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josefk

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Posts posted by josefk

  1. The conjunction of Jupiter and the moon early evening last night was a fabulous thing; naked eye, in a wide field eyepiece and up close but flicking between them. What a treat. 

    Though Jupiter in the end was the primary target - the crater Ptolemaeus was extremely eye-catching on the terminator of the moon. More specifically the lovely sawtooth shadow cast by its western ridge.

    Here's a poor tidy sketch done this morning:

    IMG_4835.thumb.jpeg.c62d96a86fb893c67a2868aeead7c0a8.jpeg

     

    i prefer the more visceral one from the EP last night:

    IMG_4836.thumb.jpeg.8c6ce4e93fafc517750b9b9daaaf2e19.jpeg

     

    Letting my imagination run away with itself what a fabulous thing it would be to scramble around the ridge in a multi-day hike (suitably equipped of course). For a personal sense of scale if this were a terrestrial thing it would take me 5hrs to cycle across the crater floor!

    BTW - i'm slightly perplexed this morning not to find any photography on line that remotely resembles how i sketched it so though i'm 99.9% sure it is Ptolemaeus if you know better be sure to let me know 🙂  

     

     

    • Like 7
  2. 10 hours ago, John said:

    I've just packed in for the night after getting some nice glimpses of Sirius B. The seeing stayed steady - earlier I had a tight but clear split of 52 Orionis, which I'm aways pleased to get 🙂

     

    After some of your comments earlier in the week about Sirius this was on my “to do” list last night as well. Unfortunately even really late on (after midnight) Sirius was a scintillating disco ball. I knew roughly where to look for “B” but even holding Sirius out of the EP it wouldn’t come for me. Next time! 

    • Like 3
  3. The little and large Takka twins getting the Sir Alex Ferguson (cold) hairdryer treatment this morning after enabling a lovely long session in the sub zero temps last night. 


    IMG_4833.thumb.jpeg.a4e11718b2268388b011dfb7949fedff.jpeg

    if you remember the father Ted “small cows” sketch of a few years ago - the TOA on the floor “isn’t small, …it’s far away”.  😂

    • Like 9
    • Haha 7
  4. Hi Ags,

    I think it’s contrast is pretty good - it’s well baffled BTW - so for DSO I feel (with little comparative evidence TBF) like I’m getting quite a high quality nicely contrasted view with the benefits of a decent aperture.  I use it for a lot of DSO at x140 and a 1.3mm exit pupil. This gives me a black sky, nice stars and a contrasty target. 

    Per diffraction on planets - I have had champion views of Jupiter re planet detail itself (marble like detail and sharpness) but what bothers me is the planet width diffraction “beams” you get shooting off into space (pretty much from the limb of the planet). This really destroys the “in orbit” feeling I enjoy. You are always aware you are using a scope whereas with a refractor (I don’t own a Mak or SCT) the blackness of space to the limb of the planet (on a good dry night) gives me the “just in orbit” sensation I like. 
     

    I think I have a sketch or two I could post of the effect - I’ll take a look. 

    Cheers

    • Like 1
  5. 15 hours ago, Ags said:

    I think it would not be bad to be "stuck" on the CC8, they seem to be rated really highly by their owners, at least those that can forgive the slightly dodgy aperture. It's heavy for its size though.

    I have this very scope Ags and really rate it. 

    PROs

    • It is a very robust physical package (though  heavy it is compactly heavy) and travels well in a car
    • on Globulars and Planetary Nebula it is really fantastic and feels like a lot of bang for its buck
    • on other DSO that fit its FOV capability it is fine (even OC) and the FOV context for any given DSO i.e surrounding stars to to the edge is also fine (i.e flat and aberration free). I do like nice edges even if i'm looking in the middle 🙂

    CONs

    • It is not 8". I trust the flashlight test and it is 185mm when checked this way - this also makes the central obstruction bigger by % if that matters to you. This is disappointing because i'm quite anal and quite  like the Interstellar Deep Sky Atlas that groups objects by 4", 8" and "large" aperture visibility probability.
    • The secondary mirror supports are quite thick and they create very bright diffraction spikes. I don't mind them on stars (i accept them as par for the course) but i hate hate hate them on planets and they completely ruin the Mars, Jupiter and Venus planetary experience for me. Strangely they are not so disturbing on Saturn which makes no sense. i bought this as a planetary oriented scope so this was a major disappointment for me - i should have done my homework better.
    • It gets back heavy fast - all its own weight is in the mirror so when you add stuff it gets harder to balance

    I struggle to get super high magnification out of it and wondered for a while if that was about the quality of its mirrors - on balance though i'm convinced its actually about the quality of my skies because on a few nights here and there (over 2-years of ownership) i have had x300+ out of it with perfect airy disks and perfectly etched (black white black white black white) diffraction rings so i think the scope itself is fine.

    Would i buy it again?  No - but that's only because i like it so much I wish i had bought the 10" version instead! There's even a very tempting 12" now but its super heavy.

     

    • Like 3
  6. 1 hour ago, bosun21 said:

    It will actually be 180 degrees ie upside down (north at the bottom).

    Hi @bosun21 - North is always 90-degrees from West (though if it isn't that would explain some of my terrestrial navigation errors).

    I find that 'find West first" concept a bit more reliable than "top" or "bottom" because they are relative depending on your heads position towards the EP or with a star diagonal the rotation of the diagonal to the objective (actually to the horizon???). West is absolute (where the stars exit) and 90-degrees anti-clockwise from West (Newtonian) or clockwise from West (star diagonal) is also absolute. I hope so otherwise i have an absolute pile of incorrectly marked up sketches! 😉 

    • Like 1
  7. This is my first winter with diabetes and the related/consequent painfully cold feet are a new and deeply unpleasant life experience i could have done without!

    My 4-season winter mountain walking boots are fine on the hill but haven't been cutting it while sitting around at the scope  - i was sooo cold out one evening last week i could hardly think straight  - so while I was mildly diverted by the idea of fur lined crocs after commentary on here (you know who you are 😉), I have more sensibly gone for full bore -20C rated boots instead. 

    IMG_4822.jpeg.289d5af5db3257bc2cbabc375835bede.jpeg

    ...extended -4C feels like -6C test on the cards tomorrow night 🙂

    Screenshot2024-01-17at11_23_58.jpeg.2c18bf4f44aa8bb7b54d37a8050623cf.jpeg

    Screenshot2024-01-17at11_28_09.jpeg.368606edffbb789f2c7e67d2d8ceae86.jpeg

    • Like 17
  8. Hi @Nikolai De Silva - do you know how to identify West in your eyepiece field of view? ...and do you know how to roughly estimate angular "size" or, for double stars,  separation between them in arc minutes or arc seconds? if yes sorry for being patronising - tell me to butt out :-).

    If no then its worth having a look here for some general principles: https://www.handprint.com/ASTRO/bineye1.html#standard. This was my online tutor when getting into the hobby.

    Long story short -

    • as long as your mount isn't moving then stars exit your eyepiece view to the west and in your newtonian scope north will be 90-degrees anti-clockwise from that point. With North and West identified you can work out everything else in degrees (North is 0-degrees, West 270-degrees, and so on)
    • your eyepiece apparent field of view [AFOV] divided by the magnification it is generating will give you your true field of view [TFOV] in degrees (roughly - there is a more complex formula for slightly greater accuracy but roughly will almost certainly do). Divide this degrees value by 60 to arrive at arc minutes and by 60 again for arc seconds.

    With these two "tools" or skills you get a world of wonder for quantifying the size and spatial relationships of what you are seeing through the scope. 

    Good luck.

    • Like 3
  9. i would chip in another datapoint for wide field viewing @SwiMatt if the priority use case would be a wide field compliment to your mak - beware the quality of your skies!

    I've got more wide field capability in my shortest-focal-length-smallest-aperture-scope than i can regularly access usefully; simply because at the big exit pupils (>4mm) generated for these wide field views the sky is fairly grey. I trust i will be blown away when i take it to a B1/B2 location but in my regular B4 location i don't use it for the very widest views as much as i thought i would, i self limit to about 3.4 degrees (4mm exit pupil) and prefer about 1.5...2 degrees at exit pupils around 1.5...2mm. Achieving this balance is also a matter of the AFOV the eyepiece not only the focal length of the scope.

    That doesn't detract from all the other small scope APO loveliness others have mentioned.

     

    • Like 5
  10. Lovely John.  It’s silly obvious but what is so rewarding with Jupiter is its nightly variation and sketching really helps capture that change and imprint it on the memory. Super. 

    • Like 1
    • Thanks 1
  11. i'm not sure you answered rightly or wrongly but i recognise the sentiment 🙂 

    - Last night i wasn't out till late and found after setting up i must have knocked my finder out of alignment (on a long focal length Cassegrain so couldn't find a thing), then it clouded over but not definitively to start with so i hung around and hung around hoping it would clear, and then when i was finally packing up (early) i ripped a glove on my tripod somehow, BUT

    - Last week i was looking at the Orion Nebula area very casually and was out for just a couple of hours overall and returned from the session incredibly recharged and amazed by what a small scope can bring as an experience.

    I think on balance that last week is the more typical experience and i's a good job for sticking with the hobby. 

    My answer to someone would be start with small simple kit and let it exceed your expectation rather than jump into big complicated set-ups and risk finding it high effort and occasionally frustrating.

    • Like 5
  12. For anyone who hasn't seen this advertised anywhere and Peterborough is in easy striking distance than i recommend Luke Jerram's Mars installation at Peterborough Cathedral  https://www.peterborough-cathedral.org.uk/home/mars-war--peace.aspx. It's on from now till the 29th January and is a free pop in if you drop by in the day. There are also ticketed "shows" in the evening where the globe is illuminated i think. It was quite fascinating viewing during the day today and got better and better from steady looking and comparing with Martian features named on Sky Safari Pro.

    IMG_4797.thumb.jpeg.a7d848a7c4ed9a38d3d3112d70819c2e.jpeg

    IMG_4799.thumb.jpeg.7b11fc395d6d3b851632dcea6a0c8c45.jpeg

    Henry VIII's first wife Catherine of Aragon is also buried in this cathedral. 

    • Like 2
  13. 8 hours ago, 900SL said:

    The level of moronia I am uncovering is beyond belief as I delve deeper into the wiring. The front end (headlights, controls, gauges etc) should connect to the main loom via 3 molex connectors according to the wiring diagram. Instead I have an old inner tube stuffed with a birds nest 🪹 of terrible connectors, all the wiring is any old colour, and there's no relays, everything is wired hot through the switches! 

    20240111_125141.thumb.jpg.675b5f0c1546fc305fbd0e58b5816d38.jpg

     

    20240111_130010.thumb.jpg.95a9e0013d7ee3f99c901e954ce38566.jpg

    Nice projects - both observing deck and great bikes.
    My son has done a rolling restoration on his old mini and once he started on the electrics he found a similar mess - it was easier to pull the whole lot out and start again with a newly made up loom.  Satisfying too. 

    • Like 1
  14. I saw a 100% clear sky for the first time since the 30th November-23! Whoohoo, what a pleasure to be back outside even though conditions in the SE were arctic.

    I was out too late for exciting Jupiter events but took the opportunity to have a look through a bit of new kit received since the last session - a Pentax 10mm XW and a 2.6 GPC for my binoviewer.

    The new exit pupil afforded by the 10mm EP (1.9mm) didn't miraculously bring me NGC 604 in M33 as i had secretly hoped so i'm writing this target off as a non-runner with 85mm of aperture now (at least in my home skies). More productively this exit pupil was excellent for M33 itself. No detail but relatively light grey bright and quite extensive - easy to find and return to after sweeping about. I think i will get on with this exit pupil and this EP for lots of targets. The XW  itself was pleasingly tight to the edge and well behaved in that regard but i struggled a little bit with kidney beaning so i need to have a look at how to cut that out - maybe with some kind of extension to the eye guard - not sure yet... 

    The new 2.6 GPC enables (with this scope and with a pair of 18mm Tak abbe orthos) a x65 2-eyed view when used alone and a x130 binoview in combo with a 2x Powermate ahead of the set-up.

    • x130 with two eyes was fabulous on Jupiter - i didn't linger due to the cold and a bit of a scope flutter in the breeze but this is going to be a great set-up for appreciating Jupiter.
    • x65 with two eyes was fabulous on M42 and it's companions. M42 was extensive, sharply defined and really nicely graduated within itself. The stars of the Trapezium where tiny and sharp (no E & F though and neither at a higher mono view magnification). The 18mm TAO really seems somehow special in its presentation of tiny stars and the characteristic seems to be associated with the EP because it is true regardless of what kit combo and magnification the EP is generating - it never disappoints. 

    Conditions really were arctic and fearing frostbite activities were curtailed after 2.5hrs. Boo.

    • Like 12
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