prefetch

bernard, interesting idea. i think they key here would be to figure out how to design the "handler" portion of the system. i'll think on it and see what i can come up with.

bernard, the problem is that i'm sort of out of room. if i slide my dovetail any more, then i start to lose contact with the DDM85 and i'll be back to having flexure problems. (btw, i really like the setup you've made for adjusting the dec - very nice!) here's the dilemma:

just to followup: i've installed the parallax rings, and now i'm finding i'm hopelessly out of balance with this new setup. it requires over 5kg of counterweights to the corrector-side of the OTA. i don't know how to add that much weight to my system without making the center-of-OTA-axis completely out of balance. i wonder if i'm the only C14 user with a DDM85 out there! i don't know how other people have solved this problem. i just have too much weight on my image train.

jay, i'm using an FLI PDF focuser. mirror is locked down tight, but i'd like to know more about what luc means by "adding 3 fingers" to the mirror to prevent sag. sounds interesting. also, i've decided that i need to get the power/data cables to route via the GALV and the USB hub in the mount. i think that will help a lot by taking off all that pressure from the image train by having a long woven cable rope hanging off it. i've also went ahead and ordered a monster MOAG guider. i just think that i can either spent an enormous amount of time and energy attempting to perfect my C14 balance and flexure, or i can just cut to the chase and go with guided images. sure, i'm kind of sad that the vision of the unguided DDM85 can't be realized with my setup, but it's still a great mount, and the software is really good too, and i'm all okay with it. it's below freezing right now, and it's cloudy - but when things clear up i'll post some flexure results and some pics of my setup.

jay, i'm using a .7 reducer, so i'm at a 2737 mm FL, which i think helps a bit. also, my CCD is a 16803, so i'm at .68 arcsec/pixel w/ a FOV of 46'. if parallax rings and improved cable management won't do it, what else do you think i should be doing to help my setup? or do you think the DDM85 just isn't capable of handling a long focal length OTA?

i just ordered some parallax rings for my C14 so i can ditch my celestron dovetail mount. i hope this makes for a more rigid setup. also, i think i need to do a lot more work on my cable management, which could be causing problems as well - especially as the temperature drops. it's nice to hear that a C11 can get 10 minute subs consistently. that's my goal, but i honestly believe i am going to have to use an on axis guider for my system. i just don't have confidence that i can get to 20-30 minute non-guided subs required for narrrowband imaging.

i'd like to start a thread to better understand the typical DDM85 user experience. OTA: C14 HD mounted accessories: laser finder installation: permanent observatory balancing: standard ASA counter-weights and MDS OTA counterweight on underside of OTA pointing file: 46 points typical maximum unguided exposure: 400 seconds what are your stats?

jay, i agree, the video is incredibly long for a relatively simple set of instructions, but i like the explanation of the radial aspect of balancing in DE, which i haven't seen explained elsewhere, and that was valuable to me. and yes, he seems to whip his scope around quite a bit more than i would. ;-) i'm curious how long people are able to take unguided images. i think i'll make a new post since this thread is getting long and wandering off the original topic of 'chirping'.

so i spent several hours trying to balance my C14 last night. i mostly worked on the radial balance step, and started with the declination. i followed the principles in this video: which i found very helpful. so the results are that it still chirps occasionally, but i can now achieve a 400 second exposure w/ round stars. before, i could only do about 180 seconds. this is all without MLPT. but i can't achieve a 600 second exposure with round stars, which frustrating to me. i have an Ha filter i'd love to use, but i believe the minimum useful exposure is about 600 seconds, and i just can't get it to work w/o getting some star distortion. any advice?

hi robert. i just go by prefetch. hope that's okay. my FOV was about 14 minutes square w/ my atik 460, so quite a bit smaller than the 46' i enjoy now. i used USNO A2.0 and had some more success with the 14' FOV, but now w/ the larger one i switched backed to GSC 1.1. so, problem solved for me, but i believe something is screwy with pinpoint and sequence. my solution was just to use a bigger chip.

thomas, i'd be interested in checking into that - strange! robert, thanks for your reply and thoughts. so, it turns out that i upgraded by camera to a 16803 ccd, and my FOV is now about 46 minutes - and suddenly plate solving is a breeze. i guess my previous small chip plus long focal length made plate solving really hard. still - it is interesting to see evidence that sequence and pinpoint seem to be not 1:1 equivalent. strange. i guess we'd have to look at the code and understand how it's implemented to figure this out.

whew. okay, this makes me feel a lot better that it's happened to you guys. i thought my motor was messed up. i'd had shuddering before, and whining before, but never chirping! alright, i'll work really hard on achieving a near perfect balance and hope the chirping goes away. thanks so much for the replies.

so i've upgraded my equipment - added a FLI centerline filter wheel, and a FLI 16803 camera. lots more weight! what i immediately noticed after i balanced my new setup and then ran a regular auto tune is that as a slewed my mount it would chirp. that's right, it would make chirping noises as it slewed. exactly like a bird or cricket would chirp. has anyone else seen something like this?? i'm going to work more on balancing to see if that will fix it. i've just never heard anything like this from my mount, and it's weirding me out! here's a video of it: http://youtu.be/2R0nvleHSqA

very cool! congrats.

lukas, thanks for sharing your thoughts. i use sequence beta 0.2.0.5. i guess the strange thing to me is that synch can fail so quickly, but manual pinpoint works for a long time to figure out how to solve something. it seems like synch is giving up too soon and cutting things off prematurely as opposed to merely calling pinpoint and letting it do all the work and waiting for it to be complete. perhaps i need to post in the beta section to find out more of what's going on.

hi all, i've been using sequence for many months now, and one thing that i've never really gotten to work consistently is the synch function in sequence. through experimentation i've found that i have to be almost within about 15 minutes of center otherwise synch will fail. however, if i use pinpoint through maximdl, i can be off by quite a bit. it seems that pinpoint "tries harder" than sequence. sequence fails after just a few seconds, whereas pinpoint keeps trying for up to a couple of minutes and many times succeeds after this long. i've switched catalogs, i've played with the "Expansion %" variable, (which i don't believe actually does anything!!) the 5x5 spiral search option is disabled on sequence. i've adjusted the Max Magnitude variable - i've increased my exposure time, decreased it (usually 7 seconds seem to get a good amount of stars) but nothing seems to help me get more area coverage for plate solving, unless of course i just use pinpoint from maximdl. i just don't know what else to do, and since MLPT and sequence fundamentally requires platesolving to actually work through a long exposure, i feel like i'm kind of crippled here. does anyone else feel like sequence synch is a lot weaker than pinpoint (even though they are supposed to be one in the same) ??? or is it just me??

hi all, i've been using sequence for many months now, and one thing that i've never really gotten to work consistently is the synch function in sequence. through experimentation i've found that i have to be almost within about 15 minutes of center otherwise synch will fail. however, if i use pinpoint through maximdl, i can be off by quite a bit. it seems that pinpoint "tries harder" than sequence. sequence fails after just a few seconds, whereas pinpoint keeps trying for up to a couple of minutes and many times succeeds after this long. i've switched catalogs, i've played with the "Expansion %" variable, (which i don't believe actually does anything!!) the 5x5 spiral search option is disabled on sequence. i've adjusted the Max Magnitude variable - i've increased my exposure time, decreased it (usually 7 seconds seem to get a good amount of stars) but nothing seems to help me get more area coverage for plate solving, unless of course i just use pinpoint from maximdl. i just don't know what else to do, and since MLPT and sequence fundamentally requires platesolving to actually work through a long exposure, i feel like i'm kind of crippled here. does anyone else feel like sequence synch is a lot weaker than pinpoint (even though they are supposed to be one in the same) ??? or is it just me??

it's always nice to hear it when people find solutions to these gremlins. thanks for posting.

perhaps you could explain how you are connecting maxim to autoslew. tell us about the ASCOM connectivity you are using, and what it is reporting.

upgrading to the beta version of autoslew (5209) seems to have worked out the kinks in my setup. anyway, hopefully these posts will help somebody someday. ;-)

well, i fixed it. i still don't really understand why the pierside is wrong, but i got it to park where i needed it. here's what i did: i ignored the seemingly incorrect pierside indicator, and went ahead and manually slewed it to the place i needed it. after that, i set the park position, and then instead of clicking on the "east" side where it actually was in reality, i went ahead and played along with what autoslew thought, and clicked the "west" side and saved the position: and after i did that, it all seems to work now - except that it sort of lies about the east/west thing still when it parks, but as long as it goes where i need it to go, i guess i'm okay with all that. i sent an email to support, so maybe someone from ASA will explain why it does it what it does.

so i've recently moved my DDM85 into an observatory, and it's creating a lot of re-learning and new challenges for me. [EDIT: k, forget the home find markings - i got that figured out.] here's what i did: 1) factory reset on autoslew. 2) set my location 3) manually slewed to zenith, pier on east side 4) synched that to park position 1 5) did a homefind these steps are just what the autoslew manual tells you to do when you first get the DDM85 (except for the factory reset.) so... this is what happens next. i try to set my 2nd parking position and then things get weird. i try to manually slew to the correct location for my setup to close the observatory (the skylight) and, well, a picture is worth 1,000 words: everything looks fine, right? well, i keep slewing to get the scope to fit under the skylight and...PierSide changes!!?? seems like as soon as i pass about 41 degrees altitude (which is where polaris is for me) then the system decides that it's on the west side, which is obviously incorrect. any ideas what's going on here?

i just finished installing my DDM85 into a permanent observatory. prior to this i have been using it in a mobile setup. so now i'm trying to figure out the "best" way to startup in this observatory. it's nearly perfectly polar aligned, but i'm confused about what the right way to get it ready. 1) power up PC 2) power up DDM85 3) open roof 4) start autoslew 5) ...? so, at this point, my OTA is sideways (facing northern horizon) so that the roof can fit over it. not really sure what the proper thing to do is. start the motor in autoslew and use the xbox controller to make it point to the zenith and run homefind? and then what? load a previous autopoint file and manually slew the OTA to a bright star, center it in the finder scope and run synch from sequence and go from there?

i'm considering getting a pier tech extendable pier system, but i'm concerned that it would lose polar alignment and generally cause problems w/ the consistency from night to night w/ pointing files, etc. i did a forum search and found a member that has one, and i sent him a PM, but he hasn't logged in for a month, so i thought i'd just post to see what people think about this idea. i read this review which seems encouraging: http://www.pier-tech.com/polar_alignment_repeatability.html the reviewer used a Tpoint model, which seems similar to our pointing file concept. seems like i would just have to do a resync each night w/ autosequence to get autoslew back on track and creating a new pointing file would probably not be required. thoughts?

wow. simply beautiful!