michael8554

Are they elongated in the RA direction ? For round stars the RA and Dec RMS figures need to be similar, but often RA is larger. Michael

If half are okay then your PA must be okay too. If there's a repeating time pattern to the Rejects then it may be Periodic Error. Michael

Well I failed at the first hurdle. Couldn't find Space Fluff on the Zooniverse link :-< Michael

Hi Louise I can see that the belt mod removes harmonics due to the spur gears, and runs quieter, but I don't understand how it can remove the fundamental, the worm and worm-gear backlash ? Michael

Actually I've changed my mind. Although the Dec Calibration is awful, because your PA is good, Dec is chugging along just fine with almost no guiding necessary. So belay the Guide Rate change, but try the RA Aggression changes. And Focus. Michael

I'd say you're getting there Knobby. The last run was RA 0.75arcsecs, Dec 0.44arcsecs. Dec was hardly getting guided at all - good. RA was overshooting a bit, try reducing RA Aggression until you see RA smoothing out, to get RA down to match Dec . The need to nudge north before Calibration isn't my idea, it's an essential requirement from the PHD2 Developers. If you don't do that you won't get a good Cal, and your Cals are still poor. Cal Step Size is correct, 12 to 13 steps on RA, but I would try upping the Guide Speed even more, to the max, and see how it helps Dec. You accepted the Guide Assistant Min Moves this time and that made a big difference. Focus is still poor. There's been suggestions to get balance spot on with belt drive, but there is still worm backlash to contend with, so that doesn't compute for me. Almost there. Michael

Yes it includes the Meade 07080 Zero Image Shift Focuser, which plugs into the Focus socket on the mount, so again needs the HBx to control it. Michael

You should have a keypad / Handbox that pugs into the HBX socket, knock off £100 if you don't. If you have it, £600 to £700. Michael

Hi knobby You were guiding on poor Calibrations, you must get Cal right before you think about guiding. I don't think you followed the instruction to nudge north to clear your large Dec Backlash before Calibrating, so PHD2 did poor Calibrations. You seem to be in denial over the Dec Backlash ? I'm only going by the Log results - perhaps FLO should comment ? You did a Guide Assistant run, but didn't accept the recommendations !! Minimum Moves and Backlash Comp for instance. So your PA was good, so Dec wouldn't need much guiding, if any at all. But you stuck with a tiny Min Move setting, so Dec was continually reacting to every tiny twitch in Seeing. Same with RA Min you could get RA down to Dec figure if the nount wasn't reacting to every twitch in the star. Don't even think about a wobbly Finder Guider to guide at 1400mm. Michael

It's a balance between the light pollution to the east, whilst the west gets darker later (sunset), and Objects "disappear" in that direction. You don't need to see Polaris on a permanent setup.... 🙂 Michael

My LX200 is in a GRP dome for the last 5 years. I cover it with an old cotton sheet, and add a small low wattage thermostatic bar heater under the cover in the winter, set to come on if it freezes. Michael

Do you really want to see below 20 degrees pointing south ? I'd say that hedge gives you a good light screen from the neighbours. If you do want a lower south view then you could move the dome further north? Michael

If I understand the i-Polar spec, this is an aid to getting good Polar Alignment ? Good PA minimises Dec drift and Field Rotation when you're guiding, But accurate moves to a target are the result of a good Star Alignment . If you have the date, time, GMT/BST, location data wrong then the scope will not slew close to the Alignment stars. Each brand of scope has it's own method of entering these, very easy to get wrong. Michael

The PHD2 Log file only has the header, no data. The time stamp is 13:29, I'd expect a late evening time stamp? Michael

Try reversing the order : Point and focus the telescope on a distant object. Lock the axis so that the scope doesn't move. Now adjust the three screws on the finderscope to centre the same distant object. The three screws need to be tight when you've finished aligning. You mention smart phone and mobile signal. I'd guess you've been watching videos of more expensive mounts that can be controlled from a smart phone, doesn't apply to yours. Michael

Ah, one of those linear ISO response cameras. I'd go with what that excellent site says. Michael

Lots of opinions on collimation, I would start with eyepieces, working up to say 300X, but final check with the camera with magnified LiveView, which hopefully won't need any adjustment. Michael

The spec says it has two modes : Video Mode, for AVI sequences of planets, which you stack to make a still image, but that mode can expose up to 5 seconds for shots of starfields etc. Trigger Mode, for 5 sec to 16 minute exposures of galaxies etc. Check focus during the day on a distant object using Video Mode and a fast exposure. With Newtonians you often can't get the focuser in far enough to focus a camera. But if you can focus, that setting you should be close enough to see star images, that you can fine-focus, try Video at 5 secs to start with. Michael

Well that Aux Mount connection doesn't appear to be working, according to the Guide Log. But it shouldn't impact on your guiding if you follow the rules of Calibrating and Guide Assistant runs on target. Something for later, after you've improved focus, upped the Guide Rate, and got good Calibrations. Michael

I deliberately used that wording as in this case he isn't using Aux mount . Page 3 of the PHD2 Best Practices that I gave a link to advises an Aux mount connection - so already covered thankyou. Michael

With your ST4 style cabling, PHD2 cannot get a reading of the mount's RA and Dec position, so you should always Cal on your target, and every time you change target. ASCOM type cabling gives PHD2 the RA and Dec, so you do one Cal pointing south at Dec 0, and use that one on every target, every night. Dec 0 is used because that's where the stars appear to move fastest in RA. PHD2 will then compensate for the smaller amount of RA guiding needed the further you go up in Dec. Michael

Depends on your next guide log, but I think you will need to be creative with your balance to prevent Dec changing direction, your PA is good so Dec should only need minimal guiding corrections. Michael

The notes on the image say Flats 20 x 10 sec ? I would aim for exposures of around 1 sec with mid-range histogram. What are ISO 400 exposures like ? Michael

Your Calibrations were getting better as the night wore on, but were spoiled by the huge Dec backlash - 15 steps, one every 2 secs, means 30 seconds to reverse Dec direction. So although your RA guiding was thereabouts in the last session, Dec was struggling. Your Guide Rate looks quite low, about 5arcsecs/sec, you should up this in the mount to maybe 12arcsecs/sec / 90% / 0.9 of Sidereal, which will help PHD2 to move the Dec axis. So what mount ? What main scope ? How are you balancing ? PHD2 is up to Version 2.6.8, your 2.6.5 is 2 years old. Don't delete the old version, just run the installer for the new version. Check in the PHD2 Mount Settings that the new Guide Rate is being shown. Focus is poor, HFD = 5.76, use the Star Profile window to get HFD down to 3 to 4. Before Calibrating, nudge the mount north at lowest slew rate until you see the star move, to take up the Dec Backlash. After a successful Cal, run the Tools / Guide Assistant, this will work out the Minimum Move settings you need. Do this routinely each night before guiding on a target to get the best settings for the conditions. First time round maybe leave Measure Backlash ticked, but it will probably fail, so next time leave it unticked. Read these Best Practices notes from the PHD2 developers: https://openphdguiding.org/phd2-best-practices/ Make some changes and post your new log including a Cal and a Guide Assistant run. Michael

Dragon is scheduled to dock on the 28th at 16:39 BST. The night before you might see it adjacent to the ISS on the 22:56 to 23:00 pass, though the Dragon is pretty small. Michael