Astrophad/IKI 12 inch Ritchey Chretien has arrived!

[RobH]

On Saturday afternoon, on his way to the football, Ian King, helped by his 6 year old lad, dropped off my new 12 inch Ritchey Chretien.

This is the first one to have been made, and is based on the GSO mirrors, but with a new OTA, this being a carbon fibre truss arrangement which is vastly more rigid than the original design of baked bean can metal!

It took 2 of us to get it onto the mount, not particularly because of the weight, but because it was impossible to see the dovetail rail, and after a couple of minutes, it was getting rather heavy

Surprisingly, for a little while on Saturday night it was clear enough to run a few tests.

I had a look at the collimation using a Takahashi collimating scope, and it was a fraction out, so I gave it a quick tweak and then attached a camera, OAG and filter wheel and slewed to several stars for testing.

Every star was egg shaped .......I tried various exposure lengths, but the shape stayed the same, and when examined very closely, it turned out that they weren't actually egg shaped-in fact they were all doubled, with one star image fainter than the main but very close, so that with any stretching they looked egg shaped.

Then the clouds rolled in, leaving me somewhat confused .

Anyway, yesterday morning I removed the camera etc, and put the Tak Coli scope back in and noticed that the secondary was just a gnat's whisker out. I adjusted this, and then last night set about testing again.

I started with various eyepieces (no diagonals) and had a good look at the Airey disc....all looked fine...no ghost stars!

Then I put a camera on with no filters......again, good Airey disc and tight stars.

I then went back to the H18/FW/OAG from the previous night.....this time, all was good.

I spent the evening doing test shots of various objects, finishing with M66 and M101 and subs up to 15 minutes.....perfect round stars and really crisp images at F8 (2400mm FL).

My suspicion is that the doubling of stars was caused by the very slight miscollimation causing a secondary reflection from the face of either the filters or the OAG prism to be reflected back and appear just next the the main image......whatever it was, it's gone now.

Conclusion....I think I'm going to like this scope a lot

Cheers

Rob

[jgs001]

Sounds great Rob and looks it too. Very nice.

[barkis]

Your base of operations is starting to look very Professional Indeed Rob.

Really looking with great anticipation to the preliminary results.

I hope everything goes well, without any glitches .

Ron.

[ollypenrice]

Korrrr!!!

Does that ever look the business?? I think the truss design will be way better than the tube for these optics. You're just in time for the galaxy season as well. Will this be running at native or will you try a reducer?

I don't know anything about the Tak Coli scope. It seems to do its job though.

Looking forward to seeing you back in long FL action. The Bubble was unforgettable.

Olly

[JamesF]

Book your overseas holidays now, folks. Looks like it's going to be cloudy for the next several years

James

[RobH]

Korrrr!!!

Does that ever look the business?? I think the truss design will be way better than the tube for these optics. You're just in time for the galaxy season as well. Will this be running at native or will you try a reducer?

I don't know anything about the Tak Coli scope. It seems to do its job though.

Looking forward to seeing you back in long FL action. The Bubble was unforgettable.

Olly

I'm running at its native FL at the moment Olly, but also plan to try my AP CCD67 reducer with it, which will bring the F-ratio down to F5.4 or so.

That F-ratio combined with the H18 binned 2x2 should make for a very quick system. There's no loss of resolution using the camera binned at these focal lengths as you're limited by the seeing.

I must say, despite having a lovely refractor (the TMB152), I've missed long FL imaging....I really like odd galaxies and tiny obscure planetay nebulae

Rob

[Jessun]

Very interesting setup Rob! I am extremely keen to see the results! I have the same reducer on my 8''RC and using CCD inspector I've recently decided not to use it but rather wait for the GSO reducer/flattener combo. I'd be keen to see how it performs on the bigger RC's tho.

Is this RC in full production yet?

[Cath]

That's just not fair!

What a lovely machine

[Psychobilly]

Wowser:eek:

Must be itching to let it rip...

Peter...

[RobH]

I have the same reducer on my 8''RC and using CCD inspector I've recently decided not to use it but rather wait for the GSO reducer/flattener combo. I'd be keen to see how it performs on the bigger RC's tho.

Is this RC in full production yet?

It's not in full production yet as far as I know, but I belive it will be shortly....I'm beta testing it but the results so far are very promising.

Re. the GSO reducer....I was going to invest in one myself, but Ian King advised against it....apparently they don't work properly!

Both he and Nik Szymanec are using the AP reducer, and that's good enough for me

Looking clear so far tonight

Rob

[Jessun]

Hmm, interesting info, I was not aware they actually existed yet. Tried to order one and got that reply...

I know my collimation has been slightly off, and I reckon that would be made worse through a reducer...

I sure would trust Ian or Nik, but how can one single lense reduce and flatten successfully?

I hope you get some nice results with your setup! Nice kit for sure!

[RobH]

Hi Jesper.....perhaps I'm confusing the GSO ones with the TS version in that case.

The AP CCD67, as you say, is only a reducer, not a flattener, but as far as I know, and from the results I was seeing last night with my M25C, the field is flat anyway until you get to the really big sensors, hence using a reducer only, not a reducer/flattener.

Rob

[Jessun]

I have the TS Flat 2'' as well, and it seems to pop up as accessory to refractors and reflectors alike. If I was clever enough to work out a way to get the distances right I'd use the AP reducer and TS flattener combined...

[morimarty]

Congratulations Rob on your new RC scope, really looking forward to seeing your images with this one!

[Daniel-K]

great set up i would love a RC have you nay pics of the subs you took?

[MikeWilson]

I've just seen this.. a 12", 2400mm fl imaging scope? Wow.

Can't wait to see what you produce with this.

[Coco]

Just stumbled across this thread, what an amazing piece of kit

Any updates and test images

[Chris]

Congratulations that really does look the business!!

[RobH]

Ian King arrived yesterday and took the scope back due to issues with astigmatism etc.

I now have the use of his own 10 inch RC (which many saw at Lucksall) until the 12 is sorted.

The idea was that I give it a shakedown and identify any issues that need fixing so this is no problem.

Before it was built, the mirrors were thoroughly tested and are fine, but we think that the problem is the GSO mirror cell, so it is likely that a new cell will be designed and fabricated from scratch.

Once this is done, it will then go to Nik Szymanec's place and get tested for a while until they are all completely satisfied, and then I get it back.

I've been using the 10 inch IKI/Astrophad for a couple of weeks now and can report that it is excellent....when the 12 behaves as well as that it will be a brilliant scope.

My plan (and why I didn't go for the already tried and tested 10) is to use the scope with an APCCD67 reducer, bringing it down to an F-ratio of about 5.4 and giving a resolution of 1.36 arc seconds per pixel with an 8300 chip binned 2x2. This is just about the best resolution I can expect from my general seeing conditions.

The combination of a fast f ratio and binned camera should make for a really quick system, and the focal length will be a bit above 1600mm....perfect for many of the galaxy targets that I'm interested in.

Plus, without the reducer, the 2440mm focal length is fine for the smaller targets.

It'll be a while before I get it back, but it should be the first of a type of very fine and reasonably affordable RC....in the meantime, I'm really enjoying the 10 inch version.

Rob

[Chris]

Very pioneering stuff Rob I'm sure like you say you'll be very happy with it in the end, some top people on the case:) I've been looking at Altair Astro's 6" f/9 RC with a focal length of 1370mm, I think something like this will be just the job once I'm set up in my shed obsy (build in progress) and guiding with my ZS66 and ST4 mod, pHd etc.. I'm going to get a second hand 150p to tide me over, am I missing any tricks in terms of budget long focal length imaging scopes? my apologies for this question on you thread but I think you might know a thing or two about these types of scope:D

[MikeWilson]

Very pioneering stuff Rob I'm sure like you say you'll be very happy with it in the end, some top people on the case:) I've been looking at Altair Astro's 6" f/9 RC with a focal length of 1370mm, I think something like this will be just the job once I'm set up in my shed obsy (build in progress) and guiding with my ZS66 and ST4 mod, pHd etc.. I'm going to get a second hand 150p to tide me over, am I missing any tricks in terms of budget long focal length imaging scopes? my apologies for this question on you thread but I think you might know a thing or two about these types of scope:D

Something to guide with and optionally a reducer too, I think?

[Chris]

Thanks Mike I'll hopefully be guiding with my ZS66 once the obsy's up and running:)

[michael.h.f.wilkinson]

DROOL!! (no drool icon available )

Amazing piece of kit.

[marcoverstraaten]

but we think that the problem is the GSO mirror cell

Is the focusser connected to the mirrorcell like the GSO version? This is a major design error if you ask me.....

I made an adapter to separate the 2, so no more weight is stressing the mirror cell. Also the mirror is glued to the cell so any weight on the focusser will cause stress in cell and mirror and thus optical faults.

[RobH]

That looks very interesting Marco. I'll send a link to Ian.

However, I don't think that this is the problem in this case as it's not causing a problem with the 10 inch, which also has the focuser/mirror cell as one unit.

Mind you, the extra leverage with a 12 inch mirror could be a factor.

Cheers

Rob