Home position is definitely useful. You can do home with the encoders or if you get a home sensor fitted. But from users accounts once its setup its not really an issue.
At least I hope so.
Greg.
You will be in an excellent position to do a what you like and what you don't between ME & AP. I only ever lost position when I synced wrongly, but then again it was just in my backyard and I could just run and correct it.
You will be in an excellent position to do a what you like and what you don't between ME & AP. I only ever lost position when I synced wrongly, but then again it was just in my backyard and I could just run and correct it.
Thanks Raki,
It will be in my backyard as well so no problem there.
The Honders likes the AP1600. Its giving nice round stars now that could stand a slight improvement still. So tonight if its clear I plan to do a monster 400+ Tpoint model and implement the accurate polar alignment adjustments! A 16 inch saddle that is on the way may also help in case there is a little bit of flexure there. The guide errors seem very low a lot of the time.
One feature that seems a standout on the AP1600 mount is the way the gears and worm engage. On other mounts they are permanently engaged. The AP1600 gears and worms seem to only engage when its tracking. Clever. The axes are stiff but you can push them with a small amount of effort. Fine balancing is not regarded as that important per the manual.
Its also dead quiet when tracking. When slewing at 600X its not that loud either. At 1200X its louder but not outrageous. It does sound like the motors have plenty of grunt which is reassuring. There is no movement in either axis when you give it a slight push. No wiggle, nothing. Amazing. The whole unit comes across as ruggedly accurate and precise.
Its also able to be upgraded at home with absolute encoders which get rid of PE altogether and gives below .2 arc sec guiding and unguided tracking for many objects. This gives you back the home position which is probably one of the best Software Bisque features of their mounts. Some time in the future I'll probably get those.
... One feature that seems a standout on the AP1600 mount is the way the gears and worm engage. On other mounts they are permanently engaged. The AP1600 gears and worms seem to only engage when its tracking. Clever. The axes are stiff but you can push them with a small amount of effort. Fine balancing is not regarded as that important per the manual.
Its also dead quiet when tracking. When slewing at 600X its not that loud either. At 1200X its louder but not outrageous. It does sound like the motors have plenty of grunt which is reassuring. There is no movement in either axis when you give it a slight push. No wiggle, nothing. Amazing. The whole unit comes across as ruggedly accurate and precise.
Its also able to be upgraded at home with absolute encoders ... This gives you back the home position which is probably one of the best Software Bisque features of their mounts ...
Greg.
Greg, there are sets of little black clutch knobs on the RA and Dec. Yours must be very loose, or finger tight only? For heavier loads, AP recommends that you tool tighten - but not excessively.
AP also have plans for homing-limit switches on the 1600. It's a kit that you bolt on. A fraction of the price of the encoders, but still giving those homing and safety stop features that we love on the SB mounts. See the 3600 page - they've been out for a while on that mount.
Greg, there are sets of little black clutch knobs on the RA and Dec. Yours must be very loose, or finger tight only? For heavier loads, AP recommends that you tool tighten - but not excessively.
AP also have plans for homing-limit switches on the 1600. It's a kit that you bolt on. A fraction of the price of the encoders, but still giving those homing and safety stop features that we love on the SB mounts. See the 3600 page - they've been out for a while on that mount.
Logan.
Hi Logan,
Are you supposed to tighten those clutches when tracking? I thought they were there only for loading/unloading the mount. I'll check that out. I just read the manual on this point. Wow, Duh. Read the manual eh? I'll tighten them now!
I'll look at that kit for the 3600 to get an idea of these homing switches.
Sounds a bit more involved than I thought. It may be better to bite the bullet and simply get the absolute encoders. Also needs the special APCCA software. I know there is APCC available not sure about the APCCA version.
Greg.
Quote:
Originally Posted by Logieberra
Greg, there are sets of little black clutch knobs on the RA and Dec. Yours must be very loose, or finger tight only? For heavier loads, AP recommends that you tool tighten - but not excessively.
AP also have plans for homing-limit switches on the 1600. It's a kit that you bolt on. A fraction of the price of the encoders, but still giving those homing and safety stop features that we love on the SB mounts. See the 3600 page - they've been out for a while on that mount.
I got some feedback from Roland on a couple of questions. I discovered that I had set my autoguiding settings wrong. At least for this mount.
I was using .5 minimum move and 2.0 or 3.0 maximum move. I was lowering it to the default .01 minimum and that seemed to work better. But tightening the maximum move should ignore moves not needed.
The 0.5 min/2.0 maximum came from the CCDWare autoguiding calculator but that is for direct guide which is a Software Bisque way of controlling the mount from autoguider corrections. AP uses Pulse guiding or relays. I can't quite tell if pulse guiding is the same as Direct Guide but I think its very similar. Both do not need an autoguider cable.
Roland said to use .01 to .03 for minimum move and .3 to .5 maximum move depending on the focal length ( I assume by that he uses .3 for the longer focal lengths?). .01 minimum move for good seeing, .03 for less good seeing.
2 to 8 second guide exposures, aggressiveness 6 to 10 with 6 in poor seeing and 10 for good seeing.
Callibrate at celestial equator. Reverse commands with meridian flip.
Backlash settings to zero. Guide frame size 16 x 16 to minimise cosmic ray hits.
I just fitted an AP 16 inch saddle to the AP1600 to hold the Honders more firmly as it has 3 tightening points and is super well made.
I am redoing TPoint models and Polar Alignment. 400 point Tpoint model in progress.
As a tip, I think its faster to use Pempro's polar alignment wizard to get PA very close rather than a series of TPoint models. Then use Tpoint to do a 35 point model and do the accurate polar alignment routine. Then a large Tpoint model and do the accurate polar alignment routine. I think that's about as accurate as it can be.
I am also going to experiment and see if I can track with no autoguiding and Protrack only and get round stars at 5 and 10 minute exposures.
Update: I did the 403 point Tpoint model Accurate Polar Alignment (a very small tweak so PA is essentially perfect). I tried a 5 minute exposure Protrack only - not too bad but somewhat elongated stars. With autoguiding - perfect. Packing out the camera to get rid of tilt. One corner seems in, weird. A tip if you do this. The image on the screen corresponds to the same corners of the camera looking at the camera from the back. So top left of screen is top left of camera looking at it from its back. That can save you a lot of time figuring that out!
Some of the lowest guide errors I've ever gotten. Up there with the PMX and AP140 a few months ago. 3 second guide exposures. 0.1 minimum move, .3 maximum move, aggressiveness 4, Pulse guiding in Sky X running the autoguider.
Greg.
Last edited by gregbradley; 08-08-2015 at 11:41 PM.
How much do you dither between subs? I found out the hard way that if I have too small a max move + too low aggression it takes forever to correct the dither. I might be wrong but I just increased my max move a lot to take care of this. Doing so didn't seem to effect guiding at all as normally I don't get any really large moves to worry about except for the dither.
Anyway, generally I wonder about how large a move you and others set for dither. Is larger generally better, or is 1 pix enough?
I also came to the conclusion a while back that using PEMPro for drift alignment is pretty quick and then I followed by running T-Point. However, with the new APA routine I'm not sure that is still the case. PA using T-Point is not an iterative process though many assume that it is or just end up using it as such. Again, according to Patrick one large model followed by PA should be do the trick. Using the older method (non-APA) ended up being iterative only because the tic marks let the process down. With APA the tic marks are just a "guide." I used to calculate my own PA corrections and then confirm the moves photographically...similar to APA but much harder to do especially in azimuth.
I suppose theoretically one large TPoint model is enough but I found APA on a 33 point model was off by a large margin. Iterative Tpoints at 33 points each got it close then a large Tpoint model AP seemed to get it very close.
The 403 point model PA is essentially perfect. I don't know what SB are talking about saying Protrack can do unguided imaging. It certainly can't.
Greg.
Quote:
Originally Posted by PRejto
Hi Greg,
How much do you dither between subs? I found out the hard way that if I have too small a max move + too low aggression it takes forever to correct the dither. I might be wrong but I just increased my max move a lot to take care of this. Doing so didn't seem to effect guiding at all as normally I don't get any really large moves to worry about except for the dither.
Anyway, generally I wonder about how large a move you and others set for dither. Is larger generally better, or is 1 pix enough?
I also came to the conclusion a while back that using PEMPro for drift alignment is pretty quick and then I followed by running T-Point. However, with the new APA routine I'm not sure that is still the case. PA using T-Point is not an iterative process though many assume that it is or just end up using it as such. Again, according to Patrick one large model followed by PA should be do the trick. Using the older method (non-APA) ended up being iterative only because the tic marks let the process down. With APA the tic marks are just a "guide." I used to calculate my own PA corrections and then confirm the moves photographically...similar to APA but much harder to do especially in azimuth.
all as normally I don't get any really large moves to worry about except for the dither.
Anyway, generally I wonder about how large a move you and others set for dither. Is larger generally better, or is 1 pix enough?
Peter
I set my dither move in Astroart5 camera control to 2 pix, this seems to work well with the NJP mount and minimises time lost for reacquiring of the guide star, which can vary anywhere from almost instantly to as much as 30sec, depending on the seeing and direction the dither move took the scope
I haven't been dithering as usually there has been a bot of drift between subs anyway. At the moment perhaps there is no drift. I don't see dithering as an option in Sky X autoguider control. I thought I saw it there a few months ago.
I had Sky X recognising my FLI CFW 4/5. Now I am using FLI CFW 5/7 it does not list it as a choice. So I have to work out whats with that first.
I intend to start using Sky X camera control for all imaging soon. I like the fact you can program more than 4 filters for an imaging run (CCDSoft only allowed 4) and this dither which I have not used before except for a short time I used a dither plug in for CCDSoft which had a bug in it as it crippled subframing which I used for autoguiding.
Peter, I see it has a delay exposure feature and a settle threshold so these could solve your problem if you are using Sky X for camera control.
Oh, I'm not saying I have a problem. I use the delay and the settle threshold so that works fine. I was mostly curious if there is a "science" to setting the dither amount? 2 pix does sound reasonable and 5 a lot. But why 5?
Greg, there are numerous examples of fantastic unguided images throughout the forum at SB. I think it really depends on a lot of factors, but the refractor people seem to nail it pretty well. I've done 6 min subs with no problem but compared to others that's nothing.
I looked at the sub I did with Protrack only again and its not that bad. Not good enough but not bad.
I imagine short focal length light scopes may have a better chance. It probably comes down more to the mount than Protrack.
The good news is the AP1600 is performing brilliantly and round perfect stars are now common. I am getting some slight flexure of the camera at the filter wheel junction to adapters. I've packed out the camera with some spark plug gap feeler gauge pieces (they worked better than brass shim for some reason). So when the camera is pointing down I am getting really good stars to the corners but at lesser angles I am not sure I get them 100% of the time. I may turn the filter wheel around so the end is sticking up in the air and make sure all its cover plate screws are tight. The other solution would be to ditch the MMOAG and use a solid adapter from the focuser to the filter wheel (it may not change anything though if its the filter wheel that is flexing) and use a Baader Vario finder with AP support bracket attached to the scope body for guiding. Some use that and find it works. Its a clever mounting system that holds the guide scope rigid. It looks to be the gold standard for guide scopes.
Oh, I'm not saying I have a problem. I use the delay and the settle threshold so that works fine. I was mostly curious if there is a "science" to setting the dither amount? 2 pix does sound reasonable and 5 a lot. But why 5?
Greg, there are numerous examples of fantastic unguided images throughout the forum at SB. I think it really depends on a lot of factors, but the refractor people seem to nail it pretty well. I've done 6 min subs with no problem but compared to others that's nothing.
Peter
Last edited by gregbradley; 11-08-2015 at 09:45 AM.
Here are some photos of the setup I took this morning:
http://www.pbase.com/image/161014757 AP RHA on an AP1600 on a Mountain Instruments portable pier (about to be changed for a permanent pier) and the CDK17 on a PME and a Pegasus pier in the background.
i am unbelievably jealous of your scopes and mounts. it is set ups like this that makes me want to double my budget ...
They are pretty setups I must say. I think the last year's images on this site though have shown very clearly that superb results can be achieved with much more modest gear these days.
Last night I was doing another night of imaging with the Honders (working beautifully) and I could see the object would be too low after about 12am. So I thought I would go at 11:30 cut the run short a tad and swap over cameras to the Trius and image a galaxy for another 4 or 5 hours from 12 to 5am. Should only take 30 minutes tops to swap the camera.
Well 4.5 hours later it was running well! A dodgy USB cable, minor mistakes, focusing, getting the camera square, rebalancing.
Got about 2 hours on a galaxy though.
The moral of the story is a setup that is all running perfectly is deceptive and gives the feeling that changing out to some other part will be a piece of cake. Think again.
Greg.
Last edited by gregbradley; 17-08-2015 at 05:19 PM.
and I could just run and correct it.
Its giving nice round stars now that could stand a slight improvement still. So tonight if its clear I plan to do a monster 400+ Tpoint model and implement the accurate polar alignment adjustments! A 16 inch saddle that is on the way may also help in case there is a little bit of flexure there. The guide errors seem very low a lot of the time.
