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#1026 Keith

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Posted 17 November 2012 - 05:35 AM

any noticeable improvement with the meade tripod vs the stock orion one?

One suggestion I might make, is that that focuser is robbing you of precious light when using the 40mm and 56mm eyepieces, it is not super obvious, but under very dark conditions you will see less stars at the edges, and a bit of darkening. I first noticed it when out of focus, the diffraction rings of stars were chopped in the outer field. I swapped over to a JMI that I had with a direct 3" thread and full 2" aperture, and bam, Peterson was right, it was an "eye opener". I now have the AP visual back I use for visual. Unfortnuately those rotating WO and GSO focusers do not have an option for 3" threads, but JMI and feathertouch do, as well as optec. I suppose a machinist could fabricate a part to fit the rotational dovetail of the GSO focuser, that threads directly to the 3" instead of the 2". Someone should suggest it to GSO as an upgrade. 3 setcrews to loosen, and a little grease to put on the new part would be all it would take to open that up to a full 2".

#1027 Douglas729

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Posted 17 November 2012 - 07:57 AM

Thank you...on the C8 with a maximum back focus of 180mm absolutely.

The 11" has a considerably longer back focus distance before loss of aperture so I resurrected an unused 2" Crayford focuser and have been unaware of any loss of light with 20/20 vision.
...but if I'm still wrong, correct me.

#1028 TxStars

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Posted 17 November 2012 - 11:16 AM

Douglas729,
What is it like when the train comes by?
Looks like you are close to the tracks.

#1029 Douglas729

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Posted 17 November 2012 - 11:35 AM

The mighty Mississippi with a big tug pushing 12 barges through Lock and Dam #24 then 100 cars of BNSF coal on a 4ft embankment every 40 minutes? ...it's break time.

#1030 Keith

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Posted 17 November 2012 - 12:08 PM

Thank you...on the C8 with a maximum back focus of 180mm absolutely.

The 11" has a considerably longer back focus distance before loss of aperture so I resurrected an unused 2" Crayford focuser and have been unaware of any loss of light with 20/20 vision.
...but if I'm still wrong, correct me.


I was a big skeptic of needing an eye opener visually for a long time, until that night on palomar when I noticed the chopped diffraction patterns at the edge, and this was just with a standard 2" visual back threaded to the 2" threads, so I was closer in than with the GSO. When I changed configs to the JMI (as a visual back only) threaded to the 3" thread leaving the whole 2" baffle open, there was a difference. I was definitely in hyper cerebral sensitive mode, but the stars remained full diffraction patterns when out of focus right to the edge, and there was clearly more stars and a brighter view at the field stop. Under average conditions and not noticing the cut of diffraction rings, it took me about 2 years to notice, all the while convincing customers that the peterson eye opener type things were only for large chip imaging.

What I realized is, it is not having a 2" baffle that is needed (I will still fight any naysayer who says it is a waste of time to put 2" on a c8, or even a c6, c5 or 127 mak for that matter!), but when you CHOKE down a scope that was intended to have a full 2" baffle, thats when the problems arise, it is all about cutting off the light cone before it wants to be cut off... and the c11, does not want to be cut down to 1.5" at the rear cel when 2" eps are used. Will it be obvious vignetting that anyone will notice? no, but in the right conditions, you will notice. MAYBE with the ep much farther back it is not an issue, who knows, I didn't test that because by then I had already returned my GSO focuser. Try drifting a defocused bright star closer to the edge with the 40 or 56 and see if it "flattens out" before getting to the field stop, THEN you know you are choking off light. Backfocus was not what I was referring to, choking down the barrel is the issue. But on the topic of backfocus, the farther you get from the back of the scope, the longer the focal length gets, and you are no longer f10, this is a little known dirty secret of all scopes with magnifying secondaries, and moving primary or secondary mirror focus, as the distance from primary to secondary changes, so does focal length, even if only a little bit. Good chance you are at f11 with that focuser though, but that was not what I was referring to.

I am still curious if the meade tripod was an improvment over the orion one, I know same diameter legs, but the bigger head might make it more sturdy, I have a friend who leaves his G11 tripod in his dome in the backyard, and brings a meade tripod with MA adapter to events (he has a pier at the club dark site), and the meade tripod handles the G11 with 10" or AR152 nicely. So I figured it might have been an improvement to the atlas as well.

#1031 Jared

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Posted 17 November 2012 - 01:13 PM

O.K., I've got two active Cassegrains now...

Planewave 12.5" CDK on an Astro-Physics 900 GTO mount (for some reason I still love having analog setting circles)

Celestron C5 on a Takahashi Teegul SP that was a wedding present from my wife in '93

Here's the family portrait...

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#1032 sbellack

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Posted 17 November 2012 - 03:18 PM

A friend of mine (Peter Khor) took a picture of my C14 wednesday night during a school sponsored star party. For those who appreciate vintage Celestrons and the late Tom Johnson, this one is for you..

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#1033 iceblaze

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Posted 17 November 2012 - 06:53 PM

My newly de-forked C8, previously on a byers drive, but now on my M2 (Thanks Keith for the ADM kit suggestion!). This setup is so much lighter than the Stellarvue 110, and a lot easier to deal with. I can carry the whole thing outside without removing the OTA. Total setup is ~22-25lbs, for 8" of aperture!

-James

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#1034 Jared

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Posted 17 November 2012 - 10:22 PM

Whoops... I think I left someone out of the family portrait.

From left to right, this is an Astrotech 10" Ritchey-Chretien, a 12.5" Planewave corrected Dall-Kirkham, and a Celestron 5" Schmidt Cassegrain telescope. Just realized I've actually got three different classes of Cassegrains represented--one with a hyperbolic primary, one with an ellipsoidal primary, and one with a spherical primary. Funny how things work out.

They are mounted, respectively, on an Astro-Physics Mach1, an Astro-Physics 900, and a Takahashi Teegul SP.

I love all three, but I think it may finally be time to find a new home for the Astrotech. Don't think I am going to use it any longer. It's just too close in bulk to the Planewave.

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#1035 MikeBOKC

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Posted 17 November 2012 - 10:22 PM

Sbellack, I think I know where that scope came from -- was that the one Pete was selling recently?

#1036 Douglas729

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Posted 17 November 2012 - 11:27 PM

You are correct again.

The previous owner of the Atlas mount was going to purchase a Losmandy and refused to include the tripod due to it being inadequate. I had previously purchased the Meade and didn't want that tripod anyway.

I recommend the Meade because I never give it a thought...it just holds up about 50 lbs flawlessly. Occasionally they're on ebay 'like new' $150-175.

#1037 Keith

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Posted 18 November 2012 - 06:43 AM

My newly de-forked C8, previously on a byers drive, but now on my M2 (Thanks Keith for the ADM kit suggestion!). This setup is so much lighter than the Stellarvue 110, and a lot easier to deal with. I can carry the whole thing outside without removing the OTA. Total setup is ~22-25lbs, for 8" of aperture!

-James

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Yep, it is quite a nice combo, getting the m3 to use with my refractors and 8", really freed my from needing to keep my dob. That M2 looks roughly the same size as my M3, but I wouldn't doubt if it was a little smoother, being a more updated design. My tripod is also older and has the chains instead of the spreader and appleply tray. ADM is a great deal on dovetails huh?

#1038 coopman

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Posted 18 November 2012 - 08:38 AM

How tall is that column piece that you added below the M2?

#1039 Bill Barlow

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Posted 18 November 2012 - 10:47 AM

I own one of the new black finished C14 OTA's and it weighs 53 pounds bare. Much heavier than what I was expecting. I think the newer rear cell design with the vents has something to do with the weight increase.

Nice pictures of various member's scopes, by the way..

Bill

#1040 Bill Barlow

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Posted 18 November 2012 - 10:48 AM

I own one of the new black finished C14 OTA's and it weighs 53 pounds bare. Much heavier than what I was expecting. I think the newer rear cell design with the vents has something to do with the weight increase.

Bill

#1041 Super08

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Posted 18 November 2012 - 10:58 AM

Thanks Bill you just saved me from going and weighing mine.

#1042 iceblaze

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Posted 18 November 2012 - 02:15 PM

How tall is that column piece that you added below the M2?


The MEC2 column is 12 inches tall

-James

#1043 jjongmans

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Posted 08 December 2012 - 03:30 PM

My new cat:

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#1044 Masvingo

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Posted 11 December 2012 - 03:29 PM

Sbellack - Beyootiful set up! :bow: :bow:

Lovely to see an orange tube C14 and toting a C5 as well!

James

#1045 Jeff B

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Posted 11 December 2012 - 10:29 PM

My new-to-me C14 makes the G-11 look small.

Jeff

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#1046 stevew

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Posted 12 December 2012 - 12:10 AM

Nice rig Jeff!
I have been tempted several times to move from my C11 to a C14 for my G11, but have so far resisted.
Is that 55 lb of counterweights you have on there?? :question:

Steve

#1047 Jeff B

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Posted 12 December 2012 - 07:39 AM

Nice rig Jeff!
I have been tempted several times to move from my C11 to a C14 for my G11, but have so far resisted.
Is that 55 lb of counterweights you have on there?? :question:

Steve


Thanks Steve and yup that's 55 pounds of counterweights.

Hopefully there will be a first light tonight. I know it needs collimation. Was cetrified by Company 7 so I expect the optics will be decent.

My winter time project will be to install an active/passive cooling system. My C11 has one and it makes all the difference in the world with regards to usibility of the instrument. May install carbon fiber tube at the same time...Hey 3.5 pounds is 3.5 pounds.

Jeff

#1048 bremms

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Posted 12 December 2012 - 08:27 AM

Here is my new Vixen.. Tube is new mount is a year old.

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#1049 hottr6

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Posted 12 December 2012 - 08:28 AM

My 6" MCT on a Vixen Polaris..... made for each other, and the colors match!

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#1050 bremms

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Posted 12 December 2012 - 08:29 AM

Wow! I have two cats and I'm not a CAT person

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