Any William Optics GT81 owners here? Do you like it?

[Jay6879]

Im looking at picking up a GT81 specifically for astrophotography. Looking for any impressions or opinions from people with experience?

How doy ou like it? Is it a worthy upgrade over a doublet?

[scotty38]

I have one and think it's great although it's my first, and only, astro scope so cannot compare with anything else personally.

One of my last images before clouds etc rolled in:

Edited February 19, 2023 by scotty38

[Jay6879]

12 minutes ago, scotty38 said:

I have one and think it's great although it's my first, and only, astro scope so cannot compare with anything else personally.

One of my last images before clouds etc rolled in:

 

Wow that's a stunning image! Nice stars, don't see any chromatic abberation, good detail on the galaxy. Ok this looks promising! Too bad William Optics doesn't make a 1x flattener for it.

[scotty38]

Thanks, that's also only had the slightest of crops (WBPP Autocrop) so I've not removed anything that doesn't look ok either. Agreed on the 1x too as fi they did I'd probably order one. I have looked at other third party options but never really sure if they'd work so haven't bothered getting one.

[rl]

I have owned several small apo doublet / triplet scopes in the 60mm - 90mm range and my example has the best optics for the aperture of any of them.

Quibbles; The OTA is not the lightest and some people complained of slightly wobbly focusers (early versions only?). The tensions are adjustable, and I haven't hears of this for a while now.

It's been around a long time in various incarnations. WO have a habit of changing the model with the weather (it's called continuous improvement..) so the fact that the GT81 has lasted this long with the optics unchanged probably says something about the commercial benefits of keeping it in production. I paid £450 for my MK1 secondhand ant it's a keeper. 

[Elp]

No GT here, but have owned a z61 for a number of years, optics are super sharp for everything I've put it through (planetary, deep sky, ha solar), visual and photographic, so it speaks for itself.

[Jay6879]

On 20/02/2023 at 03:33, rl said:

I have owned several small apo doublet / triplet scopes in the 60mm - 90mm range and my example has the best optics for the aperture of any of them.

Quibbles; The OTA is not the lightest and some people complained of slightly wobbly focusers (early versions only?). The tensions are adjustable, and I haven't hears of this for a while now.

It's been around a long time in various incarnations. WO have a habit of changing the model with the weather (it's called continuous improvement..) so the fact that the GT81 has lasted this long with the optics unchanged probably says something about the commercial benefits of keeping it in production. I paid £450 for my MK1 secondhand ant it's a keeper. 

This is good to hear! I ended up getting the gt81, it's a newer model that has the rotator built in. Unfortunately it looks like weeks of clouds ahead so Im not sure when I'll get to try it out!

 

 

On 20/02/2023 at 04:51, Elp said:

No GT here, but have owned a z61 for a number of years, optics are super sharp for everything I've put it through (planetary, deep sky, ha solar), visual and photographic, so it speaks for itself.

I also had a Zenithstar 61, fantastic scope that set me down the path of William Optics ownership. They make fantastic scopes. After that came the Zenithstar 81, and now I have the GT81. I just wish there was a 1x flattener for it!

[900SL]

There's a few TS optics 1.0 flatteners fit the GT 71 and FLT 90, so I'm sure they would work on the GT81. 

[iantaylor2uk]

I use a hotech sca 1x flattener on my GT81IV and it works pretty well

[Priesters]

17 minutes ago, iantaylor2uk said:

hotech sca 1x flattener on my GT81IV

Hi,  that prompted me to look it up on Flo and I noticed a review that suggested it needed to be disassembled and reconfigured to make it fit in the focusser.  Did you experience the same or is there an alternative way of adding the flattener into the optical train?

 

[iantaylor2uk]

There are 3 rubber bands on the flattener and you push the flattener in and screw it on and that forces the bands against the inside of the tube to self centre it. The issue with the GT81 is only two of the bands fit inside the tube. I've not found this to be an issue when imaging, to be honest.