Yes I am looking forward to it. Planewave are also developing a reducer for this scope as well which will be handy at times and make it more versatile.
I have a Paramount ME which I have never used so there'll be a learning curve with that as well. It needs 5 counterweights!
The imaging weather at the moment is spectacular. Its been a while since we've had so many imaging nights in a row here in Sydney.
I have a Paramount ME which I have never used so there'll be a learning curve with that as well.
This is something that I have to respect! What a fantastic setup you'll have Greg, and I'm sure that your talent will make the very best use of it. Well done!
Excellent. Good luck with it. I look forward so seeing some fantastic images from it :-)
Quote:
Originally Posted by gregbradley
Yes I am looking forward to it. Planewave are also developing a reducer for this scope as well which will be handy at times and make it more versatile.
I have a Paramount ME which I have never used so there'll be a learning curve with that as well. It needs 5 counterweights!
The imaging weather at the moment is spectacular. Its been a while since we've had so many imaging nights in a row here in Sydney.
And here's one of the 2 slabs. The smaller slab is 1 metre deep and full of steel reinforcing and is for a Sirius Pier and Paramount ME and the CDK17. The larger 2m x 2m x 140mm deep slab is for my usual setup of a Tak NJP mount and either a TEC180fl, AP140 or FSQ106ED on a portable pier
I intend putting pavers on the floor around the slabs like I have at my dark site observatory (this area has quite dark skies , but my dark site has almost completely dark skies but its 4 hours drive away and I can't always go down there).
It's like a Penfolds Grange or Bordeaux you buy it, cellar it and let it age for a while Talking about which I did have a nice '71 Grange the other week
Quote:
Originally Posted by that_guy
You have a Paramount ME and DIDN'T USE IT!!!!!!!!!!!! You must be Crazy!
They already have them available.
I've been tossing whether to get a reducer or not for my scope for the last few months.
Just make sure you get the focus right, as it will be tight when you add filterwheel, etc..
Theo.
Thanks Teo. I plan on using a MMOAG, FLI cameras with the same 4/5 filterwheel for both (very handy they both plug into the same opening with the same adapter). I have to conquer the MMOAG, I tried it before but no joy. I may have to talk to others who are using it with their CDK to get the exact spacers etc.
Greg.
Quote:
Originally Posted by that_guy
You have a Paramount ME and DIDN'T USE IT!!!!!!!!!!!! You must be Crazy!
Yes I know, pretty wild eh? My piers are all setup for the Tak NJP and I got the ME with the intention of mounting a larger scope which I am only now getting. Plus needing more counterweights, using new software etc as well as I imaged at a remote dark site which was already setup for the Tak mount. Still a bit of laziness there too!
Quote:
Originally Posted by issdaol
It's like a Penfolds Grange or Bordeaux you buy it, cellar it and let it age for a while Talking about which I did have a nice '71 Grange the other week
Hehehe.
Quote:
Originally Posted by RB
Wow, how cool is that Greg !!!
Congratulations on the new scope mate, I look forward to more of your wonderful images and first light from the CDK17.
Make sure you also post some pics of the new gear and observatory.
http://www.pbase.com/gregbradley/image/124516778 the 2 slabs. The smaller one is 1 metre deep with lots of steel in it. The larger one is for a portable pier and is 2 x 2m and 140 deep. I plan on laying pavers for flooring. The smaller slab will hold a 1 metre tall Sirius pier 10 inches in diameter and bolted to the slab with 6 anchor bolts (its being made currently).
http://www.pbase.com/gregbradley/image/124516961 The current "observatory" with an AP140 and FLI PL16803 and an astrotech 66Ed guidescope. I got a Vixen VMC95L as a guide scope recently and tried it out and it shows promise but it was losing the guide star so a better polar alignment is needed and that can wait to when I move into the observatory.
This is getting complicated And im digging out a real old post here, sorry.
Our man on the ground in Spain is trying to fit one of our Planewave 17" systems (FLI Proline/FW) with new a 0.66 reducer. We dont use MMOAG.
He is having dramas. Any more thoughts on this? I have searched the Planewave site and I cant find this combo in the Pdf manuals in regards to backfocus distances and adapters for the Proline..we had no issue fitting the reducer to our 20" Planewave with similar CCD.
We are looking at getting same setup going at Siding Spring this year. Planewave are taking their time replying to my emails to...
How is he planning on autoguiding then? With a guidescope? Differential flexure will be the major issue. Not impossible to overcome but when I used my guidescope I got terrible flexure. But then again my guidescope isn't the absolute best.
Per Planewave PDF on the reducer it only works with ST cameras and CFW or STL with no external CFW.
It does not work with Apogee or FLI cameras and CFW although I was told in an email it would work with my Proline and CFW but not through the MMOAG.
Conflicting data.
I imagine that it does not work with a Proline and CFW as that would be 30.23mm + 20mm = 50.23mm.
Per their chart the reducer can be spaced on a CDK17/20 (a different reducer for the 17/20 from the 12.5 inch CDK) from 43mm to 52mm.
Ideal spacing behind the reducer is 47mm. There, spot sizes are 7 micron stars and F4.51.
At 51mm you get 8.7 micron stars and F4.45. So you could whack one in front of the Proline and CFW4/5 (not CFW 4/7 which is thicker - I think its more like 25mm thick versus about 19 or 20mm for the CFW4/5). If you tried using your PL and CFW 4/7 it won't come to focus per their PDF.
So Proline + CFW 4/5 gives 50.23mm or perhaps 49.23 (have to measure it, CFW 4/5 is either 19 or 20mm thick, its probably on the FLI website).
But now you have no autoguider and have to use a guide scope. But I suppose you are now back down to 1952mm focal length so a longer focal length very rigid guide scope would work. Perhaps one of those AP 900mm focal length jobbies. I also have a Vixen 95LMC with about 1m focal length. Getting a guide star those seems hard work at that focal length.
On the other hand an STL11 with no external filter wheel or ST series cameras with a CFW work. But you wouldn't be able to use them with an AO device which is a shame as that seems to be the main drawcard for using an SBIG camera.
QSI with built offaxis guider would work I am pretty sure. A series 600 QSI is a bit more like a FLI camera now with a built in filter wheel and decent cooling and an offaxis guider. You are limited in chip choices though (smallish chips).
Perhaps SX cameras and their AO unit may be slim enough.
Basically its got to be slimmer than 51.8mm and ideally only 47mm thick.
I can email you the 2 pdfs I have on this.
I have pretty much ended the thought of using one. Unless I came up with a good autoguiding solution to 1952mm focal length. Its not totally dead as perhaps a better guidescope than what I have been using may work. I should chuck on my Vixen and see if that does it. Also use the SX Lodestar instead of the ST402 to reduce weight and flex.
Of course at 1952mm focal length and F4.45 a Proline 16803 may be in the ideal zone for pixel size and seeing. At 3 arc second seeing average you would be perfect with .96 arc secs/pixel with that setup (going for 3X sampling ie. 3 x .96 = 2.88 which is close to your seeing of 3 arc seconds). So would an STL11, both have 9 micron pixels.
So I guess the issue is you need an STL11 to match the optics with the focal reducer (smaller pixels are a slight mismatch) and self guiding or a slim line camera with an AO (Starlight Express?? or QSI but only small chips).
If you end up using a smaller chip like an 11002 or 8300 or 3200 etc then what is the point? You got a wider FOV but back to less than what a PL16803 covers without a reducer! Only gain is what you are imaging is at a fast F ratio. But then I find the CDK17 exposes images very quickly anyway because of the large aperture.
Conclusion - if you are using an 11002 or smaller chip the reducer is of little use and does meet the current needs of imagers and is too limited and the same or better results would be achieved by using a larger chip anyway. Backfocus is too limited. Probably a consequence of the CDK design with its corrector.
However, if you did have a reliable guidescope setup and you were using a large chip like the 16803 then F4.5 and a super widefield may be still appealling. Perhaps you may have to resort to 5 minute subs to prevent tracking errors from differential flex.
I am not sure how the SBIG STX fits into this. But I imagine it is also too wide and requires an external CFW as well.
Having a good guidescope is OK.
I use a vixen VMC110L on my 20" CDK, and it has a longer focal length than yours, and i get good round stars, with no tracking errors.
I cant go lower in focal length on the guider, as i will start to get errors.
I am using the Planewave mounting plate for the guider, and there is no flexing that i can see in any images. The Vixen guide scope is very light, and small, and is a perfect match.
I have attached an 11 minute exposure of IC-3639 during my Nova hunting sessions, and stars are nice and round.
For what its worth, i have the guider mounted on the bottom of my scope, and that i have a Fork mounted telescope. The mount is a MI750, and i suppose there's much less flexing on the scope as apposed to a German mount.
Having a good guidescope is OK.
I use a vixen VMC110L on my 20" CDK, and it has a longer focal length than yours, and i get good round stars, with no tracking errors.
I cant go lower in focal length on the guider, as i will start to get errors.
I am using the Planewave mounting plate for the guider, and there is no flexing that i can see in any images. The Vixen guide scope is very light, and small, and is a perfect match.
I have attached an 11 minute exposure of IC-3639 during my Nova hunting sessions, and stars are nice and round.
For what its worth, i have the guider mounted on the bottom of my scope, and that i have a Fork mounted telescope. The mount is a MI750, and i suppose there's much less flexing on the scope as apposed to a German mount.
Theo
Thanks for that tip Theo.
I have the guide scope here, its easy to setup and install, simply whack it on the top rail of the CDK. I'll check that out next time I am using the CDK. If it works it would mean I could use the reducer.
Greg.
Quote:
Originally Posted by allan gould
Greg
All the best with the new scope and mount. It's good to see such great instruments in the hands of someone that knows how to use them.
We have had no issues with the CDK's externally guided (so far).
Our 20" Planewave in New Mexico is mounted on an Ascension A200.
We dont even bother with guidnace most cases! It goes for 600 sec runs without just fine, which is more than sufficient for the clients.
The Siding Spring site will have Gordon's 17" and another 20", likely both will be on A200's. We may well change over from the PME's as our standard mount. Its that good.
Value the help Greg and have passed the info on to the guys.
. What type of mount are you going to drive it with?
What a fantastic setup you'll have Greg, and I'm sure that your talent will make the very best use of it. Well done! 
Talking about which I did have a nice '71 Grange the other week 
And im digging out a real old post here, sorry.
