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HoTech 2" SCA Field Flattener with T-Thread for f/5 - f/8 Refractor Telescope # FF582
| Brand | HoTech |
| Part Number | SCAFFT58 |
| Availability | available |
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Product Info
Manufacturer Description
High Quality Optics Designed for Refractor Telescopes! This field flattener is fully multi-coated on a two-element lens allowing the most efficient light transmission without sacrificing the precious light collected from your telescope. It accommodates f/5 to f/8 refractor telescopes. You will see bright and sharp images across the entire field.
The Field Flattener has built-in standard 2"/48mm (M48-P0.75) female filter thread on one side. On the other side is a male T-thread that accepts all kinds of 35mm cameras (Camera specific T-ring required for this is not included). The flattener's back-focus requirement is 56mm (2.2") from the male T-thread to the CCD chip on your camera. This is to be measured from the shoulder of the flattener (where the male T thread begins). The length of the male T thread is approximately 2.5mm but this will be covered by the T thread spacer or T ring. Many T rings have a thickness of 16mm, of which 5mm will be inserted into the camera body, leaving an effective optical path length of 11mm for the T ring. So, for example, threading a T ring on this flattener will provide a spacing of 16mm from the shoulder of the flattener to the end of the T ring, or 11mm to the camera lens mount. With many of today's SLR cameras, a T ring might provide all the spacing you need with this flattener. T thread spacers are sold separately if you need additional spacing.
The image of Vega below was taken with a Takahashi TSA-102 (f/8) telescope using a Canon SXi DSLR. Stack of 4 x 5 min exposures without sharpening or noise reduction. Note that the enlarged star at the right edge of the photo remains circular.
SCA (Self Centering Adapter) Brings your Camera to the Closest Optical Axis in the Drawtube/Visual back for the Best Imaging Result
To capture great images from your telescope, it is essential to position your camera firmly in and on the optical axis of your drawtube/visual back. The SCA T-Adapter center loads your camera in the drawtube/visual back with the simple threading of a compression ring forcing the built-in rubber rings outward radially, thereby centering the camera in the drawtube/visual back for optimal installation.
SCA Eliminates Drawtube/Visual Back Slop
All drawtube/visual backs have manufacturing tolerances and require a larger diameter to accept various eyepieces and adapters. When the camera adapter is inserted, the gap between the drawtube/visual back and the inserted device creates a slop problem. The rubber rings in the SCA expand radially according to the users own adjustment to fill the gaps. This makes sure that your camera seats firmly in your drawtube/visual back, becoming part of your telescope for a secure and repeatable installation.
SCA Eliminates Unstable Locking from Thumbscrew or Unified Compression Ring
The optical axis is shifted when the inserted device is locked in by the thumbscrew. In some cases, some poorly made unified compression rings can cause unstable tilt when locking in the drawtube due to loose tolerances between the compression ring, inner groove, and the uneven tip of the locking thumbscrew in a drawtube. The SCA T-Adapter fits your camera without using the thumbscrew or the unified compression ring.
SCA Accepts the Imperfection of a Drawtube/Visual Back
Have small imperfections inside the drawtube like dents or scratches? The rubber rings fill the gaps and faithfully center your camera in the tube. In addition, even if the drawtube is slightly deformed in diameter or egg-shaped, the rubber rings in the SCA will compensate for the difference and faithfully center your camera.
Short SCA Profile Prevents Oscillation
The short profile design keeps the installed camera stable from low frequency oscillation transferred from the telescope in a windy environment. The back focus of the 2" SCA T-Adapter is 19mm (0.75") measured from drawtube shoulder to the bottom T-Thread.
SCA Damps Vibration
The all-around, adjustable tightness, rubber contact dampens unwanted vibrations from the telescope providing you a sturdy attachment on your telescope for stable image capture.
Reviews
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Apr 8, 2018
Good product
Pros: Cons: Comments:t was used with Vixen ED-103S.
Bottom Line: Would you recommend this item? Yes
The surrounding stars are well revised.
It is good that the screw of M42 is a little longer.This review was provided courtesy of AgenaAstro.com
Dec 13, 2017High quality tool!
Pros: Cons: Comments:I haven't had the chance to test it, the quick once over looks very impressive, well controsted and good looking! It makes my filter wheeler and telescope look very elegant .., thanks.. Rich
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 27, 2017Awesome field flattener!
Pros: Cons: Comments:I use this with my Borg 76ED apo refractor (f/6.6), which had some really bad field curvature with my APS-C DSLR. Now I have pinpoint stars out to the very edge! It screws into my Nikon's T-ring, and then slides into a 2" eyepiece socket, and it has M48 threads on the end for filters. I did have to use flat frames in order to get my images to stack properly (there was some very weird effect in part of the image, even though the subframes look fine), but the final result came out great!
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Dec 28, 2016Excellent field flattener
Pros: Cons: Comments:Very happy with that. I use it with Explore Scientific refractor ES127 ED. Works very well to correct spherical aberration. Only need to find an adaptor to screw my Baader filters at the open end because the threads are not compatible.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jan 23, 2016Very backfocus sensitive
Pros:Good Fixation,Perfectly Centered
Cons:Not Perfect Correction,Very Backfocus Sensitive
Comments:I have used this flattener, until now, to correct field curvature on two low focal refactors: a 330 mm F/5,5 FPL53 doublet and a 400 mm F/5 achromat. The announced backfocus (55 mm) is inadequate with them. The optimal values are 77 mm with the first and 70 mm with a second, with a tolerance of about 0,5 mm. But, even with these values, the star are a little elongated on the corners of a APS-sized picture. It will probably work perfectly with longer focal length refractors, for which the best backfocus will be nearer of 55 mm. Because all flatteners have difficulties to work with a low focal refractor and this is better than many others.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Gunsmokeray New Member
- Skill Level
- Unknown
- Time with Product
- Unknown
- User Notes:
- Review by gunsmokeray of Louisiana.
Sep 25, 2015Great field flattener at a attractive price
Pros:Strong Construction,Quality Lenses
Cons: Comments:This is a great field flattener. Perfect edge to edge sharpness.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Sep 5, 2014Good flattener, needed more backfocus
Pros:Quality Lenses,Strong Construction,Accurate,Compact,Easy to Use,Lightweight
Cons: Comments:Flattener worked great once I got the backfocus correct. For my scope, WO FLT 98, I needed 71mm not the stated 56. Using a QHY8 with 21mm to the chip, a 50mm spacer brought the field nice and flat.
Bottom Line: Would you recommend this item? Yes
Hope this helps someone.This review was provided courtesy of AgenaAstro.com
May 11, 2014Used with an f/6 102 ED refractor
Pros:Strong Construction,Easy to Use,Accurate,Quality Lenses
Cons:Heavy
Comments:I bought this to correct the coma in my wide field refractor. Works like a charm! You do need to make sure the spacing between this and your camera's sensor is correct, and small shims, ( I made mine from milk jug plastic!), may be needed. Slightly heavy and will affect balance of the 'scope.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Nov 29, 2013Flattens as advertised
Pros:Quality Lenses,Lightweight,Easy to Use,Accurate,Strong Construction
Cons: Comments:Using for astrophotography to flatten those eyepieces with out of focus edges. Does a great job with my digital camera especially with the wide field 32 and 21mm eyepieces that generally only focus in the middle.
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
Jul 30, 2013Flattener on 150/1200 ziel
Pros:Accurate,Lightweight,Compact,Easy to Use
Cons: Comments:I use this flattener on my refractor ziel cosmo 3 evolution 150/1200 f8 and I found the benefits in the aps-c sensor size of my canon 60D
Bottom Line: Would you recommend this item? YesThis review was provided courtesy of AgenaAstro.com
May 30, 2013Superb
Pros:Strong Construction,Accurate,Easy to Use,Compact
Cons: Comments:The first thing that struck me when opening the box was the top notch construction. This is, simply put, an extremely well made product.
Bottom Line: Would you recommend this item? Yes
Fit and finish is superb, the product is solid and clearly designed to last, and it's even attractive in its own way.
Performance, of course, is the bottom line. The HoTech excels here as well. It does an exceptional job of reducing field curvature in my Orion ED80T CF, making processing faster and easier, and the end result much more enjoyable.
Highly recommended.This review was provided courtesy of AgenaAstro.com
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