Page 1 of 2 12 LastLast
Results 1 to 10 of 14
Like Tree3Likes

Thread: Goto GE Mount for ASTROPHOTOGRAPHY - Is there a diff between guiding and tracking?

  1. #1
    beareos4's Avatar
    beareos4 is offline White Dwarf
    Points: 3,438, Level: 38
    Level completed: 59%, Points required for next Level: 62
    Overall activity: 0%
    Achievements:
    2 Posts Achievement365 Days+ Registered Achievement!750 Days+ Registered Achievement!First 1000 Experience Points1000 Days+ Registered Achievement!
    Join Date
    Feb 2014
    Location
    Arizona
    Posts
    3
    Points
    3,438
    Level
    38
    Thanks
    0
    Thanked 0x 0 Posts

    Default Goto GE Mount for ASTROPHOTOGRAPHY - Is there a diff between guiding and tracking?



    I am researching GE Mounts trying to identify a good overall mount for astrophotography with a DSLR. I have a few questions. There are several GOTO mounts with tracking capability that also have a port for guiding. What is the difference between GOTO with tracking and "guiding". What would the added benefit of guiding be in addition to GOTO and tracking? I am assuming that using the GOTO and tracking functionality will allow me to take long exposures 5, 10, 15 , 20 minutes without getting star trails. Is that correct? Thanks for any info / guidance you can provide.

  2. #2
    jerryTheC's Avatar
    jerryTheC is offline Super Moderator
    Points: 26,893, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 10.0%
    Achievements:
    365 Days+ Registered Achievement!50 Posts Achievement!5 Threads Achievement!200+ Posts Achievement!First 1000 Experience Points
    Join Date
    Apr 2011
    Location
    Harrow, UK
    Posts
    6,029
    Points
    26,893
    Level
    100
    Thanks
    335
    Thanked 1,915x 1,623 Posts

    Default

    There are basically two different levels of goto mounts - especially when you're looking at alt-az ones - visual use, where you just want to keep the object in view (and don't mind if it moves around a bit) and imaging use, where you want to be able the object in precisely the same position, so it doesn't smear the image around. Even With the ones designed for imaging, you're unlikely to get perfect tracking performance - especially for multi-minute exposures - so you need to be able to autoguide the mount - basically, you use a second smaller scope (or an off axis guider) together with a second (guide) camera, and software that loops taking short exposures with guide camera, analyses the results (usually to sub-pixel accuracy) to check for any drift, and then sends corrections to the mount - hopefully correcting any drift before it's big enough to show up in the main image.

    Since manufacturers tend to put autoguider inputs on just about any mount that has even a vague chance of being usable for imaging, the lack of them is usually an indication that a mount isn't really suited to ling exposure AP.

    So a goto with just tracking will happily keep things in view visually - often for hours - but for imaging, long multi minute exposures usually need autoguiding - though you may manage up to a minute or so without - it all depends on the mount, and you also need a good polar alignment in any case, even with autoguiding.

    (While I've seen alt-az gotos without guider inputs, I don't think I've come across a goto EQ without them...)

  3. #3
    fmhill's Avatar
    fmhill is offline HYPER GIANT
    Points: 15,836, Level: 86
    Level completed: 82%, Points required for next Level: 64
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!Monthly Activity Achievement!200+ Posts Achievement!
    Join Date
    Jul 2012
    Location
    Rain Forest of the North East, Cape Cod, MA
    Posts
    3,710
    Points
    15,836
    Level
    86
    Thanks
    441
    Thanked 1,020x 892 Posts

    Default Re: Goto GE Mount for ASTROPHOTOGRAPHY - Is there a diff between guiding and tracking

    1st of all, GOTO is simply a function of a mount control system to look at a table of coordinates based on the name of an object you enter, and the mount control system aims the mount to the coordinate location of that object. GOTO is not related to tracking and or guiding, it is strictly a location finding method.

    Tracking is simply the function of the motor and gear train on the RA axis of the mount to rotate the telescope at the same rate the earth turns but in the reverse direction so that objects in space are maintained in the field of view. Tracking by itself is an open loop system functioning without corrections and is not the ultimate solution to tracking as it is strictly a mechanical function and is dependent upon the accuracy of polar alignment and the speed regulation of the mount control system. It is a blind system.

    Guiding is a closed loop system by which using an optical star location which is is optically captured and maintained by a secondary guide scope and camera of the auto guiding system sending tracking correction instructions to the mounts tracking system. In other words the guiding system is sending correctional feedback to the mounts tracking system.

    A comparison that puts this in layman's terms would be like driving an automobile with a blindfold on and following instructions from a computer describing the road. Auto guiding would be like driving the car without the blindfold so you can see to make the corrections by your own Observation/determination.

    As to whether a mount has a ST 4 guiding connector input or not, is not important as long as the mount is capable of ASCOM control via a computer. The ST 4 connector technology is older technology largely becoming replaced today by sending the guiding corrections directly into the mount control system over the computer communications link via the ASCOM computer interface method.
    Thanks, Mitch - K1FH
    And sidekick Shadow, the precocious one
    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.
    I made my first star trail image in 1949 and have collected too much gear to list ever since...

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

  4. #4
    beareos4's Avatar
    beareos4 is offline White Dwarf
    Points: 3,438, Level: 38
    Level completed: 59%, Points required for next Level: 62
    Overall activity: 0%
    Achievements:
    2 Posts Achievement365 Days+ Registered Achievement!750 Days+ Registered Achievement!First 1000 Experience Points1000 Days+ Registered Achievement!
    Join Date
    Feb 2014
    Location
    Arizona
    Posts
    3
    Points
    3,438
    Level
    38
    Thanks
    0
    Thanked 0x 0 Posts

    Default What is a good G.E.M. for DSLR Astrophotography

    I'm after a G.E.M that is motorised that will carry a DSLR and lens. Payload is a Nikon D800 and lenses will range from wide angle up to 600mm f4. Have read about several G.E.M. GOTO mounts and I am looking for feedback from anyone with hands on experience. Looking for something that I could possibly move into mounting a scope on in the future. Thanks for any feedback you can provide.

  5. #5
    carastro's Avatar
    carastro is offline SUPER GIANT
    Points: 18,668, Level: 94
    Level completed: 43%, Points required for next Level: 232
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience Points365 Days+ Registered Achievement!400+ Posts Achievement50 Posts Achievement!
    Join Date
    Dec 2010
    Location
    England
    Posts
    950
    Points
    18,668
    Level
    94
    Thanks
    1
    Thanked 635x 280 Posts

    Default Re: What is a good G.E.M. for DSLR Astrophotography

    Depends on how big a scope you are planning to get. If you don't think you'll get anything too big then the Skywatcher HEQ5 or the Celestron CG5 GT are both good, though I find the skywatcher more accurate in GOTOs. If you think you might want a heavier scope at some point then the Skywatcher NEQ6 is excellent. I think Orion do equivalent mounts to these. If you plan to do long exposure AP then make sure whatever you buy has a guide port.

    Carole

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

    Mount: NEQ6 &
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    Imaging
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    : WOZS71 Zenithstar APO, DMK21,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Pro ED120, Skywatcher Evostar ED80, SW130PDS
    Camera: Modified Canon EOS 1100D, Arik460EX Mono, Atik314L mono + EFW
    Guiding: Skywatcher finderguider/QHY5 Observatory: SkyPOD + PZT
    Website: https://sites.google.com/site/caroleastroimaging/home

  6. #6
    OttoMann's Avatar
    OttoMann is offline HYPER GIANT
    Points: 18,224, Level: 93
    Level completed: 31%, Points required for next Level: 276
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Got three Friends
    Join Date
    Jan 2013
    Location
    Mars Hill, NC
    Posts
    1,535
    Points
    18,224
    Level
    93
    Thanks
    298
    Thanked 464x 410 Posts

    Default Re: What is a good G.E.M. for DSLR Astrophotography

    The Celestron Advanced VX mount and iOptron Zeq25 are both very good entry level GEM's. The CG-5 has been discontinued but still available. The AVX has replaced it.
    Kurt

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    Celestron C6-N 6" Newt, AVX Mount,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    5SE
    Imaging : Canon Rebel T4i 650D , Neximage 5,
    Accessories : Orion MMAG, Celestron f 6.3
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    , BackyardEOS, DSS, PIPP, Registax, StarTools

  7. #7
    carastro's Avatar
    carastro is offline SUPER GIANT
    Points: 18,668, Level: 94
    Level completed: 43%, Points required for next Level: 232
    Overall activity: 0%
    Achievements:
    200+ Posts Achievement!First 1000 Experience Points365 Days+ Registered Achievement!400+ Posts Achievement50 Posts Achievement!
    Join Date
    Dec 2010
    Location
    England
    Posts
    950
    Points
    18,668
    Level
    94
    Thanks
    1
    Thanked 635x 280 Posts

    Default Re: What is a good G.E.M. for DSLR Astrophotography

    The CG-5 has been discontinued
    Oh didn't realise that, they are still selling them here in the UK, but limited stock so I guess that's the reason why.

    Carole

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

    Mount: NEQ6 &
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    Imaging
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    : WOZS71 Zenithstar APO, DMK21,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Pro ED120, Skywatcher Evostar ED80, SW130PDS
    Camera: Modified Canon EOS 1100D, Arik460EX Mono, Atik314L mono + EFW
    Guiding: Skywatcher finderguider/QHY5 Observatory: SkyPOD + PZT
    Website: https://sites.google.com/site/caroleastroimaging/home

  8. #8
    sidewind's Avatar
    sidewind is offline Main Sequence
    Points: 3,728, Level: 40
    Level completed: 52%, Points required for next Level: 72
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Oct 2013
    Location
    Ishøj Denmark
    Posts
    99
    Points
    3,728
    Level
    40
    Thanks
    2
    Thanked 13x 13 Posts

    Default Re: What is a good G.E.M. for DSLR Astrophotography

    What you need is a mount that holds your equipment rock solid. Better get a EQ8, Losmandy HGM Titan or the TTS160/TTS300, than a ToysRus mount.

    Now you write that you want to use it with a DSLR (I use a Canon EOS D1 mkII with up to a 800 mm f:10), and here you can use any trripod that can handle app. 7-8 lbs.

    Later you want to use it for a telescope, and here comes the catch. What telescope ? Refractor, reflector, SC ? ? ?

    What you (in my opinion ) should do is: Visit a local amateur astro club, talk with people (you have to make an efford to ask dumb questions), listen, and ask more questions. I did it the wrong way, bought several mounts/scopes, tries, got frustrated and first after a year I visited an astro club. I think I used app. ½ the time when they had their meetings, for ½ a year, before I joined the club, and in that timeperiod I found out that the first scope I bought (Meade ETX90), and the last Skywatcher/Synta EQ6 + Meade LX10 EMC, was what I needed. The first because I am set up in 10 min and the second when I want to try to take pic's of the sky.

    So now I have 6 mounts (EQ3, EQ5, EQ6, 2* CG5GT and my ETX90) 8 telescopes (4,5", 6", 8" SchmitCassegrain, 6", 8" 10" newtons, a refractor 90/900 and my ETX90), a hole in my wallet the size of app. 7500$ i didn't need to spend.

    Bottomline, join an astronomy club.

    Greetings from the land of the litle mermaid.

    Søren

    P.S. If you can't come looking for free a few times, then it is not a club for you.

    Clear skies to you
    Clear skies to ya all
    Celestron SCT C6-S / CG5GT
    Meade LX10 /
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Pro

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    10" / EQ6 Pro

  9. #9
    sidewind's Avatar
    sidewind is offline Main Sequence
    Points: 3,728, Level: 40
    Level completed: 52%, Points required for next Level: 72
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Oct 2013
    Location
    Ishøj Denmark
    Posts
    99
    Points
    3,728
    Level
    40
    Thanks
    2
    Thanked 13x 13 Posts

    Default Re: Goto GE Mount for ASTROPHOTOGRAPHY - Is there a diff between guiding and tracking

    Quote Originally Posted by fmhill View Post

    A comparison that puts this in layman's terms would be like driving an automobile with a blindfold on and following instructions from a computer describing the road. Auto guiding would be like driving the car without the blindfold so you can see to make the corrections by your own Observation/determination.
    Sorry for interupting, but this is the best ever way to explain things I have ever seen, thanks
    fmhill and analogkidhscm like this.
    Clear skies to ya all
    Celestron SCT C6-S / CG5GT
    Meade LX10 /
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Pro

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    10" / EQ6 Pro

  10. #10
    seigell's Avatar
    seigell is offline HYPER GIANT
    Points: 26,920, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 3.0%
    Achievements:
    365 Days+ Registered Achievement!5 Threads Achievement!50 Posts Achievement!750 Days+ Registered Achievement!First 1000 Experience Points
    Join Date
    Jan 2011
    Location
    Gilbert AZ (Exiled to the Marshes of Central Florida)
    Posts
    5,691
    Points
    26,920
    Level
    100
    Thanks
    182
    Thanked 1,663x 1,479 Posts

    Default Re: What is a good G.E.M. for DSLR Astrophotography

    Quote Originally Posted by sidewind View Post
    What you need is a mount that holds your equipment rock solid. Better get a EQ8, Losmandy HGM Titan or the TTS160/TTS300, than a ToysRus mount.
    There is a MASSIVE difference between these two categoriaztions of GEM Mounts, and NEITHER should be suggested for a beginning AP Enthousiast. One should always avoid the Mounts (or Telescopes) found for sale in the Big-Box Stores for prices like $100-400, as they really are only good (if that) for beginning Visual Astronomy. However, the High-end Mounts which cost more than the average Enthusiast's entire budget are also not be suggested for anyone of the apparent Beginner Enthusiast level. Instead, the middle ground (already suggested above by OttoMann and Carastro) are really the right fit. They represent enough Capacity and Capability to last Beareos4 until he decides where else to take his AP Hobby, and are more than adequate to support his intended initial DSLR with Long Telephoto rig.
    ES AR152 / ES 80ED Apo / Orion 8in F/3.9 / C9.25-SCT / C6-SCT / C10-NGT / AT6RC / ST-80 / AstroView 90 / Meade 6000 APO 115mm
    CGEM (w HyperTune and ADM bling) / 2x CG5-AGT / Forest of Tripod legs / Star Adventurer / Orion EQ-G
    550D (Modded-G.Honis) / 60D / 400D / NexImage / NexGuide / Mini 50 SSAG / ST-8300C / ASI120MM-S / ASI1600MM-Cool
    Dark Skies in SW CO when I can get there, and badly light polluted backyard when I can't... (Currently Self-Exiled to Muggy Central Florida...)

 

 
Page 1 of 2 12 LastLast

Similar Threads

  1. Adding a GOTO tracking mount at a later date?
    By bmt2116 in forum Dobsonian Telescopes Forum
    Replies: 1
    Last Post: 03-23-2014, 07:49 PM
  2. GoTo Alt-Az Mount Tracking Issue
    By Giray Gencaslan in forum Astronomy Beginners Forum
    Replies: 4
    Last Post: 08-25-2013, 12:10 AM
  3. DIY tracking mount / GOTO mount using PIC MCU's
    By arjen in forum Telescope Mounts Forum
    Replies: 2
    Last Post: 07-28-2012, 12:54 PM
  4. Auto-Tracking with AZ GOTO Synscan mount
    By Jay573 in forum Astronomy Beginners Forum
    Replies: 8
    Last Post: 04-06-2012, 08:41 PM
  5. Anyone built their own tracking/guiding or even goto mount?
    By ofranzen in forum ATM DIY Telescope Making Forum
    Replies: 0
    Last Post: 03-25-2010, 12:45 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 12:51 PM.