MaxView40

Review of Scopetronix MaxView 40 (tm) on the Dimage 7/7i digital cameras.

Special thanks to:

First, before I even start on the review, I have to give special thanks to James Young for bringing to my attention that the MaxView 40 (tm) does work on the D7/i cameras. I had pretty much given up on searching for a solution to attach the Dimage cameras to a telescope due to the large lens. James has also provided some shots for this article, some using a 24 inch telescope. Due to the large size of some of the samples, an 800 wide screen is needed to see the entire width of this article, sorry!

Note, captions are under the pictures.

This is version #3 of this article, last updated on Aug 7th, 2002

 

Introduction:

The Maxview 40 (tm) is a special 1 1/4 inch eyepiece designed and produced by Scopetronix. (www.scopetronix.com). It consists of a 40mm focal length eyepiece with a built in adjustable sleeve terminating in a standard "T" mount thread. As of this writing, the eyepiece is selling for $130.  There are four things that make this eyepiece particularly good for attaching a camera to a telescope.

1) The eye lens is very large, and thus is a better match to digital cameras that have large apertures such as the D7. The usual problem with attaching the D7 to a telescope is vignetting caused by the large lens on the D7 "looking" into the small eye lens on a standard eyepiece which is designed for the human eye.

2) The eye lens is almost flush with the top surface of the eyepiece. This lets you get your camera lens as close as possible to minimize vignetting.

3) The eyepiece has a built in T thread adapter that is adjustable. With the proper "T" to standard camera thread adapter (T to 49mm in the case of the D7), you can screw your camera right on to the eyepiece.

4) One of the reasons that this eyepiece works so well with digital camera that might not be obvious is that the MaxView 40 (tm) does NOT have a vary large apparent field of view. I suspect (but I'm guessing) that the design is the old "monocentric" design that is no longer seen very often. The smaller apparent field of view means that the eyepiece produces an image circle that "looks" small when you look into it, so that the effect is sort of like looking down a tube, but this is a perfect match to a digital camera which has narrow field of view. Most digital cameras (but not the D7) have to be operated at full zoom to use a digiscope adapter because only at full zoom is the entrance aperture of the camera lens small enough to match an eyepiece.

 

The MaxView 40 showing just the eyepiece. Note how large the eye lens is, and the T ring. Image courtesy of James Young.

Using the MaxView 40 (tm) on the D7/7i

The MaxView 40 attached to a Minolta D7. Photo courtesy of James Young

The above view shows how the MaxView 40 attaches to the Dimage camera. A T to 49mm step up ring is being used to attach the eyepiece. Because all of the weight of the camera is being supported by the zoom lens, it is a good idea to use a camera support of some type to support the body separately. James is using the Scopetronix "EZ-Pix) (tm) support shown below. Sure, you can use a home-made support, I did at first, but for $50 the Scopetronix support is well made.

James's D7, MaxView 40 (tm) showing the camera body being supported by the EZ-Pix (tm) camera bracket. Photo courtesy James Young

James's camera attached to his 10" f/4.5 Newtonian scope. Photo courtesy James Young

My D7i attached to my old Meade 2080 8" SCT. Note remote release (essential)

One minor topic of concern is how then entire weight of the camera and eyepice is transmitted to the telescope through the eyepiece barrel. If your eyepiece holder is typical, then there is only one set screw holding this in, and maybe only one set screw holding your star diagonal in if you use one. Because of this, my photo shows how I always loop the camera strap around part of the telescope (in this case a camera attachment plate). Be sure to do this, some night one of those screws might let lose, or you might even unscrew it yourself in the dark by mistake (that will never happen, right?) and your camera will drop. It is cheap insurance to loop a strap or put a rubber band around the assembly to catch it before it "hits".

Even so, this setup produces a lot of leverage on your eyepiece mount, and might overload the clock drives on smaller telescopes. It is probably only really suited for larger 'scopes.

Using the MaxView 40 setup on the Dimage 7:

First of all, realize that this setup will still vignette even on the best settings with the D7/i. While this is fine for astronomical work of course, it might not be acceptable for terrestrial work. The amount of vignetting depends on the zoom level and the the f number of your telescope. The resulting images will consist of an illuminated circle in the center of the frame (see examples below)

It is still possible to get a pretty good field of view with this setup with typical amateur scopes, 1/2 to 1 degree seems possible with most telescopes, so you can fit the entire Moon in for a shot. The actual max field of view that you will get will depend on the zoom level on the camera that you use, the f number and the size of your secondary mirror (if your scope has one). This is a very large focal length eyepiece.

The following shots show the field of view through various telescopes. I have not rotated some of these, and some are left-right reveresed. I adjusted the Camera for the least vignetting and best field of view in each case. It is worth noting that the best field of view and least vignetting on most scopes occurs at about 35mm zoom on the camera, not at full zoom as you might expect. In fact, at full zoom the field of view is very small and there is quite a bit of vignetting. Also note that the EZ-Pix (tm) bracket will not be able to extend to hold the camera at full zoom.

 

The view through a Meade ETX-90 adjusted for max field of view

The ETX-90 view, this time adjusted for best magnification by zooming with the camera.

View through my 32 year old RV-8 "Dynascope" an 8" f/7 Newtonian.

View through an 8" Meade 2080 SCT, f/10.

View through a tiny 70mm Maksutov-Cassegrain scope.

Astro Results:

Here are some sample astronomical images taken with the MaxView 40 (tm) setup.

Not typical of amateur results of course, but pretty amazing and I thought that people would like to see a few of James's shots with a 24 inch telescope using the Scopetronix adapter and the Dimage 7. Using computer control the 24" was able to take these shots of the International Space Station "Alpha" as it passed overhead. Photo courtesy of James Young.

Globular cluster M13 though the 24" with the D7. Photo courtesy of James Young.

The ring nebula M57 through the 24". Photo courtesy of James Young.

Lunar "straight wall"'. Photo courtesy of James Young.

(above) My own attempt at the ring nebula with an 8" telescope. This is a composite of three ISO 200 30 second exposures with the D7i. This is more typical of the results that you might expect with an amateur telescope. This was taken on 07/26/2002 through clouds and with the almost full Moon out, so it is definitely possible to do better. Guding was poor.

My first attempt at M13 with the MaxView 40 (tm). This is a stack of three ISO 400 30 second exposures with the D7i using an 8" SCT. Poor guiding, light clouds and Moonlight didn't help. (above)

M27. Composite of 8 stacked 30 second exposures.

Tips and tricks:

* If you are buying the Max-View 40 from Scopetronix, here are a few comments. First, you need to buy the MaxView 40, and a T to 49mm thread adapter. There are two options to get the adapter from Scopetronix, although they may not be obvious. First, you can just buy the T to 49mm adapter for about $30. Or, you can buy the "digi-T" system, which includes an adapter if you buy the system for the Minolta D7. This system consists of a ring which can attach to common eyepieces and has a T thread, and a T to 49mm adapter. Regular eyepieces aren't going to work well with the D7, but you might want to buy the Digi-T system because you have another camera that you want to use later. Second, Orion Telescopes (www.telescope.com) has a camera bracket that looks very similar to the Scopetronix bracket, and is $10 cheaper. However, I don't think that the clamp on this bracket is large enough to take the Max-View 40 eyepiece, so watch out.

* It is very difficult to focus on even bright stars with this setup and the D7. Because the view will switch to black and white light amplification mode, you can't even use the 4x magnification button to help. To focus, I've been doing this. I found an eyepiece that will focus a bit farther out than the camera with MaxvView40. In daylight, I set the camera to infinity focus, and then focused the telescope on a distant object over 2 miles away. Next, without changing the focus on the telescope, I placed the eyepiece in the eyepiece drawtube and moved the eyepiece in and out to focus. Next I marked the eyepiece barrel at the depth that focused, and placed a PVC ring on the eyepiece at that point. Now to focus the camera, I can place this eyepiece in the holder to the depth of the ring, focus with the telescope, and replace with the camera assembly. It works pretty well.

 

* The field of view isn't flat. (At least on my scope). That means that if you are going to be "stacking" several short exposures to systhesize longer ones, you need to keep the object of interest in the same position in the field. Found this out when trying to stack images taken at different times.