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David Levi

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Posts posted by David Levi

  1. Thanks for the reply @david_taurus83.

    The mount fell on concrete. It turns on and can be set up and aligned but then does not slew to the correct position to view an object. In addition while the handset is lit up and you tell it to slew to a target, the handset says slewing but the mount does not move. The red dot in the red dot finder also seems to jump when the mount does slew.

    So basically the problem could be electrical, mechanical or a combination of both, but there's damage somewhere.

  2. I was out last night in the Brecon Beacons with my 12" dob. One of my aims for the night was to witness the moon Io (It was Europa - thanks @AstroTim) emerging from it's eclipse by Jupiter.

    I had experienced this before but did not know about this phenomenon at the time and missed the moment of the moon revealing itself.  I only noticed that, one minute the moon wasn't there and then after being away from the eyepiece for a few minutes it was quite a way from the disk of Jupiter.

    Before going out I had checked the website Javascript Jupiter to see what events were taking place on and around the planet and saw that Europa would be emerging from eclipse at 10.20pm.  I made sure that I was glued to the eyepiece at the appropriate time. I didn't know what to expect - maybe a quick reveal like a magic trick!

    It was like waiting for the proverbial kettle to boil. Then it dawned on me that I could see a faint speck of light, which was better with averted vision, about a Jupiter radius away from the planet. The speck grew brighter gradually over the period of a minute or two until Europa was fully revealed. I wasn't paying attention to the time as I was engrossed in the event but it was something like that time period.

    • Like 4
  3. Hi Wouter, I like the site. Simple and clear.

    I'm working my way haphazardly through the lunar 100. When I am observing the moon for the lunar 100 I have been using Wikipedia but this requires going back and forth between pages to get from the list to the photo of the object so I think that your layout is a winner.

    P.S. I've just book-marked the site for future use. Thanks.

    • Thanks 1
  4. Here's my Black Diamond Spot 325. I think it's excellent. The fact that it turns on in the last mode selected rather than having to cycle through them was the clincher for me when I bought it a couple of months ago. I haven't found that I've noticed the battery charge state LED's (there are 3 of them on the side)

     

    BlackDiamond.jpg

    • Thanks 1
  5. 50 minutes ago, Stu said:

    Given that the reduction in pupil size is due to the muscles in the iris losing their strength

    I heard recently (can't remember where - that's another age problem) that age related focusing problems are due to the lens becoming stiffer rather than the muscles attached to the lens becoming weaker.

    • Like 2
    • Thanks 1
  6. 3 minutes ago, John said:

    the most striking feature was the Equatorial zone between the 2 main belts which was rather darker

    I'm glad you've mentioned that because I've been thinking the same thing about Jupiter during this year's apparition (but failing to mention it!). It's almost as if the north and south equatorial belts are giving off clouds into the area between them making it "less clean".

    • Like 3
  7. ... buses. Yes, it's the old joke. You wait ages and then two come along at the same time. So, it was a second night out in a row doing the same session structure; Moon, Jupiter, double stars. Telescope was the 100mm refractor with binoviewers.

    On the Moon, the craters Aristoteles and Eudoxus looked fantastic. Terrific detail on the ejecta immediately surrounding the craters. On the south western edge of the Mare Serenitatis I had a look at the crater Sulpicius Gallus. It's on the lunar 100 list at number 71 for its dark mantle. It appeared in a darker patch of ground but not sure if that's what you are supposed to see as it wasn't that impressive (there are dark patches in many places) and at number 71 in the list it should be quite hard to see but it wasn't particularly.

    Further south, close to the terminator the Albufeda Crater Chain provided an interesting view and below that the Pontanus E Concentric Crater was lit up perfectly to see the concentric ring. Apparently, concentric craters are rare away from maria.

    Proceeding down the terminator further, the overlapping craters of Maurolycus were impressive. Finally near the limb, I had a great view of the crater Boussingault. The inner crater being very clear together with detailed terracing descending to it.

    I moved on to double stars next. Tonight exploring some more obvious ones in the constellation of Scorpius and low declination Ophiuchus ones.

    α Sco, Antares, 1/5.5 mag, 2.5" sep, failed to split, although, inspired by another thread I'm coming back to it.

    β Sco, 2.6/4.9 mag, 13.7" sep

    ν Sco, 4.0(4.4/5.4) / 6.3(6.7/7.8) mag, 41", A1.4", B2.6", an exciting double double, I could only split the brighter A pair at moments of good seeing.

    ρ Oph, 4.6(5.0/5.7) / 6.8 / 7.3 mag, 156.3", 151.1, A3.0", what a fantastic 4 star system. The fainter two stars are positioned almost equidistant from the primary at a roughly 90­° angle which makes for a eye pleasing view.

    ο Oph, 5.1/6.6 mag, 10.1" sep

    36 Oph, 5.1, 5.1 mag, 5.0" sep

    Jupiter had now cleared the rooftops and it gave some really steady but not particularly clear views at approx. 200x magnification. Still a 3/1 split with the Galilean Moons as last night but less of a straight line I would guess. The equatorial bands were obvious and the south polar region was showing some darkness. Nothing really to report in the faint northern polar region.

    Another enjoyable session.

     

    • Like 13
  8. 6 minutes ago, chiltonstar said:

    I've done it in the past with an 80ED - I don't think aperture is the main issue really, it's more about seeing and as John says, having a clear S aspect (and of course having any clear nights).

    That's good to know. My location isn't great for low declination observation. SQM is roughly 19.0 at the zenith and of course there's a lot more muck to look through low down on the horizon.

    • Like 2
  9. Well done John. I feel a bit disappointed now as I've just come in after failing to split Antares with my Takahashi FC-100D. I tried to see the smaller partner star without knowing its location and after giving up and looking up its position I still couldn't see it or even imagine that I could see it. I was binoviewing at approx. 200x magnification. There was a bit of unsteady atmosphere at that magnification and the diffraction rings weren't helping. It was a fun challenge though and one I will return to now that your experience has shown that it is possible with a 100mm apo refractor.

    • Like 4
  10. 42 minutes ago, NGC 1502 said:

    BTW, when you observed the Ophiuchus doubles, you were close to Barnard’s star, the nearest naked eye star being 66 Oph.

    I did think about looking at Barnard's Star but it's quite faint at mag 9.5. I have observed it before with my reflector so it wasn't a priority last night compared with my double star hunt.

    • Like 1
  11. I started the session with a good look at the crescent Moon. Around Mare Serenitatis, the crater Posidonius was looking superb and I enjoyed studying Le Monnier, Plinius and the Serpentine Ridge. I also spotted the dark edges around the sea. In Mare Tranquillitatis, the Arago Domes were quite obvious but I didn't get a good view of the Lamont oval ridges except the ones leading from the oval. I had a look at the twin craters Sabine and Ritter but their best too was yet to come. I think the sun needed to be a bit higher to get a better view inside these. On the outskirts of Mare Nectaris the Altai Scarp was very clear.

    With Jupiter opposition approaching on the 10th of June and mostly clear skies forecast I was desperate to have a look at the gas giant.  Without a view to the east, Jupiter is now rising such that I can see it south east at a reasonable time, about midnight last night.  I was using binoviewers at I guess somewhere between 150x and 200x magnification. The seeing was not great. It took me a few seconds to realise that the GRS was in view, although after noticing it, it was quite obvious. Details of the clouds in the equatorial belts weren't very well resolved. The Galilean Moons were well strung out in a three to one split.

    The highlight of the night for me was the performance of the 100mm refractor, that I was using for the session, on double stars. Again using binoviewers, it just ate them up far better that my 8" reflector. The star shapes, and views without diffraction spikes are just so clean. Colour rendition is also better. I took in the following binary stars.

    ε Boo, Izar, 2.5/4.9 mag, 2.9" sep, much cleaner and easier split than my 8" reflector

    λ Oph, 4.2/5.2 mag, 1.6" sep

    τ Oph, 5.2/5.9 mag, 1.6" sep

    61 Oph, 6.2/6.6 mag, 20.7" sep

    67 Oph, 4.0/8.1 mag, 54.4" sep

    70 Oph, 4.2/6.0 mag, 6.6" sep, nice yellow pair

    72 Oph, 3.7/7.5 mag, 297" sep

    I was really surprised that I could see the split of λ and τ Oph.

    I did try a look at the globular clusters M10 and M12 but they were very indistinct. Not the correct targets for my location.

    From the light polluted skies of my suburban back garden a very pleasing session.

    • Like 19
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