michael8554

Out of interest I looked up the spec. Here's the Bad News I hadn't realised before: Exposure Time 15ms~500ms So no 1 sec to 4 secs Exposure for Guiding. Michael

I promise I won't joke 😂 🤣 😅 What sort of Targets would this OTA be used for ? Michael

ZWO have a fixation with advising cameras be setup with 55mm backfocus, even without a FF or FR. It's the FR or FF that determines the backfocus, so you should use the backfocus recommended by the FF maker, not the camera maker. Because not all FF/FRs have 55mm backfocus eg Meade/Celestron 0.63 FR is 105mm. I couldn't find a 0.8FF for the 80ED, only a 0.85FF, there is a 0.8FF for the 60EDF ? But you're in luck, both have a 55mm Backfocus. Michael

Red is arguably the "noisiest" signal, so this might impinge on the modded camera. I would need to see comparison jpg's of stacked 4000D and 1300D images. Michael

The 4000D spec doesn't seem to be any different to the 1300D announced 2 years earlier: 18 Megapixel sensor, DIGIC 4+ processing. Looks like the "1100/1200/1300 Range" electronics are routinely migrated down into the cheaper "1000/2000/3000/4000 Range" cameras. So performance should be similar, but Ha response will be enhanced in the modded 1300D. Michael

If your mount driver supplies PHD2 with the mount's RA and Dec, you should Calibrate near Dec = 0 and near south. Because the amount of RA guiding is dependant on the Dec position of the target, and PHD2 will compensate if it knows the Dec of the target. If not, typically with ST-4 guiding, or a poorly written driver, you should Calibrate on target, Ian has this setup. This is what the PHD2 developers stipulate. Michael

A dedicated Planetary Camera is ideal for those moon close-ups. But your DSLR will also do if you take lots of fast exposure shots and stack the best, least fuzzy shots. Cropping the result will probably give the same same size frame in pixels as the Planetary camera. Michael

The moon and planets have very dynamic orbits that many mounts don't have the data to accurately position. Unlike the stars and DSO's that are essentially fixed. Luckily the moon is big and bright enough that you don't need an accurate GoTo. Michael

Hi Ian From the GuideLog. PHD2 had to clear 23 steps of Dec Backlash before the North part of Cal could start. It would really help to improve the Cal if you pulsed north until the guidestar moves, then add a couple more pulses as there's so much backlash, THEN Calibrate. This is in the PHD2 instructions that I'm sure you've read........ ? Guidecam focus was good HFD = 3.14 px, until 19:44 when it became HFD = 5.72 , something loose ? Instead of running the Guide Assistant straight after Cal, you left it until much later. PA Error =>11.5arcmins, usually needs to be 5arcmins or better, but with bad Dec Backlash this error can be used to your advantage, see later. MultiStar Guiding allows fast exposures that would normally be "Chasing the Seeing". But in those conditions 1 second exposures were too fast, giving very choppy camera output and Star Lost messages. In the only long session at 19:30, Dec Backlash predominated for the first 3 minutes, as shown in alacant's screen grab, Once PHD2 had pulled Dec back, Dec drifted south due to PAE, and so backlash didn't come into play. If you can't improve the Dec performance, this may be how you have to guide. The calculated Guide Rates were Norm rates RA = 6.3"/s @ dec 0, Dec = 5.9"/s. Higher Guide Rates may help, say 10arcsec/sec. Michael

I believe you have to plug in the guidecam first, and select in the fork symbol next to Connect in PHD2. Then plug in the imaging cam and select in the imaging software. Michael

As above - wrong focal length. Also Polar alignment poor: PA error = 9.1 arcmins. You need to get that down to 5arcmins at least. Also you have the PulseGuide Setting too low in EQMOD: RA Guide Speed = 1.5 a-s/s, Dec Guide Speed = 1.5 a-s/s Guide speeds need to be at least 7.5arcsec/sec. Your guiding might actually be quite good, RA and Dec errors are very similar, so you should have round stars. But the incorrect settings are causing PHD2 to multiply the error figures. Michael

The middle and lower half of the image have good star shape. Then from the middle up the shapes get worse. Which I believe means it's not tilt, but perhaps misadjustment of some of those bolts. Michael

Yep

Hi geezer If you want wide angle shots of the moon you may need to ditch movie modes and stack still shots. As the moon is usually bright, ISO800 is said to be the sweet spot, and fast exposures to reduce the effect of mirror shake. For planets I wouldn't think the difference between 5X or 7X will matter, at 1200mm FL the planets will still be small enough to fit. Michael

You don't need a Bahtinov Mask for the guidecam. Just point the guidecam at a bright star, and with a fast refresh, say 0.5 sec exposure, adjust focus for lowest HFD figure in the Star Profile window. A B Mask for the imaging camera does help. What's wrong with that ? That's how you get good images ! Michael

From the GuideLog: Signs of large Dec Backlash in the Cal, which skewed the reported Dec Guide Rate a bit. The start of the final 25minute run shows that: After the Backlash was driven out the PA drifted on the south side, so backlash didn't come into play. About halfway through that run you enabled Dec Backlash Comp. But you hadn't run Guide Assistant at any point in the evening, so PHD2 hadn't established a starting setting for Dec Backlash ? Or suggested suitable Minimum Move settings, or measured PA Error. Guide Errors were RA = 1.43arcsecs, Dec = 1.69arcsecs, so round but bloated stars. Guidecam focus was poor HFD = 7.64 Michael

Total RMS values are irrelevant in this context. The individual RA and Dec figures matter. If RA = 1.0 and Dec = 0.5 then stars will be elongated in the RA direction. I'd guess your stars are elongated due to guide errors. But a Stack of long-exposure subs is a poor guide to star shape. A single short exposure Sub, stretched if necessary, will eliminate guide errors and expose any tilt, pinched optics, reducer etc problems. Michael

The RAW files created by the DSLRs are decoded using LibRaw. https://www.libraw.org/ So yes if your camera is listed. Michael

Well I just had to open this post to see wtf a Fok is........... Michael

PHD2 Calibrates RA first, so if you instantly loose the guidestar then possible the guiderate or Step Size are wrong. Or the Periodic Error is now enormous due to damage. Carry out the PHD2 Star Cross Test to see how RA and Dec are responding to PHD2. Run the PHD2 Guide Assistant for a worm period. This will show the mount's RA PE , and will measure the Dec Backlash if you tick the measure box. Michael

Your screenshots indicated you have a Dark Library for the Guidecam - good So PHD2 shouldn't select a hot pixel. Unless you selected the star ? Don't manually select a guide star, let PHD2 do that for you. Also use PHD2 MultiStar Guiding. Michael

I run my LX200GPS with a HiLink WiFi RS232 Adapter plugged into the mount's RS232 socket, and ScopeBoss on an iPhone. Try reversing TX and RX. For a PC to a mount connection with a USB to Serial converter, TX and RX are wired one way. For a mount to a RS232 adapter I found I had to reverse, then it worked. Michael

Those settings seem correct. Either a faulty Intervalometer. Or a loose connection causing the shutter to close when connection is lost. (Title says 450D, text says 550D ?) Michael

Hi Rodd May be as simple as the power button circuitry needs a sniff of the battery volts. But that failure shouldn't deter you from removing the batteries on your other laptops, just in case. Michael

A coiled lead would be worse - heavy, and pulling on the OTA. Guidescope has to be better than "pretty" solid. Flex measured in microns will mess up your star shapes. Michael