Improving the view - ZWO ADC

[chiltonstar]

After a lot of thought, I bought an atmospheric dispersion corrector - as usual FLO were prompt and efficient!

Fortunately, it came with a clear night or two, so I tried it out on Jupiter and Saturn two nights ago, and compared it to the view without the ADC in place using my 180 Mak.

Set-Up: easier than I thought, a quick read of the online manual, and five minutes making sure it was aligned.

Jupiter (14 degrees altitude): without the ADC, strongly chromatically fringed above and below, GRS visible just, banding not that clear and slightly chromatic. With the ADC, now perfectly fringe free, the banding much better contrast (refractor like), and the moons sharper and the true diameter of Ganymede visible. The GRS looked no different (but it is of course one colour only).

Saturn (9 degrees altitude): without ADC, muddy, heavily fringed above and below, Cassini just visible at the extremities. With ADC, no false colour, Cassini visible much further round than before. The view a bit fainter though (ADC absorbs some light).

So far, I'm impressed - next stop an image or two!

Chris

[Stu]

Stop it Chris, you will have me buying one for the third time! I've just never got on with them, or even enough difference to be worth the hassle, but your results clear suggest there is a benefit to be had. Look forward to more reports.

[Ibbo!]

After i finished imaging staurn this morning I put an eyethingy in the end of the scope (but don't ell anybody) and had red fringe and blue fringe and thought you idiot use the ADC it is set for imaging and lo and behold the fringing vanished as if by magic even with x285

[chiltonstar]

22 minutes ago, Stu said:

Stop it Chris, you will have me buying one for the third time! I've just never got on with them, or even enough difference to be worth the hassle, but your results clear suggest there is a benefit to be had. Look forward to more reports.

I was surprised (shouldn't have been) by the increase in line detail, eg Cassini and J's belts -I suppose light is bleeding up and down into detail like this.

I suppose the benefit may depend on scope type and fl.

Chris

[Craney]

1 hour ago, chiltonstar said:

- next stop an image or two!

Yes, it would be good to see photographic evidence of the device's effectiveness.

I'm on the fence,  but so is Jupiter and Saturn from my back garden....!!!

[John]

Interesting report Chris.

I could not see clear effects from atmospheric dispersion last night when observing Jupiter but I guess it was making some impact even if the false colour was not obvious.

 

[chiltonstar]

16 hours ago, John said:

Interesting report Chris.

I could not see clear effects from atmospheric dispersion last night when observing Jupiter but I guess it was making some impact even if the false colour was not obvious.

 

I normally see it (visually) at say x175 and more, certainly reasonably obvious at x190. Looking at recorded AVIs of Jupiter with and without the RGB align function in Registax or Autostakkert shows the extent of the fringing very convincingly!

Chris

[chiltonstar]

18 hours ago, Craney said:

Yes, it would be good to see photographic evidence of the device's effectiveness.

I'm on the fence,  but so is Jupiter and Saturn from my back garden....!!!

There are quite a few image examples on the ZWO website and references given there. I am more of a visual observer so what I see is more important to me, and of course I can't mentally RGB align the way software does on a recorded AVI, so an ADC seems the obvious choice!

Chris

[Cosmic Geoff]

When imaging low planets, I found that the images had colour fringes, which could be taken out to a degree by aligning the red & blue separately in processing.  The dispersion amounts to a lot more than the nominal resolution of the telescope.  I read that an ADC would do it better, and indeed it does. No contest.