British Astronomical Association
Supporting amateur astronomers since 1890

Secondary menu

Main menu

BAA Community Member pages
Terms of use

Daryl Dobbs

My interest in astronomy dates back to the days of Apollo where I was inspired by Sir Patrick whom I met many many times. I enjoy observing the sun through my Skywatcher 90mm refractor with a Lacerta Herschel wedge. When night comes I enjoy observing the moon, planets and star clusters. I have given talks to local societies and also contributed to newsletters on many aspects of visual observing.

2020 Sep 28

12:27 UTC

27th September 2020, 20:30- 20:58 UT, observing from Risca South Wales, 10" Skywatcher Dobsonian, seeing Ant ii-iii, eyepieces used x 184 Plossel  x 120 Altair Astro, filters used Wratten 12, 23a, 58 and 80a.

The purpose of this observing run was to investigate a report in the TLP schedule the crater Atlas observed by David Darling on 1991-4-25. Atlas had spots in it that were more intense in blue. No blinks were detected elsewhere on the moon apart from Gassendi. Cameron catalog id=425.

Thin high altitude cloud interrupted the observing run and at 21:04UT made further observations impossible, pity as I was watching for the disappearance of Epsilon Capricorni behind the Moon's unlit hemisphere. Cloud also prevented observations of the central peak of Gassendi also in the lunar TLP schedule by the same observer.  I managed to observe Atlas  in between the breaks in the cloud before it thickened ending the observing run.

The interior of the crater had three dark albedo features, the darkest on South East part under the crater wall, there were two other dark features one on the North East part and one on the North West part. The NE feature was slightly darker than the NW feature. Between these were a bright spot which gave the impression of a 'causeway leading to the centre area. I observed the area using the Red #23a filter followed by the Blue 80a filter. The contrast between these two filters did give the impression that the albedo features using the Blue filter had a deeper tone than observed in the Red. The interior of the crater is crisscrossed with riles but due to the high sun angle these were not visible. Switching eyepieces produced the same result.

Next idea was to use the following filters in sequence, #23a, #12, #58 and finally #80a, then swap eyepieces and repeat. The impression I got was the red filter makes the area appear darker including the albedo features than the blue filter which makes them stand out  from the general area. The yellow filter did not enhance or diminish the contrast between the albedo features and the surrounding area. The green filter did darken the view through the eyepiece but not so much as the red filter. The glare from the lunar surface was reduced slightly using the blue filter but far more so using the red filter. The slight reduction in the glare with the blue filter could give the impression the albedo features were more intense than with the red filter, this theory seems plausible when I used the green and yellow filters as a comparison.

To sum up; the interior of the crater is crossed by riles which weren't observable due to the high sun angle, therefore this is certainly an area where TLP is expected to occur. However I think the intensity of the spots observed is more to do with reducing the glare from the lunar surface than any change. The contrast of the spots did seem enhanced by using the blue filter which I think is more to do with the geology of the features than any TLP change. 

I made a quick sketch using the Elgar scale to indicate the tonal changes, this sketch was made without filters, I do now have a ZWO camera but still in the process of getting it working with my telescopes.

The frequent high altitude cloud in my opinion did not effect the result of the observing run. 

 0  

2020 Jun 26

12:46 UTC

25th June 2020 20:40-21:08 UT observing from Risca, 10" Skywatcher Dobsonian, seeing Ant ii transparency slight haze with broken cloud. x240 Celestron X-Cell, x184 Plossel and x133 Altair Astro Lightwave eyepieces.

Objective

Lunar crater Beaumont observed by Miranda from Brazil on 27th July 1971 during the Apollo 15 watch, saw a curious brilliance in the interior, when Moon was 70 degrees.

I saw nothing out of the ordinary as the crater floor was in deep shadow, 0 on the Elgar scale, there was no tonal difference apparent. However the outer wall was estimated to have a brightness on the Elgar scale of 4, a small portion of this on the North East sector was slightly brighter about 4-5 on the Elgar scale.

2020 Jun 25

09:20 UTC

24th June 2020 20:45- 21:23UT, 10" Skywatcher Dobsonian, magnifications used x133 Altair Astro Lightwave, x 240 Celestron X-cell, x 184 unbranded Plossel, x 48 Celestron X-cell. Filters used Wratten 80A and 23A. Seeing Ant ii-iii slight haze

The object of the observation was to investigate a report by H Bradley on 10th February 2008 of a bright pinpoint of white light in the Proclus region.

This area is well known to me due to previous observations regarding the illusion of O'Neil's bridge.

The sky wasn't dark but in my opinion this didn't effect the aims of the observation.

The brightest feature is the west wall of Proclus which appeared to be 9 on the Elgar scale, there appeared to be nothing else apparent in the area of equivalent brightness.

The inner wall was illuminated from the North through to the South West, the illumination was tapered from it's North end to a point on the South Western wall. At low magnifications this can give the appearance of a bright point. Proclus has a bright ray system under high solar illumination and therefore is relatively young.

I could see nothing else in the area which corresponded to a bright point, the inner wall of Proclus is by far the brightest feature in the immediate area. 

2020 Jun 2

12:11 UTC

1st June 2020 23.05- 23.35UT 10 inch Skywatcher Dobsonian with Celestron X-cell and Altair Astro Lightwave 1.25 inch eyepieces. Seeing Ant ii-iii, polarising filter also used.

Object of observation was Sinus Iridium due to reports of darkening over 1/4 of the floor area particularly the western rim, recommended using magnifications around x110.

Throughout this observing run I used the following eyepieces;

x240 Celestron X-cell 

X83 Altair Astro Lightwave

x96 Celestron X-cell

The bay was fairly featureless with only 2 wrinkle ridges visible on the Maria between Bianchini and Sharp, which were very conspicuous. The western rim segment of the Sinus Iridium were very bright approximately 8 on the Pickering scale. The bay itself showed no signs of any darkening on the floor of the Maria, notice was taken particularly on the western segment. I used a Baader polarising filter  on all three eyepieces rotating the eyepiece in the holder, no darkening was detected with this method and no darkening was detected without the filter.

It was noted that the seeing deteriorated during the last 10 minutes of the observing run due to local houses, but that did not effect the objective of determining if visually there were any darkening on the Maria floor which was approximately 4 on the Pickering scale.

Conclusion was the Maria floor of the bay had a uniform shade with no conspicuous darkening visible.

2020 Jun 1

12:35 UTC

31st May 2020 21.00 - 21.42UT 10 inch Skywatcher Dobsonian Seeing Ant ii-iii, x240 Mare Frigoris area around Fontenelle.

The purpose of this observation was to observe a suspected dome on the Mare Frigoris in the Plato Fontenelle area.

This is in response to a UAI request via the BAA Lunar section circular, Maurizio Cecchini seeks confirmation of a possible dome in the Plato Fontenelle area on the Mare Frigoris. All directions in this and other reports are to the IAU compass directions, IE Tycho to the South and Mare Chrisium in the East.

The only feature I could see in the area which is a candidate for a suspected dome in in the triangle made up of Plato, Fontenelle and La Condamine which was the other side of the terminator and unilliminated. As a purely visual observer and a poor draughtsman I made a rough sketch of the area whilst at the eyepiece.

Between Plato and Bliss there is a triangle of craters on Mare Frigoris, the crater nearest Fontenelle had a bright Halo.

Moving South West of Fontenelle towards the Straight Range which is on the Mare Imbrium you come across an area of broken terrain which forms the boundary of the Mare Frigoris and the Mare Imbrium. This broken terrain gives the appearance of a promontory sticking out into the Mare Frigoris. Just under the northern wall of this promontory was observed a curved line which has all the indications of a solidified lava front. This curved line was broken in the middle by the surrounding Maria , the northern segment of this curved line nearest to Fontenelle was slightly fainter than the part nearest the broken terrain. At the northern end of this fainter part of the curved line  was observed a line of peaks curving North West. The feature at the Eastern end of this curving chain gave the appearance of a low hill with a small faint shadow pointing West towards the terminator. This feature was separate from the curved line and gave the appearance of a dome or low hill. I could not see any evidence of a summit pit so often found on Lunar Domes.

With the curved line of peaks stretching away from this suspected dome it is my theory that we are not seeing a lunar dome but a submerged peak. The area has quite a number of flooded ghost craters some with isolated peaks sticking out of the Maria.

The suspected dome at the end of the curved solidified lava front was visible easily from the beginning of the observing run, however by 21.42 the shadow cast was getting smaller and fainter.

The area is shown on plate 19 sector C4 of Charles Woods 21st Century Atlas of the Moon, looking at this book just to the lower left of the M in the words Mare Frigoris is the area concerned with this observation. The thin curved lava front is visible as well as a small hill at the end of a curving chain of peaks. It is this feature that I believe Maurizio saw as a probable dome.

Observation terminated as no other useful information could have been gotten from this area.

2020 May 31

13:46 UTC

29th May 2002 21.10-35 UT Ant II-III, 10inch Sky watcher Dobsonian reflector Ptolemaeus x240 using Polarizing filter every 3-4 minutes.

The object of this observing run was to see if the emerging floor and shadow spires had any unusual features. Observation terminated due to obscuring hill and houses.

Throughout this observing run I used a Baader polarizing filter swapping it out every 3-4 minutes, each time I used the filter I rotated it in the focuser 360 degrees, however I could not detect any discernible difference in using the filter.

When I started the observing run the floor was in deep shadow, by 21.15 a light elongated area became visible under the southern wall. As the shadow spires appeared the next area to come into illumination was in the centre of the crater followed progressively towards the original area and slightly north of centre, until at the end of the observing run an area approximately 1/3 of the crater width and 2/3rds its length was illuminated pierced with shadow spires. The area being illuminated had an even tone as the area increased in size.

The first area to be illuminated between 22.18 and 22.30 had an uneven edge facing the Southern wall of Ptolemaeus, this was in contrast to the sharp edges on the rest of the shadow spires. After 22.30 until the observing run ended this turned into a sharp edge. The seeing conditions however deteriorated from Antoniadi ii to iii, due most likely to rising heat from houses nearby. From 22.15 a dark line appeared running SW to NE the area either side of this was a uniform shade, the dark line.

I could not detect anything unusual compared to previous observations apart from the uneven edge on the luminated area under the southern wall.

 2  

2020 May 29

11:43 UTC

28th May 2020, 20.57-21.15UT 10 inch Skywatcher Dobsonian reflector. Ant III slight haze- magnification x 240 

Lunar crater Maurolycus

Observed crater floor in dark shadow, central peak very prominent with the two secondary peaks either side also visable, observed a dark narrow shadow between the central peak and the eastern secondary peak making this peak seem isolated. Western peak separated from central peak by a  illuminated area slightly darker than the two peaks.

Area under western wall between crater M faintly visable. Observation halted due to Moon going behind a house.

Copyright of all images and other observations submitted to the BAA remains with the owner of the work. Reproduction of the work by third-parties is expressly forbidden without the consent of the copyright holder. For more information, please ask a question in the Website Help section of our Forum.