Adaptors for QHY8

[GyCx]

Hi All.

Can anyone tell me what adaptors I need to attach a QHY8 onto a Celestron C11 OTA (non edge)

Many thanks.

 

[misterp]

Hi,

 

Just a t2, 2” nosepiece I think

https://www.firstlightoptics.com/adapters/baader-2-t-2-nosepiece-and-camera-adapter.html

 

ian

 

[michael8554]

Assuming it comes with a 2' visual back then Ian's suggestion will work.

But imaging at 2800mm  I'd suggest you need a much more rigid attachment , such as a SCT thread to T2,  that will give screwed arrachment  to the whole imaging chain.

Michael

[GyCx]

Would I also have to extend to achieve focus?

[GyCx]

Just tried the SCT - T2 it fits the camera. Not sure if this will need an extension tho. Going to try to get focus tomorrow.

[michael8554]

Most SCTs have a huge focus range so shouldn't be a problem.

Try during the day on a distant landmark to get you in the ballpark.

Ah QHY8 not dslr, might be too sensitive for daytime.....

Michael 

[blinky]

You wont need an extension - I use my QHY8 with an SCT, I use a SCT to 2" Adapter

[JamesF]

On 25/05/2018 at 19:47, GyCx said:

Would I also have to extend to achieve focus?

No.  SCTs focus by moving the focal plane to the sensor position rather than moving the sensor position to coincide with the focal plane, so as long as your sensor is somewhere relatively near to where focus would be with an eyepiece (even several centimetres out should be fine) you should get focus.

However, there has been discussion in the past about the optimal sensor position based on where the SCT produces the best-corrected image.  I can't recall the position for a C11 (I'd guess something like 40mm to 50mm behind the visual back?), but generally I think it's roughly where you'd expect an eyepiece to need the focal plane to be (which I think is also where the OTA actually has the quoted focal length, because that varies depending on the focus position too).  I believe the figures for all the Celestron SCTs are online somewhere.  Having an extension to put the camera sensor in a similar position should give the most optimal result even if you can get focus elsewhere.

James

[GyCx]

C11	5.475 in from 3 in-2 in Reducer Plate  5.975 in from 3 in Primary Mirror Baffle Tube Lock Ring

[GyCx]

Celestrons site saying 5.475  im using a SCT camera adaptor, the standard 'Celestron' adaptor