Last updated 4/2/17

OBSERVATION METHODS: VISUAL AND VIDEO

The following information applies to expeditions organized by the author. Safety is the most important part of any observational effort.  Before venturing out on any of these expeditions I strongly recommend you carefully review the safety recommendations outlined at http://eclipsetours.com/paul-maley/occultations/asteroid-occultation-observing/

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Figure 1A. Example of a model of the asteroid Minerva and how a number of observations are used to confirm/improve the model.

The main goals of timing the disappearance and reappearance as a star is eclipsed by an asteroid:

-to improve knowledge of the size and shape of the asteroid

-to update existing model(s) of the asteroid at a particular phase angle in its rotational cycle

-to determine if the star being eclipsed might have a hitherto unknown companion

-to search for evidence of a secondary occultation within a minute of the time of central occultation to determine evidence of a possible natural satellite in orbit about the asteroid

For amateur astronomers there are two ways to participate in this project: as an independent observer or as a participant in the IOTA portable video station deploy effort. Both are described below.

VISUAL OBSERVERS

For those who want to observe from home or somewhere else with their own telescope and have no access to video or GPS timing or do not have time to participate in the video team program, there is a way to contribute.  Assuming your telescope can reach the magnitude of the star, and if you have either an Android or IPhone, you can download an app that will let you manually time the disappearance and reappearance of the star.  Even though the asteroid is passing between the star and the Earth, you only have to be able to see the star, not the asteroid!

The one mandatory requirement is that any observation must have an accurate time associated with it! Should you have a video camera for a telescope, you may be able to purchase a GPS time inserter from: www.videotimers.com provided it is compatible. If your camera does have that capability, the GPS time will appear on each recorded frame giving you the millisecond time accuracy that will meet professional timing standards! Integrating CCD cameras are not recommended. As of this date the best camera to use is the PC164EX2 obtainable from www.supercircuits.com

SMART PHONE APPS

TIMING APPS: Download one of these apps. For Android phones, the app is called “TimeTheSat”;  for iPhones, the app is  “Emerald Timestamp”.  You need to have an internet connection outside when running the apps!! timing_app1

Fig. 1B. A screen shot of the Emerald Timestamp app courtesy of Ted Blank

Once you have downloaded it, it will bring up a running clock in UTC (universal coordinated time).  For this to be used effectively, you need to have a wireless internet connection when observing.  You will need to hold the smart phone comfortably while looking through the telescope, such that your hands must not have to worry about touching the scope or anything else during the occultation—just the smart phone.  It is best to use a polar aligned telescope centered on the target star. You will begin to observe 2 minutes before the predicted time of occultation and end about 2 minutes later just in case there might be secondary occultations that could occur during the watch period.

HOW DO YOU FIND THE “TARGET STAR”?

Finding the “target star” (the star that is being occulted) can be done generally by two methods. For experienced amateurs one can star-hop by going from one spot in the sky to another to locate the target.  For others who perhaps use GO-TO telescopes and are not experienced locating a specific star, this can be more problematic.

You can locate the coordinates of the star by going to www.asteroidoccultation.com and looking up the date and asteroid. Then you can use the active link related to that occultation to find another link called DETAILS. That leads you to the location in R.A. and Dec. of the star and to 5 levels of star charts. For GO-TO telescope users you will need to spend extra time to confirm that you have located the correct star. Once you “think” you have found it, move to the right, left, up or down and confirm that adjacent stars appearing on the star charts are actually in the correct places relative to the supposed target star. Many stars look alike and it is easy even for experienced observers to be fooled by similar looking star groups or orientations.

WARNING: NEVER WAIT UNTIL THE NIGHT OF THE OCCULTATION TO FIND THE STAR. If you have never attempted this before or are unfamiliar with the sky, or even if you are an experienced observer, you are likely to fail if you do not try to use the charts to find the star in the days or weeks prior to the occultation.

SPECIAL NOTE: if pre-point charts are available (using the software tool called GUIDE), you can use them to pre-point the telescope to the correct elevation and azimuth in the hours before the occultation.  If the telescope is locked down once a star along the track has been located, the target star will drift through the field of view at the precise time of the occultation. In that case be sure to use the widest field of view eyepiece that will allow you to see the star. 

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Figure 1C. Prepoint chart

Above you can see an example of a “pre-point star chart” showing the track of the target star’s elevation and azimuth as the Earth rotates with time. The line with tick marks show that position every minute. The trick is to set up your telescope (a sample telescope eyepiece field of view is illustrated by the size of the small rectangular box) on the bright star at 03:01UT. Since most stars to be occulted are quite faint, having a reasonably “bright” star to use in the sky is very convenient.  At precisely 3:01UT, with this specific star centered in the telescope field of view, lock down the scope and let it remain in that position until about 2 minutes prior to the predicted time of occultation. Then begin watching. If you have done this properly, the correct target star will appear in eyepiece for you to see the occultation.

Within a minute of the predicted time of occultation you should be ready for the star to disappear (or in the case of a low magnitude drop, to drop in brightness, but not completely disappear).  When this happens QUICKLY tap the phone once and the time will be stored.  Keep watching.  When the star pops back into view, tap the phone again QUICKLY and the reappearance time will be stored.

Maximizing your timing accuracy is crucial. The internal smart phone accuracy is on the order of 0.1 second.  Added to this is the human reaction time of the observer using the phone and looking through the telescope at the same time.   Practice will help reduce this error; do this indoors by setting up an artificial star projection in a dark room. Another person can put his/her hand in front of the star while the observer can watch without a telescope and tap the smart phone the moment the artificial star disappears, and again when it reappears. This practice is intended to cut down on the reaction time for both the disappearance and reappearance times since visual observers will have a much higher timing error than those using a video system.

Remember that if you go out and observe and see no change in the star’s brightness during the occultation, such negative observations can help establish absolute limits of the prediction accuracy.

Report your observations by filling out the form located at:

www.asteroidoccultation.com/observations/Forms/AsteroidReportForms.html

MISCONCEPTION TO BE AVOIDED

Some amateur astronomers who have no experience with occultations often make the assumption that it is best to get together a group of people with telescopes observing the occultation at the same place. WRONG! This is a terrible waste of resources. The best approach is to distribute each observer/telescope at a separate site at roughly equal distances perpendicular to the occultation path. Should volunteer observers only be willing to observe from home, that is an acceptable alternative as long as observers report what they see/don’t see accurately. Without an “accurate” time, such observation can be of little use except in the case where a definite negative observation is made.

VIDEO TEAM OBSERVATIONS

Helping record video using one of our portable small systems is the most productive and accurate way to collect occultation data.  To make this happens requires e.g. up to 6 operators who would activate and deactivate portable video stations.

A. ROLE OF THE SITE OPERATOR

Operating the equipment requires no scientific knowledge and anyone can be trained as an operator. You do not have to worry about finding the star on your own as I will do that for all sites. Training is typically accomplished in a 20 minute hands on session the day before the occultation. Sites would be predetermined and announced in advance.  Normally they are off road such that you will usually not be disturbed by others.  After the occultation, the operator should be the one charged with disassembling the equipment and returning it safely to the meeting point.

B. ROLE OF THE SITE ASSISTANT/COMPANION

If the operator chooses to have help, this person can be valuable in keeping track of time to be sure events in the timeline occur in sequence. That person can also be aware of rising wind conditions to help reposition the vehicle to protect the equipment, to be aware of oncoming vehicle headlights and assist in blocking those lights, ward off anyone who stops, informing police or property owners of what is happening leaving the operator free to control the equipment. More than 1 assistant should be avoided and at no time should children be allowed at the site! Operator and assistant must avoid distractions that could result in equipment being disturbed after being locked down.  If the operator is driving, the assistant can serve as a navigator, especially in locating landmarks or measure distances to/from the site at night. This can be a slow process if landmarks are not readily available.

It would help if local astronomers in the area would help pick the sites that would be safe, dark, and easily accessible. On occultation night all stations would be deployed sequentially by me typically 10 to 20km apart perpendicular to the path of the asteroid shadow. Each small telescope is prepointed and left in a precise position until after the occultation. Just prior to the recording window (usually about 6 minutes long), the operator will connect power to the camera and turn on the camcorder to begin recording the star field. As the Earth turns during that 6 minute recording period, stars may be seen moving through the field of view.

I would then leave the operator (and any assistant(s)) at that site and proceed to the next site in the sequence and repeat the same process until reaching the last site which would be my own. This activity usually takes 2 to 3 hours depending upon the number of sites and distance between them.

1. WHAT DOES AN ASTEROID OCCULTATION LOOK LIKE?

Using video we can get a good idea. We consider the occultation of a 7.6 magnitude star SAO 060107 by the 76 km diameter asteroid known as (516) Amherstia. I travelled to Atlantic Beach, Florida on 14 January 2002 in order to capture this using a Collins Electro Optics image intensifier, Watec low light surveillance camera, attached to a Celestron 8 Schmidt- Cassegrain telescope. The seeing was not perfect but the occultation was clearly observed. In the frame captures below, there are small spots that do not appear in the same frame from image to image. These are NOT stars. They are caused by the image intensifier placing noise into the field of view. When only using a sensitive video camera such as the Supercircuits PC164EX2 or Watec 120N, e.g., you will not see such stray images. However, these cameras do develop “dead pixels” which will appear in the same place in the video relative to the screen boundaries.

Fig. 2A. The first image (below) shows the “target star” — the brightest one in the field of view — with the tiny image of the asteroid just to the upper right and almost appearing to touch it. This frame was taken 40 minutes before central occultation. The asteroid is magnitude 12.3. Visually, it would be easy to time the occultation of the star, but the asteroid would be too dim to detect in a typical sky condition.

Fig.2B. (below) Several minutes before central occultation, the asteroid is now immersed in the glare of the bright star.

Fig. 3. (below) Then the asteroid passes in front of the star causing a vast reduction in the star’s brightness. Notice, however, that you can actually see the asteroid by itself in place of the star.  Dead pixels (star-like objects that DO NOT MOVE) will also be seen on the small camcorder flip screen. Background noise may also be detected as small points jumping around during the recording process.

  

Fig. 4. (below) Finally the star regains full brilliance after the completion of the occultation.

This may occur instantly or gradually or in steps.

2. HARDWARE NEEDED FOR A SMALL DEPLOYABLE VIDEO STATION

Fig. 5. (above) A typical Mighty Mini arrangement featuring the 50mm half binocular with camera and Night Owl f/0.5 focal reducer inside, tripod, 12VDC battery pack with 8 fresh AA batteries, GPS  box with antenna attached, and Canon ZR camcorder. The GPS is usually located at one site while others have GPS time stamped prior to and following the occultation. This reduces the amount of equipment required to be carried to each station.

For group expeditions that I organize, I will supply all the equipment.  Using the above setup I have recently started deploying more than one station when the occulted target star brightness allows (magnitude brighter than 9.6). This portable design, created by Scotty Degenhardt, is the most productive tool so far for multi-station asteroid occultation monitoring. In the table it is referred to as “50mm mini”. I have also started to use its larger cousin the 80mm midi. Total cost of the 50mm mini (optics, camera, focal reducer, c-mount adapter, tripod, battery pack and Canon ZR camcorder) is about $370 with the GPS being around $250.  A GPS for time-inserted video is mandatory for one site; currently they can be purchased from  www.videotimers.comOnly certain models of Canon ZR camcorders will work; they are no longer manufactured but can be obtained through internet sites such as EBAY or even AMAZON.

There may be a few cords and always batteries involved which can increase the cost by about $25. Multiple stations can accrue the benefit of having only one GPS unit. If Canon ZR model camcorders (certain types only) are used to record the video, it is not necessary to attach a GPS in real-time to record the occultation to each one. A small amount of GPS time (about 15 seconds) can be recorded onto each camcorder in the hours prior to the occultation.  After the occultation, an additional amount of GPS time is recorded. The camcorder internal clocks do not drift that much and it is possible to interpolate the relationship between the absolute GPS recorded time periods and the internal clock of the Canons.  Having one of the multiple camcorders attached to the time inserter will serve as the time reference for checking the integrity of the other units’ time recordings.

Other camcorders such as the Sony TRV-340 also haven an internal clock and the same process can be used. As technology has advanced, camcorders have begun to get smaller and lighter. Video tape is being supplanted by devices with large internal memories and USB output capability enabling quick transfer to a PC for internet upload.

One device is the JXD-990 Chinese miniDVR shown below compared in size to a typical Canon ZR. The two look quite similar but the JXD990 is about 1/3 as thick as the ZR and a fraction of the weight.  There is a problem with most miniDVRs since data compression occurs inside those causing loss of frames and/or non-uniform recording at a constant 30 frames/second rate.

 

 

Fig. 6. (above) A Canon ZR (above) with the JXD990 below compared to a pencil

While the Chinese-made JXD990 (and similar models) has yet to be deployed in large numbers in the field, the device must be manually turned on/off but has 8GB of memory allowing for hours of video recording. The cost of a new JXD990 is less than a used Canon ZR. It is not known how long the JXD990 will last after prolonged field use. Chances are the internal battery will run out of energy before the memory capacity is exceeded, but if not the battery appears to last only between 1 and 1.5 hours compared with Canon ZR batteries that have a multi-hour capacity depending on the battery type. The JXD990 screen is much larger but both it and the ZR have the weakness of being unable to adjust brightness and contrast. The JXD990 controls are confusing to use and the English language instruction manual poorly written with incomplete directions/troubleshooting.

3.CHOOSING THE PROPER OPTICS

Selecting the proper combination of optics and recording equipment should be done with care. The idea is to obtain a wide enough field of view and also to penetrate deep enough into the night sky to detect the star that is the subject of the occultation. The performance of optics including cameras are affected by a number of things including proximity to local artificial lights, the moon, the sun, oncoming headlights, atmospheric stability, and cloud. The detection limits below serve as indicators.

Fig. 7. Careful planning is vital to successful observations. You don’t want to get your self into a situation that is too big for you to handle.

Some instruments I use include the 50mm mini, 80mm midi and 120mm maxi. Each is chosen based on the limiting magnitude of the target star.   maxi2a

Fig. 8. The 120mm maxi scope is an f/5 refractor mounted in an alt-az configuration. Limiting magnitude is 11.2 under normal conditions but with a Watec 120N could go down to 12.5. This mounting has proved very stable at any elevation. The counterweights are needed to balance the scope and ta 90mm right angle finder.

Fig. 9. The 80mm midi is also an f/5 refractor mounted on a tripod. Note that all instruments are spray painted black. Limiting magnitude is 10.0 under normal conditions but with software analysis, stars fainter than this can be detected. It also has the same slot in which one can insert the 90mm finder. The 50mm Mighty Mini does not have a finder attachment capability since it is made from only half of a 50mm binocular.

70mm1a

Fig. 10. A 70mm version is also a very good tool and it is easier to transport and nearly as effective as the 80mm version but has no finder scope.

3A. USE OF A VIDEO TIMER

Video learning timers can be obtained (from EBAY) which can be programmed to trigger a Canon ZR camcorder to turn on and off at specified times. Camcorders usually have 83 minute tapes which may operate as long as 127 minutes. The idea is to first record 30 seconds of GPS time prior to the occultation, then set the timer to record perhaps for 15 minutes before, during, after the occultation, then to record 30 seconds of GPS afterward. The learning timer tool can be quite valuable when you want to deploy multiple stations. Because the timers send an infrared signal to the camcorder, they must be positioned in front of the camcorder within about 4 inches and pointed directly at the camcorder’s sensor. If not, the signal may not be received and the recording will never begin. The timers are model dependent and do not work with all Canon ZR camcorder models.

Some models must be triggered and then turned off by hand. In any case ALL CAMCORDERS when deployed in the field must be POWERED ON first by hand. The video cameras attached to the optics must also be turned on at the same time. Care must be taken that the batteries in both devices are fresh and will not fail prior to the end of the planned occultation recording period! Once you leave the site after powering on and activating (either remotely or manually) you must rely on both camera and camcorder batteries to function for the duration.

Fig. 11. Support equipment include the camcorder, battery, KIWI GPS unit, VCR timer and associated cables.

When deploying multiple stations it is recommended to place all equipment for one station in a container or box. That way you dont have to waste time in the dark trying to find each item. Connecting all wires ahead of time, except for the battery power is also recommended.

4. PHOTOS FROM SOME PAST EXPEDITIONS

Fig. 12. Photo of myself and several telescope domes at Kitt Peak National Observatory.

I was privileged (thanks to the late Dave Harvey) to use the 2.3m (90-inches) Bok reflector (middle dome in the image above) on November 6, 2011 to attempt the occultation of an 11.2 magnitude star by the minor planet Oppavia. Although ultimately, there was no occultation at this site, the experience was tremendous. The instrument was used at f/9 and I attached a PC164EX-2 camera at prime focus with a nightowl f/0.5 focal reducer. The field of view was a bit more than 30 arcseconds. Even as clouds constantly covered the star during the occultation period, the star was always visible.

Fig. 13.  In the dome of the 90-inch scope.  Note the Canon ZR camcorder (on the shelf to the right of the extinguisher) and also the appearance of the 11th magnitude target star on the monitor in background. 

Fig. 14. Some of the multiple mini systems used for the Antiope occultation near Sacramento CA July 19, 2011. Photo by Wayne Hopkins.  hidemini (Top) Paul Maley and Bill Merline at site 1 for the occultation of LQ Aquarii by 90 Antiope, July 19, 2011. 

Fig. 15.  Hiding a 50mm mini scope so it cannot be seen. The light shield protects it from incoming city lights that are clearly visible in the background. Note the red sandbag to help mitigate wind effects on the very light tripod. The blue towel covers the camcorder to protect from dew and to keep the glow of the screen from being seen by passersby. Photos by Wayne Hopkins.

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Fig. 15a. My system attached to Tony White’s (Tulsa, OK) Celestron 11. Arrow points to the connected unit from the SCT back of the C11. First, the f/3.3 focal reducer attached to the Collins I3, then the tiny Watec 902H.Photo taken 12/20/07 by Tony White.

5. PHOTOS FROM INTERNATIONAL EXPEDITIONS

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Fig. 16. Observing site at the Yalicapkini Hotel, Milas Turkey, August 2014 for the 16 Psyche asteroid occultation. If you look closely you can see me and the Celestron 70mm scope at the next to highest balcony level.  L. Palmer photo.
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Fig. 16A. Many of the JVP (Jyotirvidya Parisanstha) team members assembling at a petrol station at Kondapuri, India for the 22 Kalliope asteroid occultation of a 9.2 magnitude star.  Local amateurs operated 7 of my portable video stations. All were successful including mine as the 8th.
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Fig. 17. Expedition July 20, 2014 to Cullinan, South Africa where we successfully set up 3 video stations to observe the occultation of a 7.0 magnitude star by the asteroid 451 Patientia. Left to right: Johan Theron, Lynn Palmer, Paul Maley, Bosman Olivier, Allen Versfeld, Jose, da Silva, Herman Bloemhof and Pierre Coetzee.
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Fig 17a. Delhi, India occultation group to record the eclipse of a dim star by 106 Dione on October 3, 2015.
 

Fig. 18. Observing the 554 Peraga occultation from near Shaqlawa, Iraq, April 1, 2011.

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Fig 18A. The attempted occultation of HIP57972 by the asteroid 67 Asia at Pine Trees Lodge on Lord Howe Island on Decmeber 15, 2014.  I had to use a Celestron 70mm scope on the surface of the tennis court and a light shield constructed from star charts.

Fig. 19. Observing the Tisiphone occultation from the village of Lozova, Republic of Moldova, November 3, 2010. 

Fig. 20. Observing the Leona occultation from Cape Sunion, Greece, October 31, 2010. Left to right: Vagelis Tsamis, Kyriaki Tigani, Dimitris Kapetanakis and Paul Maley.

Fig. 21. Preparing the 80mm refractor in Chisinau, Moldova.

Fig. 22. Occultation outreach expedition to Skopje, Macedonia October 2009 where university students assisted.

Fig. 23. For occultations of bright stars I use a 100mm f/2 Nikon lens and a light sensitive camera such as a Watec or PC164.  A plastic beer cup served as a light shield. This photo was taken at Varadero, Cuba March 15, 2008 after the successful occultation of a 6.3 magnitude star by the asteroid 241 Germania. Photo by Lynn Palmer.

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Fig. 24. Two systems set up in Coober Pedy, Australia 2010. The asteroid occultation and several attempts in prior years in Australia have all been unsuccessful.

6. SETTING UP A GROUP OF PORTABLE VIDEO STATIONS 10sites1

Fig. 25. An example of 10 sites set up along Hwy 549 in New Mexico

In order to set up multiple sites, especially for the first time, it is preferable to set them up perpendicular to the occultation path and at relatively close distances. This is dependent on the number of people that are helping to operate the stations, location of other observers in different parts of the country, the size of the occultation shadow, etc. The fewer the people, the more work to be done by those handling the station operations. The sites should be preselected for speed in access, they should be hidden from view, locatable at night, have a clear view of the area in the sky where the star will be occulted and they should be situated on the same side of the road. If a highway is being used one must be sure that adequate entrances/exits are available.
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Fig. 26. Sometimes high wind can be a problem. For some stars located at a low elevation angle, one can on occasion place a small scope in the front seat of a car and point it out the window. I have tried this on several occasions with success. This shows an 80mm refractor with 90mm guide scope for pointing. The rest of the gear is on the floor.

The displacement of the farthest east and farthest west sites (in this example) have been set up to cover as much area as possible across the occultation path but also set up so as not to infringe on other sites to be used by observers in other states. The distance between stations is decided based on path width, number of sites you plan to set up, and the coverage by other observers. If possible you should always have your sites consecutively positioned. For example, every 5km x 5 sites = 25km. If there are other observers not located in your area see if you can make an agreement for them to move such that your sites can remain continuous rather than having to leap frog over other locations that currently happen to coincide with one or more of your stations.

Keep each set of equipment in a cardboard box. The box should be of low height but at least 12-18 inches wide/long. If it does not have a top, then use a dark colored towel to cover the equipment if you are not remaining at the site. The idea is to make it hard for the equipment to be seen by someone walking by and also to protect from humidity/condensate/ice. In especially cold weather, hand warmers need to be kept close to equipment with moving parts and the battery. If lights or the moon are present, a light/dew shield will be attached to each station’s front end optics.

Fig. 27. An example of the results of a closely spaced set of stations from the occultation of an 8.9 magnitude star by 194 Prokne on August 6, 2011 from Denver, Colorado. The data is fitted to a two dimensional spherical form. Stations numbered 1,2,3,4, and 6 represent the planned 5km spacing of my stations. Notice the high resolution and the very consistent agreement. All stations were video records. The dashed line 5 represents the predicted center line of the path and line 7 is a single chord from K.Coughlin in Baja, Mexico.

6A. MANUAL OPERATION OF CANON ZR CAMCORDERS FOR MULTISTATION RECORDING 

ADVICE FOR VOLUNTEERS

Bring the following:

1) at least one towel or quilt or something else supportive and soft so that you can kneel comfortably on the ground in order to go through the following procedure.  A towel is needed so that the camcorder and battery pack can sit on it without being exposed to dirt.

2) red or white flashlight

3) smart phone with clock showing time to the nearest minute. This is very important so the equipment is not turned on/off at the wrong time(s). Also used for security in case of trouble. 

4) copy of procedures on how to activate/deactivate equipment that are on this web page

5) a vehicle to reach the site

6) any snacks or provisions you wish to bring with you

7) if possible bring a fresh set of 8 AA batteries in case the battery pack should fail. Even though it has been checked out ahead of time, it is always possible for batteries to fail in the field.

8) one companion (no children) for additional security (OPTIONAL)

9) if requested bring 2 five pound rocks to put against one tripod leg in case of wind

Keep an eye out for animals and people near your site.  DO NOT TOUCH THE TELESCOPE OR TRIPOD OR ALLOW ANYONE ELSE TO DO SO once I have set it up. Do not walk around the telescope such that you are within 3 feet of it. Be sure the towel is not sitting under the tripod legs. If it is, be sure when you kneel down to activate that you do not accidentally ‘pull’ on the towel or the tripod could either fall over or shift. Only the operator should be near the tripod at any time. You companion must keep back. Position the vehicle as a wind break or a device to block oncoming car lights depending upon which purpose is needed.

TIMELINE FOR April 11, 2017 occultation by Artemis

The timeline is set up for longitude 112.6 West which is just between Buckeye and Gila Bend AZ. Time conversion is GMT-7 hours to convert to local time. The star is magnitude 8.9 and located at elevation 37, azimuth 243. Sunset is at 6:38pm.

Not applicable for this event: Equipment training session. This is a meeting of all site operators to show them how to use the equipment.  Provide your cell phone number so we can contact you as necessary.

April 10/11: the event occurs early on April 11

Allow plenty of time to get to the site. You must arrive early with a fully charged smart phone. If you do not have a smart phone, you must have a digital watch accurately calibrated to the time (preferably using WWV short wave time signals or GPS time on your smart phone or by me the day before) so that you will not accidentally turn the equipment on too soon or too late and to deactivate it in a similar manner. Do not use a watch with a sweep hand. SET TWO smart phone ALARMS, one for 3.04am and the other for 3.09am. These are the key start and stop times for recording below.

6:50pm: SUNSET

7:00pm: GO/NO GO call will be issued. If you do not get an email/phone call, proceed with the timeline as follows.

11:00pm: Meeting of volunteers at TBD locatioin

[I will prepoint all stations to the right place in the sky and set up each camcorder. Once prepointed, the tripod will be locked down in elevation and azimuth. The telescopes will be set up on short tripods and *may* have a dew/light shield made from rolled up black paper secured with Scotch tape. The lens cap on each scope is removed and the shield attached with tape until it is aligned along the optical axis and secure. For windy situations it is recommended that a sandbag or large rocks be placed on at least one of the 3 leg bottoms in order to prevent movement BUT ONLY BEFORE I SET IT UP. A plastic bag may be needed to prevent dew from forming on the lens. The stations will be left in place for volunteers to activate / deactivate per the procedure below. When approaching the equipment, do not disturb the soil or surface around the tripod!! This can cause the previously pointed scope to lose its alignment.  It is OK to use a white flashlight, but only before the equipment is activated!]

Volunteers will need to be shown in advance how to operate the equipment but printing out this section and bringing it with you is helpful. The next four steps need to be performed to turn on the Canon ZR camcorders. Note that those camcorders that require activation with a remote control have a separate description below in section 6B. The timeline here assumes you are assigned to only one video station and that you will remain at this location through deactivation. 

car_blocker

Positioning your car to serve as a wind/light block 

If a plastic bag  has been put over the dew shield to prevent dew from condensing on the optics, remove it carefully immediately before the next step so as not to put any torque on the dew shield or telescope as this will cause the observation to fail!

3:04am-  connect camera power, turn on camcorder and begin recording using the following steps

1) connect AA battery pack to the camera with one connector. Be sure to gently attach the power chord to the camera chord so that you do not tug on the camera chord!

2) power on Canon camcorder with one switch throw (see next image). Push the green button IN and then DOWN; the flip screen will turn on and the background will appear blue in color; the word STOP appears in the upper right of the screen.

Figure 2A. On the right side there is a switch area with a tiny green button that can be set to CAMERA, OFF, or PLAY(VCR). The switch is normally set to OFF. Move the switch down to PLAY(VCR) in order to power on. Response: you will hear a tone!

Figure 2B. Flip screen display shows STOP in upper right corner after powered on.

3) push the REC PAUSE button (next image) which may also be labeled CARD MIX sometimes causing screen to switch from showing STOP in the upper right corner to showing PAUSE; screen will go from blue to black with small stars appearing on the screen;

Figure 3A. Push the REC/PAUSE or CARD MIX  button on the left interior of the camera as shown above. 

Figure 3B. The word STOP changes to PAUSE on the screen. Although the screen in this image is blue, it will actually be black and there may be a few stars showing. I will already have focused the optics so no additional focusing is required.

IMPORTANT: IF THE SCREEN DOES NOT TURN BLACK, IT MEANS THE 8 AA BATTERIES HAVE FAILED. IF THIS OCCURS, IMMEDIATELY REPLACE THE BATTERIES AND REPEAT THE PROCESS!

4) start the recording by pushing the FOCUS button (3rd button on the right on the push button panel). When you do that you will see REC in red letters appear in the upper right corner of the flip screen.

Figure 4A. Push the button underneath the word FOCUS and this will start the recording process.

 

Figure 4B. THE SCREEN SHOULD BE BLACK with WHITE STARS  or stationary dead pixels that look like stars! The letters REC appear in red and the hours, minutes and seconds counter (also on the screen) will begin to advance indicating it is recording.

3:06:39am – occultation is expected to occur but star will not be visible on camcorder flip screen

3:09am- stop recording turn off power and disconnect equipment

STEPS FOR DEACTIVATION:

5) turn off camcorder by pushing STOP button on side panel. Camera will go from showing black background and stars to blue background and word STOP appears in the upper right corner of the flip screen.

Figure 5. Push the button just below the words NIGHT MODE. This will stop the recording and you will see STOP appear on the flip screen. 

6) power off camcorder with one button by reversing the process from step 2 in the previous procedure.

Figure 6. On the right side of the camera push the small green button so as to move it up from the PLAY/VCR position to OFF. The camera is now powered off. Close the flip screen.

7) disconnect 8-AA battery pack from camera chord.

8) place battery pack and camcorder into  your car.

9) remove camera from tripod head using flip switch.

Figure 9A. Tripod head flip switch pulled back to the right releases the camera/lens combination

 

Figure 9B. The camera/lens combination removed from the tripod head successfully

Gently place the camera into your car and cushion it with a towel. If it has a cap, be sure to cover the front of the optics.

10) collect tripod and put it in the car. You do not have to release the legs, just fold them together so you can comfortably fit the tripod into the car.

11) Use your flashlight to check around the site to be sure you have all the gear and pick up any trash. Follow procedure to turn in equipment from each video site.

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6B. OPERATION OF CANON ZR CAMCORDERS THAT REQUIRE REMOTE CONTROL FOR MULTISTATION RECORDING

The process above uses buttons on the left side of the camcorder to transition from STOP to PAUSE to RECORD. The process below must use a remote control powered by two AA batteries.

IMPORTANT: In order for the camcorder to accept commands from the remote, place the remote so it is pointing within about 6 inches to the front (lens) part of the camcorder or else the commands will not work! There is an IR sensor located there that will receive the signal.

Fig. R1. The Canon ZR remote control

REPLACE STEP 5 (after figure A2) OF THE ACTIVATION PROCESS WITH THE FOLLOWING:

4) To transition from STOP to PAUSE, use the button shown below in RED. Push the button in the photobelow and the flip screen will show PAUSE in the upper right part of the screen

Fig R2. REC/PAUSE button

5) To record the occultation: Push the button in the photo below and the flip screen will begin the recording process and show REC in red letters in the upper right portion of the screen. The onscreen timer will begin to advance

Fig. R3.  PAUSE button

REPLACE STEP 1 OF THE DEACTIVATION PROCESS WITH THE FOLLOWING ONE STEP:

1) To stop the recording: Push ONLY the STOP button pointed at in the photo below and the flip screen will stop the recording and show STOP on the screen

 Fig. R4. STOP button location 

 

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