50mm photoguide refractor

by Astro-Tech Print

What would you like to print?
(Reviews and Documents/Videos will not be printed)

Basic Product Information
Full Description
Tech Details
Supplied Accessories
Recommended Accessories
Images

Print
More product information
The Astro-Tech AT50GS 50mm guidescope refractor is superb for guiding long-exposure astrophotography with refractors and imaging Newtonians up to 1200mm in focal length. However, it is also usable with longer focal length scopes, such as the Astro-Tech Ritchey-Chrétien astrographs.
 
Taking deep space photos used to require tedious and error-prone manual guiding through a crosshair eyepiece and a large aperture, long focal length guidescope. However, the guiding accuracy of modern CCD autoguiders allows hands-free automatic guiding of long exposure photos through smaller guidescopes with much shorter focal lengths. Using an optically "fast" guidescope, such as the 50mm f/3.6 Astro-Tech AT50GS, you save valuable time, space, and money, while still recording the pin-point star images that only autoguiding can bring to long-exposure astrophotographs.
  
How well does the Astro-Tech AT50GS perform as a guider? See for yourself. The feature image above of the Horsehead Nebula in H-alpha was taken by Dennis Wigley, John Dutton, and Kevin Davis. It used Dennis and Kevin's 80mm f/7 Astro-Tech apo refractor and John's mono Orion G3 camera. Dennis supplied the Meade LXD55 mount, Meade DSI pro guider, Orion 1.25" H-alpha filter, and Astro-Tech AT50GS guidescope. The 50mm AT50GS guided for nine 15 minute exposures and one 10 minute exposure – a total of 145 minutes of guiding. We invite you to check the roundness of the stars in the highly enlarged image above to see just how accurately the AT50GS can guide. 

The Astro-Tech AT50GS guidescope is a 50mm aperture 180mm focal length (f/3.6) achromatic refractor with a helical focuser. It has dual mounting rings with nylon collimation screws (three per ring). The rings are attached to a dovetail mounting bar. Add an optional small-chip CCD autoguider (such as the Celestron NexGuide), and you ready for automatic guiding.
 
The guidescope’s 1.23” (31mm) wide by 3.5” (89mm) long dovetail mounting bar fits into the dovetail finder base found on most Astro-Tech telescopes. If your imaging scope doesn't feature a dovetail base or has one already occupied by a finder, the included dovetail bar has predrilled holes that let you attach the Astro-Tech guidescope to almost any optical tube. It can mount in the alternate finderscope position at the 1:00 o’clock position on the rear cell of most Schmidt-Cassegrain scopes. It can also mount on one of the tube rings holding a refractor or reflector optical tube (which are usually drilled and tapped to hold just such an accessory).
 
The Astro-Tech AT50GS guidescope weighs only 15.2 ounces (20 ounces with the mounting rings and dovetail mounting bar). Its light weight lets you replace a heavier guidescope to gain a little breathing room with imaging setups that are pushing your mount's payload capacity. It measures 8-1/16” (205mm) long with the focuser collapsed. With the focuser fully extended it measures 9-7/16” (239mm) long. A 48mm long fixed dew shield shields the fully multicoated cemented doublet lens from stray light.

The  Astro-Tech  guidescope’s helical focuser has a fixed-orientation design that does not rotate your CCD autoguider during focusing. The helical focuser simply moves the attached autoguider in or out while maintaining its set orientation. This ensures that the field of potential guide stars will not rotate when focusing.
  
The focuser has two parts. The first is a drawtube with 23mm of travel slides in and out of the guidescope’s body to provide a rough focus. The tube has a scale marked in 1mm increments so you can return to the correct extension distance whenever needed. A thumbscrew holds the drawtube in position.
 
The second part is the helical focusing mechanism itself. This has a knurled focusing collar and adds another 10.75mm of travel for fine tuning the focus. A 0-10 scale on the drawtube has sub-markings that show each 1/10th mm of drawtube extension. A thumbscrew holds the helical drawtube in position.
 
The focuser terminates in a 1.25” accessory holder for those guiders that have a fixed 1.25” nose piece for connecting guider to guidescope. There are also male T-threads for a more solid and secure direct attachment of a guider whose nose piece can be removed to expose female T-threads for attachment to a guidescope.
     
When not being used for autoguiding, the Astro-Tech 50mm can be used as a finder scope. Just insert an optional Astro-Tech 24mm illuminated reticle eyepiece (#AT24IL) into the focuser and the versatile 50mm Astro-Tech guidescope turns into a 7.5x50mm straight-through illuminated crosshair finder with a 6.6° field of view and a long 20mm eye relief.
Weight:
The weight of this product.
20 oz.
Warranty:
2 years
There are currently no Cloudy Nights reviews associated with this product

User Ratings/Reviews from our Customers (www.astronomics.com)
Overall Product Rating: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics(3.67)   # of Ratings: 3   (Only registered customers can rate)

(Only registered customers can rate)

5 - Great (33.33%) (1 user)
4 - Good (0.00%) (0 users)
3 - OK (66.67%) (2 users)
2 - Bad (0.00%) (0 users)
1 - Very Bad (0.00%) (0 users)
0% 50% 100%
astronomics image
astronomics image

Sort Ratings: 

  Show these ratings: ALLGreatGoodOKBadVery Bad

loading request
Showing comments 1-3 of 3
1. Rob on 5/13/2014, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
Excellent guide scope.
I use it with a QHY5-II camera, and guiding is excellent.
Was this comment helpful? Yes No   (0 people found this comment helpful, 1 did not)
2. Tim on 3/5/2014, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
I like everything about it except that the helical focuser has some wiggle in it. The optics and rings are good but to use the scope as a guidescope I don't feel comfortable focusing with the helical focuser due to the wiggle. It won't wiggle if you crank the helical focuser all the way in or out which is what I do. Of course you then have to rely on the other focusing mechanism which is just sliding the focus tube in and out. I was told this was normal so I think you'll have to spend more $$ for a similar scope with no play in the helical focuser (Stellarvue or Borg perhaps).
Was this comment helpful? Yes No   (2 people found this comment helpful, 0 did not)
3. Dave on 2/7/2014, said: AstronomicsAstronomicsAstronomicsAstronomicsAstronomics
I got this guide scope because I liked the idea of the dual focusing feature. Although the draw tube works great, the helical focuser has too much play when tightened down to really be of any use. The only way to eliminate the play is to have the helical focuser either all the way in or all the way out and tight. Other than that, it is nicely built and the optics are first rate.
Was this comment helpful? Yes No   (2 people found this comment helpful, 0 did not)
Showing comments 1-3 of 3
We haven't recommended any accessories for this product quite yet... check back soon or call one of our experts (1-405-364-0858).
This product does not have supplied accessories... or supplied accessories have not been assigned.
Documents
No documents have been associated with this product.
Videos
No videos have been associated with this product.
There are currently no formulas associated with this product
50mm photoguide refractor

Click icon(s) below & hover image above for zoom

50mm photoguide refractorThe Astro-Tech AT50GS with the drawtube collapsed and 2mm of helical focuser extension.The Astro-Tech AT50GS with both drawtube and helical focuser fully extended.The Astro-Tech AT50GS mounting rings and dovetail.The underside of the Astro-Tech AT50GS mounting rings and dovetail.10 Exposure 145 minute total exposure time image guided by the AT50GS.
In Stock
 AstronomicsAstronomicsAstronomicsAstronomicsAstronomics (Average: 3.67 | Users: 3)  Only registered users can submit ratings - Register Here
Our Product #: AT50GS
Manufacturer Product #: AT50GS
Price: $119.95  FREE ground shipping - Click for more info
Congratulations. Your order qualifies for free ground shipping within the 48 contiguous United States.
Quantity:   

 E-mail this product to a friend E-mail this product to a friend

Your Email:  
Your Friend's Email:  
Confirm Friend's Email:  

Comments:
  200 characters or less
 

An email containing a link to this product has been sent to the email address you provided.

Clear Skies!
Astronomics

 Have a question? Do you have a question about this product?
 Found a better price? Found a lower price? Click to let us know... or call 800-422-7876 before you buy.

If you’ve found a lower delivered price on this product, let us know about it below. We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Your Name:  
Price:  
From Who:  
Context:  Magazine AdOnline
Website Address:  
Cut and paste the web address into the box above
Your Email:  
Confirm Email:  


We’ll do our best to meet or beat that price and will get back to you within one business day with our best offer. Thanks for giving us the opportunity to give you a better deal.

Clear skies,
Astronomics


The Astro-Tech AT50GS 50mm guidescope makes highly accurate autoguiding of deep space astrophotos affordable for any astrophotographer.





. . . our 35th year