TS/GSO 150mm F4 Imaging Newtonian

[laser_jock99]

I bought this scope to test as a fast, widefield imaging scope, having already owned and used the larger 8" F4 and 12" F4 GSO scopes. In this respect the smaller OTA was the same build quality as it's larger cousins and seems to be of reasonable mechanical standard.

http://www.teleskop-express.de/shop/product_info.php/language/en/info/p4762_GSO-6--Imaging-Newton---150mm-Oeffnung-f-4---2--MONORAIL.html

The scope comes with a nice standard 10x50 finder, 50mm 2" extension tube, 1 1/4" adapter, tube rings but no dovetail bar this you will have to source yourself if buying this scope. Not only that, it will need to be a longish one- at least 30cm as the focuser and spider bolts 'clutter' the centre of the OTA somewhat! Other accessories that will be required are a collimation tool (Cheshire Eyepiece and/or laser) plus a coma corrector.

The scope is pleasingly compact and might be okay for those considering portable rigs at 58cm long and 4Kg weight. Pictured here on an EQ6 with DSLR attached.

On an imaging scope the quality of the focuser is vitally important and in this respect the GSO scopes have sturdy monorail designs which can handle a good load. I hung the DSLR on racked it out to the fullest extent and pushed & pulled the camera but couldn't make it deflect or bend- a good sign! Another test I performed was checking that the locking screw did not shift the focus when tightened (the bane of my Skywatcher refractors....) again another pass. 

This scope features an oversized secondary mirror (63mm dia) which is needed for fully filling large CCD sensors without undue vignetting. At first glance down the tube it appears surprising large but in reality doesn't block too much light from hitting the main mirror. One notable effect of the large secondary is you can see it when using low power  eyepieces. I tried a 30mm Plossl and found the black blob off-putting. Using higher powers it disappears.

The primary mirror cell features three spring adjusters and three 'locking' screws. I haven't had a great deal of time to dismantle or study this assembly yet- but some tweaking here might be of benefit. Collimating is easy enough with a standard Cheshire Eyepiece. The small adjuster screws are too similar in size though to the locking screws- it's not easy to tell which one you have hold of- something I'll need to change. Tightening the 'locking screws' also changes the collimation - so check the collimation after nipping these up.

[laser_jock99]

Another view of the rear of the scope.

I was afforded about an hour to do any test images and star tests before the clouds rolled in and spoiled the fun!!

But here is one of the first light images - the scope is not well collimated here (I had made the mistake with those 'locking screws') but there's definitely potential to get interesting images. I will post more results as I get them.

NGC7000 300s @ ISO3200 unguided single sub.

[Daniel-K]

Ooo tempted that is a great FOV. Coma sucks though did you have the cc on

[laser_jock99]

Ooo tempted that is a great FOV. Coma sucks though did you have the cc on

Coma corrector was fitted but collimation was way off when re-checked later. I need to get a focusing mask too for this scope- live view in the DSLR proved rather difficult for some reason (possibly the large secondary mirror?)

[frolao]

Hope you can get really nice tests with this scope. Maybe i go for this one to start in AF

[laser_jock99]

Still waiting for the skies to clear for a second go...........

[frolao]

Hi,

Have you tested more this telescope? I'm really curious.

Regards

[laser_jock99]

Only one more imaging session since I brought it! Has been a really bad winter (plus I have other kit to play with!). I really do need to do more with this scope as think I have worked out how to collimate it now.

Rosette Nebula 180s x 5 @ ISO200 & F2.9

M42 Orion 12 x 120s @ ISO1000 Hutech IDAS D1 Light Pollution Filter (from light polluted site).

[Dave_D]

looks rather good where did you get the dovetail? looks like the sort of thing i need.

[iksobarg]

Hellooo! Thanks to laserjock for this thread. Sooo helpful to see and take in the info.

I just got one used for a very nice price! (I think!?)

It's reportedly in fine working order and I should have it within three weeks.

So I'm pretty excited but have to either share my current mount or locate another.

I'd really like to get it on a skyprodigy if that's possible. I do have to look again to see what accessories it comes with.

I hope to share my findings on this used model. More soon!

[laser_jock99]

looks rather good where did you get the dovetail? looks like the sort of thing i need.

Custom made at work from piece of 1" thick aluminium!

[laser_jock99]

Hellooo! Thanks to laserjock for this thread. Sooo helpful to see and take in the info.

I just got one used for a very nice price! (I think!?)

It's reportedly in fine working order and I should have it within three weeks.

So I'm pretty excited but have to either share my current mount or locate another.

I'd really like to get it on a skyprodigy if that's possible. I do have to look again to see what accessories it comes with.

I hope to share my findings on this used model. More soon!

Good luck with the new scope. Invest in some good collimating tools and it should serve you well.

[iksobarg]

Woohoo! http://www.celestron.com/support/knowledgebase?article=http%3A%2F%2Fwww.celestron.com%2Fc3%2Fsupport3%2Findex.php%3F_m%3Dknowledgebase%26_a%3Dviewarticle%26kbarticleid%3D2482%26group%3Diframe&title=Can+the+SkyProdigy+mount+be+used+with+other+telescope+optical+tube+assemblies+%28OTAs%29%3F

[frostynixon]

Thanks for your report! I´m looking for a wider field of view atm and most refractors are rather slow or very expensive. This scope looks like a bargain. Could you do me a favor and estimate the focus position over the tube?

best regards

[laser_jock99]

Thanks for your report! I´m looking for a wider field of view atm and most refractors are rather slow or very expensive. This scope looks like a bargain. Could you do me a favor and estimate the focus position over the tube?

 

best regards

I'm a hundred miles from the scope at the moment so can't check directly- but there is plenty of back focus on these scopes as they were designed with Astrophotography in mind. I moved the main mirror in mine up the tube by 10mm or so by installing bigger springs- so gained a little bit more distance to play with.

What I have found is that collimation is quite critical with these scopes so a quality 2" laser collimator is a must especially at F2.9 (with a reducer).

A selection of more recent images:

IC2117 Seagull Nebula single 227s sub, 150mm Newtonian at F2.9 ISO3200

Witch Head Nebula 1380s ISO2000 150mm Newtonian at F2.9

NGC7000 NA Nebula single 159s sub 150mm Newtonian at F2.9 ISO3200

M45 PLEIADES single 600s sub 150mm Newtonian at F2.9 ISO1000

[alacant]

On 28/1/2015 at 22:44, laser_jock99 said:

there is plenty of back focus

Hi. Hope you don't mind me resurrecting the thread. Am almost ready to pull the trigger on one of these; recent price reduction.

Really need to know: The focus tube position with a dslr attached. How far is it racked out? On the example I tested, it was almost at the end of its -surprisingly- outward travel. Can you confirm?

Cheers TIA and clear skies.

**any chance of re-uploading the photos? Beer on me!

[Demonperformer]

Don't know if this is me, you or SGL, but on both my phone and desktop, all your images are being displayed as attached.

 

[laser_jock99]

23 hours ago, Demonperformer said:

Don't know if this is me, you or SGL, but on both my phone and desktop, all your images are being displayed as attached.

 

Yes- unfortunately Photobucket pulled the plug on free, third party image hosting. At a stroke I (an many millions of other users) lost about seven years of illustrated forum posts. Hundreds of millions of forum posts across the internet suddenly became more or less meaningless as the accompanying photos were gone. I was quite upset about this since on this forum and a few others I had published many 'how to' posts which had more or less become reference threads- now utterly useless......

Photobucket offered everyone the chance to restore third party access for a mere $499 per year (bargain eh?). Needless to say I wasn't going to be blackmailed. The number of Photobucket users has plunged to negligable levels- I'm back on Flikr now.

Anyway- rant over. I'll re-link to some of the 'lost Photobucket images' on Flikr.

 

GSO 6" F4 besides the GSO 10" F4- as you can see it's an altogether lighter, more portable instrument.

 

GSO 6" F4 with DSLR mounted

 

Detail of the sturdy 2" focuser

 

The rear mirror cell- which as usual benefits from upgrading the factory fitted springs.

 

View down the main tube- at F4 the secondary mirror is quite large.

 

In use- typical set up I'm using, GSO 6" F4 with DSLR and Altair Starwave ED80 as the guidescope. All mounted on an EQ6.

 

Some images taken with the GSO 6" F4 Newtonian (images indicated at F2.9 used a ASA Keller 0.7x coma corrector/reducer).

 

 

NGC7000- GSO 6" F2.9 Newtonian, stack of 5x 160s subs @ ISO3200, Fuji full spectrum DSLR.

 

Rosette Nebula- GSO 6" F4 Newtonian, stack of 4x 60s subs @ ISO3200, Fuji full spectrum DSLR.

 

M45- GSO 6" F4 Newtonian, stack of 6x 180s subs @ ISO1600, Fuji full spectrum DSLR

 

Christmas Tree Cluster- GSO 6" F2.9 Newtonian, exposures totaling 1980s @ ISO3200, Fuji full spectrum DSLR

 

Horse & Flame- GSO 6" F2.9 Newtonian, exposures totaling 840s @ ISO1000, Fuji full spectrum DSLR

[laser_jock99]

On 28/12/2017 at 08:34, alacant said:

Hi. Hope you don't mind me resurrecting the thread. Am almost ready to pull the trigger on one of these; recent price reduction.

Really need to know: The focus tube position with a dslr attached. How far is it racked out? On the example I tested, it was almost at the end of its -surprisingly- outward travel. Can you confirm?

Cheers TIA and clear skies.

**any chance of re-uploading the photos? Beer on me!

Can't check the outward travel of the focusing tube right now as the scope is 100 miles away at the moment (although I hope to finally get there tomorow (snow....)).

I did mod the mirror cell of this scope to move the primary 10mm further up the tube (but I have done this to all my Newts as a matter or routine anyway (I don't think the scope manufacturers allow for stuff like OAGs and a coma corrector at the same time!!). But otherwise I have experienced no problems with rear focus.

 

[alacant]

6 hours ago, laser_jock99 said:

Can't check the outward travel of the focusing tube right now as the scope is 100 miles away at the moment (although I hope to finally get there tomorow (snow....)).

Hi and thanks for both your response and the images. The example I tested needed an extension to reach focus with my dslr so any confirmation of the actual position on your example would help me enormously.

Cheers and I hope the snow brings with it clear skies for you.