The lunar domes represent a clear testimony to the volcanic activity that happened on the Moon.
The observation of such structures can, moreover, constitute also a good observational opportunity  for the beginner who wants to come closer to the observation of the Moon in a manner more critical and not so contemplative.  The domes present  more of a low relief and a low level of inclination.  That is caused from the fact that lunar lava has a low viscosity and, contrary to how a quantity behaves on the earth, once molten it presents the typical viscosity of motor oil.  Such characteristic depends on the presence of a minor content of silica and a greater content of metals (titanium, iron) compared with terrestrial basalts.

Because of such fluidity, the lava, flows from the fissures produced from the meteorite bombardment that generated the principal lunar maria basins, it was not initially accumulated around the emission vents.  Such a situation resulted in an abundant flowing, as demonstrated from the presence of sinuous channels (ie Vallis Schroteri, is surely the more striking) originated from the thermal erosion produced from the same flow.  The successive and gradual cooling of the melt below produced also a modification of the viscosity of the lava that, once caught up by the external surface,  became less viscous and it formed in layers , depositing, the typical lunar dome (example is the domes of Hortensius).

In other cases (as the numerous domes located in the area near the crater Marius) the edifices show a greater relief attributable to the probable change of the viscosity of the lava.  The greater viscosity and softness of lava, in this case, have been in a position to producing structures more similar, in dimensions and heights, to small terrestrial volcanos.  Such change is probable from a change in the various temperature and/or chemical-physical compositions of the magma that would have differed in the course of the volcanic activities that happened in our satellite.
Some lunar domes moreover, show also the presence of small craterlets or fissures in their tops, some of which can be seen with the capability of amateur telescopes of medium diameter.
Due to the reduced dimensions, the visibility of domes neccessitates strict conditions of the incident light;  that is they will only be able to be observed in the vicinity of the lunar terminator.  It goes hold present that, being for more of low relief, the domes show only a slight shadow to in contrast to how much shown from the highest hills or mountain chains.  And this, therefore, the trick for which the increase of the altitude of the sun, the domes will show gradually out of the minor contrast with the lunar surface.

How to observe the domes

For the reasons discussed, in the moment of execution of a drawing, the opportunity to " freeze " the moment of the observation delineating on a sheet of paper the salient portions of the visible details that will allow one to finish the drawing at a later time, comfortably seated.  It is not futile to reaffirm this concept, in fact  who reports  has seen something that later " disapeared " some time later, yet the dome was evident before.
To such purpose it is advisable during the course of the observation session to estimate the Albedo of the various visible sections, assigning them a numerical values by using ones own scale of grays.  The use of a scale of grays will allow one to differentiate the Albedo of the visible details and to assign a graphical representation of the quantity observed.  The drawings could be made with the technique of the dark-light shading or with the technique of the dot shading.  Also useful is that which lends the maximum attention to the shape (elliptic, circular etc) of the dome and to its proportions.  Already a comparison with craters of known dimensions, present in the field of view of the eyepiece being used, will allow an estimate of the dimensions of the domes.  Every drawing, photograph and CCD image should also be accompanied by the time of the observation (in Universal Time UT), magnification used, estimate of the seeing, colongitude, calculable directly through a proper software, and any other pertinent notes.

It is obvious that the identification of fine details such as depressions or craters on the summit, cover more of a basic importance for a deeper study, constituting an object for the more experienced astronomer.

Which domes to observe?
In practice there is no limit!  Draw up a list, conseqently an arduous undertaking, and it imposes a forcing of the choices.  You only have to think of the domes situated to the north and the west of the Arago crater, the west of the Cauchy crater and north of the Sinas crater and, in Mare Tranquillitatis, first to have an idea of the distribution of them.  The notes and the drawings that follow are therefore only a selection of these objects that, beyond all constitute a good introductory program to such a theme, also they turn out to be relatively easy to observe in small and medium sized instruments.  In many other cases some domes are located inside of large craters like for example, Capuanus and Furnerius.

Tablular guide for the location of some domes

LONG LAT Dome
 

+60 -35 FURNERIUS

+38 +09 CHAUCY

+20 +05 ARAGO

+05 -02 HYGINUS

-09 +27 BEER

-10 -22 BIRT

-11 +18 WALLACE D

-12 +05 GAMBART C

-24 -28 KIES
 

LONG LAT Dome
 

-25 +05 HORTENSIUS

-25 -35 CAPUANUS

-30 +10 MILICHIUS

-30 -04 LANSBERG D

-32 -12 HERIGONIUS

-39 +35 GRUITHUISEN

-45 +25 PRINZ

-51 +12 MARIUS

-58 +40 RUMKER
 
 

LONG: Selenographic Longitude (IAU) with which negative values indicate to the west (to right in telescopic view) and positive values are to the east (on the left in telescopic view).
LAT:  Selenographic latitude with which negative values indicate south (up in the telescopic view for the northern hemisphere) and positive values to the north (down in telescopic view). (Opposite in the southern hemisphere).

The dome by Kies (Mare Nubium) and the dome in the vicinity of the crater Egede (Mare Frigoris) are, also for their dimensions, conspicious, potentially easy, together, also observe the presence of craters on their summits.
 

Also the  domes of Hortensius and Birt represent relatively easy structures if the lighting is right. It will be possible to see the presence of craters in the summits of them. All of the region comprised between Milichius and Hortensius show the presence of numerous domes of greatness and diverse forms, to the testimony to the volcanic processes that happened on our satellite.  In the case of Birt the observer will have the opportunity to observe in strict conditions of illumination, the presence of Rima Birt, a probable channel of lava, than bisects two of the domes to north of the aformentioned crater.
 

Near the Spitzbergen mountains, in  Mare Imbrium, it is possible to locate a series of probable domes of low relief, with the apparent presence of some superficial detail on their summits.
 

Instruments of greater diameter will show the evidence of the presence of the small  dome on the inside of the Posidonius crater, located near the rille to the east.  They represent difficult details somewhat.  Details of analogous difficulty are visible to north of the crater Prinz, in which it is possible to find the presence of some possible rilles near two conspicuous and clearly elongated domes situated to the north of the degraded crater.

The use of the visual techniques can obviously be supported with the acquisition of CCD images, which they can be subsequently processed and undergo, through specific software, geometric transformations or perspective deformations so that they represent three-dimensional models.  As in the case of the domes near the crater Arago, in the Mare Tranquillitatis, the acquisition of CCD images, by means of a simple geometric deformation, renders evident the low relief of such structures and facilitates the identification with small instruments.
 
 

A last example of application of the object of field of research of our group is constituted from the observation of a low dome located to the west of the crater Kepler. In evenings of optimal seeing and different observing sessions, some visual observers report that they have observed a depression in the central area of the dome.

The confirmation of such observations is rendered obvious from a photographic image in the archives in which it is possible to see the presence of a central depression in them, to the capacity of amateur telescopes, also it represents a difficult detail.
 
 

For who it will begin to be interested in such observations we advise to equip oneself of a good lunar atlas, as an example the Rukl, that it will allow you to locate the various observable structures easily.  It will be indispensable to fortify the perseverance and above all the humility.  There is always the necessity to document and to exchange your own experiences with other observatories.
With experience you will conquest the field!