Telescope Reviews: Mallincam finding and framing

I have been using a Mallincam for about a week on multiple scopes both with and without a second scope mounted in tandem to help find and frame objects. It has become clear that the second scope is very useful but since I wasn't always going to have the second scope mounted I felt I needed a better way of finding and framing objects for the Mallincam.

Years ago I got to use a very old flip mirror setup on a refractor for imaging with a 35mm camera and remembered the value of that configuration. After reading Roland's great review on the Vixen flip mirror and doing a little research I decided to take the plunge.

The Vixen is as Roland stated a very nice flip mirror setup. It adds about 120mm in length to the optical path, maybe a little less if you are using a 1.25" focal reducer as that will sit up inside the 1.25" barrel attachment. Here is where Vixen could make a nice change to the product. If they split the barrels in half and used the existing T thread they could take 25mm or so out of the optical path. This would help with the acceptance of the product since many setups can't handle an additional 120mm of path length. Fortunately I'm planning to use the product primarily with my two SCTs which have lots of back focus capability.

With my SCTs I wanted to use an F6.3 SCT threaded focal reducer and possibly a 1.25" F5 reducer as well. The F6.3 needs something like 110mm distance from the reducer to the film plane/chip/eyepiece. This number can vary somewhat but with too much distance the image starts to break down and back focus even on an SCT becomes a problem. The Vixen flip mirror appeared to be tailor made for use behind the F6.3 focal reducer with the exception of connections.

The nose piece of the flip mirror is a short 2" barrel style. To attach it to the SCT threads on the F6.3 reducer a 2" visual back can be used. I purchased a short or low profile TeleVue model in order to keep the overall path length as short as possible.

On the other end the flip mirror uses 1.25" barrel attachments (single set screw though

, no compression rings so be careful that the single screw is nice and tight). The Mallincam comes with a 1.25" 25mm nose piece, so that wasn't a problem. In addition my inexpensive F5 reducer threads onto 1.25" eyepiece filter threads so it also attaches to the front of the Mallincam nose piece just fine. As I previously mentioned since the nose piece (and reducer) fits up inside the 1.25" barrel it actually shortens the path length a bit. This made up for some of the length added by the 2" visual back.

So my setup ends up with the F6.3 reducer threaded onto the scope or external focuser > 2" short visual back > Vixen flip mirror > F5 1.25" reducer > 25mm nose piece > Mallincam.

So how does it work? Quite well actually. Eyepieces in the flip mirror usually require an extra 10-25mm extension to come to focus and I solved that with pieces from an old 2x barlow. The focal ratio with both reducers on either of my F10 Celestrons seems to end up just below F3.

Overall using the flip mirror is a pleasure, it's really easy to pick up objects visually and since the eyepiece and the MC are parafocal the objects are in sharp focus on the video monitor as soon as the mirror is flipped. No more hunting, everything has been centered on the video screen. This has also been useful when judging the size of very faint objects on the video screen. Many times before I started using the flip mirror I'd be searching for objects with the MC and notice that I'd often pass over very faint extended objects. The extra focal reduction and the preview in the flip mirror eyepiece have combined to ensure that I don't pass over faint objects any more.

This is a picture of the setup in question on my C6 ... I tend to try out stuff on my C6 before moving up to the C11. In this shot you can see the F6.3 reducer threaded onto the rear of the scope, the short 2" visual back (with it's extended set screws which have to be removed on my C6 when installing or removing the reducer/visual back because of interference with the FT microfocuser below them). Next is the flip mirror with a 25mm eyepiece (but no extensions in this shot), and the Mallincam. The MC's 25mm nose piece and reducer are up inside that 1.25" barrel on the right.

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Mark

C11, C6, APM/TMB115, and AT80ED
Tandem mount CGE and CG-5A, WO EZ-Touch and AT Voyager
25x100s, 8x56s, T-Mount Light, and Mark 1 eyeballs
Modded 350D, SPC900, Mallincam