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ZWO ASI1600MM-cooled

So how does this camera compare with my ZWO ASI178MM-cool?Screenshot (87)

The benefits of the ASI1600MM-cooled are:

  1. Larger sensor with larger pixels
  2. Able to image over 30 minutes, particularly when doing narrowband imaging
  3. Very low read noise, down to 1.2e
  4. Larger full well – 20k, compared to the ASI178MMC
  5. Able to cool below ambient more than the ASI178MMC
  6. Able to shorten the back focus distance

The two negatives I can think of are:

  1. Higher price of this imager (not unexpected for larger sensor imaging cameras I might add).
  2. It only has a 12-bit Analog-to-Digital converter (ADC), which may be a deterrent to serious imagers.

Having said that, I have managed to get very nice astroimages with my Olympus E-PL5 which also has a 12-bit ADC, so I suppose only time will tell how I fare with it for astroimaging. It is going to be the assessment of the imaging results that will tell the true story.

Now another product that ZWO came up with was a tripod collar mount for their ZWO cooled cameras. I did not manage to borrow one of these, but it so happened that my friend had loaned me his Canon 300mm F4 L IS lens with its tripod collar mount a while back to use for astrophotography. Hence I took out the tripod collar mount, to see how it compared with the size of the ASI1600MM-cool and was pleasantly surprised to noted that it fits the ZWO cameras perfectly.

Canon 70-200mm F2.8 and 300mm F4 L IS lens tripod collar mount adapter
Canon 70-200mm F2.8 and 300mm F4 L IS lens tripod collar mount adapter

Researching into this showed me that the Canon Tripod Mount Ring B for the 70-200mm F2.8 lenses, 100-400mm F4.5-5.6 L IS and 300mm F4 L IS, has an internal diameter of 78mm, so is perfect for the job of holding the ZWO cooled cameras if you can’t get hold of the ZWO tripod collar mount or already have one of these in your possession.

As I have a thin T2 to Nikon F adapter, I’ve used this together with my Xagyl motorized filter wheel and connected my Coastal Optics 60mm F4 APO to the ZWO camera. With this combination, it is possible for me to achieve infinity focus even with my ZWO ASI178MM-cool; so there was no need to take off the T2 female to T2 female adapter from the ASI1600MM-cool and shorten the back focus distance.

Mounted on Tripod collar with Xagyl 1.25" motorized wheel, T2-Nikon F adapter, Coastal Optics 60mm F4 APO lens
Mounted on Tripod collar with Xagyl 1.25″ motorized wheel, T2-Nikon F adapter, Coastal Optics 60mm F4 APO lens

Now there are many questions I have about this new camera, and I hope to be able to answer them by doing the relevant tests. So these are the first two tests I did:

Q1. Will there be visible vignetting in the corners with my 1.25″ filters mounted in my Xagyl filter wheel?

As I already own a set of narrowband and LRGB filters, I do not wish to buy a whole new set of larger filters (36mm or larger) just to be able to use this camera.

Hence I setup as above pointing the camera and lens out of my bedroom window at the houses, and ensuring these were in focus. I used Sharpcap for this test, as I am more familiar with this. This was the resulting image.

Vignetting test - no black corners from the 1.25" Astronomik CLS-CCD filter
Vignetting test – no black corners from the 1.25″ Astronomik CLS-CCD filter

Answer: No. There is no visible vignetting in the corners with 1.25″ filters mounted on my Xagyl Filter wheel.

Q2. How much can the sensor be cooled down by, as it is claimed that it can go 40-45 degrees C below ambient?

Cooling test Gain 200 (ambient temperature 22.7 deg C) - Sensor temperature -18.8 deg C
Cooling test Gain 200 (ambient temperature 22.7 deg C) – Sensor temperature -18.8 deg C
Cooling test at Gain 0 (ambient temperature 22.7 deg C) - Sensor temperature -19.8 deg C
Cooling test at Gain 0 (ambient temperature 22.7 deg C) – Sensor temperature -19.8 deg C

Answer: Between 40-45 degrees celsius below ambient temperature, which is definitely better than what my ASI178MMC can do, by about 5 degrees C.

So far the ASI1600MMC does look to be performing as described, and has some pretty impressive specifications. There are other tests I will be doing with this camera, so stay tuned. But it may be a while before I can do Deep Sky Imaging due to work commitments, and the fact I am in the process of installing my upgraded telescope mount.

Boon

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