Page 2 of 3 FirstFirst 123 LastLast
Results 11 to 20 of 22
Like Tree15Likes

Thread: Unguided imaging on 2000mm focal length sct

  1. #11
    bapaden's Avatar
    bapaden is offline Main Sequence
    Points: 1,648, Level: 24
    Level completed: 48%, Points required for next Level: 52
    Overall activity: 47.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Mar 2018
    Location
    San Jose
    Posts
    96
    Points
    1,648
    Level
    24
    Thanks
    38
    Thanked 21x 21 Posts

    Default Re: Unguided imaging on 2000m focal length sct



    Thanks Pauls72, That was my suspicion. I suspect it is time to start autoguiding. I just want to make sure I have the rooes down with the mount before adding complexity to the system.

  2. #12
    bapaden's Avatar
    bapaden is offline Main Sequence
    Points: 1,648, Level: 24
    Level completed: 48%, Points required for next Level: 52
    Overall activity: 47.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!365 Days+ Registered Achievement!
    Join Date
    Mar 2018
    Location
    San Jose
    Posts
    96
    Points
    1,648
    Level
    24
    Thanks
    38
    Thanked 21x 21 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Thanks Mag95On,

    I usually connect to my car battery and leave the engine running. Could this cause problems?

  3. #13
    Pauls72's Avatar
    Pauls72 is offline HYPER GIANT
    Points: 19,323, Level: 96
    Level completed: 6%, Points required for next Level: 377
    Overall activity: 36.0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!1000 Days+ Registered Achievement!3 Years + Achievement
    Join Date
    Jul 2009
    Location
    LaPorte, IN USA
    Posts
    1,984
    Points
    19,323
    Level
    96
    Thanks
    6
    Thanked 660x 511 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Although that is more than enough voltage, you are wasting a lot of gas. You douldn't need to kep the car running as it should take quite a number of hours to run down your battery.

    I would get a 120V adapter if you image from a place that has power available or get yourself a 12V deep cycle battery or power pack.
    Something like this works well and they have a 20% off coupon too:
    https://www.harborfreight.com/automo...ter-62306.html
    https://www.harborfreight.com/
    Juno16 likes this.
    Mounts: EQ1, LXD55, Atlas EQ-G (one with Rowan belt mod, EQ6-Rail and one without)

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    C11, 8" Reflector, 102mm MCT, ST80, W.O. FLT98, 6" RC, Lunt LS50THa/B400
    Cameras: Canon XTi, DSI-C, DSI, ST402, QHY8L, QHY183C, QHY163M, ASI120MC-S (Allsky)
    Some of my Pic's http://www.astrobin.com/users/Pauls72/

  4. #14
    Gx8ES102's Avatar
    Gx8ES102 is offline Bright Giants
    Points: 3,784, Level: 40
    Level completed: 90%, Points required for next Level: 16
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!
    Join Date
    Jan 2018
    Location
    space
    Posts
    530
    Points
    3,784
    Level
    40
    Thanks
    94
    Thanked 145x 105 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Make your life a bit easy and use the FR6.3 or with a small sensor a used Meade FR3.3 IMHO. Have you tried different levels in DSS for star recognition?
    C90 (USA Rubberized, 1996), C8 (2000), ES 102 Triplet (2018), Orion ST 80 w/2" GSO focuser (2018), Starmaster 20 x 80 (2015), Eagle Optic Rangers 10 x 50 (2004), Sirius AZ-EQ G PRO (2018), LXD75 (2" legs, 2007), SLT (2008), Manfrotto 055 CF (2007) , ZWO224, Panasonic Gx8 (8 second live view, 4 shot stacking in camera)
    I tend to keep my Astro stuff Forever
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Lots of software and other "Stuff".....

  5. #15
    KathyNS's Avatar
    KathyNS is offline Super Moderator
    Points: 173,046, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 54.0%
    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
    25,172
    Points
    173,046
    Level
    100
    Thanks
    6,660
    Thanked 14,985x 9,542 Posts
    Blog Entries
    3

    Default Re: Unguided imaging on 2000m focal length sct

    Quote Originally Posted by Pauls72 View Post
    Although that is more than enough voltage, you are wasting a lot of gas. You douldn't need to kep the car running as it should take quite a number of hours to run down your battery.

    I would get a 120V adapter if you image from a place that has power available or get yourself a 12V deep cycle battery or power pack.
    Something like this works well and they have a 20% off coupon too:
    https://www.harborfreight.com/automo...ter-62306.html
    https://www.harborfreight.com/
    I second the portable battery. The gas it will save will pay for it in a couple of observing sessions. Not to mention the emissions.

    I use a 65 Ah marine battery when I am away from home, but 17Ah jump start batteries are popular and will typically last a couple of nights between charges.

    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.

  6. #16
    Mag95On's Avatar
    Mag95On is offline Bright Giants
    Points: 3,420, Level: 38
    Level completed: 47%, Points required for next Level: 80
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!50 Posts Achievement!5 Threads Achievement!365 Days+ Registered Achievement!
    Join Date
    Dec 2017
    Location
    Greater London
    Posts
    263
    Points
    3,420
    Level
    38
    Thanks
    406
    Thanked 61x 61 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    I think that this can cause irregular and inconstant power, with alternating current. My advice don't use a running battery from a car. Inexpensive power units are best. I think this is why your tracking is off, and you are getting star trails!
    Magnus
    OTA: Altair Starwave 70ED F6, SW 150mm PDS // Mount:SW EQ3 Pro, Vixen polarie // Imaging: ASI120mm-S; Canon 100D, 7D, 6D, Samyang 14mm,85mm // Solar:Quark Chromosphere; Baader Solar filter //
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    : CdC, GRIP, DSS, LR 6, Sequator, Adobe PSE 8, Sharpcap, AS, RS 6, MagicLantern

  7. #17
    Pauls72's Avatar
    Pauls72 is offline HYPER GIANT
    Points: 19,323, Level: 96
    Level completed: 6%, Points required for next Level: 377
    Overall activity: 36.0%
    Achievements:
    First 1000 Experience Points365 Days+ Registered Achievement!750 Days+ Registered Achievement!1000 Days+ Registered Achievement!3 Years + Achievement
    Join Date
    Jul 2009
    Location
    LaPorte, IN USA
    Posts
    1,984
    Points
    19,323
    Level
    96
    Thanks
    6
    Thanked 660x 511 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Quote Originally Posted by Mag95On View Post
    I think that this can cause irregular and inconstant power, with alternating current. My advice don't use a running battery from a car. Inexpensive power units are best. I think this is why your tracking is off, and you are getting star trails!
    Alternators generate AC current, but it is converted to DC and regulated before it ever leaves the alternator.
    12V auto or deep cycle batteries are at 12.6V to 12.8V when fully charged.
    Alternators on vehicles output around 14.6V in order to charge the batteries. Then when the battery is fully charged they may back down to someplace in the 13V range just to keep the battery topped off.
    Having the car running will not cause inconsistent power nor will it cause tracking problems. Unless you drive a beater that has electrical problems.
    Juno16 likes this.
    Mounts: EQ1, LXD55, Atlas EQ-G (one with Rowan belt mod, EQ6-Rail and one without)

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    :
    C11, 8" Reflector, 102mm MCT, ST80, W.O. FLT98, 6" RC, Lunt LS50THa/B400
    Cameras: Canon XTi, DSI-C, DSI, ST402, QHY8L, QHY183C, QHY163M, ASI120MC-S (Allsky)
    Some of my Pic's http://www.astrobin.com/users/Pauls72/

  8. #18
    seigell's Avatar
    seigell is offline HYPER GIANT
    Points: 27,209, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 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
    5,693
    Points
    27,209
    Level
    100
    Thanks
    182
    Thanked 1,663x 1,479 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    As you have already made significant efforts to tackle your issues via Drift Alignment, your next step really should be AutoGuiding.

    Yes, it adds a bit of complexity (at first), but is one of the elements which can soon become "Push Here Dummy" Simple (PHD2 Guiding Software). Total setup time for AutoGuiding will likely be less than a round of Drift Alignment, and the resulting improvement in number of "Keeper" Exposures will skyrocket.

    You haven't given us a full list of the equipment that you use (still don't know the Imaging Camera nor the exact model of SCT), but you have the choice of going with a Discrete Guidescope or an OAG setup.
    The OAG configuration has a steeper learning curve on hardware and setup, but has compensating benefits once in use - OAG also combats "Mirror Flop" of all SCTs without Mirror Locks.
    The Discrete Guidescope configuration will require a good 60-70mm Guidescope with a longer-than-usual Focal Length or else mounting a lightweight 70-80mm Scope in Piggyback.
    In either case, you are looking at a $400-500 budget.
    Juno16 likes this.
    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...)

  9. #19
    Clete's Avatar
    Clete is offline Main Sequence
    Points: 559, Level: 11
    Level completed: 18%, Points required for next Level: 41
    Overall activity: 5.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!
    Join Date
    Dec 2018
    Location
    Houston, TX
    Posts
    59
    Points
    559
    Level
    11
    Thanks
    59
    Thanked 9x 9 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Quote Originally Posted by bapaden View Post
    Hi,

    I’ve been trying to take 30 second subs of Andromeda on an 8” sct with a 2m focal length without guiding. The images look OK; not great. The ones I do not discard have somewhat elongated stars. They are probably 50% longer along one axis than the star’s diameter. I drift aligned very carefully, but I cannot eliminate an observable periodic error with amplitude of something like 2-3 arcmin and period of around 10min. I focus as best as possible with a bhatinov mask through the preview screen of my dslr.

    I cannot get deep sky stacker to register these images. I have tried on four evenings with the same results. My speculation is that the lack of autoguider together with the long focal length makes 30 second exposures impossible. Does this sound like a reasonable hypothesis to others?

    Here is one of the images:
    https://www.dropbox.com/s/jmgdeugib3...%20PM.jpg?dl=0
    I have the same mount and scope! I'm no expert but based on what your image looks like, that's not a problem with the mount but rather with your polar alignment. I only say that because I think I've taken that exact same image!

    The problem is that with your 8", 2M fl SCT, any tiny misalignment is going to show up.

    The AVX does not come with a polar scope built in (really dumb on their part). If you haven't already bought one, you just have to do so. That's all there is to it.

    But even with a polar scope, you're just so far zoomed in with a 2 meter focal length that it's just all but impossible to achieve the level of precision that would be required to get sharp stars.

    Personally, I gave up on imaging anything other than the Moon with my 8" SCT. My AVX came with a cheap 6" Newtonian with a 750mm fl. It gives a much wider field of view and is way more forgiving when it comes to alignment and other tracking issues. I don't have a field flatener for it so now I'm dealing with coma around the edges of the image but nice round stars are pretty easy to achieve with 30 second exposure times.

    I took the image below with it two nights ago (12/2/18). 185 subs and 30 seconds each from a horribly light polluted back yard. My CLS filter wipes out a lot of the nebulosity but the point is that the stars look pretty good. I might be able to pull out more nebulosity with additional processing but I'm not too good at the post processing yet.

    https://www.dropbox.com/s/qp7qd8xff1...bs%29.tif?dl=0


    I've never had a problem with DSS not stacking images like you describe. If I hadn't removed the few images with airplanes slashing through the image, it would have just stacked them right in there with everything else.
    Which version of the software are you using and have you changed any of the settings?

    Clete
    Last edited by Clete; 12-04-2018 at 03:43 PM.
    Juno16 likes this.

  10. #20
    seigell's Avatar
    seigell is offline HYPER GIANT
    Points: 27,209, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 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
    5,693
    Points
    27,209
    Level
    100
    Thanks
    182
    Thanked 1,663x 1,479 Posts

    Default Re: Unguided imaging on 2000m focal length sct

    Quote Originally Posted by Clete View Post
    The AVX does not come with a polar scope built in (really dumb on their part). If you haven't already bought one, you just have to do so. That's all there is to it.
    Celestron considers the Polar Scope an "Option" on the AVX. This is because of the functionality of the All-Star Polar Alignment (ASPA) routine embedded in the Hand Controller of all Celestron GOTO Mounts. It obviates any need for a Polar Scope. In fact, it produces Polar Alignments in line with those from long Drift Alignment sessions (20-60 Arcsec) - while the best a Polar cope can do is 1-5 Arcmin.
    BABOafrica and bladekeeper like this.
    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 2 of 3 FirstFirst 123 LastLast

Similar Threads

  1. Imaging with long focal length
    By kencrichton in forum Telescope Mounts Forum
    Replies: 3
    Last Post: 06-08-2016, 09:09 PM
  2. Poll: ISO? Focal Length? Subframe Length?
    By Stephanisk in forum Astronomy Digital Cameras Forum
    Replies: 4
    Last Post: 02-08-2015, 06:13 AM
  3. Replies: 11
    Last Post: 04-24-2014, 02:42 AM
  4. Replies: 3
    Last Post: 12-04-2009, 05:36 PM
  5. Scope focal length vs Eyepiece focal length
    By PS Surfer in forum General Astronomy Forum
    Replies: 1
    Last Post: 09-22-2003, 11:57 PM

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 03:29 AM.