michael8554

The LodeStar X2 has a 6.45mm x 4.75mm sensor, so any OAG with a 8mm x 8mm prism will do. Just get one with fittings that match your kit. Some of the premium OAGs look to be identical to the no-name ones 😆 A helical focuser makes focusing the LodeStar so much easier, but the extra length can sometimes make it impossible to match the main image camera to prism distance. Baader make a low profile helical focuser. Michael

What I use with an OAG on a Meade SCT FR'd to 1400mm. Those big pixel aid sensitivity and yield a 1.24arcsec/pixel guide pixel scale. I use the LodeStar SXVR driver. Michael

Hi Phil Looking at the PHD2 Log: 1) The key to Good Guiding is a Good Calibration. So trying to guide with issues Last Cal Issue = Orthogonality can be a waste of time. You might have got a good Cal by clearing Dec Backlash first. 2) The sudden dive of RA and Dec in the GA run. PHD2 was reporting the star position to be moving (without any guide commands of course) as shown in the graph, and the guide star wasn't lost (yellow trace): This can only be due to external influences - a cable snag, the guidescope or camera rotating, Sidereal tracking stopping etc. Focus was reported to be poor. Michael

In the daytime any distant landmark such as a small feature on a pylon or church tower will do nicely. Michael

Being an SSD you don't have to worry about mounting it where it will be shaken about. But my Telrad used to fall off my OTA using the provided sticky tape. The improved Velcro design of the Dual Lock looks secure, but I'd add some rubber bands to reinforce the sticky tape attachment ! Michael

Great result for a beginner. "but had to bin 75% of the lights, due to the star adventurer mini." I'm sure there are many SA users getting better percentages than that. What errors were you getting ? Dec drift due to Polar Alignment ? RA due to Periodic Error ? 180 sec exposures suggest you are guiding, but I don't see mention in your equipment list ? Post the GuideLog, or if not take shorter exposures. Michael

To avoid this confusion, "Camera Backspacing" is often called "Flange Distance". For instance all Canon EF lenses focus 44mm behind the lens's mounting bayonet. That focus distance is fixed, so the camera's Flange Distance has to be 44mm. Unlike a telescope, where any camera can be attached and focus found using the scope's focuser. Michael

So you are using ZWO's recommendation for Back Spacings for two different manufacturer's OTA's with built in FF's ? Does WO recommend 55mm Backspacing? Does Askar recommend 55mm Backspacing ? As I said, "you said the OTA's don't need a Backspacing for best star shape. And cameras don't have Backspacing, so no need for a "55mm Backspacing". That's only necessary if there's a 55mm backspace FF or FR involved. Michael

1) It's impossible to compare the star shapes in these images because they are all 300 secs exposure, so will show differing guide errors. Take one short exposure with each at max gain, stretch if necessary, post a jpeg, 90MB tifs aren't necessary for this analysis. 2) "both scopes didn't require an accurate back spacing as they are both Petzval designs. " "I used a ZWO asi294mm camera (bin1, gain 120, -10 degrees, with suggested 55mm back spacing)" Confusion here. As you said, the OTA's don't need a Backspacing for best star shape. And cameras don't have Backspacing, so no need for a "55mm Backspacing". That's only necessary if there's a 55mm backspace FF or FR involved. Just focus the camera. Michael.

Hi Andrew Assuming you have the mono MM and not the colour MC, I expect that Binning 2x2 should give you Bin 2 mode. Michael

You need to address the soft-tipped screws holding the guidescope in the rings, a lot of the Diff Flex will be due to those. I would favour your first solution, gluing sounds so "last resort". Ditch the short guidescope mounting bar and mount the rings with longer bolts through the new bar. Michael

I assume you're guiding through an Off Axis Guider for that long 1570mm focal length. A colour camera is sometimes not sensitive enough for OAG use, how are you fairing ? The guiding pixel scale is 0.62arcsec/pixel. If you had the mono version you could bin that to a more sensible 1.24arcsec/pixel, and the increased sensitivity would help too. Michael

"JWST spies concentric rings around a binary star" I knew it ! It's really a CIA funded dark mission to spy on aliens ! Michael

This ribbon looks to be slanted in the socket: Michael

Possibly a ribbon not fully reinserted, did you mark a Sharpie line across the ribbons to show how far they have to be reinserted ? Did you correctly re-insert the black pipe into the white receptacle ? Are all the ribbons around that area inserted ? Michael

Hi Roger What do you mean by a "nice bright glow" ? Do you mean you want more saturation ? Do you mean you want more contrast ? Post your image. Michael

1) Use Auto, and correct in image processing. 2) Custom White Balance, read the user guide on how to, I'd say you'll still need to tweak in image processing. If you're using a refractor or camera lens you'll need to add an IR cut filter, to prevent star bloat. Michael

"meat Different,people ?" Would you like to "meat" zombies with a chainsaw 😆 ? Seriously, post some interesting questions and you'll get plenty of replies. Meeting people may be tricky as most SGL members are in the UK, and you're in the USA. Michael

We often have an Airbus A400 cargo plane fly over on it's way to Salisbury Plain for maneuvers. Comes around half a dozen times at low altitude. I always wave, such a cool aircraft. I haven't seen Tom Cruise hanging on though......... Michael

5.6um x 5.6um Michael

"Since moving over to the OAG I haven't managed to get PHD2's guide assistant to run successfully, due to Dec backlash not giving enough movement South." The GA run was successful. The optional final measurement, you didn't have "Measure Dec Backlash" ticked. Because I guess you already knew that previous GA runs had advised the backlash was too large to measure. Need to adjust that. "Dithering I was working on the assumption that with the OAG the guide camera & imaging camera had the same pixel size then I should use a setting of 1 in Astro Photography Tool" Well the figure you set that to depends on how much dithering you need, 12 pixels is a commonly quoted figure. "Another suggestion I read about, was to increase the size of the box around the guide star in PHD2. When the scope is pointing at lower altitudes I sometimes get large deviations which make subs unusable." That will only work if the "large errors" are moving the star out of the box - shouldn't happen. Michael

Looking at the star shapes of the 10s exposures, I'd agree that more backspacing is required. The 180sec exposures will have guide errors, so don't judge the backspacing using those. Looking at the GuideLog for the 19th: The Calibrations had warning messages after the Cals, and again in the Guide Assistant results: "Last Cal Issue = Rates," "Norm rates RA = 17.6"/s , Dec = 14.3"/s; ortho.err. = 7.6 deg" "GA result- Recommendation: Consider re-doing your Calibration (Prior alert)" Which you seem to be ignoring ? You would get better Cals if you pulsed north until the guide star moves consistently, showing that Dec Backlash had been taken up. THEN Cal. Near south and near Dec = 0 if possible, but Dec = 28 isn't too far out. It would be worth Binning the guide camera, to improve sensitivity and pixel scale. Your Dithers are only a maximum of about 6 pixels on the imaging camera. Pretty much the same errors on the 25th. Michael

"450D, 600D, 60D, 700D, 70D, 2000D, maybe the 800D or the 80D" Canon DSLR's are grouped by the number of digits in the model number, nnnnD to nD. So the 2000D is a budget camera, the 6D is a prosumer camera. But often a nnD is a nnnD with the same electronics in a metal case and with a few more switches. If you run tethered to a PC, the 550D is the same as a 600D, but without the flip screen, and is usually overlooked so cheaper. Michael

Hi Dave Not much info on your setup and exposure duration. I assume these are "long exposures" ? IMO both shots display guiding errors - all the stars are elongated in the direction top left to bottom right. I would eliminate guiding errors, then test. Look at a single short exposure, stretched if necessary. 0.4RMS means nothing if individual RA and Dec errors are not similar. Michael

Diagnosing what happens post-flip will requuire the GuideLog. Michael