Vixen Polarie - Compact Star Tracker

[Gary]

Another alternative to Astrotrac.

http://www.vixenoptics.com/mounts/polarie.html

http://www.rainydaymagazine.com/RDM2012 ... an0412.htm

[maguro77]

UPDATE: The Latest Vixen Polarie setup (Feb 2013) is updated here viewtopic.php?f=3&t=11765

Thanks Gary, for pointing this out.

I decided to buy one whilst in the US recently ... my continual quest to look for a lightweight, compact wide field imaging set up. Got a chance to try this out and would like to provide a preliminary review on the Vixen Polarie Star tracker.

My set up is as follows:

1) The Polarie is mounted on a manfrotto 410 Junior geared head.
2) A second ballhead is needed to attach the camera to the Polarie. Best to get a ballhead with a lever type locking mechanism (like an oversized wing nut, if you know what I mean) rather than those with small round knobs. I use a Velbon QHD 61 which fits onto the Polarie camera mounting block by a spring loaded screw. The mounting block is then secured to the polarie body via thumbscrews. Wish the thumbscrews were longer as i am constantly tightening it to ensure the mounting block doesnt slip.
3) The telescope is the mini Borg 50 mm with 7885 reducer on a modified Canon 500D with LP filter. Focal length is about 200+ mm and cam + scope weighs about 1.2 kg. The Polarie is rated to carry up to 2 kg.
4) Rough polar alignment is done with a compass. There is a compass that fits nicely into the polarie but its not very accurate. Its best to use another compass that has graduated scales for more accurate alignment especially for longer focal lengths.

For imaging with the Borg 50, it is necessary to do drift alignment - which is why the manfrotto 410 junior head is needed for the fine adjustment. I attach a Vixen GA-4 illuminated guiding adapter to the borg scope with a high power eyepiece and drift align until i can get the star to stay still for 1 minute. This adapter is great cos you can move the cross hair around instead of having to move the scope to centre the star. Important when you dont have fine controls on the scope as in a normal EQ mount.

Because our latitude is near zero, the polarie is at horizontal level, which means the telescope is difficult to maneuver and certain parts of the sky cannot be imaged. Unless i can find a ballhead that is taller such that the camera clears the top of the Polarie.


Set up by tuna7777, on Flickr

Here is a crop picture of the orion nebula taken last nite with this set up. Stacked six 1-minute images at ISO 400 with four dark frames, with basic photoshop processing skills. Dont know why my pictures always look grainy...


Orion Polarie by tuna7777, on Flickr

Original image looks like this - with Gibbous moon and thin layer of clouds plus horrible horrible light pollution from Pulau Bukom/Jurong.

IMG_3934 by tuna7777, on Flickr

The polarie tracker looks promising although things can be improved - looking to replace the Velbon ballhead mount for something that has slow motion controls. Also figuring how to get a laser pointer attached to the top of the scope to help in pointing the scope.

Despite having to carry two tripod head mounts, when coupled with the mini Borg, the complete set up packs nicely into a Lowepro camera bag with total weight of 7.5 kg excluding laptop and tripod. I hope this review is of use to those considering it. Always welcome to hear any ideas or improvements to my set up.


P1050749 by tuna7777, on Flickr

[Gary]

Brilliant! Thanks for sharing your experiences and photos!

Since I am not an astrophotographer, I will let the experts answer your queries regarding the noise. Most probably you need to do some PS layers-related noise reduction and/or dark-frame subtraction techniques.

But to me, your final image is already quite impressive. Stars are round and not elongated. Brings back fond memories of how the "dagger" looks like in a widefield refractor under dark clear skies.

[orly_andico]

stars always look round at short focal lengths.


i still have Joyce's old old table-top Orion EQ-1 which probably was her first iteration in the "portable imaging setup" quest. it has a broken worm block (typical China stuff) but one of these days i'm gonna find the part to repair it and build a stepper motor drive for it with periodic error correction! (because the EQ-1 has hundreds of arc-seconds of periodic error)... somebody has actually already done this (PEC on an EQ-1).

of course that day will come after i've run out of things to do with my three other mounts.

[kochu]

Hi Joyce,
a very artculate description of an articulated contraption.


Kochu

[maguro77]

Thanks guys for the encouraging and articulate comments. The images from this set up are no where near Kochu's wonderful pictures... But hopefully will get me trying my hand at imaging again. Maybe this is my final iteration for the elusive 'do-it-all, go anywhere, cant be heavier than a bag of rice' imaging set up.

[Gary]

Venus super near M45 tomorrow. Give it a shot!

[Bergkamp_]

upzz!! =)