Dismiss Notice
New Cookie Policy
On May 24, 2018, we published revised versions of our Terms and Rules and Cookie Policy. Your use of AstronomyConnect.com’s services is subject to these revised terms.

Nebula's Astronomy Den

Discussion in 'Observing Celestial Objects' started by Nebula, Feb 2, 2018.

Nebula's Astronomy Den

Started by Nebula on Feb 2, 2018 at 8:12 PM

567 Replies 74260 Views 5 Likes

Reply to Thread Post New Thread
  1. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    Thanks Reggie, (;

    I can tolerate an exit pupil hemm, my smallest exit pupil is 0.94, it's still good but it's the limit. Once the views are clear with a good atmosphere, I don't see the floaters much. But bellow that.. I would need a bigger/longer telescope to reach higher powers with larger exit pupil.

    The expanse
    https://www.telescope.com/6mm-9mm-15mm-20mm-Set-Orion-Expanse-Eyepieces/p/20095.uts

    If you like them that's all that count. I find my Xcel Lx so impressive, they are considered average.

    ====================

    I had another absolutely incredible moon session tonight, the views were even more stable then yesterday. I decided to drop the filters and used only the eyepieces. My better eyepiece tonight was by far my 7mm Orthoscopic, it has a good eye relief and it needs a custom eye cup.

    143 X super stable with good seeing and and good transparency, I am amazed again.

    I did 3 sketches of items inside Mare Imbrium.

    First crater was Lambert and the impressive Mons La Hire (Solitary mountain) 25mm large 1.5 kms high casting a very long shadow. It's not that high, I was expecting something like 16km high but no, it's only 1.5 and with a very pronounced shadow. Very impressive object, sketch was done a 286x, the OR-HD and the barlow. Al right!

    [​IMG]

    I had a great time again, man!, that Orthoscopic 7mm is kicking ass!

    [​IMG]
     
    Ruud likes this.
  2. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,919
    Trophy Points:
    113
    Great sketches Neb. Sounds like you had a great session. I have a set of Japanese ortho's, some are Astro Hutech, some KK and the 9mm is a Circle T.

    7mm.jpg 7b.jpg 6 7.jpg

    The 4mm is the smallest.

    IMG_20180323_130738.jpg
    IMG_20180323_130637.jpg
     
    Nebula likes this.
  3. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    You have a nice collection there, I don't have any regret for my purchase, the 7mm they are really safe value. Definitively strong planetary and lunar tool, my 7mm is used at almost all observations has a fast grab high power with no Barlow.

    I had a very great observation, I still thinks about this today, the views were clean and when I can use 286x it's a special night (2 nights in a row). From now on, Ill look at the height of the moon on stellarium to select the period when it's at the highest point in the sky, the difference is major.

    It's rare we can have it very high WITH very good seeing and transparency condition. You have the cold temperature of the spring with less humidity in the air, perfect period.

    I will have a week of vacation the 3rd week of May, impossible to take my week in April like I wanted because of a large project we have, we need to deliver a 110 million building for April 25th and we are not doing too well now.. May will be hotter and with mosquitoes but perhaps not that bad either.
     
  4. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,919
    Trophy Points:
    113
    I finally have a full set of marbles, sorry, I mean ortho's. I even have a pair of 25mm Hutechs and 18mm BCO's.

    IMG_20171117_132825.jpg

    These sometimes get used in a Baader Q-Turret Barlow in conjunction with my ST80.

    IMG_20180327_175641.jpg

    The Barlow gives the ST80 a 900mm focal length and makes it f/11.25. The corresponding magnifications of 36x, 50x, 72x, 100x, 128.5x, 150x, 180x and 225x are useful for some DSO's and splitting binaries. The slower focal ratio helps with CA,
     
    Nebula likes this.
  5. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    36x, 50x, 72x, 100x, 128.5x, 150x, 180x and 225x

    This is a range of powers I really like, an elaborate pallet of power between 30 and 225, you are sure to get maximum quality all the time with that.

    I wanted to start a thread on SGL about CA but decided not to do it. The fact of the matter for me @Mak the Night

    Every single time I look at the stars naked eye, I see coma, lines coming out of the stars the exact same thing I see in the eyepiece with the telescope. If I get drops of water in my eye, tears, the coma is even worse or I can just move my eyeball to see a pinpoint star. So coma seems like a natural thing and a very insignificant matter for me now, I am never going to buy a Coma corrector with that current setup.

    You would be surprised how the views are with my F5 and eyepieces, not bad at all. I compare with naked eye and there is not much of a difference.
     
  6. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,919
    Trophy Points:
    113
    I have that range on my 150mm, f/6 Newtonian as well. Although 180x would be a more realistic limit for the ST80 for lunar viewing. 192x would be a maximum limit on the Moon with the ST80. I can get 337x on the Moon sometimes with the f/6 Newtonian. You really need an EQ mount with the speed RA moves the image at 337x,
     
  7. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    198x on the moon is very good, i played with 2 powers last night 143x and 212x and looking at the very faint details on the surface and around the craters and mountains. It's undeniable, 212x is even more interesting then 143x but harder to keep a steady image, it seems, because of the atmospheric condition primarily. Yesterday 143x was +-80% of the time steady but 212x maybe +-50% of the time steady image.

    143x it's steady with larger exit pupil and almost no floaters
    212x is far less steady with smaller exit pupil much much more floaters, but when i get a patch of steady atmosphere WOW much more faint details visible with a an image has sharp has 143x.

    I wonder if a larger telescope like 16 inches could hold a steady image of the moon at 286x the same has now with 8" with 143x or its maximum power is limited by atmosphere, whatever the size of the scope.

    I've got the EQ5 mount it's very effective, a very impressive mechanical device. I can hold still 286x no problems even an exceptional 424x easily.(You have the same one, you already know that!)

    My 2 best moon friends (:)
    [​IMG]
     
  8. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,356
    Trophy Points:
    113
    Thanks for jarring my mind regards Mosquitoes! Ack! We lost about 90% of our Little Brown Bats to a once-rare infection dubbed the 'White Nose Syndrome' or just WNS. It's a respiratory disorder - usually fatal to Bats. It's spread by stupid people going 'caving' without washing and sterilizing their gear in between caves. You can see why it's called this in this image of a Little Brown Bat suffering it -


    Little_Brown_Bat_with_White_Nose_Syndrome_(Greeley_Mine,_cropped).jpg


    And here's a healthy one of the little fellahs -


    Little Brown Bat d.jpg


    My surrogate son was terrified of Bats. And I'd had enough of his phobia so I commanded him to stand still and, using my arms to imitate a swarm of Mosquitoes, I called the Bats I saw across a pond. And they reliably surrounded us - diving and swooping at the fewer-than-a-swarm of the buggers' flying around us. After having them up that close to his face lowered his fears about them after that! Once he stopped sweating! :eek: :cool:

    So I've been looking at Mosquitoe-proof netted clothing. Found a place that sells off-beat science-goodies such as this. One less concern on my quest to Mars-Watch this Summer! Not getting eaten alive!:p
     
  9. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    What a strange animal.

    Makes me think of the VERY BEST Batman introduction of ALL Batmans. With the absolute best version of the symphony.



    But hey I promise to take care of the bats if I ever go inside a cave (((;
     
    Last edited: Mar 27, 2018
  10. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,356
    Trophy Points:
    113
    I studied speleology in school, and we'd go on caving expeditions. We discovered and mapped two new caves in upstate New York - not far from me now. The Onondaga Limestone in the foothills of the Adirondack Mountains is riddled in them. We wore old-style carbide-lamps on our helmets - with jets of fire lighting our ways. I had to be careful with that torch! A quick glance up, while crawling on our bellies through hundreds of meters of tunnels no bigger than we were, would often be met with a "Eeeeeep!!" when I'd singe a Bat! I learned quick not to do that again! I liked the Bats - but not for dinner.

    They can eat their own weight in Mosquitoes every night. Most of the caves are on private lands. The owners are not allowing anyone other than professional scientists - and about time too. Nothing like making your way a half mile underground, and finding some idiots bottle of Jack Daniels' - empty, of course. I was hoping to find the skeleton of it's owner.....
     
    Last edited: Mar 27, 2018
  11. Mak the Night

    Mak the Night Well-Known Member

    Joined:
    Jul 10, 2016
    Posts:
    4,919
    Trophy Points:
    113
    A rule of thumb for highest achievable lunar magnifications is 60x per inch of aperture. As the Moon is so bright, and relatively close, this can often be reached in optimum conditions. It can at least be used as a yardstick to gauge high magnifications with.

    Manufacturers often quote 60x per inch as the maximum for marketing reasons. Of course, over six inches and it tends to break down as magnifications of much over 400x aren't realistic for most people. I can often get a good 337x on my 150mm/6" Newtonian.

    Refractors will also fare much better and sharper than reflecting scopes and will more easily achieve a higher magnification. In really good conditions you might get 400x out of a 200mm/8" reflector though.

    A 60mm refractor (about 2.4") should be able to achieve 144x maximum on the Moon and possibly slightly more compared to a 60mm reflector.

    In my experience, an 80mm (3.15") refractor can reach about 190x or even 200x in good conditions. I've had 187.5x and 190x respectively with 6.4mm Meade and 6.3mm Sky-Watcher Plossls and even 200x with a 6mm BCO.

    IMG_20180328_100044.jpg

    These EP's were used with a 3x Barlow. My favourite 3x Barlow is the TeleVue, but at 13cm it's a tad long for a diagonal so I used a Celestron X-Cel 3x. The X-Cel is 8.5cm and lighter, so less chance of it rotating the diagonal. This Barlow also makes the ST80 f/15! Which is slower than most Mak's.

    IMG_20180320_003455.jpg

    I normally use a 2.5x TS Optics (GSO) Barlow instead of the X-Cel 3x though as it is lighter.

    IMG_20180320_003709.jpg

    Above: Barsta/Omegon 2x, X-Cel 2x and TS/GSO 2.5x Barlows. 180x on the Moon with an ST80 is a perfectly achievable magnification though.

    The resolving limit of most scopes is about equal to its aperture width in millimetres, which roughly corresponds to a 1mm exit pupil I believe. With an ST80 that means any magnification above 80x will not resolve any greater detail but would be easier to perceive as it is a bigger image in the eyepiece.
     
    Last edited: Mar 28, 2018
    Nebula likes this.
  12. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    @Mak the Night

    My telescope is rated for 400x maximum for marketing purpose but the quality will start to decrease from 200x. Others factors could be involved like collimation, for me that 60x per aperture is pure garbage. (Perhaps true in world of refractory, I can't say)

    I did not check carefully the range between 200x and 286x for my telescope because I don't have any eyepieces to do it. 286x is usable occasionally but the quality will never be has sharp has 212x. With my current experience I would say without a doubt the real range for my instrument for maximum power is around 30x per inches of aperture.
     
  13. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
  14. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    2018-04-02 - REPORT - CAPELLA

    Here is my short observation where I took most of the time doing that sketch then packed the telescope immediately after.

    I was very impressed again by the power of my 8" newtonian, it can capture a large amount of very faint stars between the higher magnitudes and that's a point I am exploiting more and more.

    This exercise was about the surrounding of Capella (in the middle of course) I tried to log has much faint stars has I could during the sketching session and it took forever. At some point, I even wanted to give up.

    [​IMG]

    But I finished Capella and it's fairly dense surrounding. Many stars in my sketch are between magnitude 10 and perhaps up to magnitude 11, I tried to copy accurately the magnitude of each stars.

    I hope you like this work! I am pretty happy with my sketch because Capella is one of my favorite stars. And using my very best and favorite eyepiece the ES68 34mm
     
    Last edited: Apr 2, 2018
    Ruud and Orion25 like this.
  15. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    A very rich place with many different magnitudes of stars available at the same time.
     
  16. Orion25

    Orion25 Well-Known Member

    Joined:
    May 23, 2016
    Posts:
    1,895
    Trophy Points:
    113
    Location:
    Georgia
    That's an incredible sketch, Nebula! Auriga is one of my favorite regions to explore, along with Cassiopeia, Orion, and Cygnus. So many stars and clusters. It's a stellar wonderland! I greatly admire your patience and effort in sketching this area. What is the TFOV of this sketch?
     
    Nebula likes this.
  17. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    @orion 25, I tried to put the stars at the right place with the closest magnitude. It looks like nothing but there was high concentration involved in this exercise.

    I agree with you Auriga is a stellar wonderland totally.

    Capella has a very characteristic beige color for me too.

    "It's not yellow, it's not white, it' Capella."
    -Nebula


    The eyepiece gives a bit more then 2 degrees TFOV it's so well corrected too, the fields are clean up to the edge, perhaps one of the best purchase in my life. (Or at least one I highly appreciate)

    it's my first sketch of Capella too. It's something important that was covered last night. I have to sketch the field of many other stars , not one scene is the same.

    Thanks for you appreciations @Orion25
     
    Orion25 likes this.
  18. Orion25

    Orion25 Well-Known Member

    Joined:
    May 23, 2016
    Posts:
    1,895
    Trophy Points:
    113
    Location:
    Georgia
    "It's not yellow, it's not white, it' Capella."
    -Nebula


    I like that! It's so true. Capella has its own flavor.
     
  19. Dave In Vermont

    Dave In Vermont Well-Known Member

    Joined:
    Jan 5, 2016
    Posts:
    3,356
    Trophy Points:
    113
    That really is a wonderful sketch, Nebs! Your depictions of the differing magnitudes is excellent! Great stuff.

    Capella is a quite rare star - a yellow-supergiant. Not part of the main-sequence. Another, and quite surprising, representative of this star-type is Polaris! That very much surprised me - and still does!

    More info:

    https://en.wikipedia.org/wiki/Yellow_supergiant_star
     
    Nebula likes this.
  20. Nebula

    Nebula Well-Known Member

    Joined:
    Aug 5, 2016
    Posts:
    1,822
    Trophy Points:
    113
    I see that thread again it's filling me up with joy. Glad you liked that @Dave In Vermont. and thanks for the wiki also, Ill read it right after I am finished cooking.

    Capella the Super giant!

    *I was not aware Polaris was a super giant too.

    All these scenes are incredible. :)
     

Share This Page