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Posts posted by Uranium235

  1. Wow... you should have got more for 6 min :) what target is it BTW? And what scope are you using? ISO setting on cam?

    Are your tracking problems coming in RA or DEC? The hysteresis is used to average out RA tracking to stop sudden changes, the higher it is - the smoother it is. The max setting is 50.

    But like I said earlier, choice of guidestar and polar alignment are just as important (if not more) than messing with the PHD settings. Use the star profile window to choose one that shows as a sharp spike which isnt bloated, if you have adjusable guidescope rings (very handy) you can choose the best star on screen and move it to the bullseye area before performing PHD calibation.

    Dont worry, plenty of time for practice next week cos there is going to be a lot of clear sky and fair weather (wed-fri hopefully) :D

    Addition: Just a thought - If youre having problems with one target, try another spot in the sky and see if the problems go away or reduce - try not to sit there getting really angry (like I do...lol). I had a problem getting M101 once, so I just slewed round to M3, tried again and it was perfect (that told me it was a balance problem).

  2. In PHD:

    RA Agressiveness = 105

    Hysteresis = 50

    Dec guide mode = Auto

    Max dec duration = 300

    Calibration step = 1000

    Exposure time 0.5 - 2sec (depending on availablility of good guide stars)

    On mount:

    Anti-Backlash RA and DEC = 0

    You can try that (the settings i used last night), but if youre still having problems after that it could be something do do with either your choice of guidestar, polar alignment or balance... or all of the above!

  3. Nice work... I'd like to say I told you so....


    Thanks Peter! Looks like im eating humble pie for Sunday lunch...lol... :D

    Lukebl, im using 15x3min subs for both of them - with 10x3min darks too. I didnt want to push the exposure length too far given the dec problems ive had recently (less wasted subs). I can understand the hassle youre having, mine was eventually solved by polar-aligning twice and finding a better guide star (wish id done that at the start of the session!).

    The camera is new and straight out of the box (unmodded), its unlikely its ever going to see a real camera lens so Im mulling over whether to have it modded or not. Which leads to to a question, if I had it astronomized is it better to have a filter change, or the filter removed totally?

  4. Just finished stacking last nights results and in conclusion, the Canon 1000d knocks the socks off the Nikon D60 when it comes to taking long exposure subs. Focusing was a breeze with live view over USB, and the control software is fantastic too (set up & walk away). No sign of the volcanic ash cloud either (yet).

    I managed to get remote assistance up and running too so I could watch it all from the basement :D In the end though the guidescope kept dewing up every 5 min so PHD lost tracking (something like 3am that was). Despite some polar alignment problems that took a while to fix, i managed to get 45 min on M82 (I cropped out M81) and M3 AND get some proper darks and flats done (at sunset). Proper darks & flats are worth the hassle.

    Canon Rules..... Nikon Drools! :)

    15x180 sec Light, 10x180sec Dark, 10 Flat, 10 Bias



  5. I know, I have a friend trying to get back from Schipol in Amsterdam - its costing him a fortune in extra subsistance and insurance companies wont pay out because they call it "force majour" or "an act of god".... yeah right.

    I dont think jets would be allowed to fly so low becuase at that that altitude I think they become less efficient and burn more fuel. Lol..... BA wanted a strike.... now they cant work even if they wanted to!

  6. lol... unlikely anyones ever gonna try that without a very long ladder and balls of steel! Nothing that a .22 cant solve :)

    I went out last night and didnt see any interesting sunset either, but the volcano has managed to make its way onto Sat24.com. Flights are cancelled for a second day, so fingers crossed it will end soon. However, a vulcanologist on BBC news explained that if the eruption changes phase into a lava producing phase.... then it could last weeks... even months! :D

    Lets hope not.

  7. I got the scope rings today :p sorted! Had to hacksaw down a couple of bolts tho but its all fitted now and it looks great.

    I did have a reminder of why its wise to have a good guide star because PHD was sooo much better last night. It could have been better, but its better than a poke in the eye with a sharp stick :)

    I had a fiddle with the positive DEC anti-backlash on the mount (set it to 14), that improved things a bit more.


  8. Yeah, i forgot to mention that I had the same idea as yourself with just going back into the menus and changing the alignment stars - but it wont let you for some odd reason. Thats why I power off and go from scratch again, and after your first alignment star is done most other stars that follow are already in (or just in) your EP, so no need to faff about with the finderscope.

    The whole thing should take no more than 20min tops.

    Oh, and like the man says above - get your own spirit level on the case :)

  9. Update:

    After more doses of bad DEC, ive decided to finally invest in some ADM guidescope rings, that should help a lot when picking the right guide star. At the moment my guidescope rings are fixed, and more often than not I end up picking a guidestar well outside the "bullseye" zone.... but no more of that from tomorrow :)

  10. Ahhh just as I thought, It must be the power cable then.

    I was out last night and had no problems this time, probably because everything was taped up.

    Still had problems in DEC with PHD :p:mad::):mad: I was at the verge losing my temper with it - the OTA was cam heavy (as told to), still the same sawtooth in DEC. It only started working properly in the last 5 min of the sessions when id already decided to pack away.

    It seemed to work when I picked a better guide star nearer the centre of the screen, but its not like my scope and guidescope point at the same things (I cant adjust the guidescope) as its just bolted on top of the main OTA... hmmmm i think i need some proper guidescope rings :) at least then I will be able to pick better targets for guiding.

  11. Heh... better check my dec cable while setting up tonight then :p

    Im just wondering if the same thing can be caused by a dodgy power cable, I gave it a wobble at the jack end once and the handset did some very strange things. I think im going to take the step of using masking tape to stick the power cable to the mount legs to stop it flapping about so much.

    The more I think about the power cable, the more im sure thats the prob becuase sometimes the mount has reset itself while im polar aligning (and fumbling about looking for the alt/az knobs), must have caught the power cable i guess.

    Heh, looking forward to tonights session tho, I popped out to tesco earlier and got a folding chair with a drinks holder in the armrest :) no more sitting on buckets or breeze blocks for me! :)

  12. Thanks, ive a feeling it might be a cable, but I cant be sure as thats not the only wierd thing that it sometimes does - like continuing to slew past its target (slowly)until it tries to cause a mount collision (that happens while calibrating sometimes too).

    Ive only had it 4 months so it cant be that much wear & tear. I hope to god its not the handset, that would be not cheap to replace. :)

  13. Lets just say I had about £450 to improve my setup, what would give the biggest performance boost? My main targets are Messier objects and id just like to be able to get a lot closer, like ive seen in other posts (ie: a real nice, colour close up of M51).

    a) A new OTA - an APO EQ80 for clarity or SCT for focal length, ie: a C6?


    :p A dedicated CCD imager (imaging source DFK 41AU02.AS Colour)

    Just window shopping of course :)

  14. Right, now ive finished the great strimmer massacre on the lawn maybe I can get round to posting what I got up to last night. It was a perfect night for AP, not a could in the sky with the only limiting factor being my endurance (2am), believe me... its not comfy sitting on a upturned bucket!

    I got about 40 min each in 2min subs on the M13 globular cluster, M99 pin-wheel and M104 sombrero (I love that one, shame I cant get closer without barlowing up and all the trouble it brings). Also did 12 darks (1min), flats and bias.

    Not much sign of the PHD problems that have been hassling me over the past few nights, probably because my chosen targets were lower in the sky at the time, no doubt it will return to haunt me at some point. :)




  15. Right, sit rep....

    Last night I went ahead and created an imbalance in DEC (made it nose heavy by sliding the OTA forward a bit), then fired it up.... slewed to M101 and got exactly the same problem again! :p

    After almost pulling my hair out and on the verge of packing it in for the night I decided to slew round to M3 as a last-ditch try.... and hey presto! No problems at all! It seems pretty hard to create an imbalance in DEC (using gravity) when your OTA is almost pointing vertical, is there any way I can get around that problem?

    To prove that lower objects worked better, I decided to slew round to M104 (Sombrero Galaxy) and again - no guide problems. Its only in that M51/M101 ursa major area that i seem to be getting all the trouble.

    Heres what i managed to get anyway, given the problems I only managed 30 min on M3 and only 4 subs of M104... heh... always the way - things dont seem to start working until its time to pack away! :)



  16. Hiya,

    Just looking for some help in getting to the bottom of a problem im having with PHD. When guiding, the RA axis is always perfect - but the DEC often goes into a sawtooth waveform (drift, drift, drift.... massive overcorrection). I will attach a pic to demonstrate it, its not the real thing, but a mock-up i drew of what it looks like.

    Is this down to balance or polar alignment?... Its probably a mixture of both, but last night i took care with both - and still the same result. In the end i just went into the advanced options and changed the Dec pulse time to 2000ms, only that seemed to calm it down a bit... but that cant be the answer.

    Just for info, my polar alignment method for the CG5-GT is:

    1: Rough align with polaris through polar axis

    2: After setting up the GoTo (2 stars), use the polar align feature in the handset - using the last alignment star (usually procyon).

    3: switch off/on the mount and do another GoTo config (5 stars)

    Do I have to switch off/on the mount and re-configure it after using the polar align function? Thats what ive assumed becuase it was never mentioned in the manual, it might be that i could just go back to the hand set and run through the Goto setup again..... but I tried that and it wouldnt let me replace any of my alignment stars (just said "alignment cancelled"). It could be that I need to de-activate sync (as that is used when polar aligning). :)

    Also, is the a "best spot" in the sky for choosing a polar alignment star with a CG5? (like near or away from the meridian?)

    Thanks in advance for any enlightenment! :p


  17. Got mine now, its a little different to the Nikon fit but ive measured it and its exactly the same profile as a T-Ring combo, so focus will be ok. Now im just waiting for Jessops to cough up the 1000d and I will be ready to rock.

    Clear sky alert for this evening too :) Find a sheltered spot in the garden tho, theres a light breeze.

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