Flip mirror diagonal...

[arad85]

Arrggghh... I hate having long focal lengths, a small CCD chip (DMK) and trying to get objects on the chip!

After a very frustrating night last night (not least as it got cloudier and cloudier here), I'm wondering if investing in a flip-mirror system plus illuminated reticule eyepiece is the way to go to help get everything on chip.

Typically, I'm at F30 with my DMK and the slightest misalignment and I'm searching for objects for ages. I was thinking of perhaps the following imaging train:

C9.25->WO SCT crayford->Orion Flip mirror->barlow->AtikMFW->DMK.

A couple of questions

- The Flip mrror system has a focuser - is this to focus the main imaging train or to focus the offset for the eyepiece?

- What is the quality like? I have a decent crayford and wouldn't want to make it redundant.

Anyone have any experience of this system/suggestions for a better one?

TIA

[red dwalf]

i`ve just bought a flip mirror for the very same reasons as you, i`m using a webcam, anything over f 20 and the object is very hard to find, can`t tell you alot about my experiance as yet as i bought it without any adapters and am struggling to locate any to fit it at the front to sucure it to the rear of my sct

[Merlin66]

I use various Flip mirrors on the Lx200 sct's.

The Meade sct flip mirrors have a collection of adaptors which allow you to focus the camera on one side and the "guide" eyepiece on the other. They should be parfocal.

The Vixen 2" model has T threads on each port so you can add spacers etc ( recommend the Baader Helical focuser).

I have a flip mirror mounted on my guide scope so that I can eyeball a guide star then flip over to the QHY for guiding....

The Meade flip mirror has as good a UHTC coating and surface accuracy as their diagonals.... so you don't need both.

Just use the flip mirror a a visual diagonal...

Ken

[arad85]

Hi Ken,

Thanks. Hmm.. the Meade 2" does look tempting (although expensive - but I could sell the WO as I'm primarily visual with the dob) as I could then use it for DSLR photography. Any idea what the rear thread (the one that you attach the various cameras to) is natively?

Andy

[arad85]

Am I going to have focusing issues if I use the Meade after the WO crayford? From memory I can manage to get focus with the DMK with the following: C9.25->WO Crayford->WO diag->Celestron Ultima->Atik->DMK. Is that about teh same distance as I'd get with C9.25->WO Crayford->Meade 2" flip mirror->Celestron Ultima->Atik->DMK

[Merlin66]

The Meade #647 2" flip mirror doesn't have a "rear thread" but a deep recessed shoulder flange; this allows the various T thread and 2"/ 1.25" adaptors to be fitted and rotated independently of the flip mirror position.

Measuring the body with the shortest T thread adaptor, it's 100mm from the SCT face to the T thread connection.

Ken

[arad85]

Hi Ken,

Thanks very much. Any idea what length the 1.25" eyepiece adaptor length is? I.e. how much extra I'd add to the image visual chain from the rim of the SCT back thread (which I'd use with a 2" adaptor) to the end of the 1.25" adaptor in the CCD path? I have a 2" extension tube I could rig up a long path with here to see if it worked through the diagonal....

[Merlin66]

Changing the short T thread to the 1.25" adaptor adds 30mm to the length (100mm becomes 130mm)

Ken

[arad85]

Cheers Ken. Will see how much focus I have left with the diagonal and extension in place

[arad85]

Anyone else with any comments?