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

De-weighting and remounting a Meade 7" Mak

  • Please log in to reply
14 replies to this topic

#1 hlritter

hlritter

    Sputnik

  • *****
  • topic starter
  • Posts: 25
  • Joined: 03 Sep 2014
  • Loc: Toledo, OH, and Sun City, FL, USA

Posted 20 April 2019 - 11:20 AM

I was fortunate to encounter a nearly pristine LX200 7" Mak on consignment at a camera store, put there by a customer who had bought it from them years ago, found that what they saw thru the EP didn't look like Hubble photos, and put the scope aside for a decade. I got it for $800 and am very happy with the optical and mechanical performance. In fact, it produces such a fine image that I'd like to consider the idea of removing the OTA and putting it on my A-P 600 mount in place of the 155 mm refractor for astroimaging in the field.

 

Does anyone have advice on removing the OTA from the fork, and the counterweight from the OTA? How about any other enhancements, like the focuser?

 

Thanks,

Howard


  • clusterbuster likes this

#2 junomike

junomike

    Hubble

  • *****
  • Moderators
  • Posts: 16175
  • Joined: 07 Sep 2009
  • Loc: Ontario

Posted 20 April 2019 - 11:50 AM

Removing the weight is messy not that easy IMO.  See this thread for more info.

If you plan on doing some Planetary Imaging I think a wedge would be more than adequate

and a far easier solution (again IMO).



#3 clusterbuster

clusterbuster

    Viking 1

  • *****
  • Posts: 628
  • Joined: 13 Mar 2016
  • Loc: Tampa Bay, Fl.

Posted 20 April 2019 - 12:55 PM

I just got one last week from Apopka, Florida. Man, This Telescope is the BEST that I have ever looked through.PERIOD !

Mine has the weight still in it, mine rides on my AVX Mount just fine. I only do visual. The fan motor works well. I do not want to remove the weight because the OPTICS are simply Stunning !!

There was another thread where a guy had 5 Takahashi Telescopes and this model Meade7" Mak.. 

Speaks Volumes,, I LOVE MINE, I am in Tampa,, not far from Sun City, Congrats.. Jupiter and Saturn NEVER looked so good, can't wait for oppositions !!!

Mark



#4 hlritter

hlritter

    Sputnik

  • *****
  • topic starter
  • Posts: 25
  • Joined: 03 Sep 2014
  • Loc: Toledo, OH, and Sun City, FL, USA

Posted 20 April 2019 - 01:29 PM

Thanks for the encouraging words! It looks like removing the OTA from the saddle might be a little tricky. How did you do it? Are you a member of one of the Tampa Bay area clubs?

#5 hlritter

hlritter

    Sputnik

  • *****
  • topic starter
  • Posts: 25
  • Joined: 03 Sep 2014
  • Loc: Toledo, OH, and Sun City, FL, USA

Posted 20 April 2019 - 01:32 PM

By the way, how could you tell I’m in Sun City?
  • clusterbuster likes this

#6 jgraham

jgraham

    Hubble

  • *****
  • Posts: 19899
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 20 April 2019 - 02:02 PM

I have a pair of Mak 7s; one on an LX90 for visual the other on an Atlas for imaging, both had their weights removed by their original owners. Sooo, I don't know how to remove the weight and I'd be tempted to leave it in unless it became a problem. However, getting it off of the forks is easy. There are 3 screws holding the tube to each fork, you may need to cut off an Allen wrench to reach 2 of them. You will also need to loosen the 3 bolts that hold one of the forks to the base to spread the forks wide enough to remove the tube without scratching it. Do not re-install the mounting screws back in the tube, they are too long and may touch the mirror. Instead, buy a set of shorter screws from a hardware store and hold onto the originals. To mount the tube on an Atlas I bought a Losmandy rail from ADM, they make one specifically for the Mak 7. For imaging I added a Meade electric micro focuser.

 

Enjoy your new scope!

 

P.S.

 

My imaging Mak 7...

 

Atlas LX50 Mak 7 (11-3-2017)-1.jpg

 

...and my visual Mak 7...

 

LX200 Mak 7 (11-14-2017)-3.jpg

 

Modern UWA eyepieces are a joy to use in the Mak 7 offering an excellent balance of image scale and field of view.


Edited by jgraham, 20 April 2019 - 02:12 PM.

  • gfstallin likes this

#7 jgraham

jgraham

    Hubble

  • *****
  • Posts: 19899
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 20 April 2019 - 02:11 PM

M1 – The Crab Nebula in Taurus
Telescope: Meade LX50 Mak 7 at f/15, Orion Atlas EQ-G
Camera: ZWO ASI071MC, Orion Imaging Skyglow Filter
Sensor Temperature: -10C, Gain: 300, Offset: 50
Guide scope: Astro-Tech 60mm, Meade DSI Pro II, PHD
Exposure: 56x240sec saved as FITS
Darks: 32x240sec saved as FITS
Flats: 32x30sec, LED tracing tablet
Average Light Pollution: Red zone, fair transparency, waning gibbous moon
Lensed Sky Quality Meter: 18.3 mag/arc-sec^2
Stacking: Mean with a 2-sigma clip.
White Balance: Nebulosity Automatic
Software: Nebulosity, Deep Sky Stacker, Photoshop

 

M1 (11-8-2017)-2j.jpg

 

Imaging at f/15 can be a bit of a challenge, but well worth the effort. The Mak 7 offers a surprisingly flat field that is almost completely free of coma. It also makes an excellent lunar and planetary scope.

 


  • Jim Davenport, Tyson M and clusterbuster like this

#8 hlritter

hlritter

    Sputnik

  • *****
  • topic starter
  • Posts: 25
  • Joined: 03 Sep 2014
  • Loc: Toledo, OH, and Sun City, FL, USA

Posted 20 April 2019 - 03:34 PM

That's a very impressive image from only 7" of aperture, and it's very encouraging to me, as I'm just getting started in astroimaging. (That's one of the reasons I'd like to put the OTA on a GEM.) I'm further encouraged in that you made it under observing conditions in the Dayton (?) area apparently worse than mine in either the Tampa-Sarasota or Toledo areas, and that you're using the same software as I have been. I don't yet have autoguiding capabilities, but I plan to add them. 

 

I take it that you've replaced the stock finder with the Astro-Tech guidescope?

 

I'm now actively looking forward to returning to Toledo for the spring just so I can get the Mak set up again and put to use imaging!

 

On a different topic: My impression, having moved back to the Toledo area only shortly before coming down to Florida at the beginning of this year, is that the club up there isn't too active. I believe that the MVAS is much bigger and more active, and for the opportunity to join in larger group outings to John Bryan (I had lived in Ohio previously as well and had a close friend in Dayton who was in the group), as well as occasional meetings, I'd be willing to join and make the 2 1/2-hour drive. Can you tell me a bit more about MVAS, or put me in touch with someone else if you'd prefer?

 

Thanks again for posting the information and the photos.

 

Howard Ritter

first dot last dot mac dot com

 

--howard



#9 jgraham

jgraham

    Hubble

  • *****
  • Posts: 19899
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 20 April 2019 - 04:16 PM

Yep, you need a good autoguiding system to image at f/15 and I have found that the Astrotech works great with my larger scopes.

 

I have been a member of the Miami Valley Astronomical Society for 43 years and we're still a very active group. In fact, we're in danger of out-growing our meeting room at the Boonshoft Museum of Discovery's Apollo Observatory!  I haven't been out to John Bryan in 25 years, but we still have a very active group using and maintain the facility. (I'm just not up to the 45 minute drive to/from the observatory these days. Maybe after I retire.) For more information you can visit our web site at MVAS.org and contact the club president (Linda Weiss) at Pres@MVAS.Org for more information.

 

Have fun!

 

P.S.

 

We had the usual miserable Ohio winter this year. Ugh.



#10 hlritter

hlritter

    Sputnik

  • *****
  • topic starter
  • Posts: 25
  • Joined: 03 Sep 2014
  • Loc: Toledo, OH, and Sun City, FL, USA

Posted 20 April 2019 - 04:56 PM

Thanks for the information. Here in Sin City Center (sorry, SUN City Center!) south of Tampa, we had good enough weather that I was able to get started in imaging over the winter. This is my first Omega Centauri, a few nights ago, with enough waxing gibbous moonlight and light pollution from Sarasota, directly under Omega (and from a zone that's already on the border of orange and brown) that the globular, at 8° elevation, was invisible w/o optical aid. This is just very basic imaging, a single exposure of 30s at ISO 200 with a Nikon 810A at, not very good polar alignment, and no guiding. and Photoshop. Lots of room for improvement with good polar alignment, really dark sky, 15° of elevation, multiple longer exposures, and maybe some deconvolution.

 

The scope is an AP 155 EDF on an AP 600E mount on a good wood tripod in my driveway.
 
I'm hoping to image Omega again before I leave, from a DS site in the Everglades and no Moon.

 

 

OmCenps1sm.jpg


Edited by hlritter, 20 April 2019 - 05:11 PM.

  • 3 i Guy, Jim Davenport, Tyson M and 2 others like this

#11 clusterbuster

clusterbuster

    Viking 1

  • *****
  • Posts: 628
  • Joined: 13 Mar 2016
  • Loc: Tampa Bay, Fl.

Posted 20 April 2019 - 07:36 PM

By the way, how could you tell I’m in Sun City?

Hi Howard,

Sun City Center, Fl. is on your signature, I didn't pull mine off of the forks, mine was deforked when I got it, I actually would have preferred that it had been left on the LX200 Mount.. as I really like those, the fan works well for cooling the Telescope, i put a nice SCT Dual Speed Focuser on it and it is a beautiful Telescope, I love it !!!

 

Mine has a Losmandy rail and I have a Vixen rail for it..

The OPTICS in this Telescope are the best that I have ever owned, I have read about these for years and have always wanted one, then this one came up on a classifieds add only 90 miles from me, I had to get it and I am glad that I did. 

 

Mark


Edited by clusterbuster, 20 April 2019 - 08:56 PM.

  • payner likes this

#12 munirocks

munirocks

    Messenger

  • *****
  • Posts: 467
  • Joined: 21 Oct 2013
  • Loc: Bourne End, UK

Posted 21 April 2019 - 06:56 AM

Many Mak users now use the insulation approach rather than the fan-cooling approach for internal temperature eqilibration. If you use the insulation approach, does this mean that the internal weight in the 7" Meade Mak is no longer an issue, temperature-wise? Is it possible that it might actually help?



#13 jgraham

jgraham

    Hubble

  • *****
  • Posts: 19899
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 21 April 2019 - 09:37 AM

That is an excellent question. I am intrigued by the insulation approach and I'm going to have to give that a try. Cats are so compact that insulating the tubes is fairly easy. It may also reduce the need for a heated dew shield as the slow heat loss through the corrector may be enough to keep the dew under control.

 

It'll be fun finding out!

 

:)



#14 SeattleScott

SeattleScott

    Aurora

  • *****
  • Posts: 4835
  • Joined: 14 Oct 2011

Posted 21 April 2019 - 03:49 PM

Correct if anything the weight would help stabilize the internal temperature. You want want to cover the fan vent if you insulate.

Scott

#15 mconnelley

mconnelley

    Viking 1

  • -----
  • Posts: 658
  • Joined: 14 Mar 2006
  • Loc: Hilo, HI

Posted 22 April 2019 - 12:40 AM

Hello:

      

  We have a 7" Mak here at work that I pulled the weight out of, just to make it lighter.  We had de-forked it years before, so we were using on a GEM anyways.  It wasn't too hard, just need to take it slow and be careful.  First you pull off the lens (which is fairly heavy), then pull the primary mirror out.  Take the focuser knob off and fans while you're at it.  Set these aside, far from where you're going to do the heavy duty work.  The weight is held in with some rather tenacious rubbery glue, so slow steady prying is what's called for with a sturdy screw driver.  Once it's loose, you'll find it's too big to fit through the hole that you just took the primary mirror out of.  Dang.  I pulled the weight out as far as I could, clamped it to our bandsaw table, and cut out about a 3" section of the steel weight.  That gave enough clearance to pull the rest of the weight out.  I put the scope back together, and the images were great and I didn't even have to collimate it.  

Cheers

Mike




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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics