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  • Latest Posts

    • Thank you it can be quite calming like photography and just being out under the stars observing the key is to not get overly critical and just keep at it just like anything else.
    • Thank you very much, I find with averted vision and often when I blink that they suddenly become brighter and seem to have more detail whether that’s my imagination or simply the light hitting the correct photoreceptors in the back of my eye I don’t know but it always quickly fades and they dim to faintness.    I would love to do some Solar sketching have you posted yours? I would love to see them I find some of them quite fascinating to look at, especially during periods of high sunspot activity. 
    • Anyone who looks at this photo and sees the beauty of Marius crater and its surroundings doesn't even notice the Herodotus Omega dome, in fact most of us put deep sky observation on hold when lunar glare intrudes on dark skies. But why, instead of limiting your telescope, don't you take the opportunity to observe the Moon itself? The waxing moon phase is a good time to familiarize yourself with one of our satellite's most evocative features: its domes. Many of the Moon's characteristic landscapes were created by the impact. Craters, rays, mountain ranges, seas and basins abound. Lunar domes are different. They formed as a result of the Moon's own internal volcanism. Similar to shield volcanoes in Iceland and Hawaii (including Mauna Kea on the Big Island) and Olympus Mons on Mars, they form when highly fluid lava erupts through a central caldera on the surface. They are almost all low-explosive, unlike their cousins, Earth's more violent stratovolcanoes that grab headlines. Like sheet after sheet piled up after lava seeps beneath the crust, a dome slowly builds up over time, forming a wide, gently sloping mound resembling a warrior's shield with a raised center and lower edge. Shield volcanoes can be small, like the Icelandic and lunar varieties, or wide and huge, like Olympus Mons. A typical lunar dome measures between 5 and 7.5 miles (8-12 km) in diameter with a peak or caldera ~900 feet (~300 meters) high. The slopes are very gentle with only a few degrees. The Marius Hills region was volcanically very active in the past and contains numerous volcanic features, including winding riles north of Marius, as well as numerous hills that are actually domes and can be seen quite clearly in my photo. In this region there is also a well, probably a cave that was identified for the first time in images from the SELENE/Kaguya probe, which I already described in another post on AstroBin, and can be found here: https://www.astrobin .com/322549/?q=Marius.%20astroavani More than 300 lunar domes are known, many visible in amateur telescopes with apertures from 3 inches upwards. There are two key requirements for good observation of a dome - good atmospheric stability (seeing) and observing the dome near the terminator shortly after lunar sunrise or before sunset as was done in this photo with the Domes of Marius and Herodotus Omega, this one being particularly easy to identify with good seeing even with a small telescope, as it is 10 km wide and has a hole in the center Most domes are subtle, low-contrast features that become scorching with poor seeing. Low light casts long shadows on crater peaks and rims, and makes their gently sloping shapes have the best contrast. You will be more excited when you can see the caldera. When you see the dome hole, you really see a dome for what it is: a formerly active volcano in the days when the moon still had intense geological activity. The next time you go to observe the Moon near the terminator, do not forget to pay attention to those rounded shapes that easily stand out in relation to the surrounding terrain, do not forget that one day the Moon had its active volcanoes and even today it is far away of being the dead world that many believe.
    • On switch on, it will draw significantly more current for a fraction of a second, compared to its specifications while the electrolytic capacitors on your mount's circuit board charge up. This is perfectly normal and is what's causing the over current protection to trip if it's set too close to the specified current rating. An electrolytic capacitor is effectively a short circuit when a DC voltage is applied to it. They are used as voltage reservoirs, connected across voltage rails to smooth the DC supply and help remove noise. They quickly charge up to the applied voltage and once charged their current draw is small. OCP is effectively a quick acting fuse. If you want to use the OCP I would set the trip threshold to at least 8 or 10 amps. A common cartridge fuse type is called 'anti-surge' to prevent them blowing when a device is switched on because of this switch on current surge. A standard brick type power supply rated at say 5 amps can deliver much more current for a short time without being damaged. It's output voltage may dip during this current surge but that's quite normal. OCP and current limiting are different things. OCP is usually used to protect the power supply and is normally fixed just above its maximum current rating but should allow a short duration surge current above this value. Current limiting just limits the current to a maximum value, but doesn't shut off the supply. It looks like you have the option of using the current limit value as the OCP trip threshold, but in this case it's not allowing any switch on surge current. Alan
    • A much needed modification was made this evening.  The 10 inch dob has always set to low for me.  So the leveling board came into the woodshop for the Mark II redesign.  New legs and levelers went into place.  Since i am the kid sort of husband i set the height so the wife can look into the eyepiece at zenith.  This will make life so much nicer for us....when and if the coulds and smoke ever clear 
  • Recent Topics

  • Recent Status Updates

    • BobTheSaxon  »  CCD Imager

      Hi Adrian,
      I was after the lens mainly, so please sell the mounting frame.
      cheers,
       
      Bob
      · 0 replies
    • Hawksmoor

      I'm getting really envious of the rest of the UK, high pressure and transparent skies.  In  Lowestoft wall to wall cloud and cold for days on end. The weather is very weird here. Did a crop and enlargement of another video clip of the sun in white light that I sneaked during a very brief break in the clouds the other day. Surprised how much detail my new planetary camera delivered whilst using my 66mm Altair Astro ED scope a a telephoto lens. QHY make fine value for money cameras!

      · 0 replies
    • RT65CB-SWL

      Just to letting you know that I have changed my username from Philip R to what you now see.
      · 0 replies
    • Earl

      upping the ISO to 1600 tonight against the usual advice and changing the aspect ratio.
      · 0 replies
    • Dazzyt66

      Getting back the 'AP' (and I use that term loosely) legs now after a couple of test runs in Ekos
      · 0 replies
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