michael8554

On non-astro cameras such as your G26, the ISO setting is effectively your "gain" setting. You will have to search for the best ISO setting. (It's APT, not AST) Michael

Canon DSLR models in the 600D, 650D, 700D etc range, sometimes seem to suffer from horizontal banding on long exposures. It seems to be worse on hot evenings. Not everybody experiences this. Michael

An often quoted Dither is 12 DSLR pixels. If the selected Dither is Random i.e. each Dither is in a random direction, and a random amount up to 12, then maybe a larger setting, to give an average of about 12 ? Michael

Are you asking if Canon lenses will fit on your Nikon ? Cos your title says "Internal Nikon LPF" ? Michael

Sounds like RA ran into one of the two stops that prevents the cables inside the mount getting twisted too much. Alignment should always be started with RA unclutched and moved to about halfway between the stops. There's more than 360 degrees between the stops. Michael

It's the "Fabric of Space" that is expanding, carrying Matter with it - Galaxies, stars, planets etc - which aren't getting "bigger". In the very early Universe, that Fabric briefly expanded at many multiples of the speed of light, which Einstein's Theories allow for. Beyond the "edge" of the Observable Universe at 13.8 Billion LYs, the galaxies and stars are being carried away at faster than the speed of light, so we will never be able to observe those galaxies. So the real "edge" of "our" Universe is currently about 40B+ LYs away from us. However, consider an astronomer looking at earth from a Planet 13.8 BLY away from us. If he turns his scope 180 degrees, he will see galaxies a further 13.8 BLY away. And an astronomer in one of those galaxies will see........ etc etc So how big is the Universe ? An infinite number of 13.8 BLY "bubbles" ? Michael

A lot depends on which scope you attach it to. It may fail on the 150P due to the usual Newtonian in-focus problem, I'm not acquainted with the 150P. If the OAG is connected directly to the C6 and Sony, the C6 should be able to focus. Now the 290MC - a colour camera is often not sensitive enough to reliably pick up a guide star on every target, mono is better. The key to OAG is getting the distance from the prism to the Sony sensor, and from the prism to the guidecam sensor, exactly the same, so that they're both in focus. Depending on the OAG that first distance would be roughly half-OAG thickness + T-Adapter + Sony E Flange Distance, say 5 + 11 + 18 = 34mm. If you can't get the guidecam that close to the prism, then you'll need a spacer on the imaging camera path, so OAG + Spacer + T-Adapter + Sony = more than 34mm. Michael

And about time to. Michael

Yes. A colour camera is often not sensitive enough for guiding, particularly with the Off Axis Guider (OAG) you should use with your very long FL scope. Michael

Hi Andrew I reread the PHD2 instructions and you're correct, 1.2 is the preset Min Star HFD - my bad. From the GuideLog: The Calibration Step Size on your guiding run was 900mS, not 5000ms - is 5000ms something you set in EQMOD ? Your HFD from the guidecam is 4.17pixels, you might be able to improve that. A Min Star HFD setting of 3 is too close to 4.17, so may be rejecting good stars, back that setting off to 2. Your guidestar SNR is only about 7 which seems low to me, but depending on the camera can be as low as 20, and up to 800 or more. You have Star Max Detection ticked, this might be rejecting good stars too. RA Error is 1.28arcsecs, and is quite choppy, so try Aggression = 80% or lower to smooth that out, changes of only 1 or 2 % are too small. Give each change time to settle. Or try the PHD2 PPEC Algorithm for RA guiding. PA is good, but Dec is still swinging around the axis due to Backlash, and taking 20 seconds to correct. If you do a Guide Assistant run on Target, that will give you Min Move settings, and a Dec Backlash Compensation setting, which you have switched off. And you should slightly unbalance Dec to stop it wobbling. Michael

Not sure what you mean by minimum star reference size - do you mean Minimum Star HFD ? If a Hot Pixel = 1, so a setting of 2 or 3 would work, not sure why you have fractions of pixels in the setting. The Pulse Duration of 5000 I suggested was for Manual Guiding, so that won't have made any change to normal guiding ? Although your guiding is looking good it would be worthwhile posting the PHD2 GuideLog. Michael

Hi George Your main expense - the CPC925 - is ideal for Planetary imaging with a Planetary camera. For DSOs the CPC925 with FR needs a larger chip camera to use it's full field of view, so consider short exposures with a cheap DSLR such as the Canon 600D, which is simple to use. Or sell up and start over with an EQ mount and a refractor........... Michael

An image of a wheel would really help......... If the boss protrudes you could drill through the boss and drive shaft, and nut-and-bolt the wheel onto the shaft. I think the motor torque will unlock any Araldite or LocTite connection. Michael

Hi Andrew A puzzler, some unusual conflicting results. From the GuideLog: You started with two brief guiding sessions. Guide Rates were RA = 1.3 arcsec/sec, Dec = 1.6 arcsec/sec Usual rates are 7.5 or more. Then I assume you increased the EQMOD rate to 7.5arcsec/sec and made four more Cals which took about 60 RA steps instead of the usual 12. Similar result with five more Cals at 13.5, still took 60 steps. Then at 1.5arcsec/sec, still took 60 steps. I can't explain that I'm afraid. Another puzzle. In half the Cals the West move was towards 11 O'clock, the other half towards 5 O'clock - all at the same RA and Dec and side of pier !! I'm unfamiliar with EQMOD, apart from the common Pulseguide Rate too-low setting, so hopefully someone will comment on your screenshot. Try this in PHD2: Tools / Manual Guide, Pulse Duration 5000. Try all four directions for correct movement and direction. Are W and E opposite, S and N opposite ? Each press will move 5000, holding down doesn't issue more pulses. You have Have a good read of the PHD2 Manual: https://openphdguiding.org/manual/ Michael

What spacing was that, have you tried at the recommended 55mm ? Experiments like this should be based on a single sub, not a stacked image that contains guiding and stacking artefacts. Take a single sub at max ISO and short duration, then stretch that to look for coma etc. Michael

Camera lenses typically have a Mounting Flange to Sensor distance of about 44mm. The ZWO ASI290MC is 12.5mm. Sounds like the lens has a M42 x 0.75 thread on it that fitted nicely. Or was it a M42 x 1 thread that seemed a bit tight ? Either way, you can get infinity focus at a shorter distance reading on the lens, if it's mounted too close to the sensor. Or if it's further away from the sensor............I can never remember which ! Good luck ! Michael

As alacant said. If the 750D is not retaining the Custom White Balance over battery changes, then perhaps the tiny data battery in the camera has failed ? Unlikely on a fairly new camera. It eventually discharges if the camera is stored without the main battery, If that's the case the date and time resets too. Michael

EQMOD ASCOM Puleguide setting too low. Set to 0.5 or more Michael

ZWO ASI120MM - 120 is ZWO's model number. Cameras don't have a focal length, lenses and telescopes and guidescopes do. Cameras have a "Camera Flange Distance", the distance from the front mounting to the sensor, 8.5mm in this case as previously mentioned. Your Guide Scope has a focal length, 120mm as previously mentioned. As for ASIAir choosing it's own guide star, the brightest star is not necessarily the best choice for guiding. The ASIAir choice will not be random, choosing a better star than your out-of-focus over-exposed choice. Michael

My bad, I made the mistake of assuming the OP had the common sense not to poke a metal item inside the mount while it was switched on......... Michael

Ingenious. PHD2 should stop guiding and just carry on tracking when the guide star is lost, but more often than not goes way off-piste before giving up. I think a lot depends on the Star Mass Detection setting, but I've never experimented with that. You've tried hard to support the large overhang of that kit, but I wonder. Michael

Best to start with the manufacturer's figure, 100mm or 105mm, they show two ways to measure it: https://optecinc.com/astronomy/catalog/lepus/index.htm You just need to have that figure between the FR and the ZWO ASI1600 MC-Pro sensor, so don't put the new focuser in-between, as it will vary that distance. As you can see from the link they make many versions to suit push-fit or screwed-in connections. Michael

Why not ? Michael

Thanks Mark Didn't help as much as I thought it would........ :-< Here's a section of that sub: These appear to be blocks of pixels that are darker than the surroundings, so I don't think it's light pollution. Another manifestation of "banding" ? Michael