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Where are the Mak-Newt people?

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#101 glend

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Posted 03 May 2016 - 06:53 PM

I like the idea of that Starlight adaptor ring. Moonlight has made a complete base replacement and it probably costs more ($160-190 I think). Honestly you don't need much backfocus for say a Canon DSLR, and any EP you use for visual use could be accomodated with a 2" extension tube which many people already have.  David, what was the cost of the Starlight complete solution?

 

BTW I lived in Calgary and Lethbridge for many great years working for Northern Telecom and AGT, I really miss the province.



#102 David_Ritter

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Posted 03 May 2016 - 07:10 PM

Yes, the ring worked out quite well. Originally Starlight was going to make a complete base for me but after they looked at the base I'd sent in they came up with the ring idea. Much cheaper for me and easier for them too I think.

 

I don't recall the exact cost but it was around 675 $CDN or so, which included shipping. I think it was about $400 US for the focuser, a little under $100 US for the ring and the rest was for shipping.

 

NT and AGT... that takes me back. I worked for a computer equipment supplier back in the '80's and serviced some equipment at a Northern Telecom shop in Edmonton. And AGT, of course ran all the phones except in town here it was Ed Tel until AGT took them over just before they privatized...

 

Things are still pretty good here despite the drop in oil prices. Yes, lots of people have been laid off but the economy in general is accustomed to highs and lows and you wouldn't really call it a recession unless you read the papers. (or lost your job... then its a catastrophe of course!) And its HOT! Today its 29C, hotter than even Arizona is. And the skies are clear finally, no bugs yet and my 190 is already set up on the EQ8. Looking forward to nightfall tonight!



#103 Yu Gu

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Posted 04 May 2016 - 07:27 AM

David, thanks for posting the photo! It looks like a nice design. I have the OTA and the focuser, just need to get the ring...

Gu



#104 dr.who

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Posted 04 May 2016 - 05:16 PM

 

When it arrives I will be happy to. Anything in particular you are looking to see? As to performance, I had one before. It performed very well with crisp clean pinpoint stars to the edge of the field. It was very close in performance to my 127 APO which is why it was sold. Too close in performance. I am buying it again because it will be for outreach use and some EAA. I plan to test it with my QSI and Astro Toaster to see if the 814 chip will do as well as the APS-C for near real time observing (NRTO) of DSO.


This sounds really good. Was it sharp to the edge with the ES 82 degree 30mm? How was the high power for planetary viewing? It would be good to see close ups of the primary mirror cell adjustments and the secondary housing. Did you do any star test?

 

 

I didn't use it with the 82 degree 30mm I used it with the 18mm and 24mm 82* and it was flat to the edge (going by memory). It took power quite well and gave refractor like views of DSO and planets with similar scale. OK. when it comes in I will shoot that for you. I did not do a full on star test ala Dr. D.



#105 rolo

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Posted 04 May 2016 - 07:42 PM

I realized a long time ago that a MN wasn't worth it. Why spend thousands on a MN8 when a good 8"f/6 Newtonian will do the same for a fraction of the price. The Newtonian cools faster, is lighter, easier to manufacture, gives just as good performance if not better and no dew issues.


Edited by rolo, 04 May 2016 - 07:43 PM.


#106 Dwight J

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Posted 04 May 2016 - 08:33 PM

"I realized a long time ago that a MN wasn't worth it. Why spend thousands on a MN8 when a good 8"f/6 Newtonian will do the same for a fraction of the price. The Newtonian cools faster, is lighter, easier to manufacture, gives just as good performance if not better and no dew issues."

 

Although the Newtonian has some advantages over an MN, maintaining collimation is not one of them.  I have never collimated my MN.  At F5 I don't need a coma corrector either.  My secondary is small, no spider vanes to add diffraction/lessen contrast.  It cools nicely with a fan mounted behind the primary and vents surrounding the meniscus.  Dew is managed by a dew cap.  In terms of performance, I will put my scope up against any 8" Newt.


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#107 David_Ritter

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Posted 04 May 2016 - 08:38 PM

Yes... what he said :graduate:



#108 tazer

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Posted 05 May 2016 - 07:35 AM

Although the Newtonian has some advantages over an MN, maintaining collimation is not one of them.

 

I supposed it depends on the manufacturer. For the price of a Ceravolo I would be very upset if it wouldn't maintain collimation. For the price of an ES Levy Comet Hunter it's kind of a given.

 

Newtonians are definitely easier to collimate than a Mak-Newt. So if that's a concern to someone then either stick with a Newt+CC or spend the money to get a well built MN.

 

Mark 



#109 dr.who

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Posted 05 May 2016 - 12:25 PM

Mark et al. How do you collimate a MN? I thought it would be pretty similar to how to collimate a Newt save for possible rotation of the secondary mirror which should be straight forward to deal with using a sight tube... no? Oh and I read the article on the Collimation of the IM MN and my take away from it was make sure the secondary is squared up then collimate as if it were a regular Newt.



#110 tazer

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Posted 05 May 2016 - 01:40 PM

With a regular Newt you align the secondary under the focuser as your first step, you then align the focuser-primary axis by adjusting the primary, and finally you eliminate residual misalignment with the use of a sensitive tool like an autocollimator. The tilt of the primary is of less concern in this design as you can ultimately adjust the secondary/focuser to compensate.

 

With the MN you need to ensure that the primary mirror is aligned with the corrector as your coma-free field will be compromised if it isn't. You also need to make sure the focuser axis is coincident with the primary-corrector axis. In a well designed and well produced MN this isn't a problem. The ESLCH is an inexpensive model so compromises were made. That's not a bad thing, it just is what it is.

 

How I do this with the ESLCH is to align the secondary under the focuser with the TeleCat XLS. Instead of adjusting the focuser-primary axis I put in the BlackCat XL (any collimating eyepiece will do) and rack the focuser all the way in. Shining a light into the OTA I observe the retaining ring of the corrector and make that concentric within the primary reflection (by adjusting the primary.) Ideally the focuser is now aligned with the primary-corrector axis as well. I then check alignment with the XLKP autocollimator and will make small adjustments to the secondary/primary as needed. I'll then recheck the primary-corrector axis to ensure it's still reasonably concentric. If it isn't, I start over.

 

I had to play with the depth of the secondary before things finally magically lined up. I'm not sure if I messed it up at some point or not, but once I got it right the views were so much better. My mediocre performer on planets was now superb.

 

I'm not saying you anyone should do a "soup to nuts" collimation, but if you feel it's not performing as well as it should, it'd be worth noting how concentric the corrector retainer is in the primary reflection. Actually, I'd be interested to know how concentric it is on your scope when it arrives dr.who. 

 

Mark



#111 dr.who

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Posted 05 May 2016 - 06:46 PM

Thank you Mark. I will check it. Assuming it is decently close to concentric are the steps for collimation the same as I noted above? I need something that is not going to be a PITA to deal with collimation wise and the more I read about the ES CH the more it looks like it could be a PITA and a better option would be a plain old newt...



#112 Jeff B

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Posted 05 May 2016 - 09:24 PM

With my Intes NM's:

 

1. My first step at collimation is to pull the secondary holder up against the backside of the meniscus, secure it there and rotate the secondary till it looks right.  

 

2. I then translate the focuser until it's centered front to back over the secondary and recheck its rotation.

 

3. I use the push-pull tilt screws for the focuser with a sight tube to square up and center the focuser over the secondary as best I can with the focuser fully racked in and out.

 

4. I repeat steps 2 & 3 if a tweak is needed (not very often)

 

5. Using my Glatter laser, I adjust the secondary screws so that the laser hits the primary's center spot.  The adjustments are usually small since I've pretty much squared the secondary with the meniscus in step 1 and the focuser over the secondary in steps 2 & 3.

 

6. I use the primary push-pull screw sets to adjust the now barlowed Glatter laser so that the shadow of the primary center dot is centered over the laser's aperture.  I run the focuser in and out to make sure the shadow stays reasonably centered (which it usually does).

 

7. I recheck everything with the sight tube.  There may be some slight unevenness in the dimensions of the fully illuminated field but experience tells me this is quite ok.

 

8. Star test at high power to make sure.  Paying special attention to how the diffraction patterns behave at high power close to focus (1-3 rings, each side) and the airy disk at focus.

 

Jeff


Edited by Jeff B, 05 May 2016 - 09:28 PM.

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#113 tazer

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Posted 05 May 2016 - 09:35 PM

If the primary & corrector are concentric then you only need to do some minor tweaking to get collimation finalized. I can't recommend the Catseye tools highly enough both for MN and for Newt collimation.

 

If I could go back in time, though, I'd have bought an 8" Newt with a quality coma corrector or a quality MN with a 20-25% CO. As it is the ESLCH is a compromise. The 8" Newt is the same weight as the 6" ESLCH, isn't a dew magnet, can have a coma free field with a Paracorr, is easier to balance, similar obstruction, easier to collimate, cools quicker, focuser adapters are readily available for it (it seems there are few to none for 6" scopes), etc.

 

That being said, I'll probably have my ESLCH for years and years. It produces good wide coma free views and can handle ~300X on planets with no diffraction spikes to distract you. The contrast really is surprisingly good and you can pop the plastic plug out of the primary cell and attach a fan to the back for quick cooling.

 

Mark



#114 dr.who

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Posted 06 May 2016 - 12:11 PM

Thank you Mark and Jeff. That makes the CH much less attractive as an outreach scope. I need it for that and it sounds like a Newt will do a better job for the same price...

#115 George Kiger

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Posted 06 May 2016 - 01:11 PM

... wide, flat field of a MakNewt ...

 

The field of a Maksutov-Newtonian is neither flat nor coma free. Field curvature is the same as the equivalent focal length Newtonian. Coma is much reduced compared to the Newtonian, but not zero. It is possible to build a flat field Maksutov-Newtonian but that requires the introduction on non-spherical curves (and no mass produced scope does this).

 

That being said, I am a big fan of the Maksutov-Newtonian. I have seen some wonderful high power views through them. My guess is that they are, in general, manufactured to deliver better correction for SA than the typical Newtonian.



#116 tazer

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Posted 06 May 2016 - 01:51 PM

You can get a 203mm f/4.9 Newt from Orion for $259.99. Tack on a Paracorr 2 for $405 and you're at ~$660. You'll need to add rings/dovetail, but the ESLCH will run you about $700 for everything. Good thing about the Paracorr is that you won't add that $405 onto the next Newt you get as you already have it. Or if you get a Newt f/6 or over then you don't really need one to begin with. I can't comment on it first hand though as I've never used the combination but, as I understand it, the Paracorr is the #1 accessory that never leaves the focuser and will travel from OTA to OTA.

 

The ESLCH is a great little scope, but if you're not imaging and diffraction spikes don't bother you, then get a Newt.

 

Mark



#117 glend

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Posted 06 May 2016 - 08:46 PM

"I realized a long time ago that a MN wasn't worth it. Why spend thousands on a MN8 when a good 8"f/6 Newtonian will do the same for a fraction of the price. The Newtonian cools faster, is lighter, easier to manufacture, gives just as good performance if not better and no dew issues."

 

Although the Newtonian has some advantages over an MN, maintaining collimation is not one of them.  I have never collimated my MN.  At F5 I don't need a coma corrector either.  My secondary is small, no spider vanes to add diffraction/lessen contrast.  It cools nicely with a fan mounted behind the primary and vents surrounding the meniscus.  Dew is managed by a dew cap.  In terms of performance, I will put my scope up against any 8" Newt.

I have a 10" f5 imaging newt sitting in my study, the MN190 is sitting on the pier in the observatory - that says it all as far as I am concerned. It is a joy to use, and produces wonderful images. It is being used with my mono Canon 450D right now for narrow band imaging.  No coma corrector required, no vanes, better contrast than the 10" newt, as stated cooling is not an issue especially in the observatory where it is always at ambient. 



#118 dr.who

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Posted 06 May 2016 - 09:18 PM

Thank you Mark. This is a public EAA and outreach scope for me so I need minimal fuss and muss. I will have to ruminate on it over the weekend. To be honest I wouldn't buy a Orion Newt. I had one. It was a Astrograph. I wasn't very happy with the build quality or the focuser and the fact that I had to spend over $700 to get adapters and a quality focuser for it. I am very interested in the Skywatcher Quatro CF but its no longer on the market. Also interested in the ES 203mm CF. They won't be in until June at the earliest though. That said the Mak-Newt's have always been a favorite of mine. I just wish the collimation of them wasn't such a hassle.

#119 bierbelly

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Posted 07 May 2016 - 07:24 AM

IDK man, one of the oft cited benefits of mns is that they hold collimation extremely well. I cant speak for all the newer versions, but IIRC the Ceravalo and Intes were legendary
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#120 dr.who

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Posted 07 May 2016 - 10:56 AM

Ceravolo's are amazing! Two club members own them... Wow! Just... Wow!

#121 tazer

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Posted 07 May 2016 - 01:18 PM

IDK man, one of the oft cited benefits of mns is that they hold collimation extremely well. I cant speak for all the newer versions, but IIRC the Ceravalo and Intes were legendary

 

Indeed. But you can't expect a $700 mass produced MN to be equivalent to a Ceravalo or Intes. The ESLCH is great for what it is, but it's definitely not on that level.

 

 

Thank you Mark. This is a public EAA and outreach scope for me so I need minimal fuss and muss.

 

It'll probably just fine for that. That's what I'm using mine for these days. Getting it close to collimation is a pain, assuming it's not already there when shipped. Once there it's easy enough to keep collimated and if you're not sensitive to coma, or you're not imaging, then it's not that bad at all.

 

I wanted the ESLCH to be better than it is but my expectations are more suitable for scopes in the $5000+ range. If you go into it with an appropriate mindset it'll be a good scope. 

 

Mark



#122 JohnH

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Posted 07 May 2016 - 04:20 PM

"I realized a long time ago that a MN wasn't worth it. Why spend thousands on a MN8 when a good 8"f/6 Newtonian will do the same for a fraction of the price. The Newtonian cools faster, is lighter, easier to manufacture, gives just as good performance if not better and no dew issues."

 

Although the Newtonian has some advantages over an MN, maintaining collimation is not one of them.  I have never collimated my MN.  At F5 I don't need a coma corrector either.  My secondary is small, no spider vanes to add diffraction/lessen contrast.  It cools nicely with a fan mounted behind the primary and vents surrounding the meniscus.  Dew is managed by a dew cap.  In terms of performance, I will put my scope up against any 8" Newt.

Dew is to ONLY major problem I run into my my various Mak/newts and Casses. heating has never been a problem once I started storing them in an unheated garage when I expected to use it.

 

Ceravolo's are amazing! Two club members own them... Wow! Just... Wow!

I concur. I had a chance to talk to Peter Ceravolo at TMSP 2015 about making high quality Maksutovs. He said smooth accurate curves with proper baffles do most of the job.



#123 rkayakr

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Posted 08 May 2016 - 07:30 AM

Another MN190 here in NE Ohio. I've only had it a few months but am very happy with it's performance. I think that the views are much sharper than my C8, particularly the C8 with reducer. My next largest GEM scope is an ES127 APO which is sharp, but the larger aperture, faster  MN190 usually gets the use these days.

I have a 10" dobs that is great for visual, I considered a newt astrograph, but the forums are filled with owners complaining about flimsy construction and articles on rebuilding them to stiffen. I was considering importing a more expensive  TS newt  when the MN190 went on sale last Fall and I jumped on it.

Here is a pic of use last Winter with a SV60ED on the top as finder/guide scope/ wide angle scope.

 

colsScope.jpg


Edited by rkayakr, 08 May 2016 - 07:31 AM.

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#124 tazer

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Posted 10 May 2016 - 09:38 AM

I used the ESLCH for the Mercury transit at a local university (public outreach). I'll have to say that it traveled, sans-case, in my front seat for 22 miles and only needed a smidge of an adjustment, based on the Catseye XLKP reflections, when I got there. So changing the springs on the primary makes the scope so much more reliable.

 

IMO, this makes the scope much more attractive to me. It's a bear to have to do (perhaps they changed springs in a recent revision?) but once done it does produce great views, and now that it travels well it'll be used a lot more.

 

The other cons still exist (e.g., dew, mediocre quality focuser, mid-range contrast due to CO%, etc) but they're acceptable if the scope can hold collimation well. 

 

Mark



#125 bierbelly

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Posted 10 May 2016 - 02:25 PM

I'd like to take a poll.  How many of you here have actually owned a MN and gotten rid of it in favor of a conventional Newt of the same size?




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