I own an 8 inch Meade LX90 GPS with a polar mount, a DSI Pro 1, and an LPI Imager.  After having fairly successful images using only 15-30 second exposures stacked, I am very ready to get some type of guider to take upwards of 5 minute exposures.

First I was looking into getting a refractor, but I found out that those are apparently very bad when used with a Schmidt-Cassegrain.  http://www.astrocruise.com/articles/guiding/guide.htm

I then found out that an off-axis guider would be best. http://www.opticsplanet.net/meade-off-axis-guider.html

I have several questions though.  I keep reading that you have to put an eyepiece in the slot where you are not taking pictures so you can MANUALLY do corrections using the telescopes keypad.  Are you not able to hook up another camera in this slot and use the autoguide function in autostar suite? Would I have to get a better guide camera than the LPI Imager in order to have a low exposure rate when tracking dim stars near my deep space object? Can I have two cameras going at once using autostar suite or do I have to buy another program?

 

Thank you for your time,

Fritz Laun

Hi, Fritz

Yes, you can use a second camera (but probably not with a focal reducer) and Autostarsuite will run both cameras simultaneously.

I would definitely recommend something more sensitive than the LPI for a guide camera - I use a DSI-Pro for this.

I know a number of people who use a refractor as a guidescope with their LX-90 quite successfully. Truth be told, most of us using Meade SCTs piggyback a nice 80mm refractor & find ourselves imaging through the refractor as much if not more than the main scope.

You don't mention if you have a wedge. If not, you should check before you spend $ on a guiding solution because I don't think you can guide in alt-az mode.

Chuck

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Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
http://autostarsuite.net/forums/1427/ShowForum.aspx

 

Chuck,

I use a wedge for polar alignment.

My LX90 has a focal ratio of F/10 and my focal reducer is a 3.3 F, not sure exactly where that puts me when I use the focal reducer, but would it be impossible to use this off-axis guider with that if I used a DSI pro for the guiding instead of an LPI and bought a DSI Pro II for pictures?

Can autostarsuite run two DSI pros at the same time?  Is there anything special I need to know?

A refractor would be nice indeed and allow me to take another world of pictures. Can you point me in the right direction of a refractor to get and mounting gear if I was to get one?

Thanks,

Fritz

 

Hi, Fritz

==> Responses inserted below...

Chuck

Fritzo130 wrote:

 Chuck,

I use a wedge for polar alignment.

==> Good - Great - you will need that :-)

My LX90 has a focal ratio of F/10 and my focal reducer is a 3.3 F, not sure exactly where that puts me when I use the focal reducer, but would it be impossible to use this off-axis guider with that if I used a DSI pro for the guiding instead of an LPI and bought a DSI Pro II for pictures?

==> I highly recommend the DSI Pro guider / DSI Pro-II imager combo. Probably THE best bang for the camera buck on the market today.

==> The FR / OAG combo is a different problem. You will need to keep the FR close to the imaging camera in order to achieve proper reduction without vignetting & coma, which means it will have to go behind the OAG. So you will be faced with the problem of focusing the guide camera at F10, and the imaging camera at F3.3 (or F5). Just can't be done, from what I am told.

Can autostarsuite run two DSI pros at the same time?  Is there anything special I need to know?

==> Yes, Autostarsuite is designed to do this & works well. No "special" considerations, you will quickly learn to pay attention to which camera you are seeing in the application :-)

A refractor would be nice indeed and allow me to take another world of pictures. Can you point me in the right direction of a refractor to get and mounting gear if I was to get one?

==> There are a number of very good 80mm APO's out there. The Orion 80-ED is an excellent choice for quality of optics, although the focuser could be more robust. The AstroTech AT80-T is another good one. After that, Williams Optics, TMB, Televue, Stellarvue, etc. & so on. Don't go any larger than 80mm with your LX-90 mount, though.

==> For mounting, I recommend the Losmandy rings & 3-D balance kit (get 2 5lb and 1 2lb weight to balance an 8lb. refractor, and go with 125mm rings. ADM is another respected name you might consider here

Thanks,

Fritz

 

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Chuck Reese
CDIP Certified: Nebula, Galaxy, Solar System, Stars & Clusters Imager
CDIP Mentor: Nebulae & Solar System Categories
For information on the Certified DSI Imager Program, see:
http://autostarsuite.net/forums/1427/ShowForum.aspx

I can't thank you enough, Chuck!

I will look into everything you have mentioned. Definitely sounds like I will be getting a refractor now.

I'll be sure to post back if I have any more questions :P

I use Envisage to guide and image at the same time using two DSI Pro's and it works fine. I occassionally add a color DSI as a third camera, but to keep things simple I usually uncheck the Live box on the camera that's idle; either the imaging DSI Pro or the color DSI, which ever isn't being used for imaging at the moment.

-John