Celestron Edge 800HD .7X Focal Reducer, Celestron 93648 Off Axis Guider incompatability when used with Canon 650d DSLR

[Polaris Starstruck]

Anyone had this issue?

I have a Celestron Edge 800HD, tried some astrophotography with my Canon 650d and liked it.

Looked at the Celestron website and bought the above focal reducer and off axis guider to use with my Canon 650d, I know

my camera is not astro modded, but as it is early days it will do for now until I progress.

It now appears the Focal Reducer 94242 and the off axis guider 93648 used with any Canon DSLR cannot achieve the required Back Focus

of 105mm.

Steve / FLO has placed the above problem with Celestron on my behalf, thanks very much Steve. 

We are waiting for Celestron to reply.

I have read previous threads similar to my problem, but not exactly the (now) problem.

Any clues to solve my problem(and to help any others who have bought the same items) would be much appreciated.

Thanks

Geoff

[dementedgr]

Great! Just great!!! I just received the same OAG and was going for the FR sometime in the future...

Waiting for the weekend to test it though...

Seriously, any input from someone with the same setup??

[ollypenrice]

While an OAG is to be preferred with any reflector you could still get away with a guidescope, I think. You might lose the odd sub.

Olly

[Polaris Starstruck]

Thanks Olly, I have the Celestron guide scope package, I had not read anywhere that the Celestron FR and OAG may not be compatable, annoying to say the least, one of the problems is when you ask various suppliers if they are compatable, the general view was yes, funny eh!

Hopefully Celestron will come back with a remedy.

Geoff

[Clockwork_Orange]

Hi Geoff

I don't have the edge just the standard SE8, so not sure if this can be done with yours? I have placed the 6.3FR after the OAG then attached a celestron T adaptor to put the camera at the required spacing. The edge maybe different, but I've attached a photo below

Hope this helps

John

[Merlin66]

The significant difference with the EdgeHD design is that the optimum focal point is fixed relative to the in-built corrector.

This then only allows 105mm backfocus for all the add-on gear.

The original SCT's did not have this restriction.

[FLO]

I have a Celestron Edge 800HD, tried some astrophotography with my Canon 650d and liked it.

Looked at the Celestron website and bought the above focal reducer and off axis guider to use with my Canon 650d, I know

my camera is not astro modded, but as it is early days it will do for now until I progress.

It now appears the Focal Reducer 94242 and the off axis guider 93648 used with any Canon DSLR cannot achieve the required Back Focus

of 105mm.

Steve / FLO has placed the above problem with Celestron on my behalf, thanks very much Steve. 

... annoying to say the least, one of the problems is when you ask various suppliers if they are compatable, the general view was yes, funny eh!

Hopefully Celestron will come back with a remedy.

Welcome to SGL Geoff. 

Your posts are a little ambiguous so forgive me if I mention you haven't purchased any of the above from us. We are however happy to help

When you contacted us my colleague SteveB advised you there is a known issue then contacted Celestron on your behalf for an update (that was one week ago so I'll ask him to chase them). 

Have you contacted your supplier? Most UK astro retailers are good folk so can be trusted to do the right thing in situations like this. 

HTH

Steve 

[PNJ]

Hi

i use a QSI 583 and had no problems, however the off axis is built in the QSI   my total back focus was 50.1mm

I did use a canon 60D  on the edge telescope with no probs too, however not with a off axis guider.   I also had the  edge version of the SCT to T adapter. which might make a difference.

I sure you would be within the limits. of 105mm and 133mm 

Paul J

[CharlesW]

It is interesting that you lose 28mm of back focus with the reducer. I do seem to recall reading somewhere that this was the case. It won't be cheap but you might have a Precise Parts adapter made that would replace the SCT adapter and get some or most of that distance back.

[Polaris Starstruck]

Thanks for all your replies, and John for the photo, but the Edge FR is a different size to yours.

I did not purchase the OAG or the FR from FLO, but contacted Steve out of frustration as the two individual suppliers

could not give me an answer.

I made a purchase from FLO of another item last Friday which they had in stock, as I had been waiting six weeks for the same item from another supplier (who has also got full payment for it in advance).

I hope Celestron will come back with an answer about the OAG and the FR.

Geoff

[PNJ]

Geoff what is the distance or back focus of your off axis guider.  If its the new version Celestron off axis guider it will work.

you do away with the sct to t adapter as the off axis replaces this part

Paul

[Merlin66]

According to the spec sheet, the backfocus of the reducer is 105mm.

Allow 55mm for the DSLR and T2 adaptor, this leaves 50mm for the OAG......

I can't find any tech specs on the Celestron OAG....

[FLO]

I did not purchase the OAG or the FR from FLO, but contacted Steve out of frustration as the two individual suppliers

could not give me an answer.

I made a purchase from FLO of another item last Friday which they had in stock, as I had been waiting six weeks for the same item from another supplier (who has also got full payment for it in advance).

I hope Celestron will come back with an answer about the OAG and the FR.

Geoff, unfortunately Celestron have just confirmed you currently cannot use the 0.7x EDGE HD Reducer (94242) and Off Axis Guider (93648) together with a DSLR. 

Best to contact your supplier to see if they will accept the items back. 

Please don't shoot the messenger

HTH, 

Steve

[dementedgr]

This is so frustrating... How can thay make a product that is not compatible with their own products???

This is an OAG packed with great features (albeit a tad heavy) but its practically useless unless you have the patience to image at f/10...

From the OAGs manual we have, 29mm for the body, 12.5 mm for the M42/M48 adapter plus 55mm for the DSLR + T ring, we go up to

96.5mm. I checked and even the shortest part created from precise parts for the connection to the reducer is 11.4mm, thus > 105mm...

The only way this part could work would be in the configuration of Clockwork Orange, however is it even possible with the Edge versions?

   

[dementedgr]

Now I understood Merlin66's comment, sorry! So I guess even that configuration will not work...

Great, I guess we just have to return/resale the product and get another OAG unit...

[FLO]

This is so frustrating... How can thay make a product that is not compatible with their own products???

This is an OAG packed with great features (albeit a tad heavy) but its practically useless unless you have the patience to image at f/10...

We share your frustration because, as you say, the Celestron OAG is beautifully made but it cannot be used for DSLR imaging with their EDGE focal reducer. But I can see it from the manufacturers's perspective. If quality and rigidity are important then the OAG must be large, like the Celestron and Atik OAG, but then they are too large for some imaging setups. And slim OAGs are notoriously flimsy. If anyone knows of a slim OAG with build quality equal to the Celestron and Atik please say, we would almost certainly add it to our stock

Steve 

[Polaris Starstruck]

Thanks Steve for the Celestron reply and everybody else for their comments,  so, if I can't use a DSLR with the OAG & FR, what camera can be used? and has anyone got that setup?

Yes Paul it is the latest Celestron OAG & FR for the Edge 800HD. The FR reducer instructions say 105mm back focus from the rear of the reducer to the camera sensor.

Geoff.

[PNJ]

Hi Geoff,

The reason i asked is that i used this off axis guider a few times with my QSI fitted with WG cover, back focus 35mm   (QSI with its own off axis is 50.1mm)

using the reducer

The reason i tried it was as the off axis has a built in rotator.

However DSLR is just past the critical distance.       But i wonder if it would make a large difference !!

Paul J

[Polaris Starstruck]

Paul J

Thanks for your input, when you say you do away with the SCT to t adapter and the OAG replaces this part, how does the OAG attach to the rear of

the FR?

Good to know you have used the OAG, I'm not familiar with the term "WG cover"

Have you used the OAG & FR with your QSI 583 ?

As we have the same scopes, do you recommend buying a QSI 583?

GEOFF

[PNJ]

Hi Geof,

No i not used the OAG & reducer with my QSI.     But have used it without the reducer.

The OAG guider comes with lots of adapters specific to the OAG,  to fit to the reducer and visual back of the telescope.

however, i use the QSI with its own OAG  with reducer.

You could use a separate guide scope for imaging at f7,  and still use the OAG at f10  (133mm distance to chip)

Paul J