Bruce L. Gary; Hereford, AZ

This web page was created in 2004 and discontinued a year later. Its original purpose was for the purpose of data exchange with other TrES-1 observers and data analysts at a time when a group of amateurs suspected a "brightening" just outside the transit feature. Such a brightening after egress (and before ingress) could be produced by forward scattering of a ring system around the TrES-1 hot Jupiter, TrES1b. Since it might be usefual in serving as a tutorial for exoplanet observing and analysis procedures I will leavit up for awhile (this is 2007.11.22). For a more comprehensive and up-to-date web page of amateur observations of TrES-1 go to http://brucegary.net/AXA/TrES1/tres1.htm

Links internal to this web page:

    Transit of 2005.04.26  
    Schedule for 2005
    Combined data light curve
    Test Observations on a non-transit night   
    2004 October 08 transit (ingress)
    2004 October 02 transit (ingress & mid-transit)
    2004 September 23 transit (mid-transit & egress)
    All BLG Data
    Equipment and Observing/Reduction Procedures (tutorial for exoplanet observing)
    General Introduction to TrES-1 Star Field
    Links to text data files
    Links to other relevant web sites

Transit of 2005.04.26

April 26, 2005 transit

Figure 1 Transit of April 26, 2005. Individual 1-minute exposures  are shown with dots, while 4-minute and 8-minute averages are shown using purple and red symbols. A hand-fitted line is shown with symmetry about the predicted transit time. The first observations were made at  an elevation of 12 degrees and the last data were made at an elevation of 54 degrees. Ensemble photometry used 7 reference stars that surrounded TrES-1. The RMS scatter about the hand-fitted trace is is 2.9 mmag for 4-minute average data and 2.1 mmag for the 8-minute data.

Based on this data I no longer believe that TrES-1 has a bump upon egress, and I'm discontinuing my observations of this object.

These observations were made with a red filter. The flat field frame was a median combine of 25 individual flat frames with maximum counts between 25,000 and 32,000, all with exposures between 1 and 10 seconds, and they were made with a double T-shirt aperture cover at sunset. The dark frame consisted of 27 1-minute exposures, median combined, made with the CCD at the same temperature as the TrES-1 observations (-25 C). A SBIG AO-7 tip/tilt autoguider was used, with an exposure time of 0.2 seconds using a star with a V-magnitude of 10.6. A dither parameter of 1 assured that each image was randomly offset from a nominal location by approximately  3 pixels. An observing sequence was employed that specified 16 1-minute exposures with a 5-second settle time before each exposure (to allow the AO-7 to re-center the autoguide star). Processing was done using MaxIm DL's photometry tool, with aperture settings of 11, 3 and 9 pixels. The FWHM for each 1-minute exposure ranged from 3.6 "arc to 7.5 "arc (the larger values were confined to the 12 - 20 degree elevation region). A spreadsheet analysis showed no correlation of TrES-1 departure from a regional average with FWHM.

Measurement precision improves with elevation angle. The following graph shows precision versus air mass for the three averaging times: 1-minute, 4 minutes and 8 minutes.

Precision vs averaging time

Figure 2 Measurement precision versus air mass for three averaging times. The fitted traces suggest that for air mass =1.5 the measurement precision is ~5, ~2 and ~1.3 milli-magnitude for averaging times of 1, 4 and 8 minutes.

Ensemble photometry offers the opportunity of estimating the magnitude of RMS variation a suspect variable object should exhibit based on its brightness. For example, the TrES-1 observations were reduced using 7 reference stars and 7 check stars. Thus, 14 non-variable stars provided an estimate of expected variability due to scintillation and stochastic noise as a function of brightness, and TrES-1 exhibited much greater variability than the expected amount, as shown in the following figure.

RMS vs Rmag

Figure 3 Measured RMS  versus brightness for the 7 reference stars and 7 check stars (green circles) and TrES-1 (red square). The dashed trace is a model for precision that involves a constant (i.e., scintillation) and a term that is inversely proportional to star flux (stochastic component). The RMS is for magnitude readings from 1-minute exposures.

If  TrES-1 were non-varying it would have exhibited an RMS variation during the 3-hour observing period of ~0.004 magnitude, based on the variability of the reference and check stars. Instead, it had an RMS variation about its average of 0.0115 magnitude. Presumably, the transit light curve in Fig. 1 is "real."

The following image shows which stars were used for reference.


Figure 3 Image of TrES-1 region showing 7 reference stars used to perform the ensemble photometry for this night. All magnitudes are for R-band. North up, east left; FOV = 16.4 x 15.7 'arc. [Total exposure time is 115 minutes.]

Schedule for 2005

[This section was prepared before I decided to discontinue exoplanet transit observations. I leave it here because it might be useful for others wanting to schedule observations for their site.]

Every observer should consider identifying which TrES-1 transits can be usefully observed at their site. I will present graphical and table representations of what I have determined for my site in Southern Arizona. Differences in longitude are more critical than latitude for making these identifications. There are two factors to consider when assessing a specific transit's observability: 1)  TrES-1 elevation above the horizon, 2) Sky darkness (sun's elevation below the horison and the moon's phase and proximity to TrES-1). First, I will show a graphical representation of these factors.

 2005 observing schedule

Figure 4 UT times for sunset (blue) and sunrise (orange) are shown versus date. Dotted lines are used to indicate when the sky is dark enough for observations to be made (offset 45 minutes from sunset and sunrise).  UT times when TrES-1 rises and sets through 20-degree elevation are shown with green lines. The TransitSearch times for ingress and egress are shown with small open squares. Vertical lines join ingress to egress times for those transits that occur when it is dark and when TrES-1 is high in the sky.

For all of the transits identified as observable in the graph the moon is below the horizon. This is fortunate for observers in the Western United States. Europeans will have a completely different set of circumstances, and may in fact be bothered by the moon in 2005.

Here's a table of the 9 transits that I have identified as observable from Southern Arizona for 2005.

 Sun night
 May 2
 Wed night
 May 5
 Sat night
 May 7
 Thu eve
 Jul  29
 Sun eve
 Aug  1
 Wed eve
 Aug  4
 Sat night
 Aug  7
 Tue night
 Aug 10
 Fri night
 Aug 13

For egress only observing (i.e., foresaking ingress) there are at least 4 more observing opportunities: April 26 and 29, and July 23 and 26 (UT).

Combined Data Light Curve

The following figure shows light curves for the TrES-1 data that has been made available to me. They have undergone small adjustments for temporal trends and time shifts (see details for details). Tonny Vanmunster (VMT) has measurements for the dates 2004.09.01 (abbreviated hereafter as "4901") and 2004.09.04 (abbreviated as "4904"). My observations (GBL) are for the dates 2004.09.23 ("4923"), 2004.10.02 ("4A02") and 2004.10.08 ("4A08"). Tonny's data is high quality, and mine are not as good but still useable. Here's a plot of sliding boxcar averages of our data.


 Figure 5.
Magnitude measurements of TrES-1 transits made by Tonny Vanmunseter (VMT) and the author (GBL) are plotted with respect to "time after mid-transit" with magnitude offsets that achieve zero away from transit. The VMT data with a sample interval of 2.4 minutes have been smoothed with a 24-minute "sliding boxcar filter"and adjustments were made for temporal trends and slight timing offsets (to achieve symetry about the predicted mid-transit time). The GBL data have a sampling interval of 3.1 minutes, a 22-minute sliding boxcar averaging interval, and two of the three data sequences have been adjusted for temporal trends and one was adjusted for a time offset. The VMT 2.4-minute data exhibit an RMS scatter about their average trace of 1.7 and 2.8 milli-magnitude (for 4901 and 4904). The GBL 3.1-minute data exhibit a RMS scatter about the average trace of 4.5, 4.5 and 4.8 milli-magnitude. The trace for "GBL 4A08" goes below the others during transit when high air mass conditions were encountered (no temporal trend correction was attempted for this data sequence).

Tonny Vanmunster's measurements are much more precise than mine, so any "features" in his light curves should be viewed as more credible. The purpose for my 4A08 observations was to evaluate "bumpiness" during a time when no transit was expected, in order to know whether any "bumps" during transit should be taken seriously. My non-transit light curve data for 4A08 "wander" about zero with an amplitudes of ~1.5 milli-magnitude. I will take the position that any features in my light curves that are smaller than 2 milli-magnitude should be disregarded as mere stochastic and systematic wander. In addition, for the 4A08 data sequence I will assume that starting at -110 minutes there is a systematic fading trend that amounts to ~0.005 magnitude that is not real, and for which a plausible explanation is that some effect related to increasing air mass caused this fading trend. Thus, the 4A08 "soft shoulder" during ingress is to be disregarded.

Considering only the GBL data for now, and adopting the guideline that stochastic and systmatic error wander can be expected to exist at the 2 milli-magnitude level, I conclude that there are two candidates for real anomalies that might be attributable to TrES-1: 1) an ingress brightening of "GBL 4A02" at -110 minutes, and 2) an egress brightening of "GBL 4923" at about +90 minutes. I'll return to a discussion of these features later.

Considering the VMT data, there is insufficient coverage away from transit to allow the same evaluation of stochastic and systematic error wander (in the same way that this was done for "GBL 4A08"). VMT data have much better stochastic properties, but it is difficult to assess the magnitude of VMT systematic error wander.  One approach is to compare the two VMT curves, and assume they have the same systematic error wander properties and also assume that the TrES-1 light curve is the same for each transit. If this were done then the inferred VMT systematic error wander would be ~1.0 milli-magnitude (slightly better than attributed to GBL). Under this assumption the VMT data show only one anomaly: an egress brightening of "VMT 4904" at about +80 minutes.

With only this limited set of data, from only two observers, the case for a brightening before ingress and after egress is unconvincing for me. Let's consider these light curves under the assumption that the TrES-1 light curve is the same every transit. The following graph shows my best estiamte of this combined data light curve.

VMT&GBL all data avg

Figure 6. Average of all VMT and GBL data (adjusted for temporal trends and time shifted). This light curve is based on data points that are themselves temporal averages (24 and 22 minutes) so there is no possibility for the presence of shorter timescale features.

If it is assumed that every transit has the same light curve then this last figure is an approximation of it.  Any  egress brightening for such a light curve would have an amplitude of ~2 miili-magnitude.

It is my personal opinion that this set of data cannot be used to argue strongly for or against the presence of anomalous features in the TrES-1 transit light curve. This data set is limited to just two amateur observers (with AAVSO observer codes VMT and GBL). The TransitSearch group is in possession of a much larger data base for the TrES-1 transits, and Ron Bissinger has performed a very good analysis of it. When a web site for that analysis is available I will put a link to it here.

Test Observations on 2004 November 04 (Non-Transit Night)

To satisfy my curiosity I observed TrES-1 for 3.4 hours on a non-transit night to see what level of variations would be observed using the same observing hardware configuration, observing technique and the same data reduction procedure that was used for the transit observations.  Here's what I got for a light curve.

 LC 2004.11.04 avg

Figure 7. Measured R-magnitudes on a non-tranist night for TrES-1 (red) and a check star (green) using same hardware and procedures as during the transit nights.  Three stars served as reference ("comp").

 LC 2004.11.04
Figure 8. Light curve plot of same data as in previous figure. A 5-minute running average is shown. The observations began with air mass = 1.10 and ended when airmass = 2.32. The RMS deviations from the running average increase with air mass from 3.07 to 3.84 milli-magnitude for the check star and they increase from 6.85 to 8.58 milli-magnitude for TrES-1.

TrES-1 exhibits an RMS variation about the 5-minute running average trace that is greater than for the check star. For example, at low air mass the two RMS values are 3.07 milli-magnitude (check star) and 6.85 milli-magnitude (TrES-1). The RMS fluctuations are in the ratio 2.22 instead of the expected 1.12 (based on brightness ratios). I don't understand this.

The 5-minute average trace for the check star exhibits a range of variation of ~6 milli-magnitude, whereas the range of variation for TrES-1 is about 10 milli-magnitude. Clearly, for my transit observations features similar to those in the above figure should not be believed. Specifically, a 5-minute feature with an amplitude of 2 milli-magnitude is too subtle for me to detect with one observing session (especially when TrES-1 is at a high air mass).

LC 4B04 5-min Grp Avgs

Figure 9. Light curve plot of same data as in previous two figures. 5-minute independent group averages are shown. The 5-minute group averages for the check star exhibit an RMS about their ensemble average of 0.88 milli-magnitude at low air mass to 1.56 milli-magnitude at high air mass. For TrES-1 the RMS deviations from the ensemble group average is 2.25 milli-magnitude at low air mass and 2.42 milli-magnitude at high air mass.

The check star 5-minute independent group average of 0.88 milli-magnitude at low air mass agrees well with the value expected from the 10-second individual image RMS of 3.07 milli-magnitude (0.89 milli-magnitude). The check star's high air mass RMS is slightly higher than the expected value, 1.56 versus 1.11 milli-magnitude. I interpret this to be evidence that high air mass observing conditions produce systematic errors that wander by amounts greater than the stochastic uncertainty (for my system). This appears evident in the check star's 4 milli-magnitude "fade feature" at about -575 to -555 minutes. TrES-1's 5-minute independent group averages undergo a greater fluctuation than the check star, as predicted from their greater RMS for individual 10-second images. The TrES-1 5-minute groups exhhibit approximately the expected RMS values for both low and high air mass, being 2.25 versus 2.00 milli-magnitude for low air mass and 2.42 versus 2.48 milli-magnitude for high air mass.

Using the 5-minute independent data groups it is possible to predict the level of features that can be expected to appear during a real transit event, assuming stochastic SE and systematic wander characteristics are the same both observing nights. TrES-1 and the check star tell the "same story": we should expect to see non-real 10-minute features with amplitudes ~2 milli-magnitude at low air mass and ~3 milli-magnitude at high air mass. Given the better stochastic behavior of the check star (than TrES-1) these systematic error wanderings will be more apparent for a star that is stochastically well-behaved (like the check star was). For a star with poorer stochastic behavior (like TrES-1) the systematic error wandering will be less apparent (although it is approximately the same as for the stochastically well-behaved check star).

Another way to approach the question of whether to believe features in an exoplanet light curve is to perform a transit simulation using non-transit observations. This is done in the next two figures.

 Simulation using check star

 Figure 10. Simulated light curve using measurements of a nearby check star and adjusting them using a hypothetical transit light curve with TrES-1 properties.

 Simulation using TrES-1

Figure 11. Simulated transit light curve using TrES-1 non-transit observations and adjusting them using a hyothetical transit light curve with TrES-1 properties.

The two figures, above, were created from the non-transit measurements of 2004.11.04 by applying a hypothetical transit light curve shape adjustment to the non-transit observations. These plots show what can be expected when observing a transit. If the "eye" detects features in these light curves then the "brain" should intervene and say "no, they're not real; they're roduced by systematic error wander." Indeed, in the second of these simulated transits (based on TrES-1 non-transit observations) note the apparent "bump" before ingress. There is no corresponding brightness bump after egress, and in fact there appearsto be a fading after egress. The first of these "features" must be attributed to systematic error wander and the latter feature may be due to wander associated with high air mass.

The "message" from this simulation is that instrumental anomalies having amplitudes of ~3 or 4 milli-magnitude should be expected from an observing system (and analysis procedure) used by the author of this web page. If other observers want to argue for the "reality" of their anomalies then it may be instructive for them to conduct a simulation using non-transit observations similar to what I have described on this web page. As an alternative light curves obtained by several observers could be combined to see if all of them, or most of them, show the same anomalies. That analysis will be performed for the TrES-1 2004 October/November observations by Aaron Price (AAVSO) in the near future.

In the above two figures notice the better "behavior" of the check star compared with TrES-1. As stated earlier, I do not undersxstand why TrES-1 has a higher stochastic SE than the check star (whose brightness is only 12% greater). It may have something to do with nearby faint stars with PSFs whose edgtes wander in and out of the signal aperture or sky reference annulus. Or maybe the three reference stars were better located for removing flat field errors (i.e., the reference stars "surrounded" the check star better than TrES-1).

This exercise illlustrates some of the considerations and supporting observations that can lead to improved understanding and performance in exoplanet transit monitoring.


2004 October 08 (ingress)

This section (and the following ones) describe my TrES-1 transit observations.

   2004.10.08 LC

Figure 12. Each datum is from a median combine of five 30-second exposures, and represents an observation taken within a 200-second observing window (which allows for image download time). A photometric R-band filter was used. The first observations were made just after transit and the observations end when the elevation was 19 degrees (m=3.1). Two "outliers" occur (near 5.0 hours) when I was negligently changing the focus setting. The residuals from an average trace have an RMS = 0.0038 magnitude (excluding the two "outliers").

2004 October 02 (ingress & mid-transit)

 2004.10.02 LC

Figure 13. Each datum is from a median combine of ten 10-second exposures, and therefore represents an observation taken within a 190-second window. An R-band filter was used. The residuals from an average trace have an RMS = 0.0044 magnitude (excluding one "outlier").

2004 September 23 (mid-transit & egress)

This is my first observation of TrES-1. I used a V-band filter and unguided 10-second exposures. After 5 sequences of 10 exposures I re-centered the telescope so that the exoplanet was at the center of the FOV.

 2004.09.23 LC

Figure 14. Observations of September 23, 2004 (UT). A V-band filter was used for 10-second exposures, median combined in groups of 10. Each datum is therefore from a total exposure of 100 seconds occurring within a 180-second observing window (which allows for image download time). The RMS residual from the average trace is 4.7 milli-magnitude. A "meridian flip" was required at ingress which accounts for the slight gap at that time (never buy a German equatorialmount for exoplanet work). The early data are near zenith whereas the late data correspond to 50 degees elevation.

In this light curve there appears to be a "bump" at egress, or maybe a dip after egress. This bothered me until I saw other light curves showing a similar bump/dip feature after egress. That's when I alerted the TransitSearch discussion group (September 29) about this interesting anomaly (the discussion group's first "post"). Greg Laughlin (who set-up the TransitSearch discussion group) received an e-mail from Joe Garlitz pointing out the same feature. I suggested that maybe the TrES-1b planet had a satellite in a synchronous orbit that produced a second smaller "transit"  after the planet had completed its transit, but  David Blank discounted that idea using stable orbit theory, and suggested that rings might be a better explanation (October 2). On the same date Ron Bissinger called attention to a presentation at the 2003 AAS DPS meeting in Monterey by Barnes and Fortney describing what a ringed planet transit would look like (also described in Sky and Telsecope, January, 2004). Rings have remained the best candidate explanation so far.

All BLG Data

There is merit in combining data with comparable quality to look for patterns before combining data with disparate temporal sampling and quality for the same purpose. All of my data have approximately the same temporal sampling, were taken with the same instrument, processed using the same procedure, and they exhibit approximately the same RMS residuals with respect to an average trace. Hence, these three data sets are suitable for combining into one larger data set. The following graph is a superposition of the three data sets shown in the above sections.

 All BLG Data

Figure 15. All data in the previous light curve graphs are combined in this graph. The average trace is for 20-minute chunks of data. The vertical offsets were subjectively chosen.
This figure suffers from a lack of data near egress. Only three dates of ingress data are shown, and there are no unusual departures from a smooth ingress shape in this graph. This does not rule out the presence of unusual ingress shapes for other transits but it argues against a persistent ingress shape having a temporal scale of 20 minutes. The egress anomaly could be viewed as a dip following egress, with presumably a return to a pre-transit brightness past the dip. The argument for a dip instead of a positive bump in brightness is based on the way I chose an offset for this date's data; I chose an offset that provided best agreement with data from the other two dates (mid-transit and pre-ingress). However, using just this set of data it would be foolish to believe in an anomaly near egress. The egress data from 2004.09.23 were at lower elevations than the earlier data so it is possible that extinction effects compromise data quality near the end (at egress).

Using just my data I would not take a position concerning the existence of ingress or egress shape anomalies. It will be necessary to combine data sets from many observers to arrive at some concensus, and this is what Ron Bissinger is currently doing.

One additional comment can be made from inspection of this figure. The average trace appears to exhibit a precision of 0.001 magnitude, based on the pre-ingress data. Averaging seems to have worked its magic, in this case, without apparent degradation by unknown systematic errors.

Equipment and Observing/Reduction Procedures

My location is Southern Arizona, 90 miles SSE of Tucson (near the border with Mexico). The site is on the western edge of a 15-miles wide valley (San Pedro Valley), with the Huachuca Mountain Range a few miles to my west. My altitude is 4660 feet, and my coordinates are 110.2378 West, 31.4522 North. I use a Celestron CGE-1400 (14-inch aperture) Schmidt-Cassegrain telescope configured for prime focus using a a HyperStar (Starizona product) transition lens. The f-ratio was 1.86. My CCD camera is a SBIG ST-8XE and I use a SBIG CFW-8 filter wheel with photometric filters. This configuration produces an image scale of 2.81 "arc/pixel and the FOV was 72x48 arc. Since the "atmospheric seeing" typically is 2.5 to 3.0 "arc (FWHM), the prime focus configuration point-spread function has a FWHM of ~7.5 "arc. The telescope is located in a sliding-roof shed 50 feet from my house, and it is controlled using 100-foot buried conduit cables from my house office. The MPC has assigned my observatory an "observatory code" of G95 and name "Hereford Arizona Observatory."

I use MaxIm DL 4.0 to control the telescope and camera. A typical observing night starts with dusk sky flat frames for each filter to be used. I place a "Double T-shirt Cover" on the aperture and point to zenith for flat frame exposures. This assures that no stars show up on the flat frame images. Exposure times longer than 1 second are used (dark frame subtracted), with exposure times chosen so that the maximum count is under 40,000 to assure that saturation effects will be small (my CCD is non-ABG). All dark frame images for a given filter are then averaged. The CCD cooler is then set to a value of about -18 C, and during cool down the telescope pointing and focus is verified near the region of interest.

Observations of the exoplanet are preceded by a focus check and a star field position placement that provides a suitably bright star on the autoguider chip. It is common practice for exoplanet observations to use a filter, such as V or R, in order to minimize extinction effects as the airmass changes during along observing session. The exoplanet is almost always placed at the center of the FOV since with the prime focus configuration the autoguider chip almost always has suitably bright stars present. My goal is to maintain this placement of the star field with respect to the main chip for the entire duration of the night's exoplanet observations. This is an important observing goal since errors in the flat field are an important source of systematic changes in exoplanet brightness. Exposure times for the exoplanet images are kept short enough that none of the reference stars produces maximum counts that exceed 40,000. For TrES-1 and R-band this exposure time could be as high as 60 seconds for my system, but so far I have used only 30-second exposures. I use MaxIm DL's "sequence" observing feature to take many sets of 10 "light" images and one "dark" image.

For data analysis I also use MaxIm DL, including its Photometry Tool for photometric analysis of groups of images. I manually load 5 images at a time, calibrate them (flat field and dark), and save the median combined (or sigma-clip combine) image. I am very wary of cosmic ray effects creeping into light curve analyses, so I always use median combined (or sigma-clip combined) images for my photometric analyses. After several groups of 5 raw/calibrated images have been processed to produce "clean" images I perform a photometric solution for several clean images using the MaxIm DL Photometric Tool.  The exoplanet "object" is chosen, and several "reference stars" are also chosen and their magnitudes are entered in to the Photometric Tool. The choice of signal aperture radius, gap width and sky reference annulus width are important, and for the prime focus configuration I usually use 5, 2 and 4 pixels. The stars typically have FHWM = 2.7 pixels, so use of 5 pixels for the aperture radius is "conservative" in the sense that for images when the FWHM is larger than for other images there will be minimal effect on the "intensity" reading. Occasionally a star field has interfereing stars near a reference star (or the exoplanet) and this requires a different choice for aperture/gap/sky reference. The Photometric tool creates a CSV-file containing a Julian Day time tag and magnitudes for the object and reference stars. These are imported to an Excel spreadsheet and processed in a straightforward manner. Checks are usually performed to validate constancy of the reference stars with respect to each other, which is another way of using these stars for the role of "check stars."

For those wanting a more complete tutorial on exoplanet observing try http://brucegary.net/ILAqr/

General Introduction to TrES-1 Star Field

The exoplanet system TrES-1 is located in the constellation Lyra at RA = 19:04:10, Dec = +36:37:57. The star, TrES-1a, has a V-magnitude of 11.74. Several non-variable stars are nearby with approximately the same brightness and these can serve as reference stars. Here's a wide field image of the TrES-1 star field:

   Large FOV of TrES-1 star field

 Figure 16. Wide angle field of view, 69 x 46 'arc, with TrES-1 circled.

The following image shows which three stars I use as "reference stars" (also called "comp stars") by the MaxIm DL Photometry Tool.

TrES-1 cropped FOV

Figure 17. Zoomed and cropped version of previous image, FOV = 14 x 12 'arc. TrES-1 is indicated by a double circle, and three reference stars with their V-magnitudes are shown.

 R-band reference stars

Figure 18. R-band reference star magnitudes. FOV = 10.8 x 12.7 'arc.

Links for Text Data Files

To download the text data files of my transit observations click on any of the following links, copy the displayed data to your Windows clipboard, open Notepad, paste the contents of the Windows clipboard to the blank Notepad document, save the Notepad document, and finally import that document to an Excel (or whatever) spreadsheet. Each datum represents ~150 seconds of total exposure time (for the last two dates); each datum (for the last two dates) is a median combine of 5 exposures, each 30 seconds long (which removes cosmic ray artifacts).


Links to other relevant sites

    TransitSearch summary of TrES-1 transit light curves
    My exoplanet observing tutorial
    Bruce's AstroPhotos
    Amateur Exoplanet Archive
    Exoplanet Observing for Amateurs (book)

My e-mail address is b g a r y @ c i s - b r o a d ba a n d . c o m 


This site opened:  October 10, 2004 Last Update:  November 22, 2007