First light, Orion Optics CT8

[iantaylor2uk]

Tried out my OO CT8 for the first time last night. Used a ZWO 071 Pro MC camera, but did not use a coma corrector or UV/IR filter, just to see what the raw images looked like. Not surprisingly, towards the edge of the image I could see the effects of coma, so will need to use a coma corrector if I want to use the whole of the sensor. Took 100 shots each, at 30 second exposure, of M51 and NGC4565 (with sensor cooled to -5C) to see what it could do. I did collimate the telescope before use, and took calibration frames. The best 80% of frames were stacked in DSS and then processed in Nebulosity 4. The images below are crops, but looks pretty good to me for a first outing, and not bad for just 40 mins or so of integration time for each object. I used an ASI Air Pro on a Losmandy G11 for autoguiding, dithering, etc.

 

[RolandKol]

Hi  mate,

Any updates? Any new Images with CC?

How is the primary colimation between the sessions or meridian flip?
How is the default focuser? Any tilt with heavier (for example, Mono setup?)

Asking, as planing to upgrade my 130 PDS.

 

 

[iantaylor2uk]

Sorry no more recent updates - i've mainly been using the CT8 for visual, as I've been getting great results from my Tak TSA 102 refractor, which is a similar focal length. Was also getting some strange halos on some of the stars with the CT8, not sure if that was the L-enhance filter or something else. 

Once the nights get shorter in the UK I may try again with the CT8 as it's lower f ratio is definitely an advantage. 

 

[ONIKKINEN]

2 hours ago, iantaylor2uk said:

Sorry no more recent updates - i've mainly been using the CT8 for visual, as I've been getting great results from my Tak TSA 102 refractor, which is a similar focal length. Was also getting some strange halos on some of the stars with the CT8, not sure if that was the L-enhance filter or something else. 

Once the nights get shorter in the UK I may try again with the CT8 as it's lower f ratio is definitely an advantage. 

 

Does the CT8 come with the same focuser as the VX8?

Looks like this, might even be this but without the logo: https://www.firstlightoptics.com/astro-essentials-focusers/astro-essentials-2-dual-speed-low-profile-crayford-focuser-for-newtonian-telescopes.html

If that is the case then i can answer parts of the question below.

On 13/10/2022 at 14:34, RolandKol said:

Hi  mate,

Any updates? Any new Images with CC?

How is the primary colimation between the sessions or meridian flip?
How is the default focuser? Any tilt with heavier (for example, Mono setup?)

Asking, as planing to upgrade my 130 PDS.

 

 

This particular focuser is ok, workable for light loads. But not ideal for imaging and wouldnt recommend for heavy mono setups. For ease of use and reliability i would recommend a better one, like the Baader diamond steeltrack. Will need to drill holes for it, but you could ask Orion optics to install one from the factory and they might comply. Drilling the holes is not rocket science however and is easy to do yourself.

[ollypenrice]

In both images the right hand side looks OK while the left shows elongation radiating roughly from the centre.  I don't know what would explain this but I'd bear it in mind while trying to sort the telescope out.

Olly

[RolandKol]

22 minutes ago, ollypenrice said:

In both images the right hand side looks OK while the left shows elongation radiating roughly from the centre.  I don't know what would explain this but I'd bear it in mind while trying to sort the telescope out.

Olly

yep  
kinda strange... No heavy CC and EFW and the tilt is very visible...

 

[ollypenrice]

1 hour ago, RolandKol said:

yep  
kinda strange... No heavy CC and EFW and the tilt is very visible...

 

 

[ollypenrice]

Just now, ollypenrice said:

 

I did wonder about tilt but felt that tilt tends to give fairly parallel elongation whereas this is radial. On the other hand these anomalies rarely follow simple logic, alas.

Olly

[ONIKKINEN]

5 hours ago, RolandKol said:

yep  
kinda strange... No heavy CC and EFW and the tilt is very visible...

 

If its the same focuser that my VX8 had, its a strong recommendation from me to get rid of it. If the CT8 has the same secondary spider that the VX8 has (looks like it in photos), same story. Not sturdy.

[RolandKol]

6 hours ago, ONIKKINEN said:

If its the same focuser that my VX8 had, its a strong recommendation from me to get rid of it. If the CT8 has the same secondary spider that the VX8 has (looks like it in photos), same story. Not sturdy.

it looks like the only solid newtonian option at the moment, -  TS Photon ONTC sub-brand.... At least I was not able to find anything what looks better on paper and from user experience.

Btw, which uses Orion's Optics mirrors