A VERY frustrating night!! Help Needed Please

[KE400]

Hi all,

The heading says it all really. Over the past 3 months I have been researching & buying new kit to add to my set up. Namely a FeatherTouch Micro Focuser & a PGR Flea3 ccd. Due to a mixture of work commitments & our dreadful weather, the last time I had an evening out was in late June!

Finally had a chance to get out and try a 1st attempt on Jupiter with my new set up last night. My scope is a C9.25 and I have an NEQ6 mount too.

I had followed the installation instructions provided by Starlight with regard to the focuser to the letter and was ready to try it with a 2 star alignment. Scope slews to the 1st star only to find I ran out of available focus travel to get the star in focus. I had a nice doughnut white ring so must have been just short of getting focused!! Didn't know what to do so tried removing the Micro bit of the focuser and replacing with the 2 FeatherTouch focuser knobs (black & gold = course & fine focus). Tried again to focus on the star and still the same effect??!! I then removed the FeatherTouch and replaced with the rubber original cased focuser supplied with the scope and could focus on the star no problem??? Not sure what to do now. The only thing I have thought of today is that it could of been something to do with I had a flip mirror fitted too to the set up and maybe that could effect it being too far from the scope or something but haven't a clue really. Has anyone else came across this problem with the FeatherTouch & C9.25??

My 2nd frustration was with the Flea 3. So far it's been a bit of a nightmare trying to get it connected to my laptop with it running on Firewire 800. I've had numerous attempts of trying to get a suitable cable that can power up the cam while also being a fair distance in order to be able to run from scope to warm room. I've managed to eventually sort that problem but after firing it up last night through FireCap software, the image was very poor, I mean that as in black & white, (cam should be colour) and also no matter what I adjusted within the software I couldn't get any kind of decent image before the laptop kept crashing soon as I tried to begin a capture!! More help advice needed on this, is it something to do with the firewire through PCIMCA not being able to send enough data or a laptop problem?? My laptop runs Vista and again, I don't know what to do?

After the difficulties with the Flea 3 I decided to give my SPC900 a shot and managed some images of Jupiter at last, even though they wheren't the best and I found it very difficult to get any really good focus with any kind of barlow fitted, I still felt it a small success and at least I had something for my troubles!

So overall, a very frustrating night really, I packed it in around 3am, very frustrated & tired not knowing what to do to overcome these obsticles. Any advice or help would be greatly appreciated.............

[cs1cjc]

I'll try to tackle the focus problem. If it is out travel you need,f then you should be able to move the eyepiece out slightly to get focus. An extension tube is a more permanent solution. If it is in travel you need, then it can be more difficult...

[KE400]

Thanks Chris,

I think it's in travel as the focuser was turned clockwise when focusing in. That's why I was thinking the removal of the flip mirror may help, (haven't tried it yet).

[Merlin66]

I have the Feathertouch micro focuser on my C9.25...

I use it with a spectroscope which needs about 80mm backfocus ( from the rear cell) I've never had any problems/ concerns/ issues finding or getting focus.

Sounds like there's something wrong somewhere........

[michael8554]

Like Merlin suggests, it's very unusual for an SCT to have insufficient back-focus for the usual stack of acessories.

I hope you realise that the microfocusser has a very limited range of focus and that the mirror focusser still has to be used initially?

Start with the microfocusser in the middle of its adjustment range.

Then get rough focus using the SCT mirror focus knob.

Then find the focus sweetspot with the microfocusser.

Apologies if you've already sussed that

[KE400]

Thanks for the reply Michael, I'm a little confused as to your advice though. The focuser I have bought actually replaces the SCT mirror focus knob so I'm unable to follow your instructions. I'm now thinking, "have I bought the wrong focuser for my scope?". The FeatherTouch I have installed is the one below which is the one recomended by Starlight for the C9.25 XLT. Thanks again for your reply.

[Merlin66]

Kevin,

I think Michael was confused between the Feathertouch micro focuser and the Feathertouch Crayford focuser....

The illustration you show is identical to the one I fitted to my C9.25

I have no problem finding focus with any accessories.

What actually happens to you when the black knob is rotated? How many turns from one extreme to the other??

[KE400]

Hi Merlin,

I was thinking that but then was thinking should I have bought the crayford type, I've counted around 18 full 360 degree turns from end to end on the black focuser.

I've had the focuser on and off so many times trying to see if there was anything that looked obvious that could cause a problem but couldn't see anything. When the focuser was off I could push the internals in and out via the threaded bar that the focuser attaches too and it was free in motion reaching either stop in & out so don't think it's anything internal. When I attached the focuser the last time I ensured that when the focuser (black dial) was wound in to it's stop,(clockwise) the actual internal movement was also at its stop too hopefully meaning that it would be able to travel the full distance inward when focusing which seemed to be the limiting factor when trying to focus the other night. (Hope that last bit of info is readable as it's difficult to explain!).

I haven't tried it out yet since that adjustment but I'm kind of hoping that it may also have been a factor??

[Merlin66]

I'll double check the total movement later and compare...

You don't need the crayford...the mirror slop on the C9.25 is not a problem.

What you have should work...

watch this space.

[KE400]

Thanks, will do

[Merlin66]

OK

I've just counted the full 360 degree rotations of the black knob from tight one way to tight the other......and the answer is..................

46.5 turns

Something wrong, if you only get 18 turns!

[KE400]

Oh dear, I've just tried the scientific measurement of turns and the new figure is 23 turns of the black focus knob. Seems to be about half the travel????

I don't know what to do now????

Anyone got any suggestions.......................help

[Merlin66]

On the assumption you have the correct Feathertouch focuser unit for the C9.25....

I'd remove it (once again!) and check that the actual mechanism can i nfact turn 46 times...

If it's connected properly to the Celestron focus shaft then it "should" work....

[KE400]

Thanks, I'll try that, looking at the FeatherTouch it states "SCT micro" on the outside of it. When I ordered it, it did say it was for the C9.25. I'll look through my emails and double check the order details too!

Thanks for your help & time, hopefully I can get to the bottom of it.

[ollypenrice]

I don't know either the scope or focuser but I'm wondering how the focuser is attached as far as the 'starting point' is concerned? Does the mirror need to be wound all the way in or all the way out prior to swapping focusers?

Feathertouch have a big reputation when it comes to service. Have you tried them? They will have seen it all.

Olly

[KE400]

Thanks for the reply Olly, I may have to do just that and give them a call. However you have also made a good point to with regard to the mirror needing wound all the way out to change the focuser??

I've just checked my order details and the focuser I bought is this one linked below which states it's for my scope.

Starlight Instruments Feathertouch Microfocuser Celestron 9.25 SCT

[Merlin66]

If there's anything I can check on my unit to assist, just let me know.

[Merlin66]

I've just re-read the installation instructions... it doesn't mention anything about setting mirror position - I assume it's non critical....

[Alma]

I have one on my C8 and had no problems fitting it. I just looked at the Starizona website and the fitting instructions state that the tube must be horizontal when fitting the microfocuser and that the mirror shouldn't move during the process. Maybe a quick call to Starizona in the U.S. might be in order?

Alan

[Merlin66]

I was thinking about this problem.....

Can you check that there's nothing in the tube preventing the full movement of the mirror along the baffle?

Use a bright torch, look into the front and see if maybe there's a long screw say from the finder backet or a dovetail mounting screw in the rear cell which may be interfering with the mirror.

There's not much edge clearance inside the cell....

Just a thought....

[KE400]

Hi Merlin

I've shone a torche into the scope and can't see anything that looks like snagging it. Out of interest, would you measure the size of the focuser from the base of the scope to the beginning of the black dial. I measure 4cm, after more experimentation today, I've also found that when the focuser is fully wound out to the stop when not fixed to the scope, I can't push the inards of the scope all the way in as they come to a stop therefore meaning that the focuser needs screwing in a fair bit to be able to attach to the base of the scope. This could point toward something snagging maybe.

I still have reservations about something snagging though as when I attached the original rubber covered focuser the other night, I achieved focus no problem therefore pointing the problem toward the FeatherTouch!

(Hope all this makes some kind of sense?!)

[Merlin66]

Just measured...yes it's 40mm

Turning the black knob anti-clockwise moves the mirror forward to the stop ring on the baffle.

I can only think there must be some interference in the mounting area of the focuser.

If the old bearing is removed and the feathetouch "extension" fixed to the end of the mirror shaft - there's not much left in there?????

[KE400]

I'll have to see what happens next time out, hopefully tonight and try the focuser again to see if anything has changed. I'm still limited to the 23 full turns of the black focusing knob which doesn't fill me with hope!

Thanks for all your help so far and I will report back.

[Merlin66]

Kevin,

I don't think 23 turns will do the job for you. have another look at the connections between the feathertouch shaft and the mirror rod/shaft - compare with page 2 of the installation sheet.

[KE400]

Will do, thanks