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malc-c

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About malc-c

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    Hertfordshire
  1. Just posted this yesterday on my build thread - still fully functional, although I tend to remote into the observatory PC from the lounge these days rather than sit in the "warm" room, especially as I've fitted a small workbench in there as well, so it doubles as a small workshop which can be isolated from the scope room
  2. Well it's that time of year for the observatory's annual maintenance, a lick of preservative There was the odd lose board that needed a screw to secure it back in place, and the winter storms produced a small leak where the felt wraps over the wood section that prevents the roof falling off the warm room, which in hindsight could have been a tad thicker to reduce the angle the felt needed to be folded, but it's done now, and to resolve that means rebuilding the entire warm room roof and that ain't gonna happen ! - Especially as its a very small leak, and I have an idea how to fix it without too much work. I've attached an image showing the difference in four years, and other than the above, this thing has lasted well (faired better than the patio chair that is now falling apart !) considering it's now 8 years since construction commenced. The conifer tree that we thought was going to die off has made a recovery which is a good thing on one hand, but on the other it now needs 4' lopped off the top as it's obscuring a good chunk of the Western sky. The hedge is now a lot lower, and the tree behind the observatory has been pruned back considerably. The warm room now doubles as a workshop with a bench and my late father-in-laws pillar drill, but other than that nothing else has changed since the last image in 2016. Its rewarding to see that after 8 years of winter storms, with winds of 60+mph, 2' of snow, -11c in winter and +35c in summer, that the design and build has stood up to it all, and for the cost of £8 for a gallon of preservative and a few screws each year
  3. Have a look on YouTube for Dions guide to balancing the OTA. https://youtu.be/hGduG2jB9ec?t=131 and his recap https://youtu.be/uK2bXfVNoQU They are old videos, but the information is current. It deals with one issue that is often overlooked and that is the Centre of Gravity (CoG) Basically with the mount as sweetly balanced, either with or without the bias for imaging it means that the guide system doesn't have to work harder or over compensates. With belt modified mounts there are less items in the drivetrain to create backlash. If the mount has been converted to a Rowan belt mode by the retailer, then the worm meshing and backlash should not need touching as they would (should) have set this up prior to selling the mount. My scope hadn't been used for nearly three years until recently when I gave it a full overhaul and set it all back up from scratch and then went through lots of fine tuning over several nights with PHD in order to get the best out of my finder guider. Now the scope is performing really nice given the limitation of using a finder as a guide scope.
  4. I thought if you choose ASCOM driver in the PHD2 connection box it used whatever settings the driver (EQMOD) was set to... didn't realise you also had to set the guidrate in PHD's profile settings too ! I might go back and double check my settings
  5. I presume you are using EQMod to control the mount ? If so the rates are changed by moving the sliders under "ASCOM pulse guide settings" top right of the application (need to expand the default view by clicking on the spanner and >>> button)
  6. OK it's obvious that you are trying to get into astro-photograpy on a budget. But IMO the mount is not going to give you the accuracy and stability to do so. The drive is intended to maintain position for visual observing where it won't matter if the polar alignment is off, or if the battery is running low and the tracking is slightly slower. The drive is a simple DC motor system and the mount will have a fair bit of backlash and lacs the precision required to produce sharp detailed long exposures. It will be fine for taking pictures of the moon, or wide field constellations where single 20-30 second exposures with a 55mm lense will not show any error, but for any deep sky work that requires a scope or heavy lens and long exposures the mount simply is not up to it. The mount is the most critical part of any true imaging rig, which is why you see pictures of HEQ5 / EQ6 / EQ8 with relatively small scopes on them. Its their ability to precisely track even whilst carrying a lot of weight that they are used. And as anyone who ventures into imaging it is not the cheapest side of the hobby compared to visual observing.
  7. Can you advise us what make and model the mount is as some will be better than others. It's really difficult to advise when we have no idea on how capable the mount and motor drive is But if the motor on the RA axis is designed to work with the mount you have then it should provide good enough tracking for wide angle shots with your camera and lens. Provided you can polar align the mount well there would be little to no tracking errors in a wide field image. It's only when you start using long focal length lenses or telescopes that the alignment becomes critical, and limits the exposure duration before guiding is needed in order to prevent star tailing.
  8. Good point... could it be that the filter changed at that point (although if the 14 exposures were on the same filter that would mean it was 84 minutes before the change whereas the issue occurred around 47 minutes into the guide)
  9. It look like the star just disappeared around frame 590. Whilst the S/N and Starmass is up and down (possibly related to the guide rates being low) at that frame it dropped completely. Could it be that after the 47 minute mark the star went out of the fields of view of the OAG or cloud cover ?
  10. What mount do you have.... given that most DSO need stacked long exposures the mount is probably just as much, if not more important than the scope used.
  11. If you have the log file enabled and saved, maybe post that to help diagnose what the issue my be.
  12. malc-c

    PCB design

    Looks good - not sure what the project is, but you could always make and sell them to other forum members unless the project is very unique ?
  13. Thanks for the summary of what you have and what you have tried... Just to clarify things (not that I may be able to offer any more to the cause as other posters are more knowledgeable on PHD), are you still having the same issues as the first HEQ5, regardless if EQMOD or the Synsan app is used? One observation I made is that with your scopes 1400mm (as per calibration data) focal length (presumable you are using a reducer as the C8 is normally over 2000mm f10), and an OAG, could the issue be that the calibration pulses are moving the star too much, or that it moves it out of the FOV of the OAG?. Could it also be a factor that what has been suggested as poor seeing could be a combination of a faint star and f10 ratio giving a faint image of the star ? My experience of guiding has been with short fast guide scopes like the ST80 and now the 9 x 50 finder, with no experience of OAG, so apologize if my comments are irrelevant, or my assumptions are wrong.
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