ED80/FR/FW Spacing Nightmare

[SnakeyJ]

Having finally lashed out on a small CCD (Atik 414EX M - thanks Astro Mick!), I am now discovering what a huge PITA it is to assemble an image train of the desired length.

I picked up an ED80 and the matched SW Reducer/Flattener back in the spring and have a an SX filter wheel, off axis guider, a huge selection of adaptors and T2 extension tubes - but after hours spent trawling through the loft, shed and garage, it seems the OAG just isn't going to fit without pushing the image train 8-9mm longer than the prescribed 55mm.

Sadly this will mean guiding with 60mm guide scope, and purchasing more bits (a M48-T2 adaptor and pack of delrin spacers from FLO).   To offset my despondent mood, I added an HA filter to the order.

I was really looking forward to having a neat, simple and well balanced imaging setup for my HEQ5 - I realise now this was an ecstatic delusion

I'm pretty sure I could manage without the FF on such a small chip, but it would be a full stop slower!

[Uranium235]

The solution is simple, lose the OAG. Its always going to be tricky to get one of those in the mix when working with a spacing distance of just 55mm (unless you swap out the FW for a filter drawer).

Theres nothing wrong with using a finderguider with the 80ED - plus it will help balance the rig out a bit, because as it stands that setup will be quite camera-heavy. Plus the finderguider can be instantly interchangeable with other telescopes if mounted on an upturned vixen saddle, like this:

PS: Just remember that if you want to mount another vixen bar on top of your tube rings, you need either 1/4" UNC or whitworth bolts

[RayD]

Yes very hard to get an OAG and FW in 55mm.  I think with the majority of filer wheels the only chance you would have is with one of the slim ones like the TS 9mm.

I use a separate guide scope on my Esprit 100 for this reason and it works fine.