Completely new to astrophotography!! Need help with equipment selection!

[gustavo_sanchez]

Hi,

I started using my scope only a few months ago, and I would like to take some pictures with it. They do not have to be professional grade or anything like that, just some nice pics of the planets or simple DSOs. I have an Omni XLT 120 refractor with an 1.25" eyepiece kit, and my camera is a Sony Alpha 290 DSLR. I just ordered an Minolta AF T-ring to link my camera to the scope, but I am not sure which other accessories I need to start taking pics. I understand that my scope has a built-in T-adapter to accept the T-ring, but I suppose I cannot get any eyepiece zoom with that setup. I was looking at the Celestron 8mm-24mm zoom eyepiece since it supposedly has a built-in thread like the T-adapter, so maybe I could use it to get some magnification.

What suggestions can you give? It is true that the zoom eyepiece has the thread on it?

Thanks!

[brantuk]

It does have a thread but you'll need an adaptor to fit it to a T-adaptor. I think it's a 54-T. Same with the hyperion ep's too that need a 58-T. I might have it the wrong way round but you can check sizes on FLO or RVO.

[gustavo_sanchez]

I am not sure I got your response correctly. I am under the impression that the T-ring that is attached to my camera couples directly to the thread on the zoom eyepiece, and then I can insert the eyepiece on the diagonal's draw tube, just like any other eyepiece would be attached. I am thinking that with this setup I do not have to use the built-in T-adapter on my scope focuser. Something like this: Camera -> T-ring -> EP -> Diagonal. This configuration is possible or appropriate for taking pics?

I would like to buy the EP if it works, but I would like to be sure before I spend the money. There are many other accessories on my wish list .

Thanks for the help!

[Cornelius Varley]

I have not heard of the Celestron zoom having a t-thread, only the more expensive Baader zooms. The thread on the Baader is larger than a t-thread (54mm on older models and 43mm on the mark III). Planetary photography with a DSLR is difficult, the best camera to use is a webcam or similar type of camera with a small sensor and a 2x or 3x barlow. For DSOs I would connect the camera directly to the telescope using the built-in t-thread and not use an intermediate lens. You should find the coverage provided by the telescope adequate for DSO photography. Also, don't use a diagonal in the imaging path, you may find that with the diagonal there is insufficient focus travel and also the diagonal will degrade the light falling on the camera sensor.

Take a look at this site FOV calculator, it will give you an idea how much focal length is required tio image various objects. Select your telescope and camera and then the object you wish to photograph. Press the submit button and a photographic representation of the object will appear below at the scale it will appear in the camera.

Peter

[Psychobilly]

Popping the rubber eyecup of the end of some of the "budget" 8-24mm zooms reveals.....

a T thread..

Peter...

[brantuk]

Sorry Gustavo - I misread (in fact totally missed) the word Celestron. Pretty crucial really - I was of course referring the the Baader ep's and zoom.

Please scratch my previous reply - think I must have been tired or something

[gustavo_sanchez]

Brantuk,

Don't worry. Thanks anyway for responding. Maybe you can help me now that you know the facts.

Peter,

Thanks for your advice. I will take out the diagonal while taking pics. Also, that site you posted is very nice. I will study it more thoroughly later.

So, if the Celestron zoom EP does have a thread as Psychobilly (thanks to you too!) asserted, does it offer any advantages for taking planetary pictures? Does it being a "budget" EP means that its quality will be too low? Does anyone has used it before? Sorry for all the questions!

[brantuk]

I only have the hyperion zoom and ep's (and camera connectors) so I can't help on the Celestron ones unfortunately

[ollypenrice]

You won't want an eyepiece when shooting deep sky. That is done at prime focus or even with a focal reducer. The faster the focal ratio the better for this.

For the planets you do need to boost the image scale with an EP, Barlow or Powermate.

Olly

[gustavo_sanchez]

That's one of the main things I would like to do, to take planetary pics. So I think I will get one those zoom eyepieces to get started. And since I have an achro refractor, I should get a minus violet filter...

[gustavo_sanchez]

I just got the Celestron zoom eyepiece, and as hoped, it fits directly the camera t-ring adapter. I just need to wait until I can get the equipment outside and see how it works...