AVX 6" Newtonian... Is it a bird-jones design?

[Herzy]

Well the title basically says it all... I'm looking to get a AVX 6" Newtonian Telescope but I don't know how to identify a bird-jones design. If anyone has this scope please tell me if it is indeed a bird-jones.

[John]

I believe it's a conventional F/5 newtonian with a parabolic primary mirror. That would match the specifications that Celestron publish:

http://www.celestron.com/browse-shop/astronomy/telescopes/advanced-vx-6-newtonian-telescope

 

 

[brantuk]

Far as I know the AVX is the Celestron mount that replaces the old CG5GT mount - nothing to do with the scope - but it is a good mount. You can then get a Newtonian scope to put on it if you want. Or you could get the Celestron Advanced VX 6" Newtonian package like this one which combines the two:

http://www.celestron.com/browse-shop/astronomy/telescopes/advanced-vx-6-newtonian-telescope

You would need to check with the supplier that it isn't a Bird Jones design, which uses a spherical mirror and a correcting lens in the focuser tube. In the one I linked to it uses a parabolic mirror (which is better for focusing) - so not likely to be Bird Jones design. But if in doubt just ask the supplier - and familiarise yourself with the Bird Jones design first so you can tell if the supplier is being straight with you. Hth

Woops - crossed with John again

[Chris]

Hi, I have this telescope and it's a parabolic f/5 Newtonian

I think Bird Jones designs tend to have higher f-ratios. They get around aberrations created by spherical mirrors by placing a barlow inside the focuser somewhere in order to increase the f-ratio to the point where aberrations get reduced to an 'acceptable' level (well I think that's the idea?).

My CN-6 Newt is definately F/5, and there isn't anything in the focuser other than the view of the secondary mirror

The scope has a very basic 1.25" R&P focuser, but if you can live with that it's great value for money

 

 

 

[Herzy]

Thanks everyone! As for Chris, I plan on upgrading the focuser in the future.

[Alan64]

If you're wanting an AVX mount, purchase it separately and along with this model...

http://www.highpointscientific.com/celestron-omni-xlt-150-newtonian-reflector-optical-tube-assembly-ota-31057ota?utm_source=google&utm_medium=cse&utm_term=CEL-31057-OTA&gclid=Cj0KEQjw5Z63BRCLqqLtpc6dk7gBEiQA0OuhsPl-XdYVIwTnIEOdC-Mg29AVYiEyjdM_w66wwPvIn-EaAoCV8P8HAQ

It comes equipped with a 2" focusser, and with no need to upgrade.

[Chris]

4 hours ago, Alan64 said:

If you're wanting an AVX mount, purchase it separately and this along with it...

http://www.highpointscientific.com/celestron-omni-xlt-150-newtonian-reflector-optical-tube-assembly-ota-31057ota?utm_source=google&utm_medium=cse&utm_term=CEL-31057-OTA&gclid=Cj0KEQjw5Z63BRCLqqLtpc6dk7gBEiQA0OuhsPl-XdYVIwTnIEOdC-Mg29AVYiEyjdM_w66wwPvIn-EaAoCV8P8HAQ

It comes equipped with a 2" focusser, and with no need to upgrade.

I wish you could buy the OMNI xlt OTA seperately over here, they only seem to come packaged with a CG4 mount this side of the pond.

It's probably worth getting that one for the xlt coatings as well as the 2" focuser

[Alan64]

Ah, but you may, you most certainly can, if you don't mind black in the blue's stead.  This one is exactly the same, save for the colour of the optical tube...

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ota.html

But I'd go with this one, for only a little more, and for its two-speed 2" focusser...

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-ota.html

The "DS" variant is also ideally configured for imaging to boot.

 

I have the one that comes bundled with the AVX, and branded "Orion"(U.S.)...

The plastic focusser, as it comes, is wretched.  I've had to do a good deal of work on it just to make it decent.

All four mentioned are made by Synta in China, and most probably in the same factory.

[Alan64]

Herzy,

You can also get Synta's 6" f/5 Newtonian with the two-speed 2" focusser, if you don't mind ordering it from Canada.  This is just one of several Canadian dealers who carry it...

https://www.kwtelescope.com/telescopes/reflectors/sky-watcher-bkp-130-otaw-dual-speed.html

I ordered a telescope from Canada last September: $25 shipping.

 

[happy-kat]

If it were to be used for imaging would a dslr reach focus?

[Chris]

3 hours ago, Alan64 said:

Ah, but you may, you most certainly can, if you don't mind black in the blue's stead.  This one is exactly the same, save for the colour of the optical tube...

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ota.html

But I'd go with this one, for only a little more, and for its two-speed 2" focusser...

http://www.firstlightoptics.com/reflectors/skywatcher-explorer-150p-ds-ota.html

The "DS" variant is also ideally configured for imaging to boot.

 

I have the one that comes bundled with the AVX, and branded "Orion"(U.S.)...

The plastic focusser, as it comes, is wretched.  I've had to do a good deal of work on it just to make it decent.

All four mentioned are made by Synta in China, and most probably in the same factory.

Hi, nearly the same but not quite, Synta don't apply the xlt coatings to the skywatcher range. The skywatchers are of course a great alternative, and I dare say most of use over here use these  I've observed and imaged with lots of these over the years, 130pds x3 (I don't know why I sell them as I always end up buying another), 150p, 150pds, and 200p. I've never gone bigger than that though. 

It would be nice if we could buy the OMNI xlt 150mm f/5 Newt OTA alone over here, but there are plenty of alternatives as you say

[Alan64]

31 minutes ago, Chris Lock said:

Hi, nearly the same but not quite quite, Synta don't apply the xlt coatings to the skywatcher range. The skywatchers are of course a great alternative, and I dare say most of use over here use these  I've observed and imaged with lots of these over the years, 130pds x3 (I don't know why I sell them as I always end up buying another), 150p, 150pds, and 200p. I've never gone bigger than that though. 

"Unique enhanced multi-layer mirror coatings made from precise layers of aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and Si02 (silicon dioxide). Reflectivity is fairly flat across the spectrum, optimizing it for both imaging and visual observing." - Celestron

"SKY-WATCHER DELUXE MIRROR COATINGS ... ALL Sky-Watcher reflectors are Multi-Coated with Silicon Dioxide as standard for Optimum Durability and Long Term Performance." -  Sky-Watcher

Until I see concrete proof to the contrary, I must remain skeptical as to said coatings being proprietary and peculiar to Celestron-branded products only.  The "Starbright XLT" mirror coatings reputedly consist of titanium dioxide infused into the aluminum itself,  and the now "enhanced" aluminum coated with silicon dioxide(quartz); but Sky-Watcher's mirrors are coated with quartz, too. 

To me, it's all a marketing ploy, and nothing more.

[Chris]

2 hours ago, Alan64 said:

"Unique enhanced multi-layer mirror coatings made from precise layers of aluminum, SiO2 (quartz), TiO2 (titanium dioxide), and Si02 (silicon dioxide). Reflectivity is fairly flat across the spectrum, optimizing it for both imaging and visual observing." - Celestron

"SKY-WATCHER DELUXE MIRROR COATINGS ... ALL Sky-Watcher reflectors are Multi-Coated with Silicon Dioxide as standard for Optimum Durability and Long Term Performance." -  Sky-Watcher

Until I see concrete proof to the contrary, I must remain skeptical as to said coatings being proprietary and peculiar to Celestron-branded products only.  The "Starbright XLT" mirror coatings reputedly consist of titanium dioxide infused into the aluminum itself,  and the now "enhanced" aluminum coated with silicon dioxide(quartz); but Sky-Watcher's mirrors are coated with quartz, too. 

To me, it's all a marketing ploy, and nothing more.

So as an analogy it's like when Homer Simpson goes to the Duff bear factory and tries all the different bears, but they all come from the same big pipe!

Maybe? I don't see why they would claim a difference if there wasn't? I know someone who would love this question so I'll give them a shout

[John]

1 hour ago, Chris Lock said:

So as an analogy it's like when Homer Simpson goes to the Duff bear factory and tries all the different bears, but they all come from the same big pipe!

Maybe? I don't see why they would claim a difference if there wasn't? I know someone who would love this question so I'll give them a shout

Celestron also advertise their versions of the Synta refractors as having aspheric objective lenses. Any different from the Skywatcher versions as they are all made by the same manufacturer ?. I wonder ......

 

[Skyline]

The nice thing about the OmniXLT reflector is the mirrors are supplied to a higher grade, maybe the correct word is better 'figured' slightly better contrast when imaging. Also the mirror suffers less in spherical aberration, you can see the effect around bright stars. Hence the reason for higher price tag. Also the QC has always been better then other brands out there.

One thing is a definite Celestron have been in this telescope manufacturing game for a long time, longer then skywatcher, so they must know a trick or two when it comes to commercial mirror manufacturing and coatings. Some more information about StarBright XLT coatings.

http://www.celestron.com/university/astronomy/starbright-xlt-optical-coating-system

The Bird Jones design is much shorter in overall length wise.

[Alan64]

A most interesting read... http://company7.com/celestron/index.html

Years ago, Dobsonians with high-quality optics were branded "Celestron" as "Star Hoppers", from 1995 to 2000; but the mirrors within were made by Discovery Telescopes...

http://www.discoverytelescope.com/discovery/pdhq.html

[Herzy]

Is it really worth the extra $120 for a better focuser and some other additions? $100 for a 150mm Newtonian is certainly a bargain. I have like $920 atm so if I bought the AVX alone I wouldn't be able to buy an optical tube with it for a few months. However if I do just buy the AVX C6-N ($900)) I will be fully equipped to start imaging with some coma issues.

[Alan64]

Woodland Hills, there in the States, sold the C6N optical tube for $180 for a while, but no longer; surplus factory stock, I imagine.  So, you'd be getting the C6N 6" f/5 for $80 less, and for visual primarily if not exclusively.

Astronomics of Oklahoma makes no mention of the C6N being capable of prime-focus imaging however; only "piggy-backing"... https://www.astronomics.com/celestron-6-newtonian-advanced-vx-mount_p20046.aspx

But there is the capability of afocal astrophotography, and web-cams, if the wind isn't blowing.  The size of the optical tube would act as a sail, catching every breeze and throwing the tracking off, making the images soft and blurry.  Although, for prime-focus astrophotography, with a DSLR attached in place of the eyepiece, you'd need at least an EQ6 or EQ8 to image with a 6" f/5 Newtonian, preferably the latter...

 

That is, if the base C6N OTA bundled with the AVX is capable of reaching focus with a DSLR in the first place, which is doubtful.

The stated budget, whilst considerable, is quite limiting for an imaging set-up; although adequate for a visual kit, and that's what the C6N/AVX bundle is in fact.  For DSO-imaging, you'd need something along the lines of this with the AVX...

https://www.astronomics.com/astro-tech-at72ed-72mm-refractor-telescope-white-gray_p18452.aspx

You can use the C6N/AVX kit for visual -- and perhaps some casual, short-exposure astrophotography -- whilst saving up for a fast 60mm to 80mm ED or apochromatic refractor.

If imaging is your primary goal, you'd have more success with this 5" f/5 Newtonian instead... https://www.kwtelescope.com/telescopes/reflectors/sky-watcher-bkp-130-otaw-dual-speed.html

But since that telescope would eat up a goodly portion of the budget, you could opt for this EQ5-class go-to equatorial instead... http://www.bhphotovideo.com/bnh/controller/home?O=cart_accessories&A=details&Q=&sku=1124463&is=REG&bundleId=1124463REG

That one could be tuned in future, improving its performance, but the AVX requires a trip to a vendor for tuning.  All of these mounts are made in China, and require some or a lot of tweaking once they arrive.