffered in that we never had a sensitive enough (nor quiet enough) receiver. The antenna this time around is a full dipole for 10 and 20m with a simple yagi style reflector wire underneath for a beam aiming, simply enough, up. The receiver is a Yaesu FT1000mp from my shack. I figured I could put it to good use in radio astronomy while using my ic-756 pro III at home for ham play. Using a wide receive mode (AM), we should be able to get at least the Sun, the central Milky Way and interactions between Io and Jupiter. We’ll see! If all else fails, it makes a cool ham shack.

Painting and home ownership: We’ve almoist finished painting the interior in Northwood. The ceilings up the stairs and in the two bedrooms are the last to do. General touch ups will be needed, but the place is looking really good. We tore out the old now unused HO train table in the basement to make room and recycle the wood. The broken and messy parts? Into the burn pile. The mice in the observatory: dead thanks to poison. Trapping and being kind just did not work. Sorry guys. Some times a rodent just has to go, and they were making a big mess in the dome between leaving droppings and nut shells, and then wrecking the cables and fiber feeds. Bad mice. Gone now.

Oh – geocaching: We hid our first geocache this last week in the woods off of Drinkwater Road in Exeter: Astrocache1. Go seek it. A few people already have been by and signed the log. The trails there are well kept and can be walked or biked. Bugs: bring repellant. A link to the geocache entry for you here.

There: that should keep you all posted for a while.