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Equipment Discussions >> Cats & Casses

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eyepiecedropper
member


Reged: 12/31/11

Loc: aschaffenburg, germany
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5819895 - 04/24/13 02:14 PM

hi bob, itīs just a crude variation of a commercial cat cooler.

http://www.lymax.com/sct/photos.php
http://www.lymax.com/sct/how.php

the air duct on mine is not centered but the concept is exactly the same.


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dweller25
Pooh-Bah


Reged: 08/30/07

Loc: Lancashire, UK
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: eyepiecedropper]
      #5819977 - 04/24/13 02:53 PM Attachment (109 downloads)

Here's how I cool my 7" Mak......

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rob cos.
scholastic sledgehammer
*****

Reged: 03/11/04

Loc: New England
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: dweller25]
      #5819987 - 04/24/13 03:01 PM

Quote:

Here's how I cool my 7" Mak......




David, did you drill a hole in the diagonal and just attached the fan to it? Is there some kind of filter at the eyepiece end of the diagonal?

Thanks for sharing!

Rob


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dweller25
Pooh-Bah


Reged: 08/30/07

Loc: Lancashire, UK
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: rob cos.]
      #5820020 - 04/24/13 03:21 PM

Quote:

Quote:

Here's how I cool my 7" Mak......




David, did you drill a hole in the diagonal and just attached the fan to it? Is there some kind of filter at the eyepiece end of the diagonal?

Thanks for sharing!

Rob




Hi Rob,

Yes I just drilled a hole in the side of the diagonal - a cheap 2" Skywatcher - which is surprisingly good !!

I have removed ALL filter fabric - the Mak mirror is much easier to clean than my 8" Newt


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions [Re: eyepiecedropper]
      #5820736 - 04/24/13 08:09 PM

Quote:

hi bob, itīs just a crude variation of a commercial cat cooler.

http://www.lymax.com/sct/photos.php
http://www.lymax.com/sct/how.php

the air duct on mine is not centered but the concept is exactly the same.




Look at that! Now I understand. I didn't even know these existed. I'm going to have to see what I can do here....I have a 14" SCT now, and if I can have two tubes, we're in business! Thanks so much for your posting.
Regards,
bob


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5822008 - 04/25/13 12:49 PM

does anyone know what the prime focus for the Orion 180mm is? I mean how far beyond the rear of the rear cell it focuses? I'm trying to figure out if I order the adapter to schmidt-cass ring, and add a 2 speed focuser, if it'll have enough in-focus with a 1.5" focuser body and 90* diagonal......
Thanks
Bob


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Asbytec
Guy in a furry hat
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Reged: 08/08/07

Loc: La Union, PI
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5822288 - 04/25/13 02:15 PM

Bob, that seems to depend on the mirror lens spacing. You can come to focus quite a bit outside the visual back by changing that spacing using the focus knob. If you mean "prime focus" as being the proper mirror lens spacing, really I am not sure. Maybe somewhere near the top of the diagonal, as a guess. I am not sure how to set the proper spacing to check the focus.


Edited by Asbytec (04/25/13 02:20 PM)


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dbledsoe
Pooh-Bah
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Reged: 06/09/06

Loc: Boise, Idaho USA
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: Asbytec]
      #5823875 - 04/26/13 09:27 AM

What is the origin of those two little fans shown in this thread? I could use one for my Intes 6" f/12 Mak.

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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5824246 - 04/26/13 12:00 PM

Quote:

does anyone know what the prime focus for the Orion 180mm is? I mean how far beyond the rear of the rear cell it focuses? I'm trying to figure out if I order the adapter to schmidt-cass ring, and add a 2 speed focuser, if it'll have enough in-focus with a 1.5" focuser body and 90* diagonal......
Thanks
Bob




Here's the 'answer' I got, I must admit, quite fast, yesterday about prime focus and a 2" visual back/focuser....

Dear Bob

Thank you for contacting Orion.

Unfortunately I don't have the spec for the point of focus for the 180mm MC
but it is quite far back.

One caution, the port in front of the visual back is relatively small (less than 1.25") so I'm not sure how you would benefit from going to 2" accessories.
Clear skies and good observing,
XXXXXX

OK, then why does Orion sell an adapter to 2" SCT like accessories for it? Ug.

How do you define 'quite far back'?

If its true that the 'port' is less than 1.25", going to 2" would be worthless, except that you can use your 2" stuff. But then you'd have to be sure you could come to focus.

Does anyone make a 1.25 SCT dual speed focuser?

Can an owner of a 180mm Mak, either Orion or Skywatcher confirm the diameter of the visual back 'hole'? Thanks
Bob


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astro_baby
scholastic sledgehammer


Reged: 06/17/08

Loc: United Kingdom
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5824545 - 04/26/13 02:27 PM

The hole is quite narrow. I use a moonlite dualmspeed on the back of mine with a 2" diagonal. You can get away with 2" fit EPs so long as the field lens is no bigger than the hole in the back.

I will be able to measure mine tomoz if no one else has answered by then. I have yet to have a 2" EP fail tomcome to focus. Theres a lot of focuser distance in the Mak 180, well mine has at any rate.

Widefield EPs ? Some are tolerable in the Mak some less so. The ES14mm 100' works ok ish. The 30mm 82' less so.

Mostly I use a 2" diagonal and 1.25 orthos in the scope.

Hope tha answers some questions at least.


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: astro_baby]
      #5825090 - 04/26/13 07:00 PM

Quote:

The hole is quite narrow. I use a moonlite dualmspeed on the back of mine with a 2" diagonal. You can get away with 2" fit EPs so long as the field lens is no bigger than the hole in the back.

I will be able to measure mine tomoz if no one else has answered by then. I have yet to have a 2" EP fail tomcome to focus. Theres a lot of focuser distance in the Mak 180, well mine has at any rate.

Widefield EPs ? Some are tolerable in the Mak some less so. The ES14mm 100' works ok ish. The 30mm 82' less so.

Mostly I use a 2" diagonal and 1.25 orthos in the scope.

Hope tha answers some questions at least.





Thanks Astro Baby. Always nice to get information directly from owners, especially of these Maks.
Not being that well informed about EPs and their functioning, you mention 'field lens'. Thats the exterior/last glass that you look into, right? (sorry
Also, did you have to get an adapter for the threads in order to use the Moonlite? Like the one Orion sells possibly?
I have a lot of wide field EPs, like the ES's. Why is it that the wide field, 30mm+ have trouble? (once again, not that EP smart)
Thanks
Bob


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Eddgie
Postmaster
*****

Reged: 02/01/06

Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5826198 - 04/27/13 12:23 PM

Quote:

OK, then why does Orion sell an adapter to 2" SCT like accessories for it? Ug.




For the simple reason that the SCT thread is something of a "universal" thread.

Lots of accessories attach using SCT threads.

Examples are focuser (you can use a 2" focuser with a 2" to 1.25" adapter) T-adapters for imaging, and accessories like the Baader 15mm SCT to T thread adapter for attaching binoviewers.

Of course the limit of the SCT back is the fact that it offers a small rear opening, so larger SCTs have a 3.25" back, but these are normally provided with a stop down adatper to, guess what, the standard SCT thread. Most owners remove the 3.25" plate and go to a AP , Eye Opener, Clicklock, or some other port that opens to 2".

Anyway, hope this answers your quesiton. The reason they sell SCT tread adapters is because there is a use aftermarket of accessories that are either 2" (like eyepeise) or specilized (imaging, binoviewing, etc).


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astro_baby
scholastic sledgehammer


Reged: 06/17/08

Loc: United Kingdom
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: Eddgie]
      #5826287 - 04/27/13 01:09 PM

Spongebob.....

The exit hole on the back of a Skymax 180 is 25mm in diameter (I have an older version of tyhe scope but I would think its safe to assume the newer ones are no different in this respect although the external fitting is different I believe) the exit port with the threads on acts as a field stop as far as I can tell as the light baffle is slightly wider inside the scope.

The field lens is the bit of the eyepiece nearest the telescope and furthest from your eyeball. ie the one at the bottom of the EP.

I find some EPs with wider field lenses work ok so long as your happy with the vignetting prodiced by the telescopes small rear aperture of 25mm. The widest bit of glass I have used iss an ES 30mm 82' and its horrible - the scope induces the EP into the 'ring of fire' syndrome where the edge of the EP glows with a bright ring. Its very distracting and generally very undesirable. On the other hand the ES 14mm 100' works ok(ish). it vignettes but the view on the centre of the FOV is perfectly fine. Lets face it if you want mega wide views of things then a Mak isnst really the ideal instrument to be using. Thats not a genative againts the Mak - all telescopes have their downsides (Newts are fussy with collimation and create coma, Achromatics produce CA and APOs are hellish expensive so nothings ever perfect - its always a compromise to some degree).

If you want a full on hit/review of my own experiences with a Skymax I wrote it all up here http://www.astro-baby.com/reviews/Skymax%20180/Skymax%20180%20Review.htm

The article covers my own personal journey with the scope and you may find it of interest.


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: astro_baby]
      #5826714 - 04/27/13 04:45 PM

Quote:

Spongebob.....

The exit hole on the back of a Skymax 180 is 25mm in diameter (I have an older version of tyhe scope but I would think its safe to assume the newer ones are no different in this respect although the external fitting is different I believe) the exit port with the threads on acts as a field stop as far as I can tell as the light baffle is slightly wider inside the scope.

The field lens is the bit of the eyepiece nearest the telescope and furthest from your eyeball. ie the one at the bottom of the EP.

I find some EPs with wider field lenses work ok so long as your happy with the vignetting prodiced by the telescopes small rear aperture of 25mm. The widest bit of glass I have used iss an ES 30mm 82' and its horrible - the scope induces the EP into the 'ring of fire' syndrome where the edge of the EP glows with a bright ring. Its very distracting and generally very undesirable. On the other hand the ES 14mm 100' works ok(ish). it vignettes but the view on the centre of the FOV is perfectly fine. Lets face it if you want mega wide views of things then a Mak isnst really the ideal instrument to be using. Thats not a genative againts the Mak - all telescopes have their downsides (Newts are fussy with collimation and create coma, Achromatics produce CA and APOs are hellish expensive so nothings ever perfect - its always a compromise to some degree).

If you want a full on hit/review of my own experiences with a Skymax I wrote it all up here http://www.astro-baby.com/reviews/Skymax%20180/Skymax%20180%20Review.htm

The article covers my own personal journey with the scope and you may find it of interest.




Hi Astro Baby and Eddgie,
Thanks so much for your 1st hand information.
I'm a bit surprised how small the hole is. I guess with a f/15 scope, that light cone is really long and tapers down quite slowly.

As to the wide fov EPs, that absolutely makes sense that wide EPs / wide fov's are not what we're going for with this scope. Luckily I have a couple ortho's and plossls. This will be for me, my lunar and planetary and tight DSO backyard scope.
Field lens. duh,.... sure, that's the lens next to the field stop I should've known that!
Thanks for the link. I read it with great interest, especially the Moonlite focuser part. So a focuser at this point in this kind of scope really doesn't give you anything more than a 2 speed focuser and the ability to use 2" accessories. And it not too long to create any problems with in focus when used with a 2" diagonal. I'm kind of torn right now. Perhaps I'll wait until mine is delivered to make that decision. I have a Baader clicklock 2" diagonal which I love and I love being able to rotate the focuser. I do as much observing sitting down....another benefit of a Mak-Cass during 3-4 hour observing sessions...less fatique.

Do I assume correctly that you bought the Mak thread to Cass thread adapter so that the SCT Moonlite would work?

Well, thanks again for the information!

Regards
Bob

Edited by spongebob@55 (04/27/13 05:07 PM)


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5826767 - 04/27/13 05:16 PM

Well, I ordered an Orion f/15 Mak. Won't be delivered until mid June, but that's OK. I don't want to close this thread down yet; I'm sure I'll have more questions, and I think that the Mak-Cass platform has a lot to offer to an informed observing audience. Well, I'll see, won't I?
Keep your 'cards and letters' coming. And you readers, if you have a question, join the conversation. You see how informative these guys are! Thanks.


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astro_baby
scholastic sledgehammer


Reged: 06/17/08

Loc: United Kingdom
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: spongebob@55]
      #5826978 - 04/27/13 06:53 PM

Spongebob,

I wouldnt buy a two speed focuser until you have used the scope and mace up your own mind about whether you find the image shift caused by a Maks focusing to be acceptable or not. For me it was bearable but I wanted better, others find its fine as it is. In many of these things its a matter of taste.

I did get the an afapter to connect the Moonlite to the scope. The ealy scopes though, and mine is from among the first ever available had different threads go later models so it would be wise to wait and see and/or consult a dealer. I believe, but dont know for sure, that the later scopes have a standard SCT thread whereas the early ones had a sifferent sized thread. Slightly smaller than an SCT thread on the orginals.
Lucky for me I hac an adapter thrown in with the scope.

Perhaps somone else can afvise on ghis on later models.


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Wil2010
super member


Reged: 08/17/10

Loc: Millville, CA
Re: Orion 180mm Maksutov-Cassegrain Questions new [Re: astro_baby]
      #5829845 - 04/29/13 10:22 AM

Hello.

Looking at the Orion 180mm for imaging moon and planets using Mallincam Signature Video Camera. I understand that these scopes provide nice views of solar system objects due to its high f/15. Seems like a challenge is the cooling down, I live in northern California.. very warm in summer.. 100 F during daylight, high 70's low 80's at night. so do you think the cool down will be long. Again, Im looking to use this OTA for lunar and planetart video imaging. Thanks for any input.. I havnt ordered one yet, but have a few interested sellers..


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spongebob@55
scholastic sledgehammer
*****

Reged: 12/26/11

Loc: Bergen Co. New Jersey
Re: Orion 180mm Maksutov-Cassegrain Questions [Re: Wil2010]
      #5830006 - 04/29/13 12:00 PM

Quote:

Hello.

Looking at the Orion 180mm for imaging moon and planets using Mallincam Signature Video Camera. I understand that these scopes provide nice views of solar system objects due to its high f/15. Seems like a challenge is the cooling down, I live in northern California.. very warm in summer.. 100 F during daylight, high 70's low 80's at night. so do you think the cool down will be long. Again, Im looking to use this OTA for lunar and planetart video imaging. Thanks for any input.. I havnt ordered one yet, but have a few interested sellers..




Good for you! Will you keep it in a A/C house? Then matching a, say 78 degree house with a 70 degree night shouldn't be too bad. Or plan and put it out in a shed, if you have one. Or your basement, if you have one. Or take a look up this thread about the Mak coolers....
I do these with my 14" SCT, which has much more glass than a 150 Mak, and have no problems. But video/imaging is more intense, so if you know this going in, then you'll be prepared. Why don't you go over the the imaging forums and ask for some 1st hand advice there. Of course they'll say, get a refractor or a 5 or 6" SCT..... and it might be better. I'm visual, so that's the place to ask I would say.


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Wil2010
super member


Reged: 08/17/10

Loc: Millville, CA
Re: Orion 180mm Maksutov-Cassegrain Questions [Re: spongebob@55]
      #5830490 - 04/29/13 03:16 PM

I can keep it out in the garage.. garage is in the shade... I was thinking
the 180mm Mak because of the feedback on its excellent performance with lunar and planetary.. so I was assuming it would be best for video imaging.. from what I get from your post, maybe not??


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Wil2010
super member


Reged: 08/17/10

Loc: Millville, CA
Re: Orion 180mm Maksutov-Cassegrain Questions [Re: spongebob@55]
      #5830491 - 04/29/13 03:16 PM

I can keep it out in the garage.. garage is in the shade... I was thinking
the 180mm Mak because of the feedback on its excellent performance with lunar and planetary.. so I was assuming it would be best for video imaging.. from what I get from your post, maybe not??


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