Results 1 to 10 of 10
Like Tree2Likes
  • 1 Post By petrochemist
  • 1 Post By cardogab7341

Thread: Got my DSLR mated to the 'scope, how do I achieve more magnification?

  1. #1
    spaceprobe's Avatar
    spaceprobe is offline White Dwarf
    Points: 1,276, Level: 20
    Level completed: 76%, Points required for next Level: 24
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points
    Join Date
    Aug 2016
    Location
    UK
    Posts
    38
    Points
    1,276
    Level
    20
    Thanks
    16
    Thanked 3x 3 Posts

    Default Got my DSLR mated to the 'scope, how do I achieve more magnification?



    I've got the correct T adapter to connect the DSLR to my scope and it all seems to work fine - except we haven't had clear skies here to actually test it out properly. But in fiddling around and trying to test it out on distant street lamps and such, it seems the image will be very "wide field".

    This will be perfect for some of the objects I want to capture, but how do I achieve a more "magnified" image for the others?

    I'm using a Canon 30D (APS-C / 1.6 crop factor), and the scope is a Bresser NT150L.

    Thanks as usual, for any help, tips and suggestions.
    Bresser NT150L (Hexafoc) | EXOS-1/EQ4 | Red dot finder
    Solomark Plössl 8mm | Bresser Super Plössl 20mm | motor drive | polarscope

    Next Purhcases: More/better EPs, Revelation 2" 2x Barlow with 1.25" adapter

  2. #2
    Ashchest's Avatar
    Ashchest is offline Bright Giants
    Points: 5,449, Level: 50
    Level completed: 50%, Points required for next Level: 101
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!2 Posts Achievement20 Posts Achievement!Gallery Achievement!50 Posts Achievement!
    Join Date
    Jul 2015
    Location
    South Africa - PTA Centurion
    Posts
    346
    Points
    5,449
    Level
    50
    Thanks
    17
    Thanked 83x 75 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    A longer focal length scope or a smaller sensor and /or pixel size camera.

    These are the decisions all of us wanting to get into AP have to dabble with. Different scope and focal lengths for different views and applications. Different sensor and pixel sizes for different targets!

    But if I am correct, the scope you have is F8 which is not that wide. Next up would be an SCT at F10 and then a MAK at F12. F8 should give you plenty options and is actually in my opinion a perfect field of view. Only for planets and small planetary nebula and small clusters you might struggle a bit. Your planetary struggle will be mostly due to the large pixel / sensor size of your camera.

    A full moon will fit nicely in there!
    LAT25.75 LONG28.20 - 5", 6" SCT, AVX & CG4, 6.3 reducer, TO7500type 2+
    50mm finderguider & QHY5IIL. Canon 100D,760D. 50mm F1.8, EF 70-200 F4L,Tokina 12-28 F4
    18mm X-Cel, 3 x X-Cel, 12mm Reticle, 25mmOmni, 8mmEpic ED II ,40mmOmni
    CS6,Lightroom CC,Autostakkert, DSS,Firecapture,PHD2,EZplanetary,Registax
    -Anton Louw

    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.

  3. #3
    CamelHat's Avatar
    CamelHat is offline Bronze Supporter
    Points: 52,896, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    50 Posts Achievement!5 Threads Achievement!First 1000 Experience Points2 Posts Achievement20 Posts Achievement!
    Join Date
    Dec 2011
    Location
    Santa Barbara, CA
    Posts
    5,809
    Points
    52,896
    Level
    100
    Thanks
    1,170
    Thanked 1,720x 1,388 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    The mount capacity is 7 kg while the OTA is 6.5 kg. For astrophotography you need twice the capacity of the weight of the OTA plus accessories, as a rule of thumb. At a focal length of 1200 mm I predict that you will have trouble tracking, so the last thing you need is more magnification. Less would be better. Note also that the Newt is rather long so the momentum is mechanically not helpful (wind). That may very well be why your telescope is rated for moon and planetary astrophotography only, not DSOs.

    A DSLR works well for the moon but for the planets you need a webcam type camera with a frequency of 120 Hz or more and a much smaller chip with smaller pixels. That will give you more magnification. The images will be stacked with AutoStakkert. The mount will be adequate for that because accurate tracking is less important because of the high frequency. An ASI120 type camera is often used for that type of work. The relatively long focal length will help as well for this type of target.
    ... Henk. Telescopes: 6" Mak-Newt (Comet Hunter), ES ED127CF, ES ED80, Zhumell Z12, Coulter Odyssey 10, AT6RC, Venture RX-7, Celestron Skymaster 20x80, Mounts and tripod: Losmandy G11S, AVX, LXD55, Tiltall, Cameras: Fuji X-a1, Canon SX40, Xt, XSi, T6, ELPH 100HS, DIY: Dob and camera barndoor trackers, afocal adapter, Dob with foldable base and Az/Alt setting circles, Accessories: SSAG, Plossls, Barlows, Telrad, laser collimators (Seben LK1, Z12, Howie Glatter), Cheshire, 2 Orion RACIs 8x50, Software: DSS, ImageMagick, PHD, Nebulosity, Photo Gallery, Gimp, CHDK

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

  4. #4
    petrochemist's Avatar
    petrochemist is offline Main Sequence
    Points: 502, Level: 10
    Level completed: 4%, Points required for next Level: 48
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!Gallery Achievement!50 Posts Achievement!
    Join Date
    Oct 2016
    Location
    NE Essex, UK
    Posts
    62
    Points
    502
    Level
    10
    Thanks
    15
    Thanked 19x 15 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    There are several ways of connecting a camera to a scope. Prime focus gives the best results which is without either an eyepiece or a lens on the camera & will typically give about as wide a FOV that the scope is capable off. Many Newtonian scopes have focus issues with this configuration.
    Using an afocal configuration (both eyepiece & camera lens used) allows much higher magnifications but is more difficult to get right. For the moon just holding the camera at the eyepiece should do OK. Changing eyepiece & camera lens will alter the magnification compared to prime focus.
    Effective focal length of the configuration can be worked out as camera lens Focal Length * barlow magnification * Telescope Objective Focal Length / eyepiece Focal Length.

    There are also projection configurations that again have no lens on the camera but use either an eyepiece (called 'positive projection' or 'eyepiece projection') or just a barlow ('negative projection') after the main scope. I've never heard of a setup using a camera lens but no eyepiece.

    One of my eyepieces has a T2 thread to simplify connecting a camera to it, and there are other adapters that hold the eyepiece within them. It seems the permutations are endless!

    As above comments show your system/technique/conditions can severely limit the usefulness of higher magnifications. Note: The quoted maximum useful magnification of a scope will of course require everything else to be perfect getting good results at half this will be challenging.
    Mike
    A Photographic dabbler, diversifying into astrophotography.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    130EQ on motorised Stellavue EQ3 mount, & loads of photography bits...

  5. The Following User Says Thank You to petrochemist For This Useful Post:

    spaceprobe (10-21-2016)

  6. #5
    petrochemist's Avatar
    petrochemist is offline Main Sequence
    Points: 502, Level: 10
    Level completed: 4%, Points required for next Level: 48
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!Gallery Achievement!50 Posts Achievement!
    Join Date
    Oct 2016
    Location
    NE Essex, UK
    Posts
    62
    Points
    502
    Level
    10
    Thanks
    15
    Thanked 19x 15 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Quote Originally Posted by Ashchest View Post
    But if I am correct, the scope you have is F8 which is not that wide.
    F8 has NOTHING to do with how wide the FOV is. I have 2 camera lenses that are fixed at f8, one is 600mm (extreme telephoto) the other a 9mm fisheye. The FOV of one is <2° and the other 140° when used on the same camera.

    The Bresser NT150L scope has a focal length of 1200mm which I agree isn't particularly wide, but it's the focal length that determines this not the focal ratio.
    Mike
    A Photographic dabbler, diversifying into astrophotography.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    130EQ on motorised Stellavue EQ3 mount, & loads of photography bits...

  7. #6
    Ashchest's Avatar
    Ashchest is offline Bright Giants
    Points: 5,449, Level: 50
    Level completed: 50%, Points required for next Level: 101
    Overall activity: 0%
    Achievements:
    365 Days+ Registered Achievement!2 Posts Achievement20 Posts Achievement!Gallery Achievement!50 Posts Achievement!
    Join Date
    Jul 2015
    Location
    South Africa - PTA Centurion
    Posts
    346
    Points
    5,449
    Level
    50
    Thanks
    17
    Thanked 83x 75 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Quote Originally Posted by petrochemist View Post
    F8 has NOTHING to do with how wide the FOV is. I have 2 camera lenses that are fixed at f8, one is 600mm (extreme telephoto) the other a 9mm fisheye. The FOV of one is <2° and the other 140° when used on the same camera.
    Aaah. Not to hack the thread... You are touching an interesting subject here. We are talking about the TELESCOPE and not a camera lens where the F number is actually used differently. For telescopes the F number actually indicates how wide the field is. In camera lenses you have many optical elements which corrects the light path to keep "field of view" constant and in correspondence to the lens length regardless of the f number.
    LAT25.75 LONG28.20 - 5", 6" SCT, AVX & CG4, 6.3 reducer, TO7500type 2+
    50mm finderguider & QHY5IIL. Canon 100D,760D. 50mm F1.8, EF 70-200 F4L,Tokina 12-28 F4
    18mm X-Cel, 3 x X-Cel, 12mm Reticle, 25mmOmni, 8mmEpic ED II ,40mmOmni
    CS6,Lightroom CC,Autostakkert, DSS,Firecapture,PHD2,EZplanetary,Registax
    -Anton Louw

    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.

  8. #7
    petrochemist's Avatar
    petrochemist is offline Main Sequence
    Points: 502, Level: 10
    Level completed: 4%, Points required for next Level: 48
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!Gallery Achievement!50 Posts Achievement!
    Join Date
    Oct 2016
    Location
    NE Essex, UK
    Posts
    62
    Points
    502
    Level
    10
    Thanks
    15
    Thanked 19x 15 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Quote Originally Posted by Ashchest View Post
    Aaah. Not to hack the thread... You are touching an interesting subject here. We are talking about the TELESCOPE and not a camera lens where the F number is actually used differently. For telescopes the F number actually indicates how wide the field is. In camera lenses you have many optical elements which corrects the light path to keep "field of view" constant and in correspondence to the lens length regardless of the f number.
    F number in both cases is DEFINED by focal length/aperture.

    Using an on-line telescope FOV calculator https://astronomy.tools/calculators/field_of_view/ and entering typical values of 1200mm scope FL, 120mm diameter, 12mm eye piece & an eyepeices FOV of 55 gives a viewing FOV of 0.55° & f10. Changing the just the scopes aperture to 60 leaves FOV unchanged but will change the scopes F number F20. Next just change the scopes focal length to 600 & FOV doubles to 1.1° at F10, finally reduce aperture to 30mm will bring f number back to f20 but FOV is still 1.1°
    Similar results are found in imaging mode where with the camera kept constant FOV changes with focal length not aperture.

    While most camera lenses might have multiple optical elements I have at least one that is a single element - changing the aperture still has NO effect on FOV. Nor should it according to any of the optical theory I've studied. I think you're thinking of zoom lenses where the placement of the aperture needs careful thought to prevent F numbers changing wildly as the focal length changes. Of course F number has a significant effect on DOF but this is pretty much irrelevant for astronomy where everything is effectively at infinity.
    spaceprobe likes this.
    Mike
    A Photographic dabbler, diversifying into astrophotography.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    130EQ on motorised Stellavue EQ3 mount, & loads of photography bits...

  9. #8
    cardogab7341's Avatar
    cardogab7341 is offline SUPER GIANT
    Points: 9,261, Level: 66
    Level completed: 71%, Points required for next Level: 89
    Overall activity: 0%
    Achievements:
    2 Posts Achievement365 Days+ Registered Achievement!20 Posts Achievement!First 1000 Experience Points750 Days+ Registered Achievement!
    Join Date
    Mar 2015
    Location
    Richardson, TX
    Posts
    667
    Points
    9,261
    Level
    66
    Thanks
    43
    Thanked 254x 211 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Getting back on-topic, one way to increase your magnification, and one which I use to image planets with my canon 70D, is to use a barlow lens in between the camera and the scope. I also use the 5x digital zoom feature, which effectively crops the sensor to the center. These 20Mp sensors have so much resolution that a 5x digital zoom still gives decent resolution for planetary imaging. I access this cropping feature through BYEOS. Regarding the barlow, using a Newtonian you may have trouble reaching focus.
    jaetea likes this.
    Gabe Cardona
    Telescopes: Celestron C9.25 Edge HD
    Mount: Astro-Physics Mach1GTO
    Cameras: QHYCCD QHY12, Canon 70D (Unmodified), ZWO ASI-120MC-S
    Guidescope/Camera:
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Thin Off-Axis Guider/StarlightXpress Lodestar X2

    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.
    Tool (APT), BackyardEOS, PHD2, PixInsight, Photoshop CC, SGP

  10. #9
    Leveye's Avatar
    Leveye is offline HYPER GIANT
    Points: 67,034, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!200+ Posts Achievement!
    Join Date
    Jan 2013
    Location
    Newport Oregon
    Posts
    8,984
    Points
    67,034
    Level
    100
    Thanks
    2,117
    Thanked 2,557x 2,243 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Televue made a powermate barlow that unscrews and a t-ring can be attached to that so your DSLR camera can be used and you'll have more magnification. Works really well. You have to be careful when buying one though for not all of them have this feature. You'll see that the older ones have a 2 part construction.
    My eyes
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    1984 Meade 2120 10" SCT- 1998 U.S.A. made Celestron C8 SCT -StellarVue SV80ED Doublet- 1960's Homemade 6" F5.6 Newt - Astro Tech AT8IN Imaging Newt- Vintage 1961 H.O.C. made ATCO 80mm/1200mm refractor w/ original vintage eyepieces - 20x70
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Little Giant II binoculars w/ original 1997
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    SkyMount Parallelogram-Zhumell, Orion, Astro Tech 9x50 finderscopes - Orion Atlas AZ/EQ-G
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Skyguider Pro Unmodded Canon 5DMKiii - Modded Canon 700D/ T5i- ZWO ASI178MC
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    - Meade DSI II Mono CCD APT-DSS-PHD-CDC-PS-LR


    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 Leveye For This Useful Post:

    spaceprobe (10-21-2016)

  12. #10
    spaceprobe's Avatar
    spaceprobe is offline White Dwarf
    Points: 1,276, Level: 20
    Level completed: 76%, Points required for next Level: 24
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!First 1000 Experience Points
    Join Date
    Aug 2016
    Location
    UK
    Posts
    38
    Points
    1,276
    Level
    20
    Thanks
    16
    Thanked 3x 3 Posts

    Default Re: Got my DSLR mated to the 'scope, how do I achieve more magnification?

    Thanks, everyone, for your help here.

    My plan, at first, is to take loads of fast snaps whilst just manually keeping the target in the middle of the shot, and relying on the stacking software to register them. Experimenting, developing my own techniques, learning from mistakes and experience is what I'm looking forward to the most.

    I realise the scope is not the best for some things (I wanted a good all-rounder), but I love a challenge. And I'm pretty certain that 7kg rating for the mount is very conservative - I've found it to be extraordinarily stable.

    K.
    Bresser NT150L (Hexafoc) | EXOS-1/EQ4 | Red dot finder
    Solomark Plössl 8mm | Bresser Super Plössl 20mm | motor drive | polarscope

    Next Purhcases: More/better EPs, Revelation 2" 2x Barlow with 1.25" adapter

 

 

Similar Threads

  1. Scope magnification without eyepiece?
    By Linot00 in forum Astronomy Beginners Forum
    Replies: 7
    Last Post: 09-28-2016, 02:52 PM
  2. Polar scope: FOV and magnification?
    By jpaulo in forum Astronomy Beginners Forum
    Replies: 0
    Last Post: 10-24-2015, 12:09 AM
  3. How much magnification when I hook up my DSLR to my scope?
    By danram90 in forum Astro Imaging Forum
    Replies: 1
    Last Post: 01-14-2015, 12:36 AM
  4. Effective Magnification with DSLR
    By Jeff McClure in forum Astronomy Beginners Forum
    Replies: 10
    Last Post: 04-24-2012, 03:33 PM
  5. Magnification with DSLR
    By Jay573 in forum Astronomy Digital Cameras Forum
    Replies: 17
    Last Post: 04-02-2012, 04:24 PM

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 03:58 PM.