What Reducer/flattener for ED80 for imaging

[Deneb]

Hi

I am looking to buy a reducer/flattener for my C80ED f7.5 in combination with imaging with a DSLR or a CCD Camera.

I would like to hear from you, what reducers/flatteners you have been using & how you rate them. Also what adaptors you have used in conjuction in connecting them to your ED80 scopes & imaging gear.

Cheers

Nadeem

[BlueAstra]

I use a TeleVue x0.8 TRF-2008 with my Meade 5000 ED80 APO:

Tele Vue Optics Article Page

It was recommended by Ian King at Astrofest, and works great with my Canon 1000D. Thats over a 3 deg field, and no significant coma!

[steppenwolf]

Nadeem, you have a PM

[Starjumper]

Hi Nadeem,

I too would be interested to hear the outcome of your question.

John

[step_hen]

Me three! Please let us know what you come up with!

[Ben Ritchie]

I found that the AP CCDT67 worked very well with a Atik 16HR on an 80ED - it's not a flattener (which can be a good thing, as spacing isn't so critical) and can't fully illuminate a DSLR-sized chip, but if you're using a smaller CCD it's a good option.

I've heard the TRF-2008 works well with the 80ED, but never tried it

[Starflyer]

I also use the TRF-2008 with my WO ZS80FD and ZS66SD, it's excellent on the 80mm and good on the 66mm. Spacing is fine with just a standard T-ring on my 450D.

[Ben Ritchie]

Spacing is fine with just a standard T-ring on my 450D.

Yeah, the TRF-2008 (and a fair few other flatteners) are designed for the standard DSLR T-ring spacing, CCD's are the painful one where you've got to get the CCD and filter wheel spaced to 56mm with a 2mm tolerance. Each CCD/FW is different, i've accumulated a large supply of small spacers...!

[Marmite]

Until recently the traditional choice for use with an 80ED was the WO Type II FF/FR.

The other WO FF/FRs weren't very effective, but the Type II worked well.

Now there are the new Synta FF/FRs available that are made specifically for the 80mm, 100mm and 120mm ED refractors.

They are marketed by Sky-Watcher and Orion and there's a thread about them here: http://stargazerslounge.com/sponsor-announcements-offers/89898-new-skywatcher-focal-reducers.html

[steppenwolf]

As several people have expressed an interest in this thread, I thought it might be of interest to post the contents of my PM to Nadeem:-

From what I understand the WO Type III has a 2" push adaptor which will fit into my moonlite focuser no problem, also the distance between lens & chip is 56mm according to the WO website, but im not sure if that is relative to a DSLR or a CCD camera.

The 56mm dimension is ready out of the box with a DSLR that has a ‘T’adapter attached to it and assumes that the ‘T’ adapter is the ‘standard’ 10mm in depth. The sensor to mounting face on CCD cameras varies from make to make and bears no relation to that of a DSLR so suitable spacers must be acquired to get the spacing right.

I have a Starlight Xpress SXVF-H9 that I am using with an ATIK USB filter wheel and a WO FR III so the mathematics are as follows:-

Total distance of sensor to rear of WO FR III is 56mm

SXVF-H9 sensor to mounting face = 17.5mm

Depth of ATIK Filter Wheel = 19.5mm

Depth of male to male ‘T’ adapter = 2.0mm

Total distance = 39.0mm

Depth of adapter required to fit between

WO FR III and ATIK Filter Wheel = (56.0 – 39.0) = 17.0mm

Your ATIK Filter Wheel has a female ‘T’ thread so you can unscrew that 1.25” nosepiece and replace it with a ‘T’ male to ‘T’ female adapter of 17.0mm length to get it all to work.

This is what is looks like (the custom adapter is the bit that fits in between the Filter Wheel and the WO FR III):-

Now I believe (but you must check this) that your ATIK CCD has an 18.0mm measurement from sensor to mounting face so deduct 0.5mm from my figure above.

Now, I have a SW FR here for review but have not had a chance to try it out yet as time is the enemy BUT this also requires a 56.0mm spacing and you can buy a special adapter from Steve @ FLO to fit either a Nikon or Canon DSLR but this won’t help you!! The mathematics are the same as for the WO FR III but for me to use the SW FR with my set-up, I would need to make up a custom adapter with a ‘T’ male to 48mm female thread adapter of 17.0mm length to get it all to work as the SW FR has a male 48.0mm thread on the camera end.

My custom adapter has a strange outside profile - the reason for this is that it also doubles as an adapter for my Baader MPCC, allowing the MPCC to fit deep inside my SW 200 Reflector's focus tube so that I can obtain focus and keep the 56mm spacing also required for the MPCC. The chamfered end is a direct fit in SW's custom focus tube collar.

My experience of the WO FR III is that it does a fair job with the SW ED80 but stars out at the edges of the FOV, although much improve from a spherical aberration point of view, appear a little ‘spiky’.

[Merlin66]

Steve,

Some good info there...

neat set-up!!

Baader do a 48mm filter thread to T thread adaptor rings (available from TS)

BTW I thought the "standard" back focus for a DSLR+T2 adaptor was 55mm (???!)

Ken

[steppenwolf]

The standard measurement appears to be 55.0 or 56.0 depending on where you look - the FRs (and the MPCC for that matter) are designed for use with DSLR's but there is variance here as well as, for example the very popular Canon has a sensor to faceplate measurement of 44.0mm whereas a Pentax is 45.5mm yet both are considered 'standard'!!

[Deneb]

Until recently the traditional choice for use with an 80ED was the WO Type II FF/FR.

The other WO FF/FRs weren't very effective, but the Type II worked well.

Now there are the new Synta FF/FRs available that are made specifically for the 80mm, 100mm and 120mm ED refractors.

They are marketed by Sky-Watcher and Orion and there's a thread about them here: http://stargazerslounge.com/sponsor-announcements-offers/89898-new-skywatcher-focal-reducers.html

Don't get me wrong, the Type II reducer is a good reducer, unfortunatly sold it with the ZS66 package I had, but still no regrets about that. I found it quite good apart from the pointy stars from the fov edge & some elsewhere. The ED80 SW reducer would probably be more optically matched for my C80ED f7.5, but I would have to find a push in adaptor for it to fit into a moonlite draw tube, plus the appopriate adaptor(s) to fit onto the filterwheel afterwards. Maybe a phone call to Ian King is needed to see if he has any adaptors.

Cheers

Nadeem.

[Psychobilly]

T adaptors vary in thickness depending on the lens mount so as to achieve 55mm flange to FP distance...they arent a standard 10mm thick...

Very useful Resource here...

http://www.graphics.cornell.edu/~westin/misc/mounts-by-register.html

Peter...