View Single Post
  #1  
Old 17-09-2011, 10:46 PM
DJ N
Registered User

DJ N is offline
 
Join Date: Jul 2006
Location: Adelaide, South Australia
Posts: 423
First Light - Hotech SCA Field Flattener

Hi everyone,

This week I received my Hotech SCA Field Flattener. I was very surprised to how compact it is, especially when compared to my William Optics P-Flat IV. I decided on giving the Hotech a shot, as I was really after a flattener that would not reduce the focal length on my ED120. This Hotech fits the bill from that perspective. It is designed for f5 to f8 telescopes.

The other interesting feature is the self centering. Once you slide the flattener into the 2 Inch focuser on the scope, you just tighten the adjuster on the flattener. As you tighten it, 3 rubber rings press against the focuser ensuring a central fit. Technically you do not need to worry about the compression ring/screws on the focuser itself. However, being paranoid, I did tighten the focuser compression ring ever so slightly.

According to the manufacturers specification, a distance of 55mm is required from the CCD face to the flattener. With the QHY8L, I needed to make up 32mm, however I could only get 30mm with the spacers I have at the moment. I do have the appropriate spacers on order, so hopefully my next test will be done at the proper spacing.

Anyhow, pretty happy with the initial results. I have tried the flattener with both the ED120 and the ED80 and things are looking very promising.

Looks like I might put the WO PFlat 4 onto the classifieds!!

Anyhow, here are the intial results from tonight;

Image 1 : M8 and M20 with the ED80 and the Hotech SCA Flattener, imaged with the QHY8L (4 x 8 minutes)

Image 2 : M20 with the ED120 and flattener, imaged with the QHY8L (3 x 10 minutes)

Cheers,

Daniel
Attached Thumbnails
Click for full-size image (M8 and M20 17Sep11 ED80 QHY8L 4x8m  Hotech Flat 30mm Post.jpg)
150.0 KB417 views
Click for full-size image (M20 17Sep11 ED120 QHY8L 3x10m  Hotech Flat 30mm Post.jpg)
147.4 KB363 views
Reply With Quote