DSLR on 127 MAK?

[Nomad Z]

Not looking to do serious AP, but would like to get an idea of what's feasible for better 'happy snaps' than holding a phone or digi compact over the eyepiece for lunar and white light solar stuff.

The astro equipment is a Skywatcher 127 MAK with a Baader prism diagonal (and BST EPs), on an EQ3 goto mount.

I also have a Canon EOS 30D DSLR (APS-C crop frame, no live view) with a remote release cable. I'm interested in using this for prime focus photography.

Can I get a T2 adapter for the camera and a 1.25" nosepiece, stick it on the diagonal, focus through the camera's viewfinder, pick a shutter speed, and take photos? Would I need to remove the diagonal and maybe (or not) use an extension tube? Is there likely to be an issue with the size of the sensor and being able to get things like the sun and moon to fit? (Projecting 0.5° over 1500mm gives 13.1mm, which is a bit smaller than the sensor's 14.8mm height, but maybe marginal enough to be a possible concern?)

Basically, can I do it cheap and easy, or is this likely to get rather involved and expensive?

 

[Cornelius Varley]

The best option is to remove the diagonal and attach the camera using the t-thread on the small extension tube and t ring.

[JohnSadlerAstro]

It won't really be necessary to keep the diagonal in the optic train, it will only cause a bit of false colour. As Peter says above, you would most likely need to use an extension tube, as the diagonal obviously adds quite a lot of outwards focus when it's in place.

FOV wise, you should be ok, I haven't got experience of a scope with that long a focal length, but my 130pds is about half that length, and with my 1000d the moon and sun are really quite small, probably about 1/3 - 1/4 of the image width.

FLO runs an extremely useful set of calculators, including a visual/imaging FOV calculator. I'd suggest you try putting your scope and camera into it and see what you get!  

http://astronomy.tools/calculators/field_of_view/

This is what I got when I put your kit in:

John

[Mr niall]

I've done that - works well for the moon, some of the brighter doubles are achievable too which are quite pretty.

The only thing you need to buy isthe T2 ring - as the 127 has the right threads on the back already - you dont need the nosepiece. You can get Canon EOS T2 adaptor rings for about £7 on ebay.

Below is one I took using this method on the 127's little brother (skymax 90). Its a great way to get started (this is just a super low res version, full version looks better but you get the idea)

[Nomad Z]

Thanks all.

John, that looks just about what I expected with my quick calculation of 0.5° at 1500mm (ie, just fits with a bit of wiggle room).

I found an EOS T2 adapter with a (removable) nosepiece for 7 quid, so ordered that. Also found a set of T2 extension tubes which go from 5mm to 50mm in various stacks. Enough to be playing around with, I think.

[JohnSadlerAstro]

With that kit you will be fine, and with an EQ3 there should be plenty of headroom for some DSOs, as well--brighter but smaller objects like trapezium in M42, and M27 (Dumbbell). (Although it depends on how willing you are to go down the mine shaft of astrophotography! ) 

I would recommend using the extension tubes so that the focuser isn't far from being pushed all the way in, when the camera is focused. That way, the focuser barrel and assembly will be shorter and  hopefully able to take the weight of the camera far easier. Theres nothing worse that a half kilo camera on far the end of a focuser at maximum extension! ? 

Do post your results, it will be interesting to see how accurate the FOV calculator is!  

John

[Andywilliams]

I put my cameras directly on to the scope via and adapter (as below) and here are some of my results. good luck ?