Best way to Barlow DSLR on 200P

[Marci]

Wotcha folks... am looking to purchase a suitable Barlow to use with EOS650D on a Skyliner 200P.

Ideally with the ability to still use 2" filters.

Was planning on replacing the native 200p dslr mount with https://www.firstlightoptics.com/adapters/baader-protective-t-ring-for-canon-eos.html

Any suggestions from those in the know?

[Charic]

I attached my D5000 to my Skyliner yesterday and in order to get some focus, I used the following 'parts'  -  dedicated Nikon T-ring adaptor, the body/threaded adaptor off mySkywatcher Deluxe Barlow, with the extension tube and Barlow off my Meade #140 Barlow, in order to achieve focus. This is for my 1.25" setup!

I've no doubt a similar or better option is also available in the 2" format.

[Marci]

I'm looking at http://www.rothervalleyoptics.co.uk/skywatcher-x2-super-deluxe-ed-barlow-lens-2.html at the mo... figuring dismantling and attaching to previous linked Baader EOS Protective T adapter will do the trick... 

does this seem a sensible approach?

[Charic]

I don't see a screw thread to attach the Barlow to the camera with the 2" you've linked too ?

Looking at the cheaper 1.25" £27 lower down in the link (it's the one I'm using, look closer and you'll see its threaded at both ends). Whatever you use, it needs to make a  secure physical connection between the T-ring and the scope. That said, you could just use a dedicated extension tube attached to the T-ring, which in-tern slots into the Barlow, like a normal eyepiece. 

Someone else here at the SGL might also  have the 2" variant, maybe they can disclose how its connected to the camera's T-ring.

[sophiecentaur]

I have been trying to get pictures of Jupiter with my DSLR. Not big enough with my 800mm refractor and X2 barlow. From what I am reading, the idea of eyepiece projection seems to be out of fashion. It's even worse in my case because I only have 2" eyepieces and the hardware doesn't seems to be obtainable except at huge cost. So I need a more powerful barlow (x5) which would fill the sensor better. The question is whether to buy a much cheaper X5 1.25" barlow or a 2" X5. With a 1.25" I would need a different T Ring adaptor  for that - but they aren't too expensive - and couldn't use my 2" eyepieces.

Also, the Powermates seem to be highly recommended but pricey. Any opinions about that?

[Shibby]

Can I just ask, what is your goal with the barlow + DSLR? If you're planning on planetary imaging, it would be easier to image with your webcam or QHY5.

Alternatively, if you're using the barlow to achieve focus with your DSLR for DSO imaging, then it will be very challenging indeed imaging at such a long focal length and almost F/12 optics...

[sophiecentaur]

On 10/05/2017 at 12:17, Shibby said:

Can I just ask, what is your goal with the barlow + DSLR? If you're planning on planetary imaging, it would be easier to image with your webcam or QHY5.

Alternatively, if you're using the barlow to achieve focus with your DSLR for DSO imaging, then it will be very challenging indeed imaging at such a long focal length and almost F/12 optics...

Thanks for the response.

My dslr is 20Mps and the sensor is half frame. I don't understand how a webcam would do better than that. Have I missed something? The camera is a pretty new design; no change to the filtering on it though as I want to happy snap the family too.

I wasn't planning on imagining  faint DSOs at high magnification - just what should be attainable with an 80/500 scope. (According to what I have found on SGL etc.)

I have no problem with planning to spend money on advanced things, once I have seen the inadequacies of what I have and the DSLR has produced some very nice images of 'easy' stuff so far. Problem about other cameras is that I don't use a laptop and I use Apple computing stuff. Bit of a double whammy at present.

[Shibby]

3 hours ago, sophiecentaur said:

I don't understand how a webcam would do better than that. Have I missed something? The camera is a pretty new design; no change to the filtering on it though as I want to happy snap the family too.

Planetary imaging is a completely different beast to anything that you'll do with a DSLR. The best images of planets (and the moon) are taken with stacked, high framerate video. Take a look at the planetary imaging forum for a wealth of information.

The sensor size is pretty irrelevant as, even with barlows, planets will not fill the smallest of sensors. Pixel size is more important (and bear in mind that a colour DSLR effectively has lower resolution due to the bayer matrix). I'm no planetary imager myself, but I would imagine your QHY5 + filters will likely be the best tool for the job.

[sophiecentaur]

On 11/05/2017 at 17:23, Shibby said:

Planetary imaging is a completely different beast to anything that you'll do with a DSLR. The best images of planets (and the moon) are taken with stacked, high framerate video. Take a look at the planetary imaging forum for a wealth of information.

The sensor size is pretty irrelevant as, even with barlows, planets will not fill the smallest of sensors. Pixel size is more important (and bear in mind that a colour DSLR effectively has lower resolution due to the bayer matrix). I'm no planetary imager myself, but I would imagine your QHY5 + filters will likely be the best tool for the job.

I realise that results will be limited but I should be able to get at least something better than I have managed  so far. I take your point about the Bayer matrix but the element size is around 4 microns, which is not too glubby. There is no anti alias filter either; the sensor is jiggled around if you have moire problems. And, of course, once I am hooked on Imaging, my spending priorities may change and who knows what I will 'have to' buy.