You are not logged in. [Login] Entrance · Main Index · Search · New user · Who's Online FAQ · Calendar

Observing >> Lunar Observing Previous   Index   Next   Threaded

Pages: 1 kraterkid Post Laureate Reged: 03/07/05 Loc: Jacumba, California Messier and Messier A : Skipping rocks on the Moon       #3155134 - 06/10/09 12:24 AM Attachment (92 downloads) Edit   Reply   Quote Quick Reply   One billion years ago, give or take a couple of hundred thousand years, a small asteroid, perhaps only a few hundred meters wide, hurtled in, low over the eastern lunar limb, impacting into the basalt plains of Mare Fecunditatis. The very slight angle of incidence into the mare resulted in an excavation of the elliptically shaped 9 by 11 km Messier crater in an explosion of ejecta, shooting laterally to the north and south sides of the crater as well as down range to the west. This butterfly pattern of rays are common in low angled impacts. In addition, the forward moving ejecta falls ahead in the direction of the impactor, creating forward facing rays. From Messier this down range ejecta appears to have impacted into the western rim of an pre-existing crater, In just a a few milliseconds it’s once relatively round rim was modified into the egg shaped, 13 x 11 km Messier A. Two rays developed as the ejecta was deflected off the rim, continuing for over 100 km and vanishing somewhere near Lubbock and Leaky. Sketch Details: Subject: Messier and Messier A (formerly W.H. Pickering) Rukl: 48 Date: 5-30-09 Time: 4:55 to 5:40 UT Seeing: Antoniadi II-III Weather: clear Lunation: 4.66 days Colongitude: 330.2 deg. Illumination: 28.3% Lib. in Lat.: +01 deg. 44 min. Lib. in Long.: +03 deg. 32 min. Phase: 115.7 deg. Telescope: 12" Meade SCT f/10 Binoviewer: Denkmeier BV-25 with 2X nosepiece 45 deg. W.O. erect image diagonal Eyepieces: Pentax XW 20mm Magnification: 305X Medium:Sketch White and black Conte' on Black 400 Strathmore Artagain paper Sketch size: 9" x 12" Post Extras:       mapofthedead super member Reged: 06/01/06 Loc: Cambs, UK Re: Messier and Messier A : Skipping rocks on the Moon [Re: kraterkid]       #3155495 - 06/10/09 10:05 AM Edit   Reply   Quote Quick Reply   I refuse to believe this is a sketch and not a photograph - absolutely phenomenal Rich! Post Extras:       Sarkikos Postmaster Reged: 12/18/07 Loc: Suburban Maryland, USA Re: Messier and Messier A : Skipping rocks on the Moon [Re: mapofthedead]       #3155585 - 06/10/09 11:22 AM Edit   Reply   Quote Quick Reply   Rich, Nice job! Makes me want to look for Messier and Messier A next time I observe the Moon. I use a binoviewer, too. Great for lunar work. But Luna must be pretty bright through a 12". Do you use a filter? Which one? I've tried several, but so far I like the #47 Violet best. Not a true natural color view, of course, very easy on the eyes at 3% VLT. Mike Post Extras:       kraterkid Post Laureate Reged: 03/07/05 Loc: Jacumba, California Re: Messier and Messier A : Skipping rocks on the [Re: Sarkikos]       #3155812 - 06/10/09 01:33 PM Edit   Reply   Quote Quick Reply   Thank you James and Mike! Mike, I use no filters when observing the Moon (maybe that's why my old eyes are fading! ) Although at powers less than 150X the light is intense, I usually sketch at around 250X or greater which helps to diminish the intensity greatly. This one was done at 305X. I'll look into that #47 Violet filter though, because I sometimes sketch at 80X-150X for those wider synoptic views. Post Extras:       dgs© Postmaster Reged: 03/29/04 Loc: West Monroe, Louisiana Re: Messier and Messier A : Skipping rocks on the [Re: kraterkid]       #3155842 - 06/10/09 01:55 PM Edit   Reply   Quote Quick Reply   I'll have to add those to my list of things to look for. Was the sketch made over one observing session or multiples? I ask, thinking that the ejecta rays look like something that would show up better under high illumination, yet the craters are in deep shadow. The sketch does look nearly photographic, but I've seen plenty of Rich's work. Post Extras:       kraterkid Post Laureate Reged: 03/07/05 Loc: Jacumba, California Re: Messier and Messier A : Skipping rocks on the [Re: dgs©]       #3155883 - 06/10/09 02:24 PM Edit   Reply   Quote Quick Reply   Thanks David! The sketch was made in one observing session, although the lighting was moderately high at this colongitude. Post Extras:       Jeff Young Post Laureate Reged: 08/04/05 Loc: Ireland Re: Messier and Messier A : Skipping rocks on the [Re: kraterkid]       #3158610 - 06/12/09 06:34 AM Edit   Reply   Quote Quick Reply   Wow, Rich, great depth of color there. Or would that be depth of gray? In any case, it has a wonderful richness to it (no pun intended). Cheers, -- Jeff. Post Extras:       kraterkid Post Laureate Reged: 03/07/05 Loc: Jacumba, California Re: Messier and Messier A : Skipping rocks on the [Re: Jeff Young]       #3158909 - 06/12/09 11:51 AM Edit   Reply   Quote Quick Reply   Thanks Jeff! I think I remember someone saying (maybe it was Ansel Adams) that black and white is more colorful than colors. It seems that when I'm limited to a gray palette, I concentrate very hard on the subtle variations in albedo. Post Extras:       LivingNDixie TSP Chowhound Reged: 04/23/03 Loc: Trussville, AL Re: Messier and Messier A : Skipping rocks on the [Re: kraterkid]       #3159034 - 06/12/09 12:53 PM Edit   Reply   Quote Quick Reply   Very nice! I caught Messier and Messier A once when the Sun angle was low, and seeing the shadow from the rim go across the lunar plains for miles was very impressive. Post Extras:       kraterkid Post Laureate Reged: 03/07/05 Loc: Jacumba, California Re: Messier and Messier A : Skipping rocks on the [Re: LivingNDixie]       #3159258 - 06/12/09 02:57 PM Edit   Reply   Quote Quick Reply   Hey Preston! Thanks! I'm hoping for sketches at lower sun angles. That must have been an awesome sight, so close to the terminator. I was surprised to learn that the rays are visible even at these colongitudes. I'm guessing that it is an indicator of crater youth. Post Extras:       Pages: 1

Previous   Index   Next   Threaded

Extra information 0 registered and 3 anonymous users are browsing this forum. Moderator:  THEPLOUGH  Print Thread Forum Permissions       You cannot start new topics       You cannot reply to topics       HTML is disabled       UBBCode is enabled Thread views: 1582 Jump to *Announcements and News* -----   Cloudy Nights Announcements   Discussion of CN Articles, Reviews, and Reports   Celestial Events*General Astronomy* -----   Beginners Forum   General Observing and Astronomy   Outreach   Light Pollution*Equipment Discussions* -----   ATM, Optics and DIY Forum   Binoculars   Binoviewers   Cats & Casses   Classic Telescopes   Equipment   Eyepieces   Mounts   Observatories   Reflectors   Refractors    Video and Electronically Assisted Astronomy*Astrophotography and Sketching* -----   Beginning and Intermediate Imaging   Film Astrophotography   DSLR & Digital Camera Astro Imaging & Processing   CCD Imaging & Processing   Solar System Imaging & Processing   Sketching   Astro Imaging/Sketching Contest *Observing* -----   NEO   Planetary and Solar System Observing   Lunar Observing   Deep Sky Observing   Double Star Observing   Solar   Variable Star Observing and Radio Astronomy*Telescope Specific Forums* -----   Celestron NexStar    NexStar GPS / CPC Telescopes   Questar Forum   Meade ACF/RCX / LX / GPS    Meade ETX*Speciality Forums* -----   Arizona Science and Astronomy Expo   NEAF (Northeast Astronomy Forum) and NEAIC (Northeast Astro Imaging Conference)   AstroArt   Astronomy Clubs and Star Parties   Astronomy Software & Computers   AstroWebsites   Science! Astronomy & Space Exploration, and Others   Space Rocks   Stellar Media*Swap and Shop* -----   Shop and Swap Audio Components*CN Feedback and Vendor Announcements* -----   Vendor and Group Announcements*International Year of Astronomy 2009 - Forums are now closed.* -----   IYA Archive Info

CN Forums Home