Astrograph f8 advice

[Dave1964]

Hi all,

Earlier in the year I got an 8 inch ritchey chretein astrograph F8. I didn't have much luck with it for imaging. Plus the weather wasn't fab last winter for trying.

I could see the moon and got that into focus with a tube extender. Yet I couldn't see anything else like deep space or other planets through it. Apart form selling it and going to for the sky watcher Quattro. I am after some hints on how to see more with the canon 60d through. I tired a few ISO settings and used bulb mode with a remote shutter release to know effect.

Any advice would be greatfuly recieved.

Dave

[Leveye]

"See more with my Canon 60D" Can you give us more to this? Are you using the live view screen to gaze at things or are you just taking pictures?

[wuthton]

At 1.6m focal length/F8 with a DSLR your pixel illumination is very low. +/- 0.55arcsec/pixel.

A reducer would help and/or a large pixel, cooled CCD which could achieve the exposure times required.

A Quattro would be out of the pan and in to the fire, why not make your life easier with an ED80?

[Thalestris24]

Hi

I think you may have to use extension tubes in order to achieve focus. At least, that's what it mentions here:

https://www.altairastro.com/product.php?productid=16346

Oops! Sorry, you said you did

[wxsatuser]

As mentioned you will no doubt need fairly long exposures at f8.

I would use ISO 1600, Bulb mode and use the in camera histogram to gauge your exposure.

I would go for at least a 5minute exposure and see where the peak of the histogram lies.

You want it around the first line from the left, around 20>25%, that should give you a good exposure.

If the histogram is always hard to the left the photos will be very dark, under exposed.

This assumes you do have the 60D at the focal point, if not you need to fiddle with the extensions to get it bang on.

[Dave1964]

Hi all,

Thanks guys, when it say see more I meant seeing more than the moon such as other planets and dso etc, I am using a focal reducer and live view. I will try again when the darker evenings arrive as I know it's a lot more trickier than reflector and refractor.

Dave

[ollypenrice]

It sounds as if you are trying to use your camera as a kind of electronic eyepiece. Is your aim to view objects with the camera or to take astrophotos? These are not the same thing. The images you see on the DS board are multiple exposures stacked, calibrated and carefully processed in Photshop or similar. The individual sub exposures of 10 minutes or so show very little other than on the brightest objects.

Olly