THE OBSERVATION OF TORRICELLI B
AND POSSIBLE TRANSIENT LUNAR PHENOMENA

 

Daniel Del Valle, Guido Santacana, Raffaello Lena, Alessandro Cipolat, PierMario Gualdoni, Francesco Badalotti , Morio Higashida.
Geologic Lunar Research group
 (figures in Appendix)

INTRODUCTION

 

Torricelli B is a 7 km crater, which is approximately at 2.7 degrees south and 29.2 degrees north. Its namesake crater, Torricelli , is a little over 50km south and the craters, Censorinus and Moltke, frame Torricelli B to the northeast and northwest respectively. This crater has been reported as the site of Lunar Transient Phenomena (LTP) in the past, most recently on January 29, 1983 when it was reported to be briefly the brightest spot on the Moon.

A possible theory about this event is connected with specular reflection of the bright ray region. The lighting conditions of that date were to be duplicated on February 9, 2001 at approximately 05:00 UT. 2001, February 9th is exactly one saros of 18 years and 10,33 days later. Sun, earth and moon will meet again in exactly the same geometrical position. An LTP alert was sent out to interested lunar observers. This opportunity would help to verify if any unusual brightening would occur again.

The Geologic Lunar Research group (GLR) set out to coordinate its team of observers for this possible LTP event. This was done completely through the internet, specifically through the use of e-mail.

Monitoring of the crater was begun at the beginning of February with almost daily observations. This was done so that the GLR observers could familiarize themselves with the location of the crater, the surrounding area, and its normal aspect under varying lighting conditions (Fig 1-20).

In our archives we found several images of this region. These serve as a comparison with the drawings and were obtained at lunar sunset .

These preliminary observations served as range finders to fine- tune our observers for the target date of February 9, 2001. Those observers unfamiliar with the region were able to study the area in a systematic way and therefore prepare themselves for any anomaly.

ALBEDO VARIATION

The observations of Torricelli B also included monitoring the crater for any abnormal albedo variance. The crater’s albedo was compared with other craters: Censorinus, Proclus and the interior of Aristarchus. This technique is similar to what variable star observers use when comparing the brightness variation of a particular variable star.

Lena, del Valle, and Santacana reported albedo values using the Elger scale and CED (crater extinction device). On this basis no significant variation was recorded on February 9, 2001. The corresponding gray (Elger scale) values were daily obtained (Table 1).

For each observation , the local altitude of the Sun and his co-longitude, were calculated with the ALPO TOOLS software.

CED (crater extinction device)

A CED does not measure absolute brightness, rather differences in contrast between a feature and its background surroundings. The highest reading is 10.0 since the CED is calibrated with the Elger scale (Table 2).

 

TABLE 1 - Features and colongitude
 
 
features
col 347.9
 
col 357.8 
col 12.3
 
col 23.3
 
col 24.6
 
 col 34.8
 
col 36.7  
col
46.1  
col  48.9 
col 61.5 
col 70.3 
 col 73.9  col 86.2  col 96.4 
floor Torricelli B
0
0
3.5 ps
3.5
4
 5
 6
 6.5
 7.5
7 7 7
spot inside Torricelli B -- -- -- -- -- -- -- -- -- -- 8.5 8.5 8.5 8.5
Area surrounding  Torricelli B
2.5
2.5
3
3.5
4
 4
 4
 4
4 4 4
West  rim Torricelli B
 
7
7.5
7.5
8
8**
 8
 8
 8
8 8 8
Small hill (SW )  Torricelli B
6
6
6.5
7
7
 7
 7
7.5 
8 7 7

 

* (---  feature not detectable in shadow,  ps feature partially in shadow)
** albedo of the north and south rim of Torricelli B
 

TABLE 2 - Features and colongitude CED
 
 
 
features
col  48.9 
 
col 61.8 
 
col 86.1 
col 100.1 
crater rim (S,E,W) 
8
 8
 8
 8
Torricelli B crater floor
6
 6
 6.5
 7
crater rim spot
(N, NE)
8
8.5
8.5
8.5
hill to the southwest 
8
 7
 7
 7
dark halo
3
 3
 3
surrounding area
4
4
  (*) CED readings with the craters Censorinus and Moltke:
Censorinus-10.0
Moltke-9.0

MOON BLINK

No significant blink was observed in Torricelli B and as a comparison reference point, Censorinus. Using a W80A and W25 filters, Lena estimated the dark halo and surrounding regolith as more red. In the blue filter these appeared darker. Del Valle reported that the dark halo was not clearly visible with a W47 filter, but that it was visible with a W25 filter.

 

PRELIMINARY OBSERVATIONS

These preliminary observations served as range finders to fine- tune our observers for the target date of February 9, 2001.

As can be seen (Fig. 1-14), with the increased sun angle over the lunar surface, features appear "washed out". It is difficult for the observer to orientate herself/himself and knowledge of the changing aspect of lunar features is necessary to avoid errors.

On the nights of the 6, 7, and 8 of February Lena, Santacana, and del Valle saw the presence of a bright spot in Torricelli B near the northern rim (Fig . 11-14). Our observations has revealed that the bright spot in Torricelli B is an observable feature visible under specific solar angle. Its albedo estimate was 8.5 on the Elger scale (Table 1).

OBSERVING TORRICELLI B ON FEBRUARY 9, 2001

On February 9 the bright spot was observed again by Santacana (03:00 UT ), del Valle (03:07-04:35 UT), and Lena (04:10-04:59). Its albedo estimate was 8.5 on the Elger scale. The rim was 8.0 Elger scale.

The area around the crater was darker than the surrounding terrain, especially to the east-southeast (Fig 15-16). No anomalies or brightening of Torricelli B was recorded. Albedo variations were normal throughout the observing period both prior to and during the target date.

RESULTS

There was no brightening of Torricelli B nor were any other anomalies seen in the general area. Our study showed:

  1. The presence of a bright spot during the lunar phases observed in the N-NE rim of Torricelli B.
  2. There was sometimes visible spurious color. For example we observed blue coloration in Censorinus, around its rim. This was not seen in Torricelli B. It is a false effect of the seeing or atmospheric conditions. In fact it was not confirmed by all our network of observers.
Our conclusion is that the bright spot in Torricelli B is real and it should be studied more. It could be the cause of LTP reports in the past (BAA).

Both the Apollo and Clementine images show bright ray material deposited on the north to north east crater wall and spilling over the rim.

This interesting feature was recorded by our group (visual and video camera) at certain sun angles. When three of our observers saw it, it appeared to fluctuate. It was thought at first that it was an effect of our eyes, but later realized that it was due to the subtle oscillation of the seeing.

The result of our study contradicts the theory that the TLP from January 29th, 1983, might have been a reflection of the suns light on the moons surface. Our group worked by using the Internet as a communication platform in real time coordinating observing programs and events.

Active international cooperations by individuals making regular systematic, simultaneous observations of the Lunar features continues to be our prime objective.

FIGURES APPENDIX


 Fig 1: The first observation was made on January 30 at 22:48 UT by Daniel del Valle using a 20cm SCT, f/10 (339-450x). The seeing was II on the Antoniadi scale. The colongitude was 347.96. The solar altitude on Torricelli B was of 17.2 ° .

Fig 2: On January 31 Raffaello Lena carried out an observation at 17:59 UT. He used a 10cm refractor, f/15 (180-300x), seeing was II-III on the Antoniadi scale. The Colongitude was 357.87 °. The solar altitude on Torricelli B was 26.7 °.


 

Fig 3: Francesco Badalotti made an observation on January 31 at 18:10 UT, using a 25cm SCT, f/10, with a video camera. Seeing was III on the Antoniadi scale. The Colongitude was 357.87 °. The solar altitude on Torricelli B was 26.7 °.

Fig 4 On February 1 at 23:00 UT Daniel Del Valle observed Torricelli B with a 20cm SCT, f/10 (339x), seeing III Antoniadi scale. The colongitude was 12.3°. The solar altitude was 41.5°
 

Fig 5 On February 2 at 20:20 UT Raffaello Lena used a 10 cm refractor, f/15 (250-300x), seeing Antoniadi II to observe the crater. The colongitude was 23.3 ° . The solar altitude over the crater was 52.3 °.


 
 

Fig 6: On February 2 at 23:00 UT Daniel Del Valle observed Torricelli B with a 20cm SCT, f/10 (339x), seeing II Antoniadi scale. The colongitude was 24.6 °. The solar altitude was 53.7° .


 

Fig 7:Francesco Badalotti-observation carried out on 3 february 2001 at 19:15 UT- SCT 25 cms f/10 video camera (seeing III Antoniadi scale). The floor of the crater is visible and the surrounding dark halo appears the same as in the previous night’s image. The arrow shows Torricelli for reference. The colongitude was 34.8°. The solar altitude over Torricelli B was 65.7 ° .

 

Fig 8: On February 4 at 23:34 UT, del Valle used a 20cm SCT, f/10, at 339x and seeing II on the Antoniadi scale. The Colongitude was 49.1°. The solar altitude over Torricelli B was 78.1 °.
 

Fig 9: Guido Santacana on 6 february 2001 at 00:08 UT Magnification- 444x Telescope- 8" SCT Seeing- 6 on the Pickering scale, Transparency- 4 .The colongitude was 61.5° and the solar altitude over Torricelli B was 88.1°.

Fig 10: Santacana also recorded the same bright feature using a Minolta camera by eyepiece projection at 222x with the 8"SCT. The images are not too sharp, but they show the albedo features well. Same data of the preceding figure.
 

Fig 11: Raffaello Lena on 6 february 2001 at 17:30 UT. Magnification- 278x Telescope SCT 25 cm f/10 seeing II (Antoniadi scale). The colongitude was 70.3° and the solar altitude over Torricelli B was 80.4°.

Fig 12: Guido Santacana on 7 februaty 2001 00:42UT Seeing was 5 on Pickering scale and transparency 4. The observation was carried out with the 8" SCT at 444x. The colongitude was 73.9° and the solar altitude over Torricelli B was 76.8°.
 

Fig 13: Daniel Del Valle, observation carried out on 8 february 2001 at 01:30 UT seeing II (Antoniadi scale). Telescope 20 cm SCT, f/10 450x. The colongitude was 86.5° and the solar altitude over Torricelli B was 64.3°.


 

Fig14: Guido Santacana on 8 february 2001 at 0:11 UT- Magnification- 444x Telescope- 8" SCT Seeing 6 on Pickering scale. Transparency 4 . The colongitude was 85.8° and the solar altitude over Torricelli B was 65.0°.

Fig 15: Guido Santacana on 9 february 2001 at 3:00 UT- Magnification- 444x Telescope- 8" SCT Seeing 3-4 on Pickering scale. Transparency 4. The colongitude was 99.4° and the solar altitude over Torricelli B was 51.5°.

Fig16: Daniel Del Valle observation carried out on 9 february 2001 at 04:35 UT

Telescope: 20.3cm SCT, f/10 Magnification: 450x Seeing: II-III Antoniadi scale.

The colongitude was 100.2° and the solar altitude over Torricelli B was 50.7°.
 

Fig 17:Alessandro Bares and PierMario Gualdoni CCD image taken on 11 february 2001 at 22:00 UT Mewlon 250 mm f/12. Seeing II Antoniadi scale. The colongitude was 133.2 and the solar altitude over Torricelli B was 17.7°.

Fig 18: Francesco Badalotti, observation carried out on August, 11, 1998 at 23:00 UT, using a 25cm SCT, f/10, with a video camera. Seeing was II on the Antoniadi scale. The Colongitude was 141.5 °. The solar altitude over Torricelli B was 9.0 °. Morio Higashida- Newton 20 cm f/6 Bitran BJ30 L. Image taken on 10 september 1998 at 18:43 UT. Solar altitude over Torricelli B 5.2 °, colongitude 145.7 ° .

Fig 19: Morio Higashida- Newton 20 cm f/6 Bitran BJ30 L. Image taken on 10 september 1998 at 18:43 UT. Solar altitude over Torricelli B 5.2 °, colongitude 145.7 ° .

 

Fig 20: Morio Higashida- Newton 20 cm f/6 Bitran BJ30 L. Image taken on 12 august 1998 at 19:19 UT. Torricelli B was in shadow (Solar altitude on Torricelli B -0.9 °), colongitude 151.8 ° .