Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Equipment/other advice needed for side by side setup with dslr lens and a guidescope

  • Please log in to reply
6 replies to this topic

#1 shitijb

shitijb

    Lift Off

  • -----
  • topic starter
  • Posts: 20
  • Joined: 12 Aug 2019
  • Loc: Seattle, WA

Posted 09 April 2020 - 01:12 AM

My goal is to setup side by side for these reasons:

  1. Plate solving
    Otherwise I end up star hopping, taking test shots at 200mm while finding and carefully slewing the target in the center, then zoom at 600mm and refocus (sometimes there is no easy nearby star to focus on so refocusing is quite difficult)
  2. Drift align with PHD2
    My balcony does not have a view of the pole star, but it would be nice if I can do some astro work from home and gradually get data on some targets

Sony camera does not have backyard eos kind of a thing as far as I know so I think this is my best bet, but please let me know if I am missing something

 

I currently have this with me:

  1. Orion Atlas EQG mount
  2. A Sony 200-600 lens and an unmodified Sony a7RIII camera
  3. Adapter dovetail that fits on my lens tripod collar and itself fits on the mount

I believe I need the following extra things to achieve my goals:

  1. A side by side saddle
    https://farpointastr...ovetail-saddle/
  2. A guidescope + camera
    https://www.telescop...ge/p/115001.uts
  3. Cable to connect my mount with my laptop so that PHD2 can control it
    This one (USB2EQ5): http://www.store.sho...products_eq.htm
    (Found this from this post: https://www.cloudyni...t-which-cable/)

Some questions:

  1. Does the saddle directly fit on the mount like the adapter in (3)?
  2. Does the guidescope fit on the saddle?
  3. Similarly does the adapter I have fit on the saddle too so that I can mount my lens on it just like I do on the adapter?

 

Am I missing anything else I need? Appreciate any help!



#2 H-Alfa

H-Alfa

    Viking 1

  • -----
  • Posts: 584
  • Joined: 21 Sep 2006
  • Loc: Spain

Posted 09 April 2020 - 08:11 AM

Your explanation suggests me that you are starting on autoguiding, so long exposure imaging. I really suggest you to reconsider an on top setup instead of side by side. Side by side is quite difficult to balance and can lead you to differential flexure between the objective and the guidescope.

Enviado desde mi Mi 9 Lite mediante Tapatalk

#3 mackiedlm

mackiedlm

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 16 Jul 2019
  • Loc: Galway, Ireland

Posted 09 April 2020 - 09:09 AM

Your explanation suggests me that you are starting on autoguiding, so long exposure imaging. I really suggest you to reconsider an on top setup instead of side by side. Side by side is quite difficult to balance and can lead you to differential flexure between the objective and the guidescope.

Enviado desde mi Mi 9 Lite mediante Tapatalk

Can you tell me how you set up an "on top" set up on a telephoto lens and mirrorless camera like the OP has detailed. I've not seen that done before so would be interested.



#4 shitijb

shitijb

    Lift Off

  • -----
  • topic starter
  • Posts: 20
  • Joined: 12 Aug 2019
  • Loc: Seattle, WA

Posted 09 April 2020 - 11:54 AM

Your explanation suggests me that you are starting on autoguiding, so long exposure imaging. I really suggest you to reconsider an on top setup instead of side by side. Side by side is quite difficult to balance and can lead you to differential flexure between the objective and the guidescope.

Enviado desde mi Mi 9 Lite mediante Tapatalk

I considered piggyback setup but from what I understand I would need to order specially made rings for my telephoto lens (itself a few hundred $) and mount the guidescope on top. While guiding would be a very nice bonus to what I want and I don plan to guide, my primary goal is plate solving and drift alignment. Also I will at some point get a telescope too so Im hoping the side by side saddle wont be wasted equipment (hopefully I can use my telephoto + camera on the other spot to image 2 things at the same time).

 

Is differential flexure a limiting issue even in dslr + telephoto lens astrophotography? Would getting a more expensive saddle like from adm actually help? My telephoto lens diameter is <3.5 inches so I think I wont be resolving a lot anyway. My preferred targets are galaxies like andromeda, triangulum, bode's galaxy, pinwheel galaxy, whirlpool galaxy. My expectations are not high, but getting close to something like this (the person used a apsc dslr + 300 2.8 lens + teleconverters) would make me very, very happy :)



#5 H-Alfa

H-Alfa

    Viking 1

  • -----
  • Posts: 584
  • Joined: 21 Sep 2006
  • Loc: Spain

Posted 09 April 2020 - 12:35 PM

I considered piggyback setup but from what I understand I would need to order specially made rings for my telephoto lens (itself a few hundred $) and mount the guidescope on top. While guiding would be a very nice bonus to what I want and I don plan to guide, my primary goal is plate solving and drift alignment. Also I will at some point get a telescope too so Im hoping the side by side saddle wont be wasted equipment (hopefully I can use my telephoto + camera on the other spot to image 2 things at the same time).

Is differential flexure a limiting issue even in dslr + telephoto lens astrophotography? Would getting a more expensive saddle like from adm actually help? My telephoto lens diameter is <3.5 inches so I think I wont be resolving a lot anyway. My preferred targets are galaxies like andromeda, triangulum, bode's galaxy, pinwheel galaxy, whirlpool galaxy. My expectations are not high, but getting close to something like this (the person used a apsc dslr + 300 2.8 lens + teleconverters) would make me very, very happy :)

Hi,

I didn't understood that you are not going to guide. Sorry, my fault. In that case I think you should be able to make drift align and plate solve directly from your main camera+lens without the need of additional equipment. Maybe you can try to connect the Sony camera to PHD. It it works, you're done.

If not, I think you will be able to put the guidescope on top of the lens with telescope rings that include knobs. One pair for the main lens, a rail attached to them, and a second pair connected to the rail too.

57f435b1c3ecaca0ec834805d0cd34e6_1024x10

Enviado desde mi Mi 9 Lite mediante Tapatalk

#6 2ghouls

2ghouls

    Viking 1

  • *****
  • Posts: 972
  • Joined: 19 Sep 2016

Posted 09 April 2020 - 02:25 PM

I've tried a couple side-by-side configurations (including with the Farpoint saddles you linked) and never liked them enough to stick with them. As Alberto points out, they typically make balance a problem. It might work for your particular use case (for platesolving), but if I were you I would take the thing apart and put the saddles on the front and back and mount the guidescope on the front. I've been doing that for years without any issues. See here for a photo: https://www.nebulaph....com/equipment/


  • H-Alfa likes this

#7 H-Alfa

H-Alfa

    Viking 1

  • -----
  • Posts: 584
  • Joined: 21 Sep 2006
  • Loc: Spain

Posted 10 April 2020 - 05:25 AM

The setup that Nico suggests is even better than the on-top as it keeps the center of masses very low (so less counterweight is needed.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics