Page 1 of 4 123 ... LastLast
Results 1 to 10 of 39
Like Tree83Likes

Thread: Field of View Degrees: What's best for galaxies?

  1. #1
    Ramsey's Avatar
    Ramsey is offline Main Sequence
    Points: 1,126, Level: 19
    Level completed: 26%, Points required for next Level: 74
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Sep 2017
    Location
    Pittsburgh, Pennsylvania
    Posts
    82
    Points
    1,126
    Level
    19
    Thanks
    53
    Thanked 1 Time in 1 Post

    Question Field of View Degrees: What's best for galaxies?



    What's the most appropriate field degree for viewing galaxies and nebulae?

    I'm looking at the EP 62, 68, and 82 eyepieces. I'm guessing the millimeters are just measuring the size of the eyepiece for the sake of eye-relief while the degrees are the metric for field of view? Galaxies are larger objects but they're also very far away and faint. Do they require smaller fields of view or larger?

    Just need some help understanding this so I know what I'm buying. I have a Celestron AVX 6 Newtonian and this will be my first time buying an eyepiece.

  2. The Following User Says Thank You to Ramsey For This Useful Post:

    carter2002 (10-16-2017)

  3. #2
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 82,971, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.8%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Slovakia
    Posts
    19,247
    Points
    82,971
    Level
    100
    Thanks
    3,693
    Thanked 5,994x 5,036 Posts
    Blog Entries
    4

    Default Re: Field of View Degrees: What's best for galaxies?

    AFOV comes into play depending on the type of scope you are using and how you want to frame the object in the eyepiece.
    A non-tracking mount benefits from a wider FOV for ease of keeping it in the eyepiece. A tracking mount can go with a smaller FOV.

    The other thing is how much background do you want around the object? 85% of the objects that can be seen with the majority of amateur telescopes can be seen in a 50° AFOV.

    Here is a good eyepiece calculator that will give you all the needed information for your scope and eyepiece: http://www.stargazing.net/naa/scopemath.htm
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier
    Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite
    Eyepieces: A-Z

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    The weakest link in the optical chain is the large nut located directly behind the eyepiece/ camera. - Gabrielle
    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

  4. The Following User Says Thank You to Gabby76 For This Useful Post:

    Ramsey (10-15-2017)

  5. #3
    Ramsey's Avatar
    Ramsey is offline Main Sequence
    Points: 1,126, Level: 19
    Level completed: 26%, Points required for next Level: 74
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Sep 2017
    Location
    Pittsburgh, Pennsylvania
    Posts
    82
    Points
    1,126
    Level
    19
    Thanks
    53
    Thanked 1 Time in 1 Post

    Default Re: Field of View Degrees: What's best for galaxies?

    Quote Originally Posted by Gabby76 View Post
    AFOV comes into play depending on the type of scope you are using and how you want to frame the object in the eyepiece.
    A non-tracking mount benefits from a wider FOV for ease of keeping it in the eyepiece. A tracking mount can go with a smaller FOV.

    The other thing is how much background do you want around the object? 85% of the objects that can be seen with the majority of amateur telescopes can be seen in a 50° AFOV.

    Here is a good eyepiece calculator that will give you all the needed information for your scope and eyepiece: N.A.A. Telescope Math Calculator
    I want to be able to see the object very clearly, so not so much background. Enough FOV to encapsulate the entire object and see fine detail, such as spirals and some local stars, while still having a reasonable amount of space around it for the sake of perspective.

  6. #4
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 82,971, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.8%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Slovakia
    Posts
    19,247
    Points
    82,971
    Level
    100
    Thanks
    3,693
    Thanked 5,994x 5,036 Posts
    Blog Entries
    4

    Default Re: Field of View Degrees: What's best for galaxies?

    I would try one eyepiece to start, the ES 18mm 82° seems to have a large following. If you find that FOV to your liking then get more over time, if it seems to large then give the 62 or 68 a try.
    Remember that for galaxy and nebulae you want your exit pupil to be 2mm and up roughly. Going after dim faint fuzzies it becomes a balance between magnification and light gathering.
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier
    Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite
    Eyepieces: A-Z

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    The weakest link in the optical chain is the large nut located directly behind the eyepiece/ camera. - Gabrielle
    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

  7. The Following User Says Thank You to Gabby76 For This Useful Post:

    Ramsey (10-16-2017)

  8. #5
    MG1692's Avatar
    MG1692 is offline HYPER GIANT
    Points: 12,974, Level: 78
    Level completed: 64%, Points required for next Level: 126
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!200+ Posts Achievement!400+ Posts Achievement
    Join Date
    Sep 2014
    Location
    Kansas
    Posts
    2,812
    Points
    12,974
    Level
    78
    Thanks
    26
    Thanked 1,280x 844 Posts

    Default Re: Field of View Degrees: What's best for galaxies?

    Quote Originally Posted by Ramsey View Post
    I want to be able to see the object very clearly, so not so much background. Enough FOV to encapsulate the entire object and see fine detail, such as spirals and some local stars, while still having a reasonable amount of space around it for the sake of perspective.
    Knowing the type of scope will help with recommendations
    Nexstar SE8 mount with Farstar C8 OTA (Caroline) Meade Series 5000 HD-60 25mm Paradigm Dual ED 25mm 18mm 15mm, Baader 21mm 17mm plus tunning rings, X-Cel LX 2X
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , various other bits and bob.

  9. #6
    Ramsey's Avatar
    Ramsey is offline Main Sequence
    Points: 1,126, Level: 19
    Level completed: 26%, Points required for next Level: 74
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Sep 2017
    Location
    Pittsburgh, Pennsylvania
    Posts
    82
    Points
    1,126
    Level
    19
    Thanks
    53
    Thanked 1 Time in 1 Post

    Default Re: Field of View Degrees: What's best for galaxies?

    Quote Originally Posted by Gabby76 View Post
    I would try one eyepiece to start, the ES 18mm 82° seems to have a large following. If you find that FOV to your liking then get more over time, if it seems to large then give the 62 or 68 a try.
    If it's 18mm, that's the size of the lens I'm looking through, right? Because I currently have a 20mm and that's somewhat of a strain on my eye. Also, isn't 82 degrees a bit big for DSO? I thought FOV trades off for magnification.

  10. #7
    KathyNS's Avatar
    KathyNS is online now Super Moderator
    Points: 172,566, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 88.0%
    Achievements:
    200+ Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!First 1000 Experience Points400+ Posts AchievementGot three Friends
    Awards:
    Reply Award
    Join Date
    Nov 2010
    Location
    Nova Scotia
    Posts
    25,157
    Points
    172,566
    Level
    100
    Thanks
    6,658
    Thanked 14,978x 9,537 Posts
    Blog Entries
    3

    Default Re: Field of View Degrees: What's best for galaxies?

    Quote Originally Posted by Ramsey View Post
    I'm guessing the millimeters are just measuring the size of the eyepiece for the sake of eye-relief while the degrees are the metric for field of view?
    In an eyepiece specification, the millimetres are the focal length, used to calculate the magnification in your scope. The field of view is the apparent field of view. The combination of apparent field of view and magnification tells you the true field of view (= AFOV / Mag), which is how much of the sky you can see.

    For finding galaxies (as opposed to viewing them once they have been found) and other faint fuzzies, you want brightness and wide field of view. Brightness comes from large telescope aperture and low magnification. Wide field of view comes from having a wide-angle eyepiece design and low magnification. Once you have found your target, you may well want to increase the magnification. Most galaxies are distant and therefore small. Only a couple (M31 and M33) are large. Magnification on faint small targets is a trade-off between getting it big enough to see details while trying to keep it bright enough to see.
    Doug James and Ramsey like this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    DSO AP:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Newtonian Astrograph; ATIK 383L+; EFW2 filter wheel; Astrodon Ha,LRGB filters; KWIQ/QHY5 guide
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ; Planetary AP: Celestron C-11; ZWO ASI120MC; Portable: Celestron C-8 on
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    pro; C-90 on wedge; 20x80 binos; Etc: Canon 350D; Various EPs, etc. Obs: 8' Exploradome;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    (pier);
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    .

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

  11. The Following User Says Thank You to KathyNS For This Useful Post:

    Ramsey (10-15-2017)

  12. #8
    Ramsey's Avatar
    Ramsey is offline Main Sequence
    Points: 1,126, Level: 19
    Level completed: 26%, Points required for next Level: 74
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!Gallery Achievement!
    Join Date
    Sep 2017
    Location
    Pittsburgh, Pennsylvania
    Posts
    82
    Points
    1,126
    Level
    19
    Thanks
    53
    Thanked 1 Time in 1 Post

    Default Re: Field of View Degrees: What's best for galaxies?

    Quote Originally Posted by MG1692 View Post
    Knowing the type of scope will help with recommendations
    I don't know how to put it in my signature so I just write it in the messages I post. I have the Celestron AVX 6 Newtonian.

  13. #9
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 82,971, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.8%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Slovakia
    Posts
    19,247
    Points
    82,971
    Level
    100
    Thanks
    3,693
    Thanked 5,994x 5,036 Posts
    Blog Entries
    4

    Default Re: Field of View Degrees: What's best for galaxies?

    In the top right of the screen click on settings, then in the column on the left click edit signature. Put your information in and click save
    Ramsey and littlejim like this.
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier
    Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite
    Eyepieces: A-Z

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    The weakest link in the optical chain is the large nut located directly behind the eyepiece/ camera. - Gabrielle
    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

  14. The Following User Says Thank You to Gabby76 For This Useful Post:

    Ramsey (10-15-2017)

  15. #10
    bladekeeper's Avatar
    bladekeeper is online now Super Moderator
    Points: 303,575, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 100.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!200+ Posts Achievement!
    Awards:
    Activity Award
    Join Date
    Aug 2014
    Location
    Lowell, Arkansas, USA
    Posts
    38,872
    Points
    303,575
    Level
    100
    Thanks
    29,120
    Thanked 17,666x 12,097 Posts

    Default Re: Field of View Degrees: What's best for galaxies?

    I do a lot of galaxy hunting, well, I do a lot of galaxy hunting when the sky cooperates.

    Anyway, I use the ES 82° series in my dobsonian for this endeavor. Of course, as Gabrielle noted, with a manual mount a wider AFOV is most useful for me.

    I typically use two eyepieces for this pursuit, and sometimes four, and these being my 18mm, 14mm, 11mm, and 8.8mm. Most often the 18mm and 11mm will suffice. Exit pupil is the name of the game with DSOs. My 18mm in my 12" dob yields a 3.61mm exit pupil, and my 11mm yields a 2.21mm. With these eyepieces, I get 84×, 109×, 138×, and 173×. Only rarely do I need to push farther on my magnification.

    You probably need an eyepiece that gives you an exit pupil around 4mm for your lower power "hunter" eyepiece, and another around 2mm to 2.5mm for your "killer" eyepiece. Depends on how faint and deep in the weeds you want to get with galaxies.

    My process is Telrad to point, RACI to hop, 18mm (hunter) to find the field, and 11mm (killer) to pull out the detail.

    Keep in mind also, that, by and large, you aren't going to get spiral arms, dust lanes, etc. with the majority of galaxies. Only on nights with excellent transparency and a dark sky will the brightest offer up those goodies (i.e. the Messier galaxies).

    That said, I have seen dust lanes in M31, spiral arms in M81, M51, M101, M74, and a few others. I had one night a couple of years ago where these were just popping out at me. They were faint and grey, but the visage in the eyepiece still haunts me.

    Most of the time, you'll get the brighter pinch of the core with some surrounding extended structure, occasionally some mottling, and once in a while a bit of a dark cut marking the hint of a dust lane. This is all very subtle, and it takes a practiced eye to begin picking out these subtle changes in light level.

    It's a fun pursuit, but it is almost as maddening as it is joyful.
    Bryan

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    f/5; Celestron C6-R f/8; ES AR127 f/6.4; ES AR127 f/9.4; Stellarvue SV102T f/7; ES AR102 f/9.8;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    MC90 f/13.3;
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ST80A f/5; Celestron Premium 80 f/11.4; Celestron C80 f/11.4; Unitron Model 142 f/16; Meade NG60 f/10
    Mounts: Celestron AVX; Bresser EXOS-2; ES Twilight I; ES Twilight II; iOptron Cube-G; AZ3/wood tripod; Vixen
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    Eyepieces: GSO Super Plössl 40mm, 32mm, 15mm, 9mm; ES 82° Series; GSO Superview 30mm; Celestron Plössl 26mm, 20mm; ES 70° 25mm; ES Plössl 25mm; Vite Aspheric 23mm, 10mm, 4mm; Orion Expanse 20mm, 9mm; KK Ortho 18mm, 12.5mm; Bresser 70° 15mm; Coulter Optical 12.5mm; BCO 10mm; ES 62° 9mm; Zhumell Z Series 5mm
    Binoculars: Pentax PCF WP II 10×50, Bresser Corvette 10×50, Bresser Hunter 16×50 and 8×40, Garrett
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    12×60 LW, Gordon 10×50, Apogee 20×100

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.


    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    Galaxy Hunter's Creed - When you play whack-a-mole, sometimes you hit 'em on the head, sometimes you miss 'em. But its always fun to play, and if you don't play, you ain't gettin no moles! - KT4HX

  16. The Following 2 Users Say Thank You to bladekeeper For This Useful Post:

    Eagleheaf (10-15-2017),Ramsey (10-15-2017)

 

 
Page 1 of 4 123 ... LastLast

Similar Threads

  1. 2 or More Galaxies, One Field of View Thread
    By andro-mike-eda in forum Deep Sky Objects Forum
    Replies: 31
    Last Post: 01-30-2015, 06:52 AM
  2. degrees in view
    By Shallbe in forum Astronomy Beginners Forum
    Replies: 5
    Last Post: 12-07-2014, 09:14 PM
  3. Calculating Field of view in degrees.
    By Ernest A. Martsching in forum General Astronomy Forum
    Replies: 5
    Last Post: 05-03-2011, 12:40 AM
  4. Binoculars field of view in degrees
    By Chris Marriott in forum Amateur Astronomy Forum
    Replies: 6
    Last Post: 09-13-2003, 04:25 AM
  5. Binoculars field of view in degrees
    By Jon Isaacs in forum Amateur Astronomy Forum
    Replies: 2
    Last Post: 09-10-2003, 12:56 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 02:23 PM.