michael8554

Hi Zak I'm not clear what you want to do here. 1) Your Nikon D3400 has a detachable lens and could be connected without the lens to the scope via a T2 Adapter. Attached to a "1.25" T2 Nosepiece" that slips into the "hole" in the focuser where the eyepiece would normally go. (That might raise a separate issue of not being able to get the camera close enough to the scope to get an in-focus image. ) 2) "but would like to have a lens for the camera too?" Do you mean a lens, or do you mean an eyepiece ? Cameras and smart phones with a non-removeable lens can take images from a telescope's eyepiece. (And avoid that separate issue I mentioned) Or you can use "Eyepiece Projection", where the camera body is attached to an eyepiece to get "high magnification" for images of planets. If it works, option 1 is the most common method Michael

If both ends are RJ and the colours run in the same order you should find one easily. But be careful, the colours may run in the same order, but may be "back-to-front". Depending on whether the cable is a "Straight Through" or a "Crossover". An Electronics Repair or PC Repair shop may be able to crimp on a new RJ plug to the existing cable. Show them the old one to get the colours the right way round. Michael

Here are two sources of star trailing in an unguided mount: 1) Polar Alignment, causes drift in Dec. That would be "up and down" if your camera was oriented with the long side of the sensor parallel to RA. Unguided the PA has to be much better than when guided. Such that your 120 sec exposure shows no drift. 2) Almost all mounts have Periodic Error in RA. A repetitive wave-like drift of RA towards east and then towards west ( "left to right" ) with a period of several minutes, the duration of the "worm period " of the mount, maybe 4 minutes in your case. When unguided all you can do is find the slowest exposure that doesn't show drift. You've already found out that 6 seconds doesn't, but you should be able to expose for longer. Michael

Many of your questions suggest you haven't read the PHD2 Instructions, or haven't understood them ? 1) Dec backlash needs at least a worm adjustment, ideally alacant's stripdown and bearing replacement. 2) "I'm disappointed that there we both approximately ~8500ms. Am I correct in thinking, that value means that when PHD2 sends a guide pulse, it believes that it is taking 8.5 seconds for the mount to respond?" The Dec axis has Backlash, so it could wobble from one end to the other of the backlash range. Once it's wobbled to one end it may take 8.5secs to move back to the middle. The PHD2 Backlash Comp can add some extra big pulses to help that along. But your Dec backlash is too large, so PHD2 won't do that, as there is then a danger of over-shooting into a repeating pattern of back and forth wobbling. 3) The first GA run reported you hadn't cleared that Dec backlash before Calibrating. PHD2 had to supply 13 pulses before Dec started moving, which marred the Cal. If you'd cleared backlash before Cal that wouldn't have happened. 4) "I note the RA PE error. Is that something that I would want to change physically (i.e. remove possible grit), or could that be trained out?" PE can be Trained if the mount has Permanent PE Correction. Strictly speaking the grit is not a PE error, it's causing a momentary spike that would be present even if the PE was perfect. 5) AFAIK the Star Tool is measuring the primary guidestar when MultiStar guiding is in action. PHD2 will select the best star(s) to guide on. Not necessarily the "very bright star", that is probably over-exposed, so has a flat top, instead of a sharp peak. That's why PHD2 is asking you to improve focus, so that star shape is as "pointy" as possible. 6) in the graphs you inserted, RA error is about twice that of Dec eg RA = 0.61arcsec, Dec = 0.38arcsecs. So stars may be elongated in the RA direction. But to an extent will depend on your imaging pixel scale. If your imaging pixel scale is much bigger than the guide errors, then the guide error is smaller than one pixel, so may not show. 6) You don't need to run the Guide Assistant for 30 mins, most of the time the suggested 2 minutes will give enough info. You can PA with SharpCap, and check in the GA run that's it good enough. Bottom line is that despite the large backlash, lucky for you your setup is guiding Dec well. It's RA that needs looking at, the grit and the PE. Michael

Hi Rich I couldn't see what you described so I stretched your image: I can see vignetting, which as an experienced imager I'm sure you're aware of. More concerning are the vertical lines all over the image. Michael

Hi Chubster I haven't got the latest PHD2 dev yet, so I can only guess that you click on each explanation to expand it. The Cal was accepted, but Advised that there was an Orthog error that might be worth improving. That might be due to a large Polar Alignment error ? Or failure to clear Dec Backlash before Cal ? The RA and Dec Guide Rates that PHD2 measured might have been noticeably different from each other. Hard to tell what's going on without a GuideLog to evaluate. Michael

For years the PHD2 guys said Polar Alignment can be no worse than 5arcmins to get good guiding. Recently after years of improving PHD2 they are quoting no worse than 10arcmins. So you didn't need to worry about a 4 arcmin error. Did PHD2 flag it up as a problem in the GA run ? No. It would have if it was too much. It did flag up exposure, focus, and Dec Backlash. From the GuideLog. There was about 25arcsecs of Periodic Error in RA. There are regular spikes in RA, may be dirt or grit at one point on the worm. Apart from those spikes, RA and Dec guiding looked to be under 1 arcsec. Focus actually got worse as the night went on HFD = 6.72pixels ! Use the PHD2 Star Profile window to reduce that to a minimum. Michael

Oops, you mentioned it worked with Artemis in your first post 😆 If there's a APT forum, contacting that would be the next step. Michael

Reduced to 357mm FL, the pixel scale would be 2.17arcsec/pixel. Unreduced it's 1.85arcsec/pixel. Michael

Doesn't appear to be between rotating parts, so perhaps It's some sort of dust gasket ? Probably fine without it. Make sure the bolts don't "bottom out" when tightening. Michael

Does it work with Artemis Capture, Atik's capture software for that camera ? Michael

I tried the FIT in DSS, and only got 3 stars at the lowest threshold 2%. DSS will reject elongated stars. All stars except possibly the bottom right corner are elongated, suggesting Tilt. But if others think they're all elongated, then guide errors. Michael

Hi yiorgi Do you have a question ? Ha versus Full Spectrum mods have been discussed to death on this forum, you just need to read the posts. Michael

I'd say that any almost every scope WITH THE CORRECT SOLAR FILTER ATTACHED would give "good shots of the sun", whatever that means. Your 430mm focal length scope will probably capture the whole solar disc. A 3000mm FL SCT would only show a small part, fine for "closeups" of sunspot groups. The sun is often captured with "Planetary Cameras" in video mode, so that the frames that are distorted by atmospherics can be rejected. With your D5300 a stack of a series of single fast exposures would give similar results. Michael

If you had perfect PA (which you never will), then as symmetal said, you wouldn't have walking noise. So you will need to Dither. And PA error of no worse than 5arcmins is easily guided, so no need to obsess over PA. Michael

Hi Chris As Geoff said, enter the location manually. In the degrees-minutes-seconds format. Google will show your location in a decimal format. -15.29, 28.29 for Lusaka. That's 15deg 48min 00sec E, 28deg 48min 00sec S for your handset. And MM/DD/YYYY for the time setting. With DST set to +2, and currently ON. Michael

Where did he go .......... ? Michael

Hi brenski Any lens will infinity-focus before the infinity mark, without modification, if you have the spacing less (or more, I can never remember) than the Flange Distance. Which is 45.46mm for a M42 x 1 threaded Pentax lens. Michael

I may be wrong, but I believe the D7000 requires a serial connection for remote Bulb exposure, it won't do Bulb via the USB. What is your image showing us ? I don't see "PC on display" Michael

I'd say because of conflicting requirements. If the primary mirror edge retainers are wrongly fitted they can cause pinched optics. Too loose and the mirror can move. Secondary mirror spiders robust enough to firmly hold the secondary will have large diffraction spikes. Too skinny and the secondary can move. Only tiny amounts of flex will show. I'm sure there are other conflicts. Michael

The PHD2 Instructions will take you through all the steps for getting started. Here's their short version: https://openphdguiding.org/phd2-best-practices/ Michael

Lots of spec, but no image or link to a problem Flat ! Michael

You have an EQ mount that happens to be on a pier instead of a tripod, so adjustment of polar alignment is the same. You can use software such as SharpCap, pointing towards the NCP. Or Drift Alignment, PHD2 or a reticle eyepiece, pointing south for the Az adjustment. Then west or east, for the Alt adjustment. Time will tell whether your adjustment method retains a good PA. Michael

Hi Martyn Upgrading, but something similar ? What feature are you wanting to upgrade ? What does your current camera not do, that you'd like the new one to do ? Michael

Hi Bish Some Moon Atlases show the moon as you see it through the eyepiece. Inverted, laterally reversed, etc, depending on your telescope. If that would help you identify. Michael