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Equipment Discussions >> Cats & Casses

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bob midiri
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Reged: 06/17/04

Loc: pa 19320
Meade 7" Mak
      #6049833 - 08/27/13 10:57 PM

Hi, I never owned or looked through a Meade Mak 7" Compound telescope. A few years ago I had a chance to get one and didn't, now an opportunity presents itself again. I have come to the realization that I like the convenience of Compound telescopes. Would any Meade 7" Mak owners please discuss some of the pros and cons of this particular scope, and does the pro's outweigh the cons. Thanks in advance. Bob

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TOM KIEHL
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Reged: 11/17/12

Loc: N.E. Ohio
Re: Meade 7" Mak new [Re: bob midiri]
      #6049850 - 08/27/13 11:08 PM

Got one, Love it, Great planetary scope, and use it for solar white light observing awesome for that. cons???? no go to

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maknewtnut
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Reged: 10/08/06

Re: Meade 7" Mak new [Re: bob midiri]
      #6049855 - 08/27/13 11:15 PM

Optical quality varies, but can be good. IMHO, this telescope's biggest issue is cooldown, and then namely with LX200 variants. Compared to the cooldown performance of other 7" Maks with provisions for active cooling, it seems like the LX200 would never cool. On one side by side, we gave up after 4 hours. The comparo was with an MN76.

In another instance I compared the Meade (another LX200) to an I-M M715. It took the Russian MC quite a bit longer than the MN tested years before, but with the same end result. It seemed like the Meade would never cool enough to provide quality images.

I have seen early Meade 7's perform admirably, but that was during warmer months when most Maks will perform at their best.


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DUCE202
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Reged: 01/03/12

Re: Meade 7" Mak new [Re: bob midiri]
      #6049859 - 08/27/13 11:19 PM

hi bob, yes ..the 7"mak (meade) is great! i bought one `bout 6-7 months ago that was on c/n or a/m ..about 4 months ago i purchased a simple orien binoviewer and use it with the 7".i have not as of yet been able to take my jaw off the ground since looking at the moon and some planets !! the view of the moon will take your breath away!! what a world of difference the bino makes along with the 7"meade. i live here in pa. duce202@msn.com '

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beanerds
sage


Reged: 07/15/08

Loc: Darwin Australia
Re: Meade 7" Mak new [Re: maknewtnut]
      #6049862 - 08/27/13 11:20 PM

I have heard that these scopes have a steel plate , a weight behind the main mirror that is the reason for the S-L-O-W , cool down times and there are a few web sites that show how to remove it , and then cool down is a reasnable 1 hour or so .
Great scopes , do a google on the plate removal .
Brian.


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DUCE202
member


Reged: 01/03/12

Re: Meade 7" Mak new [Re: bob midiri]
      #6049873 - 08/27/13 11:24 PM

...also a member of dvaa...

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bob midiri
Carpal Tunnel
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Reged: 06/17/04

Loc: pa 19320
Re: Meade 7" Mak new [Re: DUCE202]
      #6049875 - 08/27/13 11:25 PM

Quote:

hi bob, yes ..the 7"mak (meade) is great! i bought one `bout 6-7 months ago that was on c/n or a/m ..about 4 months ago i purchased a simple orien binoviewer and use it with the 7".i have not as of yet been able to take my jaw off the ground since looking at the moon and some planets !! the view of the moon will take your breath away!! what a world of difference the bino makes along with the 7"meade. i live here in pa. duce202@msn.com '




DUCE what part of Pa do you live in? Im SE Pa west of Philly


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bob midiri
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Reged: 06/17/04

Loc: pa 19320
Re: Meade 7" Mak new [Re: bob midiri]
      #6049878 - 08/27/13 11:26 PM

OK,DVAA got it

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Starman27Moderator
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Reged: 01/29/06

Loc: Illinois, Iowa
Re: Meade 7" Mak new [Re: bob midiri]
      #6050187 - 08/28/13 08:07 AM

Have one. Excellent scope Lunar and planetary views are remarkable. No cool down problem as I have an observatory.

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rmollise
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Reged: 07/06/07

Re: Meade 7" Mak new [Re: beanerds]
      #6050256 - 08/28/13 08:58 AM

Quote:

I have heard that these scopes have a steel plate , a weight behind the main mirror that is the reason for the S-L-O-W , cool down times and there are a few web sites that show how to remove it , and then cool down is a reasnable 1 hour or so .
Great scopes , do a google on the plate removal .
Brian.




Iron. And it may present even in OTAs sold without the fork mount.


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Norm Meyer
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Reged: 02/08/09

Loc: Warren, ME 04864
Re: Meade 7" Mak new [Re: Starman27]
      #6050258 - 08/28/13 08:59 AM Attachment (48 downloads)

Hi Bob,
I bought my 7" Meade Mak in 1999 from R. Tuthill.
It's really a great scope I love it. I have mine in
my small observatory. Most of my viewing is moon and planets
so it is ideal for that. At 420 power the moon is breath taking.
Regards Norm


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tomcody
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Reged: 07/06/08

Loc: Titusville, Florida
Re: Meade 7" Mak new [Re: beanerds]
      #6050301 - 08/28/13 09:27 AM

Quote:

I have heard that these scopes have a steel plate , a weight behind the main mirror that is the reason for the S-L-O-W , cool down times and there are a few web sites that show how to remove it , and then cool down is a reasnable 1 hour or so .
Great scopes , do a google on the plate removal .
Brian.



Bob,
Brian is correct about the 11 or 13? lb internal iron counter weight behind the primary mirror. Pros and cons:
counter weight keeps the dec motor balanced to prevent burnout but slows cooling time.
Removing the weight (if not done correctly) can damage the primary mirror and expose you to potential motor failure if you do not use an external weight on the back of the scope.
So, If you buy one with the weight removed, be sure the dec motor is working well and use an external weight at all times (note internal 11-13lb weight would probably equal a 6-8 lb weight on the back of the scope, some of which could be in the form of heavy binos, eyepieces and a small counter weight on the back of the ota.
like this one
web page
Rex

Edited by tomcody (08/28/13 10:32 AM)


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Joe Aguiar
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Reged: 02/10/07

Loc: none of your buss
Re: Meade 7" Mak new [Re: tomcody]
      #6050486 - 08/28/13 11:15 AM

i had the ota version last ones made USA optics with the UHTC and mirror lock best views you cant image untill you look through,weight was not that bad mine was 21 lbs only which is the same weight as all those 6 inch acros, cool down time is the main issue
joe


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bob midiri
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Reged: 06/17/04

Loc: pa 19320
Re: Meade 7" Mak new [Re: Joe Aguiar]
      #6050958 - 08/28/13 04:04 PM

Thanks Guys I have a lot to digest!!!

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freestar8n
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Reged: 10/12/07

Re: Meade 7" Mak new [Re: bob midiri]
      #6050964 - 08/28/13 04:10 PM

I have one, from an old lx50. I've written about it before. Optically I would say it is good and it does hold collimation. It does have the weight and I did remove it - but due to other factors it is not together yet - and it will be a long term project. It is a different design from a normal spherical spot maksutov because it has an ellipsoidal primary, and a larger than normal secondary obstruction with the baffle.

So I would say it is a good performer and would meet the hopes of someone who wants a 7" Maksutov - but it does depart from the image many people have of such a mak.

I had no concern about removing the weight because I did not intend to keep it on the fork. I don't know what the options are to keep it on the fork without a weight - but I assume there is some way to attach an external weight.

Frank


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dale67cameron
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Reged: 01/03/12

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Re: Meade 7" Mak new [Re: freestar8n]
      #6051999 - 08/29/13 06:58 AM

I have a friend who has the 7" mak ota on a gem. We set up frequently beside each other. It is a wonderful planetary and moon scope. I prefer the planetary views on it over my 12" newt on a gem most nights. The long focal length and 7" aperture limits its use on dso's though. It runs out of horsepower pretty quick on other objects and of course the fov is small. He is usually set up long before dark, so I haven't noticed the cool down issue.

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Live_Steam_Mad
sage


Reged: 07/24/07

Loc: Moss Bank, St.Helens, England
Re: Meade 7" Mak new [Re: maknewtnut]
      #6055103 - 08/30/13 09:08 PM

Quote:

Optical quality varies, but can be good. IMHO, this telescope's biggest issue is cooldown, and then namely with LX200 variants. Compared to the cooldown performance of other 7" Maks with provisions for active cooling, it seems like the LX200 would never cool. On one side by side, we gave up after 4 hours. The comparo was with an MN76.

In another instance I compared the Meade (another LX200) to an I-M M715. It took the Russian MC quite a bit longer than the MN tested years before, but with the same end result. It seemed like the Meade would never cool enough to provide quality images.

I have seen early Meade 7's perform admirably, but that was during warmer months when most Maks will perform at their best.




I don't understand. Are you saying that the Meade LX200 (LX200 Classic or GPS style) 7" Maksutov Cassegrain had no fan on it? Because the LX200 Mak did always have a fan on it (so "active" cooling), at least that's what it says in the LX200 Classic and LX200 GPS user manuals.

Or are you saying that the LX200 Classic Mak and LX200 GPS Mak both had fans, but the image took wayyyy longer to stabilise than other brands of 7" Mak that had fans in them, simply because of the cast iron disc in the back of the Meade Mak OTA was a thermal mass and air circulation problem which meant that cool down took a lot longer? In which case yeah that sounds likely. That cast iron weight in it is really bad.

Anyway, I have a Meade 7" Mak that I bought from a local Astronony enthusiast, it was ex-an old LX50 that someone took off the LX50 fork mount some years ago and was using the OTA in tube rings on an EQ6 mount on a pier. I bought it for 100 GBP.

It had quite a lot of fine scratches on the outside of the corrector from where someone had been too vigorous with the "cleaning", and the tube was dented in one place about 2 inches long crosswise, and there were various other marks and dings in the tube, the Meade LX50 stickers on the side of the tube were both a bit tatty, and the secondary "mirror" looked a little cloudy with maybe blue mold. And there was a ton of mirror shift and a ton of backlash in the focusser. But the collimation bolts and screws still rotatable and were not locked solid and the views were fair, and it had at least got the EMC Multi Coatings, so I bought it. I got it at the same time and from the same person as when I bought my C11.

Recently I removed the large 8 1/2" diameter x 0.75" thick, black painted, 3.568Kg (7.9 lbs) cast disc weight out of the back of my 7" Meade Mak OTA and reduced the OTA weight as a result, from 10.84 Kg / 23.84 lbs down to 7.267 Kg / 15.99 lbs!

Before this, my C11 felt easier and a little bit lighter to handle than this Meade Mak (actually the C11 was heavier but somehow the Meade Mak was more awkward to lift with it's tube rings), but now the Mak feels like a cute little baby, delightfully and quite suprisingly light and easy to carry (now as I removed the tube rings and instead want to use the Mak with radius blocks and a Losmandy dovetail, with a Vixen dovetail bolted on underneath, just like my C11 has), and now my C11 feels like a monster to pick up, it's weight is incredibly heavy.

I cleaned the old Meade (LMX ?) Petroleum based red grease out the Mak's mirror baffle tube and OTA baffle tube, the grease had become extremely thick, like clay, and there was almost nothing lubricating the baffle tube anymore. Hence the image shift I suppose. I replaced the grease with MolyTone 1000 (Rocol MTS 1000) and as far as I can tell the image shift has gone! Interestingly the wear on the baffle tube was on the SIDES and NOT on the top and bottom, the top and bottom were both still rough (turned finish) but the sides had been superfinished LOL, because the mirror is torqued (wobbled) to either left or right sides when you focus.

Unfortunately when I cleaned the secondary I scratched it a little in one place (some dirt somehow got onto my microfibre cloth even though corrector and secondary and secondary conical baffle were cleaned under running water tap before I started). And the blue mold appearance that was there but not too bad was still there after cleaning but seemed less prominent. But the view on the Moon at 90x seemed just fine thank goodness, when I took a quick look, after I had reassembled the OTA.

Before I removed the weight in the back of this Meade Mak OTA, I had used up to 333x on the Moon (the most powerful eyepiece I had at the time) with my TeleVue Radian 8mm, after the fan had been running for over an hour as I recall, on a mild night, with no Chromatic Aberration that I noticed, the view was fair sharpness and contrast at that magnification (Moon was not all that high up in the sky as I recall). Orion Nebula was very contrasty and there was a lot of it, at least as much if not more visible as in my friend Jon's LX90 8" ACF, and just as much if not more more blue / green color visible.

It's lovely to lift and handle now, and I can't wait to Star Test and try it properly, but I have no mount for it at present, I'm currently looking for a Meade LXD75 mount secondhand (I love the AudioStar on my Meade SN102 and want to stay with Meade handsets) to mount it on. I did try it with my Hubble Artificial Star and got a fair sharpness Airy Disc but I really haven't got enough room to do this properly and the views were too turbulent to do a proper collimation yet.

I would like to eventually try an 8" Mak of F10 or so. I find F15 to be too specialised really. Tec used to make an 8" F11 and STF make an 8" but the primary can be collimated (I don't like that idea!) and the Intes 8" Mak is way too expensive for me. So I'll probably end up with a 9.25" SCT just to get more aperture than Jon's 8" ACF that I am used to and have used a lot. And Celestron's UK price for it's 9.25" Edge is like 2,600 GBP (!) versus 1,250 GBP for a brand new 9.25" SCT, and I'll probably end up getting a 9.25" SCT second hand for about 725 GBP instead and waiting 5 or more years until an Edge 9.25" turns up locally so I can Star Test it / try it on planets etc. before I buy it.

Cheers,

Alistair G.

Edited by Live_Steam_Mad (08/30/13 10:17 PM)


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maknewtnut
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Reged: 10/08/06

Re: Meade 7" Mak new [Re: Live_Steam_Mad]
      #6055212 - 08/30/13 10:16 PM

I was referring to cooling vents and/or fans that allow the introduction of ambient air.

Having run across many cats and casses that require an adjustment to their primary in order to achieve true collimation, I have the exact opposite opinion in that regard. Not having it does NOT mean you won't need it. Needing it and not having it...now that's a bad idea.


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PGW Steve
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Reged: 10/03/06

Loc: Winnipeg, Canada
Re: Meade 7" Mak new [Re: maknewtnut]
      #6055498 - 08/31/13 03:53 AM

I love mine, in addition to the Moon and planets, I love checking out globular clusters.

Mine has the weight, I've been apprehensive about removing it, I love the scope too much.


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Live_Steam_Mad
sage


Reged: 07/24/07

Loc: Moss Bank, St.Helens, England
Re: Meade 7" Mak new [Re: PGW Steve]
      #6056535 - 08/31/13 06:55 PM

Here are some pictures that someone might find interesting that I recently took when I was removing the weight from my Meade 7" Mak OTA ;-

https://picasaweb.google.com/101932667412801910198/MeadeMaksutovCassegrain7Ex...

https://picasaweb.google.com/101932667412801910198/Meade7MaksutovCassegrainEx...

https://picasaweb.google.com/101932667412801910198/Meade7MakOTAWeightRemovalC...

Cheers,

Alistair G.

Edited by Live_Steam_Mad (08/31/13 08:21 PM)


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ColoHank
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Reged: 06/07/07

Loc: western Colorado
Re: Meade 7" Mak new [Re: Live_Steam_Mad]
      #6058434 - 09/01/13 10:46 PM

Quote:



Quote:
--------------------------------------------------------------------------------

Optical quality varies, but can be good. IMHO, this telescope's biggest issue is cooldown, and then namely with LX200 variants. Compared to the cooldown performance of other 7" Maks with provisions for active cooling, it seems like the LX200 would never cool. On one side by side, we gave up after 4 hours. The comparo was with an MN76.

In another instance I compared the Meade (another LX200) to an I-M M715. It took the Russian MC quite a bit longer than the MN tested years before, but with the same end result. It seemed like the Meade would never cool enough to provide quality images.

I have seen early Meade 7's perform admirably, but that was during warmer months when most Maks will perform at their best.


--------------------------------------------------------------------------------



I don't understand. Are you saying that the Meade LX200 (LX200 Classic or GPS style) 7" Maksutov Cassegrain had no fan on it? Because the LX200 Mak did always have a fan on it (so "active" cooling), at least that's what it says in the LX200 Classic and LX200 GPS user manuals.

Or are you saying that the LX200 Classic Mak and LX200 GPS Mak both had fans, but the image took wayyyy longer to stabilise than other brands of 7" Mak that had fans in them, simply because of the cast iron disc in the back of the Meade Mak OTA was a thermal mass and air circulation problem which meant that cool down took a lot longer? In which case yeah that sounds likely. That cast iron weight in it is really bad.





I believe there's a reference to the Mak 7's cooling issues buried in the impossibly long thread (now locked) regarding Meade's impending sale. If memory serves, the cooling fan in the fork-mounted set-up serves no useful purpose, other than perhaps to act as a cosmetic ruse to stimulate sales. The sad truth is that the fan's airflow inside the scope is almost completely blocked by the notorious iron weight. On so many levels, adding that internal iron weight to balance the scope was a lousy and dishonest bit of "engineering."

Aiming a fan at a blank, impenetrable wall is never going to circulate cooling air through a room on the other side of that wall. So, remove the weight to allow the fan to operate properly, mount the Mak 7 on a competent GEM, and it should be good to go.


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freestar8n
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Reged: 10/12/07

Re: Meade 7" Mak new [Re: ColoHank]
      #6058656 - 09/02/13 03:05 AM

Hi-

Yes - that was from my posting and my images. The images linked to above look different from my system - but they don't show the actual weight that was removed so it's hard to tell. In my case, when you removed the fan, you could see the weight inside completely blocking the opening - although there is a thin space between the weight and the back of the ota that would let some air through.

Frank


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Erik Bakker
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Re: Meade 7" Mak new [Re: ColoHank]
      #6058677 - 09/02/13 04:03 AM

The cosmetic fan issue gives some insight in the quality and character of choices Meade was making at that time

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Live_Steam_Mad
sage


Reged: 07/24/07

Loc: Moss Bank, St.Helens, England
Re: Meade 7" Mak new [Re: freestar8n]
      #6061393 - 09/03/13 05:42 PM

Quote:

Hi-

Yes - that was from my posting and my images. The images linked to above look different from my system - but they don't show the actual weight that was removed so it's hard to tell. In my case, when you removed the fan, you could see the weight inside completely blocking the opening - although there is a thin space between the weight and the back of the ota that would let some air through.

Frank




Here is the weight that I removed from my 7" Meade ex-LX50 Maksutov ;-

https://picasaweb.google.com/101932667412801910198/WeightThatIRemovedFromMead...

Sorry but I have no pictures of the rear holes showing the weight still there before I started. As soon as I found the weight in the back of the OTA under the vent I went about removing it without a second thought to taking photo's of the weight still in place LOL. From memory there is about 1/4 inch of gap between the back of the weight and the inside of the rear cell casting, for air to circulate... and the black RTV Silicone which was holding the weight in took up this 1/4 inch gap, so the gap may vary from 'scope to 'scope.

Regards,

Alistair G.

Edited by Live_Steam_Mad (09/03/13 05:51 PM)


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freestar8n
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Reged: 10/12/07

Re: Meade 7" Mak new [Re: Live_Steam_Mad]
      #6061558 - 09/03/13 07:46 PM

Yep - that matches mine.

Thanks,
Frank


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azure1961p
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Reged: 01/17/09

Loc: USA
Re: Meade 7" Mak new [Re: Live_Steam_Mad]
      #6062204 - 09/04/13 07:08 AM

Quote:

Quote:

Hi-

Yes - that was from my posting and my images. The images linked to above look different from my system - but they don't show the actual weight that was removed so it's hard to tell. In my case, when you removed the fan, you could see the weight inside completely blocking the opening - although there is a thin space between the weight and the back of the ota that would let some air through.

Frank




Here is the weight that I removed from my 7" Meade ex-LX50 Maksutov ;-

https://picasaweb.google.com/101932667412801910198/WeightThatIRemovedFromMead...

Sorry but I have no pictures of the rear holes showing the weight still there before I started. As soon as I found the weight in the back of the OTA under the vent I went about removing it without a second thought to taking photo's of the weight still in place LOL. From memory there is about 1/4 inch of gap between the back of the weight and the inside of the rear cell casting, for air to circulate... and the black RTV Silicone which was holding the weight in took up this 1/4 inch gap, so the gap may vary from 'scope to 'scope.

Regards,

Alistair G.




Those pics are beyond words.

Pete


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orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Meade 7" Mak new [Re: ColoHank]
      #6062521 - 09/04/13 11:52 AM

Quote:

Quote:



Quote:
--------------------------------------------------------------------------------

Optical quality varies, but can be good. IMHO, this telescope's biggest issue is cooldown, and then namely with LX200 variants. Compared to the cooldown performance of other 7" Maks with provisions for active cooling, it seems like the LX200 would never cool. On one side by side, we gave up after 4 hours. The comparo was with an MN76.

In another instance I compared the Meade (another LX200) to an I-M M715. It took the Russian MC quite a bit longer than the MN tested years before, but with the same end result. It seemed like the Meade would never cool enough to provide quality images.

I have seen early Meade 7's perform admirably, but that was during warmer months when most Maks will perform at their best.


--------------------------------------------------------------------------------



I don't understand. Are you saying that the Meade LX200 (LX200 Classic or GPS style) 7" Maksutov Cassegrain had no fan on it? Because the LX200 Mak did always have a fan on it (so "active" cooling), at least that's what it says in the LX200 Classic and LX200 GPS user manuals.

Or are you saying that the LX200 Classic Mak and LX200 GPS Mak both had fans, but the image took wayyyy longer to stabilise than other brands of 7" Mak that had fans in them, simply because of the cast iron disc in the back of the Meade Mak OTA was a thermal mass and air circulation problem which meant that cool down took a lot longer? In which case yeah that sounds likely. That cast iron weight in it is really bad.





I believe there's a reference to the Mak 7's cooling issues buried in the impossibly long thread (now locked) regarding Meade's impending sale. If memory serves, the cooling fan in the fork-mounted set-up serves no useful purpose, other than perhaps to act as a cosmetic ruse to stimulate sales. The sad truth is that the fan's airflow inside the scope is almost completely blocked by the notorious iron weight. On so many levels, adding that internal iron weight to balance the scope was a lousy and dishonest bit of "engineering."

Aiming a fan at a blank, impenetrable wall is never going to circulate cooling air through a room on the other side of that wall. So, remove the weight to allow the fan to operate properly, mount the Mak 7 on a competent GEM, and it should be good to go.



The early Meade tubes (EMC with the weight were nearly blocked, even so There was a definite benefit to havin the fan. The newer tubes with the Mirror lock had large holes bored in the weight to allow the air to flow. I have yet to observe through a 7" mak that was bad or even fair they have all been VG and one was EX. Seems the early ones hold a tiny edge in sharpness but not much. I have noticed the meniscus coatings on the earlier ones were a lot easier to scratch (personal experience on an LX50) Still among if not my favorite tubes. Only my Leo Henzl C8 ha come close to equaling them. The new 9.25's are better over all in shootouts. (so I have read).


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kingyo
newbie


Reged: 01/12/13

Loc: Hong Kong
Re: Meade 7" Mak new [Re: orion61]
      #6171151 - 11/01/13 10:06 PM

Seems that you all have a very good experience with this scope.
I am curious to know if there exists anyone who want to sell it, especially the ota version.

Regards,
KinGyo


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cavefrog
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Reged: 11/11/08

Loc: loozyanna
Re: Meade 7" Mak new [Re: kingyo]
      #6172390 - 11/02/13 06:34 PM

I purchased a Meade 7 a while back. it is the only scope I have that has built in GPS. I like it enough to not sell it. (sorry). It is very good on planets, but not as good as the 10" or 12" SCTs. I wonder why. I had one odd night out with it. I was using another scope, and set the 7 out of the way , leaving the fan on. (purposefully) to get it to cool before I used it. it ended up to be about 2 hours. When I picked it up and put it on the mount, it was completely fogged inside! I was stunned to say the least. I
am gonna try a lymax 10" cooler on it tonight to see if it makes any difference.

If one puts a Dewshield on it, they need more than a heavy eyepiece or a pair of binos to balance. Right now with a dewshield, I have a pair of binos, two 2.5lb weights, and a one pound weight. The original weight is still in it. That is what it seems to take to balance. I worry more about the
motors than cooling. I need the dewshield and and heater strip to fend off mother nature around here. last night I
had both on my 12" with the Dewbuster turned on halfway. I was out until 13:00, and the dew was still just starting on the corrector when I started breaking down and coming inside.

Theo


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cavefrog
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Re: Meade 7" Mak new [Re: tomcody]
      #6172497 - 11/02/13 07:49 PM

Quote:

Quote:

I have heard that these scopes have a steel plate , a weight behind the main mirror that is the reason for the S-L-O-W , cool down times and there are a few web sites that show how to remove it , and then cool down is a reasnable 1 hour or so .
Great scopes , do a google on the plate removal .
Brian.



Bob,
Brian is correct about the 11 or 13? lb internal iron counter weight behind the primary mirror. Pros and cons:
counter weight keeps the dec motor balanced to prevent burnout but slows cooling time.
Removing the weight (if not done correctly) can damage the primary mirror and expose you to potential motor failure if you do not use an external weight on the back of the scope.
So, If you buy one with the weight removed, be sure the dec motor is working well and use an external weight at all times (note internal 11-13lb weight would probably equal a 6-8 lb weight on the back of the scope, some of which could be in the form of heavy binos, eyepieces and a small counter weight on the back of the ota.
like this one
web page
Rex




That counterweight made by Peterson will not work on the 7. It is for 10" and up. reason being on the 10" and up, there is a removable visual back. the visual back on the 7 is not removable, it is in the cast. the Peterson weight is held on with the removable visual back.

Theo


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cavefrog
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Re: Meade 7" Mak new [Re: cavefrog]
      #6172514 - 11/02/13 07:58 PM Attachment (10 downloads)

Quote:

I purchased a Meade 7 a while back. it is the only scope I have that has built in GPS. I like it enough to not sell it. (sorry). It is very good on planets, but not as good as the 10" or 12" SCTs. I wonder why. I had one odd night out with it. I was using another scope, and set the 7 out of the way , leaving the fan on. (purposefully) to get it to cool before I used it. it ended up to be about 2 hours. When I picked it up and put it on the mount, it was completely fogged inside! I was stunned to say the least. I
am gonna try a lymax 10" cooler on it tonight to see if it makes any difference.

If one puts a Dewshield on it, they need more than a heavy eyepiece or a pair of binos to balance. Right now with a dewshield, I have a pair of binos, two 2.5lb weights, and a one pound weight. The original weight is still in it. That is what it seems to take to balance. I worry more about the
motors than cooling. I need the dewshield and and heater strip to fend off mother nature around here. last night I
had both on my 12" with the Dewbuster turned on halfway. I was out until 13:00, and the dew was still just starting on the corrector when I started breaking down and coming inside.

Theo




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Live_Steam_Mad
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Re: Meade 7" Mak new [Re: cavefrog]
      #6172669 - 11/02/13 09:54 PM

I would love to hear what difference that Lymax cooler makes on your LX200 Mak with the weight still in it when taking the 'scope out of an e.g. 18 degrees Celcius house and putting it into the outside environment at e.g. 7 degrees Celcius, then trying it on Jupiter after allowing the planet to rise to say 40 degrees above the horizon, and making sure you have no bad Jetsteam above you (can be checked easily on the Web), so the seeing is good. I'd be interested to hear how long it takes for the Star Test to be excellent and for the views to be stable at high power with the Lymax cooler.

I can't hardly wait to try my OTA with no weight and do some tests and see how long it takes for my 7" Meade Mak to cool for use at high magnification. I turned my fan around in it's housing so that the fan now sucks air IN to the tube with tip positive on my 12V power supply.

Cheers,

Alistair G.

Edited by Live_Steam_Mad (11/02/13 09:54 PM)


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cavefrog
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Re: Meade 7" Mak new [Re: Live_Steam_Mad]
      #6173016 - 11/03/13 01:37 AM

It was about 8 degrees in and out when I put it outside tonight. at about 13:00 it was 11. it will be a few days before it drops to 7 around here at night. but I did not see any real difference. I put the scope out just before sundown so it would not get heated by the sun. Then I have to wait for it to get dark, and for the bloodsuckers to get too cold to eat. that makes it about 8pm and cooling for 1.5 hrs. after 1 hr. I went out and turned the Lymax off and left the internal fan on. I don't think the Lymax was worth it yet. not cold enough to make any difference. I sure had a good night with a couple of odd EPs though. A 32mm Vernonscope and a 40mm XL Pentax were my faves tonight. as for the jet stream... I think it is pretty close, but not over me. viewing Uranus was fun. I tried to see how strong I could go on it, and 381X was way too much, 267X was still too soft, 190X seemed too round it out nicely though.

Theo


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cavefrog
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Loc: loozyanna
Re: Meade 7" Mak new [Re: cavefrog]
      #6173020 - 11/03/13 01:40 AM

I was wrong... jet stream is nowhere near me.

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Binomania.it
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Reged: 05/20/10

Loc: North Italy
Re: Meade 7" Mak new [Re: cavefrog]
      #6173106 - 11/03/13 03:44 AM

Dear friends, thank you all for the comments! My specimen of OTA Meade 7 has arrived two days ago. In my C8 and C9.25 I inserted the black velvet. Now I have a doubt: the velvet might slow down the cooling of the tube. I want to know what is your opinion.
Best Regards from Italy
Piergiovanni


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jjack's
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Reged: 04/01/12

Loc: normandy
Re: Meade 7" Mak new [Re: Binomania.it]
      #6175932 - 11/04/13 05:26 PM

Sorry guys, i had one. Nothing magic is this mak. Yes it is a good quality optic. But with 38% obstruction and F/15...
I sold it after seeing less contrasty détails on planets and the moon, than a GSO newtonian 8"f5. my old 1990's C8 (f 10 and f6.3)was as good on planets and gather more light on deep sky objects.


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