Q-Day!

[Comet Hunter]

Hi all,
After being out of the loop for the last few years, I'm starting to find more time to get back into this great past time and while I haven't posted much I have been checking in often to see what's happening and so on. I've also spent the time sorting out what I really wanted to do imaging wise. Then a number weeks ago it all became clear.... I had this bad girl delivered today! :D

http://comethunter.com/images/FSQ-106ED.jpg
Camera and mount are still a little time off unfortunately so wont get first light for a while yet.:sadeyes: The wait will however give me plenty of time to get focus/dew control etc worked out and operating smoothly.

If you ever entertain the idea of getting a Tak. run with it! - you wont be disappointed. :D

Cheers,

[leon]

Andrew, I know what you mean they are awsume pieces of equipment. ;)

Leon :thumbsup:

[h0ughy]

gee thats a huge paper weight for the Desk Andrew?:whistle:;):lol:

[Lee]

Very nice!

[iceman]

Great to have you back, Andrew! How's bubs?

[rumples riot]

Nice DMK you have there too :wink:

Lovely scope.

[jase]

Congrats Andrew.
When it comes to wide field imaging the FSQ is in a league of its own. Looking forward to seeing first light when the remaining kit arrives.

[Comet Hunter]

Thanks guys. I'm itching to take her out for a test drive but it'll have to wait - I know it'll end in tears if I do anything irrational now.

Mike, the little fella is doing great! He'll be 2 in ~3 weeks, doesn't the time fly!!

[CometGuy]

Andrew,

Looks like you attracted the rain for Brissie for the next week!

Terry

[h0ughy]

lets hope it can fill some dams and clear off. so do you have anything you can mount it on for the minute?

[Comet Hunter]

I hope so, my car needs a good wash.:doh:

All I have atm is my block of wood. I have been wondering how the old meade would take the extra weight though... :scared:

[Comet Hunter]

I finally got around to fitting the RoboFocus today. I trimmed down the adapter plate to give a cleaner result. Connected everything up and it works a treat. I need to see if I can change the direction of travel - with the way I have the unit orientated, clicking OUT moves the draw tube IN.:doh:(Update: Found it in the manual)

Here (http://comethunter.com/index.php?option=com_content&task=view&id=32&Itemid=53) are a few more photo's.

[jase]

Wow Andrew, you did trim the RF bracket down! Have you still got the two screws holding the RF stepper onto the bracket? You'll want to make sure that mounting is as rigid as possible. If there is any give or flex, it will make repeatable automatic focusing difficult. You've got a 55 micron CFZ so you should still hit it ok - with a low step size.

This is what you read in the manual;
Direction. To check the RoboFocus direction, push the OUT button. You will notice that when you push the button, the stepper executes one step (with a beep), waits for 1/2 second, then starts running at full speed. This system allows making small focus changes when operating manually. If the RoboFocus OUT button moves the focuser out (CCW on an SC scope), the direction is OK. If the direction is wrong, turn off the RoboFocus. After about ten seconds, turn on the RoboFocus while pressing the OUT button. As the RoboFocus powers up, it will sense the OUT button, will reverse itself (switching from inward to outward), and will record the new button direction. After several seconds the RoboFocus will start running outward and you can release the button. The RoboFocus will remember this direction information for future sessions.


You can also calibrate start and end points (i.e total draw tube travel) if you are keen (you need to do this to achieve automated computer assisted focusing anyway), but it will be easier when you know the final imaging train configuration as you may require some spacers for the camera to reach focus. If you're using the 2" fittings (TKP27110 and TKP31112) make sure the thumb screws are tight to avoid flexure.

[Comet Hunter]

Thanks Jase, I found it in the manual. Hope you didn't type all that out by hand! :lol:

Looking back at the photo's, they do look a little mis-leading. Basically all I've done is remove the dead weight, here (http://comethunter.com/images/RF.jpg) is the backside while the finder mount clamps the top end down hard with both bolts.

I plan to have a play with calibrating the travel later tonight.

[ballaratdragons]

Hmmm, nice.

I saw them on special at Kmart last week. :thumbsup:

Or was that a Tako-Tashi? :confuse3:

:lol:

[jase]

Yep ;) - Nah, don't be silly, I'm all for efficiency (copy and paste) - if you want to softcopy of the manual (ms word format) you can download it from my site - http://www.cosmicphotos.com/resources/robofocusins3.doc

The bracket looks good, was just a little concerned you were only operating on one screw!:D

[UniPol]

I want the Q Jase, it would fill the gap between my TOA-130 and Sky-90 nicely but alas, the coffers are very empty. Hope you have lots of fun with it.

Cheers,

Steve

[jase]

Cheers Steve, but I've already had plenty of fun with mine. I'm sure Andrew is absolutely hanging out to feed his new Q some photons. Its a hungry scope with its wide field of view.
Any news on the remain kit Andrew (this side of Christmas ;))?

[Comet Hunter]

Jase,

No new news on the CCD yet.

At this stage the mount will probably be just after xmas sometime. I've been ogling the Titans and AP's over the last few weeks, they'd be better suited for the setup we've talked about, but sadly these are well out of reach this time round. While the wait is disappointing, by the time it all comes together I'll hopefully be able to hit the ground running, somewhat. :lol:

I've been playing with the calibration of Robofocus. A stepsize of 4 (default) gives me a Max travel of ~1100. This sound about right?

[jase]

Sounds good Andrew. I feel certain you'll hit the ground running considering you've got some time to work things through.

Yep, 4 steps is the default. 1100 sounds right for the total travel. I think I made mine around 1000 (stopping short of racking the focuser all the way in). Sounds like you're up and running. You may want to do some reading up on FocusMax or @Focus so you can start automating the focusing process. Over the course of the night you'll find the FSQ will shift focus considerably as the temperature changes so you'll need to refocus quite a few times a night. Automating the focusing process saves time and you can be rest assured that you've reached the CFZ every time providing the best achievable focus.

[montewilson]

Welcoem to the FSQ club Andrew. I have a venerable but excellent FSQ. Probably the earliest one in Australia S/N 18. I love it. Tak is addictive stuff. Be prepared. Are you going to get a Tak mount? I have an EM-200. It is probably only bettered by a larger Tak mount or Paramount for performance but is still portable.

I agree with all Jase has offered WRT Robofocus. Its a valuable tool. I didn't use that pissy bracket they send with the kit. I made one out of a piece of aluminium bar. I just can't imagine there wouldn't be some tortional play in their bracket. Others may disagree and I may not need the extra strength of mine but I sleep better knowing it can't be an issue.

I have the small step value set to one. I used to set it to 4 but I found with the backlash in the gears the perfect focus point was often jumped over between steps.

I know Jase has got FocusMax working well and I plan to do the same soon. Software Bisque claim to have a similar system working with CCD Soft that I will try. FocusMax is not as easy for me as I don't have MaximDL.

Keep us informed of developments!

[montewilson]

Hey Jase - I have a RoboFocus question. Does the temp comp happen even during exposures? I see there is a manual and auto setting. The auto can be set to make changes (when required) every set period. If that happens during a shot surely this will ruin the shot. How do you have yours running?

[jase]

You don’t need MaximDL to use FocusMax! It can be used independently or integrated into CCDSoft (just as it can be with MaximDL).

Wow, that’s keen. In my opinion, a microstep size of 1 is way too small. It would take the focuser way too long to move. Ultimately, such as size does not improve the focusing accuracy and would significantly slow down any automated focusing routines performed by FocusMax or @Focus. Typically a microstep size of 3 or 4 will give you the .0005” (0.0127mm) resolution per step (this can slightly vary per stepper motor hence the 3 or 4 value). The FSQ in its native focal length (530mm) and ratio (F/5) has a CFZ of 55 microns or .0021” (0.0533mm) so the focuser must hit focus within 4 steps assuming the 0.0127mm equates to 12.70 micron (12.7 x 4 = 50.3 micron) – this is not hard to achieve for the stepper or software assuming you’ve built a good v-curve model in FocusMax (not sure of the equivalent in @Focus). As a guide the size should be 15%-20% of the CFZ, so a step size between 8 to 11 micron is acceptable. Don’t get confused by microsteps and steps. A microstep is one pulse of the stepper. What you are defining how many pulses make a single step.

With a microstep size of 4, FocusMax repeatedly hits the FSQ CFZ within ~70 seconds (acquirestar, calculate position, step through HFD calculations, then move to the best focus position into the CFZ) – too easy!

Backlash can be an issue, but this is focuser specific. I haven’t experienced such issues with the new Tak 1:10 MEF (micro edge focuser) used on the FSQ-ED. I have told FocusMax that the final movement to the CFZ must be on the “in” side of focus, thus the weight of the camera is pulling on down on the focuser. Perhaps the FSQ-N is slightly different.

Temperature compensation is considered passive focusing. Once you’ve calibrated the temp slope (temp x = focus position y) you must determine a dead zone. The dead zone defines what is an acceptable temperature change before the focusing position is changed – based on the slope value. You don’t want the focuser to be changing constantly if the temp changes by a small factor such as .01 of a degree. Hence the dead zone is important. You can set a correction rate to determine how often the temperature is checked – 5 minutes is normally sufficient. It is possible to change focus during a sub exposure without ill effect. If your temp slope is not accurate you may experience soft focus if you slightly miss the CFZ. The biggest issue I experienced with this method was vibration, so I prefer to configure the corrections to be made between sub exposures.

Having stated all this, I don’t use temp compensation at the moment – may get back to it soon. I’m presently using active focusing, that is, automatically refocusing every x minutes. So for example, if I’m collecting 15min subs for luminance data and the refocus interval is 30 minutes, the set up will take two subs before the auto focus routine kicks in and establishes focus again, then automatically continues with data acquisition (as the autofocus routine doesn’t take long, I don’t lose much time and can be assured I’ve hit the CFZ again). I’ve also saved time with filter offsets. My LRGB filters are parfocal, but the 10nm Ha filter isn’t. So when the Ha filter is selected, the focuser automatically shifts a defined number of steps to reach precise focus using this filter. No need to perform the initial focus – though the filter would be refocused anyway by the refocus interval (30 mins).

EDIT: Don't believe that temperature compensation is the ultimate in focusing. There are numerous other factors (not only temperature) that can cause focus drift. Something as simple as seeing conditions will affect focus (especially if your arcsec/pixel is small). Hence, I feel the most accurate method is periodic refocusing between subs (active focusing).

Hope this helps.
Cheers

[Comet Hunter]

Cheers Monte.

At this stage the G11 is front runner - I'm open to suggestions/discussion though. What I'd like to do is de-fork the SCT and mount both side by side. The weight of both OTA's combined is ~20Kg + accessories. I know this is really pushing the G11 for ideal imaging but I'm hoping fine tuning will help minimise the adverse effects the extra weight and bulk brings with it. As I mentioned last night, Titan/AP would be better suited but the G11 is already pushing the limit. :( Next time though....:whistle:

I agree the bracket, as provided, does leave a bit of doubt. A custom made fitting with a stronger material would be ideal. Once everything is mounted I might see about attaching a custom bracket to the dovetail - this would remove screwing around trying to get the correct angle with the finder mount while keeping the focuser square with the shaft etc.

Wow Jase, thanks for that! I was under the impression Focusmax required Maxim as well. Installing now to have a play.

[jase]

Distributed as part of the ASCOM package is the FocusAPI plug-in for CCDSoft. There are some basic instructions provided to get FocusMax integrated. The plug-in enables CCDSoft to communicate with an ASCOM focuser, by translating the FocusAPI calls from CCDSoft into ASCOM equivalent calls.

Bisque's @focus 2 capabilities I believe are now comparable with FocusMax. @focus 1 was rather lame. FocusMax is still evolving (as is @focus) as per my previous post (FMx 3.4.1 released) (http://www.iceinspace.com.au/forum/showthread.php?t=23392). I don't think either have the edge on the other. Depends on your preference and ultimately whether the software gets your camera's focal plane into the CFZ every time.

If you're scared of ASCOM and prefer to stick with proprietary code such as that developed by Software Bisque. You are stuck with @Focus 1/2 for automated focusing. I'm not saying that's a bad thing, but I feel its important to have a choice. ASCOM opens up a wealth of device support.

[montewilson]

You're right Jase @focus1 left a lot to be desired. I only got it to work once!

I know I could get Fmx to work with CCDSoft but I am not as technically gifted as you! I looked into it and beat a hasty retreat. I guess that marks me out for mediocraty because AP is full of similar challenges.

WRT the focuser on the Q, mine is quite coarse and yours has the benefit of many years of evolution. We may find there is a significant difference between them.

OK on what you said with the focuser progy and setting it up to work between exposures. I will go and harras the guys on the Bisque help forum to see what they know.

Andrew! If you want to do more than 20kg forget the EM-200 you would need an EM-400 but alas, they have stratospheric prices. A GM-11 would be a fine alternative. Don't forget a great mount will bring the best in any scope, a bad mount will bring out the worst.