Neximage 5 – UV imaging

The Celestron Neximage 5 has a UV-IR cut protective window which I removed recently to see if it would solve the Newtonian rings issue with the Daystar Quark. Now that it does not have this window, I thought it would be worth testing its UV-imaging capabilities.

Now the Neximage 5 has 3 Philips screws holding the cover on. Once this is removed, you will be met by 4 smaller Philips screws (one has some glue/resin in it). Removing these were straight forward despite the resin/glue in one of the screws.

Neximage 5 - 3 Philips screws to remove to get to the circuit board
Neximage 5 – 3 Philips screws to remove to get to the circuit board
4 Philips screws to remove to get to the protective UV-IR cut window
4 Philips screws to remove to get to the protective UV-IR cut window

Then it is just the case of breaking the UV-IR window and putting the camera back together. I did not take a picture of the window in place, a I only thought about this afterwards.

Neximage 5 sensor without protective window
Neximage 5 sensor without protective window

So the next step is to mount the lens onto the camera,which I did via a few different adapters. But there are C-mount to Nikon F adapters available to allow for Coastal Optics 60mm F4 APO or UV Nikkor 105mm lenses to be used; but with a 6x crop factor, I would use the 35mm lens so the focal length does not get too long to work with.

Mounted to 25.5-30.5mm adapter, 30.5-52mm, 52mm-42mm, M42 focusing helicoid, Petri 35/3.5 lens
Mounted to 25.5-30.5mm step-ring, 30.5-52mm step-ring, 52mm-42mm step-ring, M42 focusing helicoid, Petri 35/3.5 lens with 46-49mm step-ring and 49mm Xume magnetic adapter

As the Neximage 5 does not have a tripod mount, I decided to use my Novoflex M43 tripod mount to fit onto the M42 focusing helicoid. Do be aware that the focusing moves the camera away from the subject rather than the lens closer to the subject with this setup.

Mounted onto Novoflex tripod mount
Mounted onto Novoflex tripod mount

Finally the image I captured of one of the Marigold from my back garden, just to show the UV-dark center. I used the iCap program from Celestron to capture the image. This was captured as jpeg, although iCap gives the option of saving as tiff or bmp files; unfortunately both DXO Optics Pro 7 and Capture One Pro 8 could not read the tiff file. I used a gain of 5 (lowest possible is 4), f8 aperture on the lens and 1/2 power from my Quantum X2D flash, so there is plenty of latitude to allow imaging of more UV-dark subjects.

Interestingly I was able to boost the gain up to 30 and still not see any horizontal banding of the image like I did when doing H-alpha solar imaging, so there is possibility of boosting the signal gain if required.

Neximage 5, Petri 35/3.5, Baader U, Gain 5, f8 1/2 power from Quantum X2D
Neximage 5, Petri 35/3.5, Baader U, Gain 5, f8 1/2 power from Quantum X2D

Now this opens up many possibilities:

  1. It would be great if these astrophotography cameras could be made to work with an iPhone/Android/tablet device, so we do not need a computer to use them to capture images. We just need someone with the capabilities to produce this.
  2. There are so many different cameras out there available second hand which are easy to modify compared to DSLRs and mirrorless cameras, and can be easily adapted to work with lenses (even C-mount ones).
  3. There are mono CMOS cameras available with relatively large sensors e.g. ZWO ASI174mm 1/1.2″ 3x crop sensor, which would allow for maximum sensitivity to UV due to the lack of the Bayer layer. And the protective window is easily removed, which will allow for the imaging in UV of Venus. No need to try and debayer a camera sensor.

Boon