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GSO 12" f5 mirror first light

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#1 John Anderson

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Posted 11 July 2020 - 11:57 AM

My dob is finished, the mirror arrived and I tried it out last night ... the results were pretty good. Managed to find m3 (under Bortle 8 Minneapolis skies) and the stars were nice tiny points, although the view was rather dim and required averted vision to get the full globular effect.

 

Have to say the skies here are a bit disappointing so as a result of that I will probably do a lot of moon and planetary viewing.

 

Right now my highest power is a 9mm plossl ... have a meade 4000 6.4 plossl coming from ebay (only 24 bucks) so I will do some star testing and lunar viewing with that when it comes.

 

With the 9mm (x169) the point of best focus was obvious ... I would stop short of saying the mirror has a hard "snap" focus, but it's close. Higher power will tell more and I can do star testing. I tried some star testing with the 9mm and the out of focus image on either side of focus was very similar.

 

Overall I was pleased with the performance and for $535 from Agena Astro (with free shipping) it seems like a pretty good deal. I passed on the GSO secondary bundle and got a 2.6" 1/18 wave unit from Astro Systems.

12 inch dob.jpg


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#2 coopman

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Posted 11 July 2020 - 12:04 PM

Nice looking scope.  Congrats.



#3 Tim J K

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Posted 12 July 2020 - 07:25 AM

Great looking scope!  Please keep us posted about how it performs.

 

Tim



#4 Spikey131

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Posted 12 July 2020 - 07:32 PM

Nice scope.  You need to take it somewhere dark.



#5 John Anderson

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Posted 01 August 2020 - 09:23 AM

Observed the moon, jupiter, and saturn last night. A 9mm GSO plossl and GSO coma corrector gave x183. Jupiter was only at about 20 degrees elevation and there was a lot of turbulence but in spite of this very good detail could be glimpsed ... due to opposition the disk was large. The moon also showed showed a lot of detail through the high-speed waviness. The turbulence itself was rendered very sharply by the scope. Saturn looked nice overall but I had trouble seeing any detail besides the major division in the rings.

 

Tracking is ok at this power, I used teflon on aluminum for the altitude bearings and teflon on generic laminate for the base. Might try some sort of lubricant.

 

Also tried out the GSO 42mm superview. Yes the exit pupil is too big but the view is nice ... three moons wide and sharp in the middle, a very dramatic view of the moon and it makes a good finder eyepiece. My pupil is probably stopping the scope down to about an 8.5" f7.5 equivalent. I didn't notice any blackout due to the diagonal, however perfectionists should note that this is one of those "fuzzy field stop" eyepieces.

 

It was an all-GSO night and I have to say that the mirror is good, possibly very good. The point of best sharpness comes up nice with the fine focus knob. Saving my pennies for a 7mm nagler and 27mm panoptic.

 

20200801_083749.jpg


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#6 John Anderson

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Posted 01 August 2020 - 09:40 AM

The 6.4mm meade super plossl I ordered off ebay is stuck in the US Mail.

 

I live in South Minneapolis and our post office was burned down in the George Floyd riots ... the package is held up at some other distribution point.

 

UPS is getting through fine so I've been able to get some goodies from Agena Astro.

 

The larger reality impacting the little backyard hobby ...



#7 Mazerski

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Posted 01 August 2020 - 09:43 AM

John,

 

If you can swing it, think about investing in a night vision intensifier device... I have a 12.5” New Moon and live under east coast sky. Night Vision allows me to see DSOs like I never thought possible. I’m not into AP but did recently hold an iPhone 7 to eyepiece to snap a few photos.

Here is a CLoudyNight post where I added some photos - see Post #9

 

https://www.cloudyni...ictures-please/



#8 John Anderson

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Posted 01 August 2020 - 09:50 AM

Interesting ... the aesthetic is somewhat mil-tech but a lot is visible.



#9 jeffmac

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Posted 01 August 2020 - 08:22 PM

Make sure to blacken the inside of that mirror box with flat black paint or flocking. That should add to the scope's performance. Nice looking scope.


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