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Mons Rümker

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#1 AvaniSoares

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Posted 10 January 2018 - 05:59 PM

dPvfQ0XQ3cm6_1824x0_R5Q5puGE.jpg

THE LUNAR DOME COMPLEX MONS RÜMKER
The lunar volcanic complex Mons Rümker lies in the northwestern part of the Oceanus Procellarum, has a diameter of about 65 km and maximum altitude around 1.1 km above the surrounding surface, is the largest known volcanic building on the Moon, a huge dome of volcanic origin, composed of a cohesive grouping of domes, that is, a complex of overlapping domes of smaller domes, most with low slopes and a few steeper ones and for this it presents itself as a discrete formation. It is estimated that the estimated lava volume to create Mons Rümker was about 1,800 km³.
According to current studies it is composed of a series of overlapping lava flows. Mons Rümker is aligned with the Aristarchus plateau and the Marius Hills along the axis of Oceanus Procellarum. Several individual domes can be distinguished on the plateau. Rümker is the only dome with the name of a crater. Rümker tricked the selenographers, who in the 19th century thought it was a ruined crater.

Lunar domes are smooth undulations between 3 and 20 km wide, and at most 1 km in height. They can be of various shapes and sizes, but the most common are of hemispherical shape with a low profile. Most have very low tilt angles and are the best evidence of volcanic activity on the moon. Many have a small central crater at the peak, which occurs after the end of the magma flow with consequent falling collapse inside. Domes without a peak crater are still of volcanic origin, but appear to have had its central opening covered with lava.

Observing lunar domes is a challenging activity that requires dedication and time coupled with good observing conditions. Most domes can not be observed when away from the terminator. As its distance from the terminator increases, it loses contrast and begins to blend with the local terrain, and for all practical purposes the dome disappears from view. For the reasons mentioned, most authors recommend that observations of the domes should be performed near the terminator, where the solar altitude does not exceed 4-5 degrees. Other observers suggest 8 degrees of solar altitude as the maximum, but notably between 4-5 degrees of solar altitude, the smaller low-profile domes and the details of the larger domed surface become very visible. There are only a few domes that can withstand high solar altitudes without disappearing in their local areas, one of them can be seen in the photo and is indicated as Mairan T.

Even a small 3 "refractor telescope will show the larger domes on the moon, but for a more serious work a refractor of no less than 4" or a reflector, not less than 6 "is needed.Another item that is almost indispensable is a good equatorial mount that can provide constant monitoring Because domes are objects that are difficult to observe, it is often necessary to use high powers in the telescope, which prevents the use of a handheld telescope for long observations. and well collimated 8 "mounted on an equatorial one can make excellent observations and records. Colimation of the optics should be emphasized to have a clear and good image that is paramount in order to provide the observer with the ability to capture those evasive domes, especially when atmospheric conditions are not perfect, which will happen most of the time. It is recommended whenever possible the use of high power. In good viewing conditions there is no reason why good optics can not be pushed to achieve its maximum. Increases in the order of 200 to 300X are desirable, filters can also be used, but they are not a fundamental requirement. It is also important to mention that effective observation of the dome can not be performed with the moon too low, near the horizon. A minimum altitude of 45 degrees from the horizon is usually necessary to reduce atmospheric effects. A good seeing is important although some of the larger domes can be observed with some turbulence.

Source: LPOD - Charles Wood
             VTOL - Vaz Tolentino Lunar Observatory
             THE ALS LUNAR DOME SECTION - Guido Santacana and Eric Douglas - American Lunar Society
              JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 11 - Bruce A. Campbell, B. R. Hawke, and Donald B. Campbell
Research and adaptation: Avani Soares
https://www.astrobin...8975/B/?nc=user


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#2 BoldAxis1967

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Posted 10 January 2018 - 07:25 PM

Nice image.  Thanks for taking the time to give us a description.

 

I am going to look for MairanT next time I am in that neighborhood. 

 

L.


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#3 moonwatching ferret

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Posted 11 January 2018 - 12:55 AM

now you see I am starting to know people around here I posted my not so great image when it got windy all aof a sudden after my half way decent image of aristarchus. i posted a similar image MY guess you saw it anyway I figured you would do a wright up on it. i'll try again next month when its clear enough to image this feature. there has been a steady cycle as steady as jupiter's moon friday transits every ganymede. i get clear nights from new moon to almost 1st quarter if lucky i get to image hadley rill and clavius then the weather goes south or it gets windy then 2 nights before full it clears hence my image inventory is strong with images of clavius appeninnies tycho and aristarchus 



#4 AvaniSoares

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Posted 11 January 2018 - 08:44 PM

Hello Ferret! I know how it is, my place also has an era that makes it almost impossible to do anything. Besides, the photos I make to the West never go as good as the east, to this day I can not understand why.



#5 moonwatching ferret

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Posted 11 January 2018 - 10:38 PM

my problem is to the east its mostly stinky Florida scrub so the seeing is fair despite loads of blinding lights coming from the super market that loves to waste things like electric to light up the parking lot all night. to the west is houses all ovet so i think day time heated roof tops and thouands of ac units are to blame or it could just be florida and weather not beng stable


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#6 AvaniSoares

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Posted 12 January 2018 - 05:11 PM

my problem is to the east its mostly stinky Florida scrub so the seeing is fair despite loads of blinding lights coming from the super market that loves to waste things like electric to light up the parking lot all night. to the west is houses all ovet so i think day time heated roof tops and thouands of ac units are to blame or it could just be florida and weather not beng stable

Yes Ferret!
Low-altitude seeing is greatly influenced by the heating of buildings and roofs, but here the same thing happens.
I have as a rule that taking pictures after midnight when the buildings have already lost the heat to the atmosphere improves the images too much, the problem is that this is not always possible.



#7 rehling

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Posted 13 January 2018 - 02:56 AM

Superb! Mons Rümker can almost vanish without the shadows right, and I had a lot of wasted (poor seeing) attempts before I had some luck, but nothing like yours.

 

For people having trouble with this or similar targets, consider trying the waning crescent pre-dawn instead of the waxing gibbous near midnight. For starters, it doubles the number of chances you have to catch those longitudes of the Moon in nice shadow, and it may likely give you less heat rising off of your neighboring land/buildings.

 

I was imaging Venus as often as possible pre-dawn last summer and the seeing was on average much better than I get in the evenings.



#8 AvaniSoares

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Posted 13 January 2018 - 01:50 PM

Superb! Mons Rümker can almost vanish without the shadows right, and I had a lot of wasted (poor seeing) attempts before I had some luck, but nothing like yours.

 

For people having trouble with this or similar targets, consider trying the waning crescent pre-dawn instead of the waxing gibbous near midnight. For starters, it doubles the number of chances you have to catch those longitudes of the Moon in nice shadow, and it may likely give you less heat rising off of your neighboring land/buildings.

 

I was imaging Venus as often as possible pre-dawn last summer and the seeing was on average much better than I get in the evenings.

Yes, you're quite right, Mr Rehling. I often do the same. In my latitude and place photos below 55º hardly have success so I always try to get all objects that I photograph at higher altitude.




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