Digital Cameras and Telescopes

[Revolvor]

I have a Celestron Powerseeker 127 telescope and am considering purchasing a Fuji S9600 Digital camera. This is an SLR "look-alike", without the ability to remove the lens. The lens is threaded Ø58mm for filters.

What will I need to enable me to use the camera in conjunction with the telescope? I have seen reference to "T" rings for use with SLR's but get the impression that they are used in place of the SLR lens. Is that the case? I know that a lot of people use modified web-cams, but if possible, I would like to use a standard camera.

Thanks, John.

[Cloudwatcher]

I think you will have to use the eyepiece projection method with that camera. Skywatcher,among others, sell a 'Digiscoping Adaptor' which should fit the bill.

I believe sambo used something similar for his recent Moon image post in the Lunar-Solar imaging section.

Cheers

CW

[barkis]

John, I think CW is advising the Afocal method, which is capable of giving high resolution images of lunar and planetary subjects.

Telescope House is where I bought my adaptors from. You need to know your lens filter size. Mine was 58mm, but yours could be different.

Also, you utilise the groove in any eyepiece you use in the system. The groove is accesible, when you remove the rubber eyecup from the eyepiece.. In addition to the adaptors, I would use an added safety measure by securing the assembly with a strap of some sort, just on the faint chance of a failure in the link up.

It does look a bit iffy when it is all together. You may want to adopt the more robust approach to afocal imaging and use a bracket device.

Ron.

[Cloudwatcher]

You are quite right Ron, I did indeed mean Afocal.

Sorry for any confusion revolver.

CW

[S2]

I thought that afocal only really worked with cameras with smallish aperture lenses?

Maybe I'm being too simplistic, but if you're using a 50mm aperture camera lens and an EP with an exit pupil of 7mm, won't 85% of your pixels be wasted? :?

[beamer3.6m]

The adapter needed is the Digi-T or Adap-T (same thing).

It works well and I have had no problems with stability of the set-up with my Fuji 6500FD.

I recommend a shutter release cable as this will prevent wobbly when pessing the shutter and should allow you to take a continuos series of shots at the desired shutter speed.

Let us know how you get on.

By the way when you get the Digi-t or Adap-T you will also need a step ring to get it to 58mm, these are cheap from Jessops.

[beamer3.6m]

With regard to ext pupil it s a fair point but if you use a 25mm eyepiece or even better a 32mm then the view is easily to focus and a decent wide field can be taken, however if you want to get the affect of a 10mm eyepiece for example then you can simply zoom the camera lens which increases the magbfication.

It works well if the DSLR route is not available.

[dph1nm]

Have a look at my article on afocal imaging. Mainly done with my 8.5" Newtonian, but I have just started using the same technqiues with a Celestron Nexstar 102.

I highly recommend you get the adapters to fasten the Fuji directly to the eyepiece - makes life so much easier. As far as exit pupils go it works the opposite way to that suggested above - big lenses are good, as the lens aperture needs to cover as much of the exit pupil as possible. The S9600 has a 6.2-66.7 mm focal length lens, so wide open at F2.8 the lens aperture is only 2.2mm. So you will lose light if you have an eyepiece with an e.g. 7mm exit pupil. This is unavoidable in small format cameras (A 35mm format camera does not have this problem, as the lens aperture is much bigger - a 50mm lens at F2.8 has 17.8mm aperture). You can always increase the lens aperture in these P&S digital cameras by zooming in a bit.

It also often helps to have an eyepiece with long eye relief so that the exit pupil actually falls somewhere near the camera lens iris (which is usually well back from the glass bit at the front!).

NigelM

[Revolvor]

Thanks everyone for the useful advice. I will definitely be getting an adaptor to connect directly to the camera. Then I will need the software needed to "stack" images for improved clarity.

John

[S2]

I guess I stand corrected.

I was thinking about the physical size of the camera lens, rather than the shutter aperture, which is why I'd never tried this (all my cameras have chunky lenses). I'll have to give it a go now and see how it turns out.

I'll add my thanks to John's.

Stewart.

[lunator]

It also often helps to have an eyepiece with long eye relief so that the exit pupil actually falls somewhere near the camera lens iris (which is usually well back from the glass bit at the front!).

NigelM

This is very important.

I have a A607 compact camera that can work with my 25/18/12.5 & 9mm orthoscopics, but my S5600 which has a much larger lens will only work with the 25mm eyepiece.

Cheers

Ian

[iancandler]

If your going to go that route I would grab the cable release bracket in the for sale section as they are very hard to get hold of for the fuji's, unless of course they have an electronic release cable these days, but my S5000 didnt have.

The other downside is you will be limited to bright targets as the S range have electronic veiwfinders, so you have to rely on the rear screen.

Have you thought about trying to pick up a secondhand eos 300D or 350D on ebay?

[beamer3.6m]

I have already nabbed the shutter release bracket.

It has taken me ages to find one of these so I grabbed it asap.

Definately recommended.