Jump to content

John

Members
  • Posts

    53,756
  • Joined

  • Last visited

  • Days Won

    455

Posts posted by John

  1. I think the Morpheus eyepieces are the next step up from the BST Starguiders and do offer larger fields of view. The improvements in image quality will be subtle though because, as has been said, the BST's are not shabby performers by any means.

    If you are using the 25mm BST Starguider you are getting close to seeing the widest view that can be provided by a 1.25 inch eyepiece. A 24mm / 68 degree such as the Explore Scientific will show a little more sky but it's not a huge difference. The ES 24 / 68 will be better corrected in the outer parts of the field of view with your F/5 scope than the BST Starguider is though so the whole field will be more "usable" so to speak.

    astronomy_tools_fov.jpg.fff051b5b90ebf6ebde9fd0fa276ed54.jpg

     

     

    • Like 1
  2. Globular clusters are very, very old. Quite a few will be visible with your ST80. Messier 13 in Hercules, for example, is over 11 billion years old.

    The most distant object that you will be able to see with the scope be a galaxy and you may be able to see some, as very, very faint patches of light, that are approaching 100 million light years away.

     

     

     

     

    • Thanks 1
  3. I've not used them myself but here is the opinion of an experienced observer / reviewer:

    https://www.cloudynights.com/topic/700422-starbase-orthos-first-light/?p=10205650

    It sounds like it depends on the scope that you intend to use them with.

    The older Vixen made Or. "Orthos" were also a symmetrical / plossl type design I found when I took a couple apart for cleaning many years ago.

    I don't know exactly how much Takahashi are involved directly in the design and manufacture of the Starbase ones though :icon_scratch: 

  4. 3 hours ago, Merlin said:

    Many of the Newtonians we see today, including my own, have main tubes that are too short at the top, allowing a considerable amount of stray light to enter the tube and reduce contrast.

    If we look through the drawtube and can see out through the top of the main tube ( ignoring the flat ), we need an extension. I made a foot-long extension for the 8-inched by rolling some camping mat material into a tube and lining it with Matt black art card.

    The main tube extension fits like a glove and also acts as a dew shield for the flat. M anufacturers probably make the main tubes too short to make their ‘scopes look more compact, but this is at the expense of contrast and also makes the flat more prone to dewing.

    I agree with this.

    I use a light shield at the top of my dobsonian and it makes a lot of difference to the contrast when I'm using the scope in my back garden, where there can be quite a bit of stray light about. I use one of the "half moon" shaped ones opposite the focuser and it seems very effective. I've also flocked the tube opposite the focuser and blackened the secondary mirror edge.

    oo12march20.JPG.15e6ad8f3c58d8907d8627420b046db6.JPG

     

     

    • Like 1
  5. Had a rather frustrating couple of hours with my ED120 refractor this evening. It was all looking promising but the clouds thickened up quite quickly and it's now raining :rolleyes2:

    Managed a few glimpses of the usual late summer / early autumn targets including the brighter galaxies M31, M32, M110, M81, M82 etc, etc.

    I did also have a look at a slightly more challenging galaxy not far from the famous ones in Andromeda. This was NGC 404 - AKA "Mirach's Ghost". This small, condensed 11th magnitude circular glow lies just 7-8 arc minutes north west of the 2nd magnitude Mirach (Beta Andromedae). It's nickname is well deserved because it can easily be taken for a faint ghost reflection of Mirach in the eyepiece. I found using a zoom eyepiece helped tease this galaxy out - it was much easier to see at around 120x than it was at 42x.

    NGC 404 is a dwarf lenticular galaxy and lies just outside our local group of galaxies at 10 million light years distance. Apparently it is a bit smaller than the Small Megellanic Cloud but more luminous which is why we can see it though it's much further away than the SMC.

    It can be quite a challenge in a smaller scope (sub 8 inches aperture say) in a less than dark or slightly opaque sky. I've seen it with my 100/102mm refractors as well though, on dark nights but using 100x or so really does help to positively ID the galaxy.

    NGC 404 was the subject of Phil Harrington's "Cosmic Challenge" on the Cloudynights forum for November 2017. Here is his piece on it:

    https://www.cloudynights.com/articles/cat/column/phil-harrington-s/cosmic-challenge-ngc-404-r3118

    Looks like the rain has stopped now so I might get out again :smiley:

     

    • Like 13
  6. 15 minutes ago, Mr Spock said:

    With my 250mm I use a Telrad to point at the section of sky where my target is, then a 9x50 RACI for precise location, then, if required, a 32mm eyepiece in the scope. 

    That is how I use the Rigel and 9x50 RACI on my 12 inch dobsonian too.

    With my refractors though, I seem to get on OK with just an RACI finder.

     

  7. 12 hours ago, Pixies said:

    There's a double-transit coming up on 4 October - early evening. Ganymede and Callisto.

    https://www.skyatnightmagazine.com/advice/skills/jupiter-moons-how-see/

     

    Thanks for this :thumbright:

    Jupiter is more or less invisible for me until about 7:30 pm due to a cluttered horizon but I should be able catch the 2nd half action if the clouds co-operate (thats a big IF looking at the forecasts :rolleyes2:).

     

  8. Interesting post on the CN forum from @Don Pensack which included this:

    "If you're a planetary observer, worry less about the eyepiece and more about seeing.  There are ways you can maximize seeing, and it's ironic that so few planetary observers pay attention to them.

    • don't set up the scope on concrete or asphalt.  Choose dirt or grass.
    • use external cooling to cool the instrument and optics to the ambient temperature BEFORE viewing.
    • make sure the instrument is collimated.
    • never look at a planet above the roof of a house or building.  Heat waves rise and distort the image.
    • never observe on the lee side of a mountain.  If in the mountains, choose the windward side.
    • choose a period about 2-3 days after the passage of a front so the air movement is slow and the air a big stagnant.
    • never look at a planet below 30° off the horizon if possible.  Wait for it to rise.  If it never gets that high, look only when it crosses the meridian.
    • if in a very broad valley, try the middle of the valley over the edges.  Air flow will be smoother and more laminar.
    • in most places, observe later in the night.  The midnight to dawn period is usually more stable.
    • observe often to catch good seeing conditions.
    • watch for more than just a few minutes when looking through the eyepiece.  You may get short periods of much better seeing.
    • you needn't bother much with dark adaptation, but it is helpful to shield both the eye and the eyepiece from peripheral light.
    • Fog on the optics will destroy detail, so take steps to prevent optics fogging.
    • dust on the optics will destroy detail by scattering more light, so be sure the optics are clean.  Especially eyepieces.
    • take steps to maximize contrast in the scope, which includes a shroud on a truss scope and a light shield extension at the top on most newtonians.

    By maximizing your options, you will get better seeing and see more planetary detail."

    Here is the link to the whole post in the thread on that forum for completeness:

    https://www.cloudynights.com/topic/783415-best-tele-vue-for-planets/?p=11389399

     

    • Like 5
  9. 3 hours ago, Ian McCallum said:

    Although I get some nice views of Jupiter and Saturn, I do find much above 150x magnification, they tend to get a bit indistinct using my Sky-Watcher 200P. 

     

    Obviously I don't know your observing situation but I think your 200P should be doing a bit better than that, certainly on Saturn. On Jupiter 130x-160x often does give the best (sharpest and most contrasty) views but with Saturn 200x-250x should be delivering nice sharp views, if the seeing is anywhere near decent.

    I hate to mention the "C" word (collimation) but some mis-collimation can impact sharpness and contrast rather negatively ?

     

    • Like 3
  10. On the topic of Moonraker scopes, I missed the installation of the new public observing deck at the Lowell Observatory in 2019 by a couple of months but one of their instruments was this magnificent Mark Turner 8 inch F/12 achromat:

    moonraker_website.jpg

    As it happened, when we were there in September 2019, I bumped into Steve / @Saganite who now owns Andromeda of course :icon_biggrin:

     

     

    • Like 3
    • Thanks 1
  11. 1 hour ago, F15Rules said:

    That was a monster, John, quite scary in "Menacing Black"😁.

    Dave

    Scary weight as well. That tube weighed over 30 lbs :shocked:

    I had dreams of a scope like one of those Victorian astronomers but in the end I realised that I had "bitten off more than I could chew" as the saying goes. Even the EQ6 / Meade Giant Field tripod combo felt a bit flimsy with that scope on board. I guess a Fullerscopes Mk IV on a large pillar would have done the trick but any thought of portability would go out the door. Scopes like that need a permanent mounting in an observatory I think.

    Optically the scope was very good when I did managed to observe something with it.

    All in all, a big learning experience for me :smiley:

    If I ever get a 6 inch refractor again it will need to be an F/8 so probably not an achromat.

    • Like 2
  12. This is not a Moonraker or a Skylight I'm afraid and has a much plainer, though very well made, finish. I did buy it from John Timmins of Peak2valley though and he delivered it in person. There was also an F/15 version in his vehicle which, after seeing the size of it, made me glad that I went for F/12 :rolleyes2:

    The Istar Perseus AT150-12:

    https://stargazerslounge.com/uploads/monthly_09_2013/post-118-0-58096600-1379495995.jpg

    https://stargazerslounge.com/uploads/monthly_08_2013/post-118-0-83989200-1377563973.jpg

    https://stargazerslounge.com/uploads/monthly_08_2013/post-118-0-29748100-1377563955.jpg

     

    https://stargazerslounge.com/uploads/monthly_04_2014/post-118-0-06290300-1397061555.jpg

     

    • Like 9
  13. I think there are a lot of folks on holiday in the UK this year who would normally be holidaying somewhere on the continent with lots of night life / brightly lit promenades etc. I've read quite a lot of reports from UK holiday destinations of difficult behaviour from folks who would normally prefer to be elsewhere. No excuse for it of course.

    As an amateur astronomer I've noticed over the years that caravan and camping sites are often quite brightly lit (by the site owners) as well. To get a dark one you need almost to end up wild camping. 

     

    • Like 1
  14. I can see Pickerings Wisp plus the East and West segments on a dark night from home with my 4 inch F/6.5 refractor and a Lumicon O-III filter. With my 31mm Nagler eyepiece I can get the whole lot in the same field of view - lovely sight :thumbright:

    The ease of spotting the Wisp and the "bristles" extension to the Western segment with the 4 inch aperture depends on the transparency and darkness of the sky more than for the brighter sections.

     

     

    • Like 2
  15. On 28/09/2021 at 00:37, MZack said:

    I’m delighted to add that a while ago this summer I purchased 001 from Dave complete with the box Richard made. It is in my observatory shown here sitting on an old Irving tripod mounted on an AYO Alt Az with encoders. I have also mounted it on an APM fork mount also with encoders. Needless to say it’s performing really well and I’ve recently replaced the 100mm Skywatcher tube rings it came with, with a pair of 105mm TS Optics CNC rings. F80D63AF-DC51-4F23-8DC1-4B44614823C4.thumb.jpeg.5f71aff85bc2aaa3f51f63c90a3195ca.jpeg7444EA80-0130-4D4E-B0E1-8A27332DBA35.thumb.jpeg.ebe91efd36fb7e7dbe35f344017c4c41.jpeg

    That brings back memories - I think I observed with that particular scope at an SGL star party quite a few years ago :grin:

     

  16. 15 minutes ago, mikeDnight said:

    I'm not sure I'd agree about that John. I have quite vivid memories of how I felt when sweeping the milkyway using a SW150 F5 Star Travel at my local astro centre. It was twenty years ago but its still emblazoned in my mind. Despite the greater aperture of the many larger reflectors and SCT's, not one scope could match the beauty of the wide, rich, piercingly sharp star fields of the ST150, and DSO's seemed to glide effortlessly into the field of view. It was quite a sight to see under a dark sky, and the memory of that night still makes my heart race. 💓

    Fair enough Mike - I've not used the F/5 version of the 150 achromat. My personal feeling is that a 200mm F/6 dob would still go deeper (though not as wide) and also be excellent for planetary and lunar observing so a better all round scope rather than the "1 trick ponies" of the fast achromats.

    But I could be wrong - it's been known :grin:

     

    • Like 3
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.