Jump to content


Photo

700-800mm Focal Length Refractor for AP

  • Please log in to reply
7 replies to this topic

#1 Wembley2000

Wembley2000

    Ranger 4

  • *****
  • Posts: 316
  • Joined: 07 Jan 2012
  • Loc: SW Ohio

Posted 12 February 2013 - 09:35 AM

Hello,

I have been weighing my options for an 700-800mm focal length refractor for AP. I currently have an AT65edq which I really like, so basically I want to double the focal length for smaller objects. I have an AT6RC that I am selling to help fund this, I really do like the plug and play ability of the refractor, so I am leaning that way. I would really like to keep the budget below $1500, I currently have the AT2FF field flattener so I may not need another FF. The scope will be mounted on a Mach 1 and the camera is a QHY8. If I can find a good deal in this focal range I will have a focal length assortment if 420, 700-800, 1600, and 2500mm which should cover everything I want to shoot.

Thanks for the help,

Brian

#2 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5281
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 12 February 2013 - 03:02 PM

I'd say the ES 127mm (952mm FL) comes close. You'll need a flattener. Either the AT flattener only, or one of the dozens of combination flattener/reducers out there.

There are also a lot of 100mm f8 to f9 refractors out there. I used an Orion 100ED for a long time. Worked fine but the focuser needed help. I also have a QHY8 and that, plus OAG and guide camera, was too much for the stock focuser and even a William Optics.

.. although with a Mach1 (I got one recently) the need for OAG is much diminished if not eliminated. A simple finder guider works great since the periodic error is so small now..

If you can get one of the rare Stellarvue 100mm f8 Lomo optics with Feathertouch focuser, that would be right where you want to be. Can't underestimate the value of the focuser. And the SV 100/8 Lomo usually goes for $1100 to $1200. It is a bit slow at f/8 that's the only drawback.

If you want 700-800mm and faster, it's hard to beat the ES127 plus a reducer which would take it down to 762mm f6.


#3 Mark9473

Mark9473

    Cosmos

  • *****
  • Posts: 8553
  • Joined: 21 Jul 2005
  • Loc: 51°N 4°E

Posted 12 February 2013 - 05:04 PM

The ES127 is $1999; for that price you could also consider the AT106 f/6.5. The AT111 f/7 is even below $1600 but currently out of stock.

#4 Wembley2000

Wembley2000

    Ranger 4

  • *****
  • Posts: 316
  • Joined: 07 Jan 2012
  • Loc: SW Ohio

Posted 12 February 2013 - 07:28 PM

Thanks for the ideas. The ES 127 is a little out of my price range, and I really dont want to go much slower than f7. I have been eyeballing the At111 though, it seems to get pretty good reviews.

Brian

#5 orlyandico

orlyandico

    Fly Me to the Moon

  • *****
  • Posts: 5281
  • Joined: 10 Aug 2009
  • Loc: Singapore

Posted 12 February 2013 - 07:51 PM

Ah. I was thinking "used" ES127.

#6 Wembley2000

Wembley2000

    Ranger 4

  • *****
  • Posts: 316
  • Joined: 07 Jan 2012
  • Loc: SW Ohio

Posted 14 February 2013 - 11:55 AM

I think I am going to order the AT111 and rings from astronomics today. They are on backorder but that will give me time to sell some stuff off to help with the purchase. It looks like it could be up to 2 months to receive it. My plan is to piggyback the at65edq on it, then I can use either for guiding/imaging and have pretty easy set up times.

Brian

#7 Jason B

Jason B

    Proud father of 5!!

  • *****
  • Posts: 6590
  • Joined: 21 Jun 2004
  • Loc: Mid-Michigan

Posted 14 February 2013 - 05:53 PM

Brian,
Great choice. I do the same with my older AT111 and the AT65. I have had excellent results with both scopes!

#8 Scott Beith

Scott Beith

    SRF

  • *****
  • Administrators
  • Posts: 44470
  • Joined: 26 Nov 2003
  • Loc: Frederick, MD

Posted 14 February 2013 - 07:15 PM

The AT111 is a really good looking scope. Paired with the AT65 it should make one heck of a nice combo!






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics