Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

GSO 6inch F12 Classical Cassegrain It’s A Winner!

cassegrain catadioptric equipment
  • Please log in to reply
79 replies to this topic

#1 Spacedude4040

Spacedude4040

    Lift Off

  • -----
  • topic starter
  • Posts: 24
  • Joined: 09 Nov 2018
  • Loc: Ontario, Canada

Posted 16 January 2019 - 11:41 AM

GSO 6inch F12 Classical Cassegrain It’s A Winner!

 

I purchased this scope as my Grab & Go set up with high hope on a budget designed telescope.

The picture below is for testing in my observatory on my CGE Pro mount.
The scope arrived on Jan 4th 2019 at 3pm. So yes I have had it out a few times as of this writing.

 

 

IMG_E3561 2222  JPG.jpg
        

I was very happy to receive my new toy a 6” GSO Classical Cassegrain. I can’t believe it’s a new moon weekend with clear skies tonight for testing and 8 Degrees Celsius on January 4th in Canada. WOW! This breaks all the rules of a new Astro toy purchase with the usual two-three weeks of clouds.
I haven’t heard of any one owning this unit in North America, So I might be the only one. smile.gif  And If not probably less than a handful in total are out there.

 

 

Talk of the scope I’ll put this all in point form:
-Fit and finish very nice
-Well packaged
-Collimation off, will tweak with star.
- Was trying to attach the Vixen to a Losmandy dovetail plate to work with my CGE Pro mount. Only to find out this Vixen dovetail has two tapped hole, one at each end with ¼ x 20 and a center one that is metric with M6-1.00. Who’d da thunk?
-Looks just like a recycled RC but longer tube. Also came in a RC foam insert for shipping.
-I’m happy with 2 speed focuser, only going to do visual and it seems really smooth.
-Need a 2” spacer added to reach focus with a diagonal and an ES eyepiece. So that’s like 6”-7” pass the focuser for focus.
-Very back heavy for balancing.
-Might need some counter weight up front on dovetail to offset my heavy Baader Mark V binoviewer and Badder zooms. This could create a problem if you are near the max weight of your mount.
-Collimating this scope will be a lot more demanding then the average Newtonian scope.
-Baffles probably blocking some of the incoming light so will have to check. May pull out and foam insulate the interior then add flocking to it.
-Tube length with focuser 17” + 3.25 focuser =20.25” plus a 2” spacer for visual use. Tube diameter 7.5”
-Secondary obstruction with light baffle is around 57mm at my best guess. Primary 154mm?
-Bino-viewer with 1.7 glass path needed a 1” extension tube to reach focus.
-Didn’t try it yet but the Badder Mark V Bino viewer should reach focus without the glass path by having the focuser attached directly to the tube. Will report back on this.
-The focuser base is not square to the focuser tube, I’m not happy with that as it will make collimating a problem.
-Images made by the scope seem bright and sharp.
-Viewed the moon at first quarter with the binoviewer working at 400x and views were slightly clearer in the center. The scope performed very well allowing me to see side ledges of the larger craters at that power which equals to almost 70x per inch on a so-so night. 45x per inch the image was tack sharp.
-Viewed Mars which is about 200,000,000 km out right now and put up some nice sharp edges to the planet with no details to be seen on disc. The two speed focuser surly helped.
-Collimation is not hard but needs to be very precise to see the true power of the design.
-Still need to tweak the airy disc ring once I get some good seeing to make this scope spot on.
-Scope should hold collimation very well.
-Reworked focuser by truing up the base to the focuser draw tube.
-Cool down should be quick with little mass and both ends open.
-No tube currants have been notice but it is outside in my observatory.
-Classical Cassegrain have a slight tad of astigmatism and coma very far from axis, so it's usually designed with a very slow f/ratio to mitigate that like f/18 to f/30. This scope is F/12 so you will see more of them both.
-Use this scope for what it was designed to do which is medium to high power viewing and you will be happy.
-Funny thing is most people would think this scope has a small field of view but to me it seemed large compared to my 12.5” F/20 Dall Kirkham with RF Royce optics 6350mm native focal length. lol

 

 

Would I purchase again.......... HECK YA! ....... Not only a good price for a good scope but the images are great.
It truly is a Champagne scope on a beer budget as long as you are like me and don’t mind spikes on bright stars, it’s a true winner in my books.

 

 

 

 

 


  • George9, zjc26138, Venetia2004 and 19 others like this

#2 Stellar1

Stellar1

    Mariner 2

  • -----
  • Posts: 295
  • Joined: 08 Dec 2018
  • Loc: Ontario, Canada

Posted 16 January 2019 - 12:55 PM

I'm curious now, who makes it? and why is it so rare in North America? i would love to have a peek through it, maybe ill see it in the field at Starfest?


  • Magnetic Field likes this

#3 Magnetic Field

Magnetic Field

    Viking 1

  • -----
  • Posts: 770
  • Joined: 28 Aug 2017
  • Loc: UK

Posted 16 January 2019 - 01:48 PM

GSO 6inch F12 Classical Cassegrain It’s A Winner!

 

I purchased this scope as my Grab & Go set up with high hope on a budget designed telescope.

The picture below is for testing in my observatory on my CGE Pro mount.
The scope arrived on Jan 4th 2019 at 3pm. So yes I have had it out a few times as of this writing.

 

 

attachicon.gif IMG_E3561 2222 JPG.jpg
        

I was very happy to receive my new toy a 6” GSO Classical Cassegrain. I can’t believe it’s a new moon weekend with clear skies tonight for testing and 8 Degrees Celsius on January 4th in Canada. WOW! This breaks all the rules of a new Astro toy purchase with the usual two-three weeks of clouds.
I haven’t heard of any one owning this unit in North America, So I might be the only one. smile.gif  And If not probably less than a handful in total are out there.

 

 

Talk of the scope I’ll put this all in point form:
-Fit and finish very nice
-Well packaged
-Collimation off, will tweak with star.
- Was trying to attach the Vixen to a Losmandy dovetail plate to work with my CGE Pro mount. Only to find out this Vixen dovetail has two tapped hole, one at each end with ¼ x 20 and a center one that is metric with M6-1.00. Who’d da thunk?
-Looks just like a recycled RC but longer tube. Also came in a RC foam insert for shipping.
-I’m happy with 2 speed focuser, only going to do visual and it seems really smooth.
-Need a 2” spacer added to reach focus with a diagonal and an ES eyepiece. So that’s like 6”-7” pass the focuser for focus.
-Very back heavy for balancing.
-Might need some counter weight up front on dovetail to offset my heavy Baader Mark V binoviewer and Badder zooms. This could create a problem if you are near the max weight of your mount.
-Collimating this scope will be a lot more demanding then the average Newtonian scope.
-Baffles probably blocking some of the incoming light so will have to check. May pull out and foam insulate the interior then add flocking to it.
-Tube length with focuser 17” + 3.25 focuser =20.25” plus a 2” spacer for visual use. Tube diameter 7.5”
-Secondary obstruction with light baffle is around 57mm at my best guess. Primary 154mm?
-Bino-viewer with 1.7 glass path needed a 1” extension tube to reach focus.
-Didn’t try it yet but the Badder Mark V Bino viewer should reach focus without the glass path by having the focuser attached directly to the tube. Will report back on this.
-The focuser base is not square to the focuser tube, I’m not happy with that as it will make collimating a problem.
-Images made by the scope seem bright and sharp.
-Viewed the moon at first quarter with the binoviewer working at 400x and views were slightly clearer in the center. The scope performed very well allowing me to see side ledges of the larger craters at that power which equals to almost 70x per inch on a so-so night. 45x per inch the image was tack sharp.
-Viewed Mars which is about 200,000,000 km out right now and put up some nice sharp edges to the planet with no details to be seen on disc. The two speed focuser surly helped.
-Collimation is not hard but needs to be very precise to see the true power of the design.
-Still need to tweak the airy disc ring once I get some good seeing to make this scope spot on.
-Scope should hold collimation very well.
-Reworked focuser by truing up the base to the focuser draw tube.
-Cool down should be quick with little mass and both ends open.
-No tube currants have been notice but it is outside in my observatory.
-Classical Cassegrain have a slight tad of astigmatism and coma very far from axis, so it's usually designed with a very slow f/ratio to mitigate that like f/18 to f/30. This scope is F/12 so you will see more of them both.
-Use this scope for what it was designed to do which is medium to high power viewing and you will be happy.
-Funny thing is most people would think this scope has a small field of view but to me it seemed large compared to my 12.5” F/20 Dall Kirkham with RF Royce optics 6350mm native focal length. lol

 

 

Would I purchase again.......... HECK YA! ....... Not only a good price for a good scope but the images are great.
It truly is a Champagne scope on a beer budget as long as you are like me and don’t mind spikes on bright stars, it’s a true winner in my books.

No corrector lens like a Mak. What is the weight?

 

Could be a good alternative for people looking for a very portable  6" telescope.

 

I wouldn't be surprised it does not weight more than say a 5" Maksutov.


Edited by Magnetic Field, 16 January 2019 - 01:50 PM.


#4 George9

George9

    Apollo

  • *****
  • Posts: 1497
  • Joined: 11 Dec 2004

Posted 16 January 2019 - 05:16 PM

Way awesome. Must be about 12 lbs if same as the Orion. I will be curious to hear the cool down time. If it is measurable, I wonder about mirror thickness.

 

George



#5 Jaimo!

Jaimo!

    Gemini

  • *****
  • Moderators
  • Posts: 3211
  • Joined: 11 Oct 2007
  • Loc: Exit 135 / 40° North

Posted 16 January 2019 - 05:58 PM

I'm curious now, who makes it? and why is it so rare in North America? i would love to have a peek through it, maybe ill see it in the field at Starfest?

AstroTech, the generous owner of CloudyNights is carrying the GSO Cassegrain, see THIS large thread for more information.

 

Jaimo!



#6 desertlens

desertlens

    Apollo

  • *****
  • Posts: 1476
  • Joined: 06 Dec 2010
  • Loc: 36°N 105°W

Posted 16 January 2019 - 06:31 PM

Also available from AgenaAstro in a black tube. Better hurry, the 8" sold out very quickly and there seems to be only one 6" remaining.



#7 SeattleScott

SeattleScott

    Fly Me to the Moon

  • *****
  • Posts: 5498
  • Joined: 14 Oct 2011

Posted 16 January 2019 - 06:56 PM

Seems like a cool scope, although I am happy with my excellent iOptron 6” F12 and don’t really see what advantages this has other than weight. My Mak is a tad shorter when you factor in extension tube, doesn’t require pre-cooling since I insulated it, and has no diffraction spikes. Also the Mak is very well corrected for coma and other distortions being a Rumak. Kind of failing to see what this really offers that a 6” Mak doesn’t other than weight. Maybe it is cheaper?

Scott

#8 waso29

waso29

    Apollo

  • *****
  • Posts: 1331
  • Joined: 12 May 2010
  • Loc: Chi-Town, mother earth

Posted 16 January 2019 - 07:13 PM

I'm curious now, who makes it? and why is it so rare in North America? i would love to have a peek through it, maybe ill see it in the field at Starfest?

GSO 冠昇 (crown) is taiwan based company.

sells own brand GSO/Guan Sheng thru Agena and High Point in usa.

also rebrands for: Astrotech/ Orion/ OPT aka TPO in usa.


Edited by waso29, 16 January 2019 - 07:18 PM.

  • terraclarke likes this

#9 waso29

waso29

    Apollo

  • *****
  • Posts: 1331
  • Joined: 12 May 2010
  • Loc: Chi-Town, mother earth

Posted 16 January 2019 - 07:23 PM

at this time, orion telescopes seems to have the most documentation of the CC scope specs on their website.

they are throwing in extra finderscope saddle to differentiate from the rest.

 

https://www.cloudyni...0mm-class-cass/



#10 George9

George9

    Apollo

  • *****
  • Posts: 1497
  • Joined: 11 Dec 2004

Posted 16 January 2019 - 07:31 PM

Seems like a cool scope, although I am happy with my excellent iOptron 6” F12 and don’t really see what advantages this has other than weight. My Mak is a tad shorter when you factor in extension tube, doesn’t require pre-cooling since I insulated it, and has no diffraction spikes. Also the Mak is very well corrected for coma and other distortions being a Rumak. Kind of failing to see what this really offers that a 6” Mak doesn’t other than weight. Maybe it is cheaper?

Scott

Less dew since no corrector. Should be cheaper in theory. And may cover non-visual frequencies better (Calcium K line at 393nm, near UV for Venus, etc.). Not sure if common Mak's cover that, but they may.

 

Scott, so you insulate the tube so the mirror doesn't see a temperature gradient, but doesn't the corrector have to cool as it is in contact with the air?

 

George



#11 SeattleScott

SeattleScott

    Fly Me to the Moon

  • *****
  • Posts: 5498
  • Joined: 14 Oct 2011

Posted 16 January 2019 - 07:46 PM

Dew? What dew? I didn’t even use a dew shield on my Mak last time out. Insulation seems to fix it. I will probably still use it to block ambient light but it really doesn’t seem important for dew since I insulated my tube.

As for your question about the corrector cooling, the insulation does slow the corrector from cooling hence no dew. I don’t really know the science of it. For $10 I figured it was worth a try, and it works.

Scott
  • George9 and erin like this

#12 CHASLX200

CHASLX200

    Hubble

  • *****
  • Posts: 18223
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 16 January 2019 - 08:20 PM

Wonder if it can beat out my sharp SW150 Mak i had?


  • Exnihilo likes this

#13 SeattleScott

SeattleScott

    Fly Me to the Moon

  • *****
  • Posts: 5498
  • Joined: 14 Oct 2011

Posted 16 January 2019 - 11:25 PM

Exactly. With consistently excellent 6” Maks I am not sure what the market niche is for these classical Cassegrains. Higher maintenance, harder to collimate, cooling issues, diffraction spikes. Granted they are slightly cheaper, and maybe a bit lighter. But it isn’t like a 6” Mak isn’t portable.

Scott

#14 waso29

waso29

    Apollo

  • *****
  • Posts: 1331
  • Joined: 12 May 2010
  • Loc: Chi-Town, mother earth

Posted 16 January 2019 - 11:46 PM

decade ago, astronomics had AT6M mak.

 

variety, spice of life.....


  • psandelle likes this

#15 CHASLX200

CHASLX200

    Hubble

  • *****
  • Posts: 18223
  • Joined: 29 Sep 2007
  • Loc: Tampa area Florida

Posted 17 January 2019 - 06:15 AM

Exactly. With consistently excellent 6” Maks I am not sure what the market niche is for these classical Cassegrains. Higher maintenance, harder to collimate, cooling issues, diffraction spikes. Granted they are slightly cheaper, and maybe a bit lighter. But it isn’t like a 6” Mak isn’t portable.

Scott

Seems harder collimation would be a turn off for many.


  • Exnihilo likes this

#16 George9

George9

    Apollo

  • *****
  • Posts: 1497
  • Joined: 11 Dec 2004

Posted 17 January 2019 - 08:01 AM

I think at 6", a lot of it is that it is just fun. Even collimation can be fun.

 

But I see your point at 6". I am waiting for the 12" or 10". Not a lot of 12" Maks around, and the 10" AP Mak sold out at $22K, and the APM 12" was $24K. In that size, the real competition is a modern SCT.

 

George


  • psandelle, RichA and Spacedude4040 like this

#17 Spacedude4040

Spacedude4040

    Lift Off

  • -----
  • topic starter
  • Posts: 24
  • Joined: 09 Nov 2018
  • Loc: Ontario, Canada

Posted 17 January 2019 - 10:47 AM

George you are right. I think the 6-8" are teaser scopes and the excitement is in the 10-12" scopes and maybe more. The 6" falls into a group with a lot of good offering in the market but the 10-12" might be in a league of their own in price/quality.

For me it’s all about the STREHL thru put of the scope because I'm a planetary nut. All things being equal the Classical Cassegrain should up the game in the Cassegrain area. Here's a little info on that   http://www.whichtele.../benchmarks.htm      without changing the direction of this thread.

I needed a grab & go scope and this I felt would suit me well. My review was just to let people know that they did achieve their goal and to show people that collimation is not all that hard and really no tools needed.  Once collimated you may never have to do it again unless you really bump the thing. Only time will tell and I wish they would have produce an F/18 instead to reduce the secondary obstruction.
Mike


  • George9 likes this

#18 SeattleScott

SeattleScott

    Fly Me to the Moon

  • *****
  • Posts: 5498
  • Joined: 14 Oct 2011

Posted 17 January 2019 - 12:02 PM

Agreed at 8” and above the weight savings over a Mak becomes more significant. Largest mass produced Mak is 7”. So I could see a niche in the larger apertures but the field is pretty crowded at 6”.

Scott

#19 Phil Cowell

Phil Cowell

    Fly Me to the Moon

  • *****
  • Posts: 5856
  • Joined: 24 May 2007
  • Loc: Southern Tier NY

Posted 17 January 2019 - 07:39 PM

decade ago, astronomics had AT6M mak.

 

variety, spice of life.....

And an AT8M. Have one of each.



#20 petert913

petert913

    Gemini

  • *****
  • Posts: 3073
  • Joined: 27 May 2013
  • Loc: Portland, OR

Posted 12 April 2019 - 12:30 PM

 

Kind of failing to see what this really offers that a 6” Mak doesn’t

...No Mirror Flop with a classic Cassegrain.



#21 gustavo_sanchez

gustavo_sanchez

    Apollo

  • *****
  • Moderators
  • Posts: 1064
  • Joined: 30 Dec 2010
  • Loc: Puerto Rico, US

Posted 12 April 2019 - 04:05 PM

...No Mirror Flop with a classic Cassegrain.

No mirror flop on my iOptron Mak either...
  • SeattleScott likes this

#22 Richard Whalen

Richard Whalen

    Mercury-Atlas

  • *****
  • Posts: 2807
  • Joined: 24 Sep 2007
  • Loc: Florida

Posted 13 April 2019 - 10:23 AM

...No Mirror Flop with a classic Cassegrain.

My TEC MCT has no mirror flop, which is usually the domain of SCTs.



#23 kim.davis

kim.davis

    Explorer 1

  • *****
  • Posts: 85
  • Joined: 27 Jan 2017
  • Loc: Northern California

Posted 14 April 2019 - 12:30 AM

Question. Does it require recollimation whenever using a different spacer for camera or differentity EPs?

#24 Kevin Barker

Kevin Barker

    Viking 1

  • -----
  • Posts: 788
  • Joined: 22 Apr 2009
  • Loc: Auckland, NZ

Posted 14 April 2019 - 01:07 AM

I spend an evening using an 8 inch version of the GSO beside my Intes 603 6 inch Mak.

 

I have to say I was impressed with the images. Cool down was quicker than in my 6 inch Mak. The ota of the 8 inch was rather long though and the mass at about 20 pounds is quite hefty. My 603 dewed after an hour and a half and a bit so I put it away and used the GSO and other scopes.

 

Images were very sharp. I did not wait for Jupiter but on DSO's the images seemed good. I understand the central obstruction is around 30%. Although diffraction spikes are very pretty the scope does produce quite significant diffraction spikes on brighter stars(Sirius, Canopus etc)

 

All in all sharp stars against a black background. Nice contrast.

Way awesome. Must be about 12 lbs if same as the Orion. I will be curious to hear the cool down time. If it is measurable, I wonder about mirror thickness.

 

George


  • Venetia2004, 3 i Guy and Kunama like this

#25 macdonjh

macdonjh

    Skylab

  • *****
  • Posts: 4079
  • Joined: 06 Mar 2006

Posted 14 April 2019 - 08:50 AM

Question. Does it require recollimation whenever using a different spacer for camera or differentity EPs?

Shouldn't, collimation is collimation, though the best-focus point will be different.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: cassegrain, catadioptric, equipment



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics