ADC and 3x barlow

[KnkTheBest]

Hello, I was looking to buy the 10in skywatcher synscan dobsonian to pair with my ZWOASI 120MC-S. I have decided to buy the ZWO ADC and the Celestron X-cel 3x barlow for this dob and camera. The telescope itself has a focal length of 1200mm but with the barlow will have 3600mm. I wanted to know how much focal length it would increase by, if I then added the ADC. Is there any easy way to calculate this, and is the resulting focal length too much or too less to get the best results while imaging? Thanks!

[Cosmic Geoff]

28 minutes ago, KnkTheBest said:

I wanted to know how much focal length it would increase by, if I then added the ADC. Is there any easy way to calculate this, and is the resulting focal length too much or too less to get the best results while imaging? Thanks!

Depends if you add the ADC before or after the Barlow lens.  The increase in focal length isn't x3 anyway, it depends on how far the camera or eyepiece is from the Barlow lens.   I think that you will find that 'best focal length' is a rather variable concept in practice.

[KnkTheBest]

Thanks for the reply, does the image quality depend on if I put the ADC before or after the barlow?

[bosun21]

The ADC is recommended to be the last piece of equipment before the camera or eyepiece. I've never tried it in any other arrangement though to compare.