On February 3rd the RECON projects leads announced an optional observing event for asteroid (191) Kolga for the evening of Feb. 9th. The specifics of this event was also noted on Occult Watcher (OW) which provided many of the event details, like potential observing station information, path maps, data on the occulting asteroid and target star, etc. What many may not know, is that on the evening of Feb 9th, another event involving asteroid (154) Bertha was also predicted to occur approx. 17 minutes later then Kolga, over much of northern California and northern Nevada. The prediction paths for these two events crossed some 40-50 km northeast of Reno, Nevada. For my typical observing station in Gardnerville Nevada, I was NOT in the predicted path of either of these events, (although inside 1 sigma for the Bertha event). After some evaluation of the events and the possibility of observing positives for both, I decided to “go mobile” with an 8” SCT and attempt observing both events from a location near Lahonton State Recreation Area, which is northeast of Carson City (approx. 56 km). For this location OW predicted that I had a 78% positive observing probability for Kolga and a 98% probability for Bertha. The LiMovie generated light curves for these observations are below.
As can be seen, I was fortunate enough to record occultation events for both Kolga and Bertha. For Kolga the duration was 5.74 seconds and for Bertha 5.34 seconds. It is a rare opportunity that two events are predicted for the same evening so close in time and so close together, location wise. For me, it was even more surprising that, none of other potential obstacles to making these observations (travel, weather, setup, etc.), got in the way of a successful evening.
For those of you that weren’t able to view the early morning event, forgot about it, or maybe just didn’t care, I offer the attached composite image as seen from Gardnerville, Nevada. The lunar eclipse started around 11:48 UTC (03:48 PST) and the moon was completely within the earth’s shadow about an hour later. We had partly cloudy skies with varying levels of cirrus over the Carson Valley. The moon was approximately 36 degree above the western horizon at the start and set before coming completely out of the earth’s shadow. For those interested in the specifics of the captured images; each of the three images in the composite were taken with a Canon EOS 80D with a Tamron 150-600 mm G2 zoom at 600mm (APS-C sensor – 1.6 crop factor – 960mm equivalent focal length). Exposures for each of the images are: 1/500 sec. (left image), 1.6 sec. (middle image) and 4 sec. (right image) at f/6.3. The camera and lens system were mounted on an EQ mount for the last images due to the necessary length of exposure.
Just now starting to work on processing of images from our group TSE adventure near Shaniko, OR. Wanted to share at least one image I was able to capture.
This was the last event for February posted by Tony George. The event ocurred early evening on Feb 25 at around 7:38 PM (PST). Predicted event time was 03:38:34 UT February 26th. The target star (11.6 mag.) for the occultation was low in the west at 27 deg altitude and in the constellation Pisces. The predicted maximum duration was 1.6 seconds at the predicted centerline. On the Occult Watcher prediction map my location was just outside (2 km) on the south side of the shadow path in the 1 sigma zone. I had previously contacted Red Sumner at the Jack C. Davis Observatory to see if he could possibly observe. The observatory was only a few kilometers off the predicted centerline. Although partly cloudy most of the afternoon, the clouds started to clear by early evening and there appeared to be a good chance for an observations. Scope setup went quickly, but just before event time a small patch of cirrus moved over the field stars. I set the camera integration to 8X and the VirtualDub timer program to record for 5 minutes centered around the predicted time. Then it was just to hope for the best. Sure enough, the clouds cleared and almost exactly at the predicted time I observed a short ‘wink’ of the target star. A follow-up analysis by LiMovie confirmed an approx. 1.7 second occultaion event. Tony George was gracious enough to provide a formal R-OTE analysis as seen below.
The actual camera and VTI corrected duration was 1.670320 seconds. This event turned out to be one that could have been observed by as many as three RECON sites (Gardnerville, Yerington, and perhaps Hawthorne). It appears though that, as of this writing, I was the only positive observer. A formal report was filed with the IOTA using the OW IOTA Reporting plug-in which uses a simple Excel spreadsheet format.
Reported IOTA occultation results for all of North America can be viewed at : http://www.asteroidoccultation.com/observations/Results/
With the historic success of New Horizons, the publics interest in Pluto is at an all time high. Many in the RECON communities have been interested in using their RECON telescope and camera systems to view Pluto. From my location in Gardnerville Nevada, Pluto has recently been viewable in the low southern skies. The best times for observing have been around midnight as Pluto rises to it’s highest elevation of around 25 degrees. At magnitude 14.1 Pluto was easily discernible in the crowded star field of Serpens, if you knew where to look. You will need an accurate star chart of the star field from the internet or from a planetarium program like GUIDE from the Pluto Project, or similar program. The annotated image below is a clipped frame from an observation I made on July 16th at just before midnight PDT. The skies were exceptionally clear and the seeing was very good. Pluto has now transitioned into Sagittarius and as of July 20th will be just to the NE of mag 3.5, Xi2 Sgr, (TYC 6294 2507 / SAO 187504) at around midnight PDT. Although Clyde Tombaugh didn’t know where to look for this far off world, you can see Pluto with the help of modern technology. See if you can find it !!
As Jupiter shines brightly during its 2014–2015 apparition, quite often Jupiter’s four big Galilean moons will occult and cast their shadows on each other. A “mutual events season” like this happens about every 6 years, when Earth and Sun cross the plane of the satellites’ orbits. We are now in the later part of this season, with these mutual events, still occurring thru August. Some of these events will dim the shadow-eclipsed moon, as seen here, or the combined light of two moons during a partial or total occultation. Photometric recordings of the events provide a very accurate way to refine the satellites’ gradually changing orbits. Their orbits are morphing in interesting long-term ways due to interactions among the satellites and between them and Jupiter. Occult Watcher can obtain mutual events through the “Planet Satellites (Global)” feed under “Configuration / Prediction Feeds”.
The event illustrated above occurred on April 27 at 2300 hrs, PDT. The shadow from the Jovian moon Io was cast upon the surface of Europa as viewed from earth. The accompanying light curve shows the apparent drop in brightness during the eclipsing event. The total event was approximately 4 minutes in length out of the nearly ten minutes of recording time.
This particular video was further analyzed by Tony George for accurate timing extraction. Data was then properly format and sent to the IMCCE in Paris for inclusion in this season’s Jovian moons mutual events data set.
A Reminder for RECON Teams: The video recording of these types of events will probably require some Mallincam camera setting changes to properly record a useable video. Teams are reminded that camera setting should be returned to the proper RECON occultation settings before a RECON campaign event.
I know a few others in the RECON community were planning to attempt this event. A major obstacle for many, was the very low elevation of 14 deg. in the east. The fact that the event occurred at around 3 a.m., probably discouraged a few other potential observers. For me, those challenges, and a few more, were also very real. An interesting aspect of this event as noted on Steve Preston’s info page, was that the target star was one component of a relatively close double star (5 arc seconds separation, 12.6 and 13.8 mag). This factor was really only significant when attempting to analyze the event with LiMovie and subsequently by Occular and/or R-OTE for timing calculations. As you can see from the light curve, the event was indicated by a very low magnitude drop. The predicted mag drop was 0.5, but this was calculated for only the one component of the double system that was occulted. At the focal length used to make the recording the three components (asteroid and two stars that make up the double) cannot be separated in the aperture ring of LiMovie. Because of the additional star the resulting mag drop was somewhat lower than that predicted. A real added treat would have been if the position angle (PA) of the double system would have been such that both stars would have been occulted by Hygiea. In this case though, Hygiea passed just to the celestial north of the doubles second component. The light curve below represents my estimates of the occultation timings and is not the final IOTA official data.
The image depicted here shows the asteroids Ceres and Vesta as they appeared in the constellation Virgo on July 4, 2014. Ceres is at magnitude 8.5 and Vesta is 7.2. On the date of this image they were approximately 10 arcminutes apart. Although they look close together they are actually about 74 million kms apart with Ceres in the background. This is why Ceres might appear slightly fainter. Ceres, with a diameter of about 940 kms, is actually twice as large as Vesta.
You might notice that the asteroids appear slightly elongated in this image (moving from upper right to lower left). This is due to the movement of the bodies during the course of the 30 minutes it took to acquire the stack of images that make up this final picture. Vesta is moving faster relative to Ceres and might appear slight more elongated.
The two fuzzy objects is the lower right section are the spiral galaxies NGC 5184 (higher) and NGC 5183 (lower). They both shine at approximately magnitude 13.5. These galaxies are approx. 170 to 180 million light years from earth. The brightest star here is TYC 4966 149 (lower, just left of center) at visual magnitude 10.4.
Invisible in this image is NASA’s Dawn spacecraft having just completed it’s 2011-2012 visit to Vesta and is on course to it’s mapping project of Ceres. Dawn is scheduled to arrive at Ceres in 2015.