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Celestron 6SE and ZWO 224 camera colour

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#1 Gamewarden

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Posted 22 October 2019 - 08:42 AM

Folks

 

I have decided to purchase the ZWO colour 224 camera for my 6SE scope. My intent is to remotely operate the scope from my back deck, less than 20 feet from inside. I have CPWI and wifi portal for scope control.

I am wondering what if any additional spacers etc I will need to achieve back focus with this setup. 

I have a 6.3 reducer to replace the visual back so the camera will just fit next to this  or will I need additional spacers. Just looking to get started, I will fiqure out filters, focus motor and Starsense etc later.

I do have a long USB 2 cable to bring camera data inside to my laptop. Not using USB 3 yet.

 

I also have SharpCap pro.

 

Thanks for any input.

 

Mark



#2 mclewis1

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Posted 22 October 2019 - 01:27 PM

You'll need some form of spacers between the reducer and your camera. Which model ZWO 224 do you have?
 
Ideally you want something very close to 105mm measured from the back shoulder of the reducer (a nice edge to measure from) and the sensor in your camera. You can however use a variety of spacings and you might find it fun to try out what came with your scope and use the following setup - C6 > reducer > 1.25 visual back > 1.25" diagonal > 1.25" nosepiece and camera.  This will give you something in the area of 100mm of spacing so you won't have exactly .63x reduction but it will be close enough to try it out.

 

Commercial SCTs have a huge range of focus so you'll have "enough backfocus" but you may have to twist that focus know quite a bit when first using the reducer. Start with a low power eyepiece in the same configuration, get the object centered and then replace the eyepiece with the camera. Ideally start with the moon or a bright star. Use a short exposure setting with the gain turned up and then bring the gain down if the object is blown out. Then carefully focus and now go looking for interesting stuff to view.


Edited by mclewis1, 22 October 2019 - 01:28 PM.


#3 Gamewarden

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Posted 23 October 2019 - 06:53 AM

Have not bought the camera yet but was looking at the ZWO ASI224 colour. When I get the camera I want to have whatever spacers I need so it will be useable right away. Then learn from there, thanks for the response.



#4 mclewis1

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Posted 23 October 2019 - 01:59 PM

The numbers you'll need to keep in mind are the 12.5mm sensor depth (measured from the front edge of the camera's body) or 7.5mm measure from the bottom of the T threads on the camera.

 

If you don't want to use the diagonal setup then a good option is the Celestron SCT T-adapter (50mm) and 45-50mm of T thread spacers (the exact number will depend on a number of factors in the seutp, such as how well the spacer threads onto the front of the camera and whether or not the threads bottom out against the camera body). So a little flexibility is helpful here. The T thread (also called T2) spacers come in a variety of widths depending on which vendor's product your looking at. For example with a 30 and 15mm spacer (popular sizes) you'll be close but might want to add something like a small 5 or 7.5mm spacer and try it out. For a bit more money there are also a few variable length T thread spacers so you could fine tune things down to the mm if you felt it was necessary. Another trick that doesn't cost much is to add thin non threaded spacer rings that get sandwiched in between the T threads on the spacers, the allows you to increase the spacing in very small amounts.

 

The T threaded spacers make for a nice solid connection but it will stick out the back of the scope a bit. ZWO also has a neat little T thread to 1.25" filter adapter. This adapter is fitted at the end of the T spacer stack at that camera (it's also sandwiched in between the spacer and the camera threads) and it allows you to add inexpensive 1.25" filters you might want to use.



#5 Gamewarden

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Posted 27 October 2019 - 08:14 AM

Thanks for the input

 

So 105 mm is the distance needed for the optical train? I assume this is to get the correct benefit of the .63 focal reducer. Not sure  I would like using the diagonal as that may come loose with the weight and tend to rotate. Any thoughts on this. But it may help with clearing issues when working at the zenith. More thoughts on these remarks would be helpful. 

 

Thanks Mark



#6 mclewis1

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Posted 27 October 2019 - 11:21 AM

Yes you do need to watch for the diagonal rotating unexpectedly (especially in the cold or when the temps change a lot overnight), so keeping all the bolts tight is important. There are better visual backs available that will hold the diagonal more solidly. Agena astro  has a 1.25" model uses nice big bolts and a brass  compression band and isn't very expensive - https://agenaastro.c...-back-e-15.html . There are also quite a few solid but more expensive options such as the rotational/compression type.

 

An all threaded connection is the best/safest way to go but then it becomes all about the clearance with the fork base.




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