This is my first Mars of this apparition. Under average conditions:

Brian

I imaged Jupiter recently (not good seeing) and was reminded how quickly it rotates; even the moons go whizzing by. I think you are?right to use a Bayer camera for color images of that planet.

Have you really looked?? That would require using a mono and Bayer camera on the same night (preferably within minutes of each other) and/or extensive use of mono and Bayer over long periods."

Yes I have. I image with a Flea3 618 Bayer color camera, and? Flea 3 618 mono camera with filters on the same nights often. Same results with both cameras. I have done this for 2 years.

I have an article on one shot color camera imaging coming out in the May 2014 Sky & Telescope. Hopefully it will debunk a few myths.

"

You are obviously the exception that proves the rule! <g>"

Thanks Stan! But you see I am trying to adjust that rule a bit......

I have a color QHYL II with the same ZWO color senser and am testing it.

That?can be a difficult decision, especially if you find a used C14?to?save some serious $ compared to an Edge.

Classical C14's have had an excellent reputation for several decades and there are very few?reports of bad units.? Edge C14's are obviously an evolution in design.?In addition to the corrected field there are?improvements in the OTA, such as?vents.?But the value of most?improvements depend on?use:

Prime focus DS imaging is?the most compelling?advantage for an Edge.? But reduced FL imaging may be better?using a classical C14 paired with a quality SCT reducer/corrector (e.g. Starizona or Celestron).??When reduced, the Edge is very finicky about exact spacing and there have been numerous complaints about the performance of the Edge reducer, which is the only applicable reducer?(it is not?feasible to use a standard SCT reducer on Edge).

The C14?has become the preeminent choice for planetary imaging.??Planetary imaging is not improved by the Edge.?Most top-notch planetary imagers have retained their classical C14s.?

Visual observing?may be?marginally improved via Edge (low power / wide field).??But much of the visual experience is determined by the E.P.

Stan

" SCTs corrector plate can contribute to CA because technically it is a lens, the prescription is weak and is zero"

The primary aberration is not the usual chromatic where colors focus at different points but rather?convoluted spherical aberrations.?This is not unexpected because the job of the glass is to remove spherical.? The effect is small but does manifest in very high res imaging.??The usual SCT "sweet spot" for minimal spherical is in green light but that can change depending on the mirror spacing (which in turn is?determined by backfocus distance).? So an SCT can be tuned (wittingly or otherwise) to optimize red.

"...Human vision is way more sensitive in green..."

In?a case where the best resolution is red (for whatever reason) then neglecting the red signal and doubling (or more)?an inferior green signal (for whatever reason) will?result in lower overall resolution.? This is especially true for Bayer because the effective red pixel size is double the actual pixel sizes (because there is a?blank space between every red pixel).

"When you image mono, you get 4x green pixels"

The correct multiplier is 1x.? Every pixel in a mono camera participates in whatever filter is used.? So for every red pixel in a combined 3-filter/color?image there is?1 green pixel and 1 blue pixel.

"I have never seen the potential higher resolution actualized in my rig"

Have you really looked?? That would require using a mono and Bayer camera on the same night (preferably within minutes of each other) and/or extensive use of mono and Bayer over long periods.

"Hey, what am I, chopped liver?? :)"

You are obviously the exception that proves the rule! <g>

Though I have to wonder what you might be capable of?using a ZWO ASI120MM.

Stan

These days it is mostly "hit" on both the C14HD and the standard C14.? If you only care about looking at?or imaging the center of the field, then the standard C14 will be fine.? But if you want a nice flat field with pin point stars to the edge or even just a clear planetary image if it drifts across the field of view, then you want the EdgeHD.? Very few people are dissatisfied with the EdgeHD.? In either case, powered ventilation is easily added since both of the current versions have the same rear cell with passive vents.

Ed Thomas

Deep Space Products

Hi John,

I have had mine for about 2 1/2 years and have not had any problems with it. Optics remain consistently good.

To improve focusing and mirror flop, I have an external focuser (FLI Atlas) and carbon fibre tube.

My system is also now very rigid and I can do unguided imaging for at least 10 minutes.

Dale

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Seeing was good only briefly but I captured one decent shot:

Brian

"good seeing for my red channel data, only to be stymied with much poorer seeing for the green and blue"

That may be what is actually happening because longer wavelengths are less affected by seeing.? Also, SCTs are not immune to chromatic aberrations (e.g. chromo-spherical).?Many users find?lunar SCT imaging?is often sharpest/best with a red filter.

So a Bayer ("color") camera will probably not?improve?resolution but?rather reduce it to the lower seeing that you normally experience in green.? Bayer strongly emphasize the green?signal because there are 2x more green pixels than red or blue and those green pixels?have?wider bandwidth and usually have higher QE (esp for IR blocked cameras like DSLR).? Also, Bayer sampling is problematic so the sensor has less potential for hi-res than a mono sensor at identical sample rate.

The ?advantage of Bayer is simultaneous color (e.g. no worry about the planet rotating between color exps), which is?questionable but occasional value.?The primary argument for Bayer is convenience.? But there are?significant disadvantages to Bayer and few (none?) of the master imagers bother with it.

Stan

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I finally had some decent conditions 3 days past opposition. This is a combination of 3 sets of data taken over 11 minutes:

Brian

Dean would generally be wrong.? If you happen to have a C14 with extremely small focus shift you may be OK, but in general the C14 has the most focus shift of all the Celestron SCTs.? For imaging, a Crayford on the back is the way to go, but you have to watch out for back spacing issues with the Edge HD.? In addition, I would recommend the new Starlight Focus Boss system over the older Microtouch.? The Focus Boss system includes the new Handy Stepper Motor which can be used manually as well as electronically (which is a bigger deal than you might think) and I prefer the build materials of the Focus Boss as well.

Ed Thomas

Deep Space Products

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I?have?a ZWO ASI1200MM camera. It is a very fine camera, esp for the price. max QE = 70% and read noise is only about 3e- at maximum video gain.

It is very good for lunar planetary but also performs well on DS.? I am experimenting with?it for semi-lucky DS imaging?using sub-exps ranging from?0.2 to 10 sec.?For camera limited exps, it?suffers from the notorious unstable CMOS banding (like all CMOS) and the temperature is unregulated, both of which cause dark frame issues for semi-lucky DS.?But it is workable.? Here are a few examples:

100mm camera lens at f/4; 3sec x 2400 frames:

4" f/5 TV Genesis on unguided Vixen Sphinx mount:

Stan