michael8554

Hi Radu I don't see any information on your equipment, or how it is connected to PHD2 ? The mount is reporting RA and Dec position, but no mount driver - are you ST-4 guiding with an Aux input to PHD2 ? From the GuideLog, there are some procedures you are ignoring or skipping. 1. You were pointing at Az = 256.8 deg when you Calibrated. Near south is recommended Az = 180 deg. Unless you're in the southern hemisphere ? 2. You don't appear to have cleared Dec backlash before Calibrating, by pulsing north until you saw the guidestar actually start to move. 3. Your Cal had a noticeable Orthogonality Error that wasn't reported, because you had "Assume orthogonal axes = yes". 4. Your Guide Rates are very low, RA Guide Speed = 4.5 a-s/s, Dec Guide Speed = 4.5 a-s/s, At least 7.5 arcsec/sec is recommended If you're ST-4 guiding, try a larger Calibration Step Size. 5. Your exposure was 5 seconds, which is very slow. What did the Guide Assistant recommend ? 6. You started guiding at 22:27 and Dec immediately started to head north, with PHD2 corrections south having no affect. You Calibrated at Az = 256.8 deg, but now the mount is at Az = 176.7 deg, so as already mentioned, the "Pier side = West" might be wrong. RA has about 25arcsecs of Periodic Error that PHD2 struggled to correct, due to the slow guide rate and slow exposure. You could try the PHD2 PPEC Algorithm from the RA guide algorithm choices. Have you read the PHD2 Instructions ? Michael

"learn to do an accurate PA aligment ......... don't find how to do it manually" As I said: 1. To improve Polar Alignment error you should Drift Align, using a high-power eyepiece that has cross-hairs. This is a manual adjustment. But you may find that just the Polar Scope is accurate enough for the length of exposures you want to use. First, aim the mount's polar axis roughly at Polaris. Now point the telescope at a star that's somewhat above the celestial equator and as close to south as you can judge by looking opposite Polaris. Put in a high-power eyepiece. If the eyepiece has cross hairs, center the star on them. Otherwise put the star on the north or south edge of the field and defocus it a little. Turn on the clock drive, and ignore any east-west drift. If the star drifts south in the eyepiece, the polar axis is pointing too far east. If the star drifts north, the polar axis is too far west. Shift the polar axis left or right accordingly, until there is no more drift. Now aim at a star that's near the celestial equator low in the eastern sky. If the star drifts south, the polar axis points too low. If the star drifts north, the polar axis points too high. Again, shift the polar axis accordingly. Now go back and repeat from the beginning, because each adjustment throws the previous one slightly off. When all visible drift is eliminated the telescope is very accurately aligned, and you can take long deep-sky exposures. If your eastern sky is blocked, you can use a star low in the west and reverse the words "too high" and "too low" in the above instructions. If you're in the Earth's Southern Hemisphere, reverse the words "north" and "south." Step 4 means rotate the mount's body horizontally a tiny amount, Step 8 means alter the "tilt" of the mount's body a tiny amount. Michael

1. To improve Polar Alignment error you should Drift Align, using a high-power eyepiece that has cross-hairs. Judge how long to spend doing that by comparing with how much longer you can image for without noticeable elongation of stars ! 2. Almost every mount will have some Periodic Error on the RA axis. Causing Sidereal Tracking Rate to speed up, and then slow down, in a cyclic pattern. Over the time it takes the worm to make one turn, often 4 minutes. Due to machining tolerances in the worm drive. Nothing you can do to improve your current setup. Michael

Hi Matt Is this something new or ongoing ? Possibilities include power supply interference, or download problems . Try manually rejecting frames rather than setting to 40%. Hopefully not all the frames are like that. Michael

That would be a useful project. Because the helical focuser that comes with many OAG's is often too long to match prism-to-sensor distances. So I had to buy that low-profile Baader focuser. Michael

Just attach your camera to the Mak, there's omnly a back focus to consider if you're using a FF or FR. Unless you're after some sort of "sweet spot" ? Which might be when a combination of extensions give a Plate-Solved focal length of 1500mm. Michael

Have you tried with the fastest Slew Rate selected ? Michael

If splitting a slightly defocused Venus on the crosshairs isn't accurate enough, you need a Flip Mirror. Michael

Hi Stuart The cheap but irritating solution would be to slightly defocus. Until Venus appears as a circle slightly larger than the crosshairs. Michael

Hi Leti To my eyes the stars appear to be elongated everywhere in the whole image. Since the exposure was 90 seconds I'd say it's RA tracking. or Polar Alignment error. Is that elongation in RA or Dec or both ? Try a short exposure and stretch it, to see if it's the mount or the optics. Michael

Hi Stefan "My guiding is generally alright (around 0.4 - 0.6 RMS " But are RA and Dec figures similar, and smaller than your pixel scale ? If not you may have elongated stars. Do the subs with elongation correspond to when "DEC on PHD2 goes nuts" ? You could post the PHD2 GuideLog. Michael

"The back focus of the Antares X0.63 FR is i guess, 55mm." Many FRs have a BF of 55mm, which means they can screw straight onto a DSLR via a M42 T-Adapter. But these Antares /Meade/Celestron lookalikes have SCT threads, and are maybe 105mm or maybe 85mm BF, but IMO I don't think they will be 55mm BF. Michael

"doesn't pointing the telescope at the sun damage it? " Point the FR at the sun, not the telescope ! Only damage might be to the wall ....... 😆 Michael

Doing my own searches, the Antares may be one of the 85mm BF items Measure the focal length by focusing the sun on an outside wall. If it's about 240mm then BF is 105mm If it's about 110mm FL the BF is 85mm Michael

At the risk of rekindling an ages-long argument about the BF of Meade, Celestron, and clone FR's: The #93633-A Celestron T-Adapter SC, the T- Ring, and Canon 650d, should give you 105mm back focus. Try that and tweak by a few mm's if it's not perfect. Michael

Hi kadahl Here's what Jupiter and some of its moons should look like with your scope and the 6mm (highest magnifiying) eyepiece: Very small :-< Michael

Hi Hedlund As Stefan said, unless the focuser was right at the end of it's travel with the 450D, you shouldn't have difficulty focusing the modded 600D. The flange distance for all un-modded Canon DSLRs is 44mm. The mod only adds about 0.25mm to that. Michael

Hi Dave As a LX200GPS use I'd say the RCX is similar. But it has a USB connection as well as the time-old RS232 connection. So best bet is to post in the Meade section of the USA-based "Cloudy Nights" Forum, where several Meade experts lurk. Michael

Have a look at the info for the Petersen Eyeopener that replaces the visual back on the larger than 8" Meade SCTs " It threads onto a 3-1/4″ male thread found on the backplate of 10″, 12″ and 14″ Meade SCTs." https://petersonengineering.com/eyeopener/ It's available in the UK. Michael

I'm a Meade LX owner, but I haven't a clue what you're asking for - what's an act ? Aren't millimeters "real money" in the UK ? 86.21mm is 3.3940945 in "USA money" Michael

Hello "guy" 1. Looking at the second image, you will notice that the brighter stars are "comet shaped", one side of each star is flared. This is a defect in the lens that would never be noticed on daytime "snaps". Stopping down a lens often improves overall performance, it may improve this "coma". 2. The Orion Nebula is rich in red Hydrogen Alpha (Ha) emissions. Which are somewhat attenuated in stock DSLRs by filters in the camera that match the camera's spectral response to the human eye's response. An "Astro Modded" DSLR has one of those filters removed to give better Ha response. 3. If 2 seconds is the longest you can use without trailing, try one-higher ISO setting and see if the noise in the final stacked image is acceptable. Michael

DSLR viewfinder leakage is usually at the top of a landscape frame. Post an image of the image train. Michael

Hi Aidan The "stand" is better described as a tripod. The red-circled items are a "star diagonal" with an "eyepiece" inserted. Michael

Would need to see the PHD2 GuideLog to get the real story. Michael

Hi Doug This needs a step-by-step approach to finding the problem. 1. Mount on its own, EQMOD only , is it tracking ? 2. Connect to PHD2, loop exposures, is it still tracking ? 3. Try a PHD2 Cal, is it successful ? 4. Add other softwares until it fails. Michael