Return to the Cloudy Nights Telescope Reviews home pageAstronomics discounts for Cloudy Nights members
· Get a Cloudy Nights T-Shirt · Submit a Review / Article

Click here if you are having trouble logging into the forums

Privacy Policy | Please read our Terms of Service | Signup and Troubleshooting FAQ | Problems? PM a Red or a Green Gu… uh, User

Equipment Discussions >> Cats & Casses

Pages: 1 | 2 | (show all)
pdxmoon
scholastic sledgehammer
*****

Reged: 06/27/13

Loc: Oregon
Re: Attention all Star Max 90 Owners new [Re: rocketsteve]
      #5970962 - 07/14/13 06:33 PM

Quote:

I've owned a StarMax 90 since 2004 and have never needed to collimate it. I even brought my mak to the Grand Canyon when I took my family on vacation in 2005. It was one of my carry-on items, so it went through TSA scanning and inspection, jostling in and out of the overhead compartments, and it was perfectly fine after returning home. Even though the scope is small, it's quite robust in it's construction. It's my primary telescope when doing planetary observing.


Dropping the telescope, onto a hard surface, is probably the only thing that would wreck your collimation...




Hey Steve, what mount do you have your 90 on?


Post Extras: Print Post   Remind Me!   Notify Moderator  
CollinofAlabama
Carpal Tunnel
*****

Reged: 11/24/03

Loc: Lubbock, Texas, USA
Re: Attention all Star Max 90 Owners new [Re: pdxmoon]
      #5971103 - 07/14/13 07:54 PM

Thom,

Now this ...

Astrozap 100mm Mak

... is the one that fascinates me. Earlier I wrote the 102mm Apex isn't twice as good as a C90, which is true. But it's definitely $40 better! OTOH, I've read the focusers on these, which are Chinese but not Synta, have a bit of slop. That's NOT cool, and enough to avoid them if true. OTOH, I've read reviews of the Vixen on IceinSpace, the CloudyNights.com counterpart of Australia and the Pacific Rim. Appears the optics are good, but not as robust, and one PiTA to collimate.

Although the Gregorian-type Maksutov's that Orion and Celestron sell (the Synta models) are solid collimation-wise in my and a thousand other folks' opinions, other types of Maksutovs, Newtonian, and apparently this Vixen variety, can apparently be a genuine bear to collimate.

Enjoy the C80ED, then pick up one of Jim's or a Synta MCT later. Gotta run, 20 month old unhappy.


Post Extras: Print Post   Remind Me!   Notify Moderator  
pdxmoon
scholastic sledgehammer
*****

Reged: 06/27/13

Loc: Oregon
Re: Attention all Star Max 90 Owners new [Re: rocketsteve]
      #5971552 - 07/15/13 01:17 AM Attachment (15 downloads)

Ok, another question: Can a Mak 127 ride on a vixon Porta II? 8 pounds. And as far as mounting it on my old polaris EQ, does it need to be mounted with ring tubes, like the refractor? If yes to this, what size? I'm not clear on how I'd mount the mak 127 to this:

Post Extras: Print Post   Remind Me!   Notify Moderator  
pdxmoon
scholastic sledgehammer
*****

Reged: 06/27/13

Loc: Oregon
Re: Attention all Star Max 90 Owners new [Re: CollinofAlabama]
      #5971608 - 07/15/13 02:41 AM

Quote:

Thom,

Now this ...

Astrozap 100mm Mak

... is the one that fascinates me. Earlier I wrote the 102mm Apex isn't twice as good as a C90, which is true. But it's definitely $40 better! OTOH, I've read the focusers on these, which are Chinese but not Synta, have a bit of slop. That's NOT cool, and enough to avoid them if true. OTOH, I've read reviews of the Vixen on IceinSpace, the CloudyNights.com counterpart of Australia and the Pacific Rim. Appears the optics are good, but not as robust, and one PiTA to collimate.

Although the Gregorian-type Maksutov's that Orion and Celestron sell (the Synta models) are solid collimation-wise in my and a thousand other folks' opinions, other types of Maksutovs, Newtonian, and apparently this Vixen variety, can apparently be a genuine bear to collimate.

Enjoy the C80ED, then pick up one of Jim's or a Synta MCT later. Gotta run, 20 month old unhappy.




All great info, with my thanks. I intend to give the 80ED quite a workout. A MAK is for down the line, but it's never too soon to start the education.

Enjoy the 20 month old--all the cliches are true. You turn around and they're 27, like my son!


Post Extras: Print Post   Remind Me!   Notify Moderator  
CollinofAlabama
Carpal Tunnel
*****

Reged: 11/24/03

Loc: Lubbock, Texas, USA
Re: Attention all Star Max 90 Owners new [Re: pdxmoon]
      #5971625 - 07/15/13 03:09 AM

Thom,

Check this out ...

CN post about Steve Forbes

... and my own experiences. As I recall, I did this same thing with my old Orion AstroView (Orion's Vixen Polaris clone). Today they ship with the vixen dovetail built in, but when I got my Orion 100mm F/6 achromat sometime in 2003 (or 2004?), it came with the old, no vixen dovetail like and requiring tube ring installation per OTA like yours. I contacted Universal Astronomics and they built me a plate. I even paid less by having it sent in a metallic, unpainted manner. I like the sleek, raw aluminum silver it came it. Bolted it on where the old tube ring posts were and voilà, instant vixen dovetail saddle. I know I didn't mail my mount anywhere, btw, but Orion's got a pretty good following, so people build to it. Even tho the Vixen Polaris set the standard, it got out-cloned (like Compaq vs the genuine IBMs of the early 90's, to make a Personal Computer analogy, if that helps). But regardless, this CAN be done. Heck, I did it. You can too. Then you'd get various vixen plates, screw the tube rings to be individual plate and you remove and replace scopes from your mount at will, regardless if the tube rings of the individual scope. Orion sells rings for their 127 Mak, btw.


Post Extras: Print Post   Remind Me!   Notify Moderator  
CollinofAlabama
Carpal Tunnel
*****

Reged: 11/24/03

Loc: Lubbock, Texas, USA
Re: Attention all Star Max 90 Owners new [Re: CollinofAlabama]
      #5971627 - 07/15/13 03:18 AM

Googled "dovetail saddle for vixen Ploaris" and found this ...

ADM adapter

Found my post on this matter from 2007 here.

Looks like what you need. Call UA or ADM and ask. Oh, you'll need a vixen dovetail for your C80ED. Of course, the Orion Maks all come with one already attached, so you won't even need tube rings to attach one of them to your mount if you had a saddle installed.

I'm back in the saddle again. Out where a friend is a friend.


Post Extras: Print Post   Remind Me!   Notify Moderator  
spencerj
Pooh-Bah
*****

Reged: 11/17/04

Loc: Londonderry, NH
Re: Attention all Star Max 90 Owners new [Re: jrbarnett]
      #5972036 - 07/15/13 11:15 AM

Quote:

Problem is, like other folded catadioptric designs, the MCT uses fast mirrors to achieve a system focal ratio of f/13. Collimation criticality depends on the speed of the mirrors, not the final system in such a scope. These MCTs are every bit as dependent on perfect collimation for best results as an SCT I suspect (most of which have f/2(!) primaries; collimating an SCT is akin to collimating an f/2 Newtonian).

Regards,

Jim




I agree with Jim. I have owned a number of MCT's over the years: 90mm Apex, 127mm Apex, M503, MK66, M703. They ranged from F10 to F13 and the sweet-spot for collimation is a lot smaller than a half inch.

That is a huge target and if true, these scope would never be that far out. In my experience, very small collimation changes (1/8 turn of a screw) in these scopes make a big difference at the eyepiece. In a properly collimation MCT the images are very sharp, in a slightly miscollimatied scope, the images are soft.

I have had to collimate every one of my MCT's. Usually once set, it holds very well but it cannot be ignored. Collimation is not that difficult, but it needs to be done from time to time.


Post Extras: Print Post   Remind Me!   Notify Moderator  
pdxmoon
scholastic sledgehammer
*****

Reged: 06/27/13

Loc: Oregon
Re: Attention all Star Max 90 Owners [Re: CollinofAlabama]
      #5972037 - 07/15/13 11:16 AM

Thank you Collin!

Post Extras: Print Post   Remind Me!   Notify Moderator  
jrbarnett
Eyepiece Hooligan
*****

Reged: 02/28/06

Loc: Petaluma, CA
Re: Attention all Star Max 90 Owners new [Re: pdxmoon]
      #5972799 - 07/15/13 05:53 PM

Google for images of an SCT or MCT on the Vixen Porta II. What do you find? Not much.

Why? Ergonomics.

The Vixen is a uni-directional alt-az mount. The front of your scope *must* face in the opposite direction of the sweep of the fork arm.

Depending on where the dovetail is mounted relative to the orientation of the focuser knob, it can put the focuser in awkward places, such as pinched between the side of the diagonal and jaws of the mount saddle or above the diagonal at 12 o'clock such that the eyepiece gets in the way of focusing.

I've seen some folks rig L-brackets to allow the SCT/MCT to be mounted dovetail-down to preserve ergonomics, but that means more bits and pieces and more tinkering.

Another alternative if you end up with bad focuser placement would be to move the dovetail 90 degrees in one direction, assuming there are tappings that allow that or you don't mind drilling new tappings into your baby.

If you can rig it ergonomically though, the Port II should be able to carry that OTA.

http://www.cloudynights.com/ubbarchive/showflat.php/Cat/0/Number/777047/page/...

Regards,

Jim

Edited by jrbarnett (07/15/13 06:33 PM)


Post Extras: Print Post   Remind Me!   Notify Moderator  
orion61

*****

Reged: 10/20/07

Loc: Birthplace James T Kirk
Re: Attention all Star Max 90 Owners new [Re: pdxmoon]
      #5972831 - 07/15/13 06:15 PM

I had one for 3 years never had to touch it.
I have an ETX Astro that I have had since they came out.
I finally sold the Orion 90. The ETX was a tad better,
The Starmax lacked a bit of contrast compaired.
But you can drop them off a Mountain, and unlike Hank Williams Jr. have no need to align them. I'm sorry Hank....


Post Extras: Print Post   Remind Me!   Notify Moderator  
rocketsteve
sage
*****

Reged: 04/17/11

Loc: Southeast Louisiana
Re: Attention all Star Max 90 Owners new [Re: pdxmoon]
      #5982946 - 07/21/13 12:42 PM

Quote:

Quote:

I've owned a StarMax 90 since 2004 and have never needed to collimate it. I even brought my mak to the Grand Canyon when I took my family on vacation in 2005. It was one of my carry-on items, so it went through TSA scanning and inspection, jostling in and out of the overhead compartments, and it was perfectly fine after returning home. Even though the scope is small, it's quite robust in it's construction. It's my primary telescope when doing planetary observing.


Dropping the telescope, onto a hard surface, is probably the only thing that would wreck your collimation...




Hey Steve, what mount do you have your 90 on?





Sorry it took so long to reply...


It's your standard, run-of-the-mill EQ-1 mount with an EQ-1M tracking motor attached to it. I replaced the slow-motion control cables with radio tuning knobs that I bought from Radio Shack. They work really well and don't get hung up on the mount when the telescope rotates to the zenith. Instead of using the battery pack, that came with the tracking motor, I set it up so I could use a 6-volt, 12 amp-hour, SLA battery. The battery provides enough power to run the drive for at least two nights of observing, which comes in handy at weekend-long star parties. Also, the battery has some weight to it, so vibrations are dampened.


Post Extras: Print Post   Remind Me!   Notify Moderator  
Pages: 1 | 2 | (show all)


Extra information
19 registered and 27 anonymous users are browsing this forum.

Moderator:  Starman27, kkokkolis 

Print Thread

Forum Permissions
      You cannot start new topics
      You cannot reply to topics
      HTML is disabled
      UBBCode is enabled


Thread views: 1222

Jump to

CN Forums Home


Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics