michael8554

I said: "Once the mount has done a "Goto Zero Position" I never said to loosen the clutches to send it there. Michael

Vliav Happy-kat's link addresses many of your DSLR video objections: https://www.astropix.com/html/equipment/canon_one_to_one_pixel_resolution.html Michael

"one of the reasons I bought a planetary camera was because with a digital SLR the image scale was far too small" A planetary camera with the same size pixels as a DSLR will have exactly the same image scale. For instance, 2000D 3.72um, ASI 120MM 3.75um. With your 500mm FL scope the image scale of both is approximately 0.75arcsec/pixel Barlowed, 1.50arcsec/pixel without. Perhaps you mean the FOV was too large ? But as I said, crop the DSLR and you have the same size image in pixel width and height as the planetary cam. "Also if the image is just a dot on the DSLR screen, it will be difficult to achieve correct focus." Agreed. You can try the 10X mag on LiveView, or attach to a laptop which will have a much larger display. Michael.

Hi Ciaran PHD2 will guide well on 1 star when correctly set up. It will guide even better with MultiStar and fast exposures that would normally be classed as "Chasing the Seeing". And "9 to 12 stars" with an OAG is pretty good going. I still think that changing the OAG may only be marginally better, and may well give you disappointingly similar guiding results. Because I think your lack of round stars is down to mount and PHD2 settings, you admit to the mount being "sticky." Concentrate on the real problem. Michael

Hi Ags You'll have to explain what you hope this will achieve. Michael

Don't worry too much about the Barlowed image only being a "dot". Whether you use a large-chip DSLR, or a tiny-chip Planetary camera, the image size on the chip is the same. The Planetary camera isn't magically producing a larger image. By the time you've cropped the DSLR image it will be a similar pixel width and height as a planetary camera's output. Michael

Hi Ciarán "although Phd2 still apparently manages to pick up close to 12 guide stars while doing multi-star guiding" I take it you mean PHD2 is capable of choosing up to 12 stars. "the aperture of the OAG stalk is actually really small. It's only a circle of about 5 or 5.5mm in diameter," Your ASI290mm has a sensor 5.6mm x 3.2mm, so a pretty good match for the stalk, I can't see any need for a different OAG. Is the guidecam well focused, what HFD do you typically get ? What exposure are you using ? You could post a PHD2 GuideLog that includes the "Star Lost" situations. Michael

Hi Matt When you image galaxies, nebulae etc, with the mount set to Sidereal, there is no drift ? With the same image scale ie same camera, the sun drifts when the mount is set to Solar rate, same with the moon on Lunar rate ? Michael

Try "On Camera" for the PHD2 Mount selection. With or without the Aux mount selection, Whichever works, but with is best. Michael

I bought the Amazon panel too. In A3 to accommodate my 200mm SCT. What size is your OTA, you didn't say ? It didn't dim enough on its own dim settings, so I tried a PWM dimmer . But at a low enough setting it flickered. So I ditched the PWM dimmer and added 3 layers of ND 0.6 filter. That gave me 0.8 to 1 second exposures on the DSLR AV setting. Michael

Bolt the Canon Tripod Ring Mount to the Vixen Style dovetail bar with a long Tripod Bolt. 3/8-16 or 1/4-20 are the common sizes. A single fixing can easily rotate, so I would drill an extra hole in the ring mount, to take a smaller diameter bolt and nut. Michael

It would seem the Flats aren't correctly correcting the Subs. Post a jpeg of one of your subs, and of one of your flats. Michael

Strange. If you click "Stack checked pictures", then it will Register first, then it will Stack without an additional click. Michael

"I initially saw movement and it is like the mount is trying to re-centre." Okay, was that seen in the eyepiece ? And in which axis was it moving ? For planets the other tracking rates may hold the view for long enough. Michael

How would I know if it was on the Alt or Az side? Well is the jerking showing in images, or something you heard, or something you saw ? If in images, Az is up and down, Alt is left and right. If you can hear it you'll have to use your ear close to each drive. Michael

I've stretched the 1 second exposure to show the stars, okay would you say ? A 5 sec or 10 sec exposure may be clearer. Michael

All those earlier subs show the same elongation in the centre of frame. If you have eliminated collimation, then it's PE and PA. A single short exposure should settle the argument. Michael

Is the jerk in Alt or in Az ? Does the jerk occur when tracking in Sidereal and in Moon Rates ? I don't know the 5SE's motor drive, but if it occurs in all modes, that fast a repetition could be grit or damage to one of the faster moving gears in the gearbox. Michael

It's not clear to me whether at some point you ran PHD2 with guiding off, or ran the Guide Assistant, to examine the mount's inherent RA behaviour. Unguided RA jumps similar to that shown in the guided shot suggests a Warranty Return. Or a strip-down, which will invalidate the warranty. Michael

The OP's astro modded DSLR may have been reassembled with a small amount of sensor tilt........... Michael

"Why could you not alter the lens shape to focus the same area of sky at a different point?" That's exactly how a refractor with a wide angle of view, differs from a refractor with a narrow angle of view - the lenses have a different shape. Those Fish Eye lenses you can screw onto the front of a camera lens do that too. And a Focal Reducer on the back of an OTA appears to widen the angle of view, aka the Field of View FOV Reflectors alter the FOV by having deeper or flatter mirror shapes. Ultimately the focal length, which is determined by the lens or mirror shape, determines the FOV. Michael

The 120 sec sub has elongated stars in the middle. Inspect a short exposure taken with high ISO, to minimise tracking/guiding errors. It looks like there may be a tiny amount of tilt too. Michael

If you didn't use Flats then the centre bright-up is to be expected, it's not a problem with your shooting or stacking. Michael

Hi Carl A good start, the Canon 6D gives a very clean image. Did you Dither as you aren't using Darks ? Centre of frame seems bright, are the Flats working correctly ? Michael

Hi Steve The Starwave 0.8x Reducer V3 isn't that common, and may behave in an opposite way to other FRs. You won't be able to get back to the 63mm backfocus with the filter drawer in that position, can it go in front of the FR without vigneting ? Michael