Camera choice

[SteveT]

Hi, i intend to buy a camera or two for the following 2 purposes:

I have an Equinox ED80; C9.25 (soon); PST; CGEM mount.

1) I need a guide cam, thoughts are SX Lodestar as it is sensitive and would work on guide scope (either of the 2 scopes) or an OAG on the 925 if I go that way later on. I think I would have less trouble with this versus the costar or QHY5 in terms of reliability, support and sensitivity etc for the extra cost?

2) I have a new PST and would like to experiment with solar imaging with it and also I would like a decent cam for lunar and planetary imaging, so I need a cam that will work well with the PST and C9.25 primarily. I have a self modded 350D that I will continue to use for deep space objects etc attached to the ED80 or C9.25 (when it arrives!) with FR. My thoughts here are one of the IS cameras, maybe the new 618 versions - but which version would suit best for the intended use??? I presume the PST is the most fussy (I am aware of how to achieve focus etc) would prefer a colour image on solar and planets, don't have filter wheel (probably wont go down this route for a while), I guess if I went mono I could add colour artificially for solar but planets would be a problem? What would you do?

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[SteveT]

I have just been reading about people having issues with Bayer matrix patterns affecting images at 60fps using the new colour IS618 version cameras, it seems the IS engineers have not solved this yet. Should I avoid this version I this case?

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[ollypenrice]

You can't have a colour image from the PST because the whole point of its Ha filter is to pass an ultra narrow wavelength of light which is, by definition, nearly monochromatic. If you get a colour chip, only one in four of its pixels (those with the red filter) will pass the light from the scope. You need a mono camera for Ha solar imaging at all efficiently. The colours seen in solar images are created in graphics programmes retrospectively, as you mention. This is standard practice. For coloured planets it is either OSC or filterwheel, though. Only a mono with filters can do all that you want to do, I think.

Olly

[SteveT]

Olly, thanks for your input, I was aware of the Ha mono bit, it came out wrong, but the thought of faffing about with filters for planets was putting me off mono but I guess I could jump in. Also the issues with the 618 colour variant will go away then, so what is my best option for a filter wheel setup? I assume 1.25" is just as good as 2" if I am imaging with an IS camera? I know 2" would be better if/when i upgrade to a larger cooled CCD but for now my DSLR is good enough so no LRGB needed here.

What is most cost effective but good quality filter/wheel setup and I assume manual is cheaper and more reliable, where should I look for a supplier? Do you recommend the smaller sensor 618 IS camera ( do I need the UV filtered version for Ha and/lunar/planets?)

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[ollypenrice]

I just use a cheap Scoptechnix manual wheel for 1.25 Baader filters, all from Ian King. I have an electric wheel of my own and don't use it. The manual never goes wrong... You only need 2 inch for very large CCD sensors. For the popular 8300 chip there's an intermediate size from Baader which is a good idea if you want to be futureproofed.

Olly

[SteveT]

Right, I', sold on the Mono decision and the filter/wheels but I just need to be sure which sensor size would be best for the PST/Lunar/Planets or does one size not fit all ? If not, which is the optimum compromise ?

Also, I see Ian King sells 2 different sets of Baader LRGB filters, one at about £90 and the other twice that listed as 'new', could you tell me what is the difference and which i should get for the Scopetechnix f/w please ?

[NickK]

For Lunar/Planets/solar:

* fast shutter speed (non-mechanical),

* fast image download (remember we're looking at 1000s of frames in an image)

I would opt for the Parfocal Baader LRGB filters. Parfocal means that they match the focal points so you shouldn't need to refocus the scope if the filter changes.

[SteveT]

Nick, thanks for the tip on the filters, so it's a DMK21AU618 then,, just an observation but for the cost of the filters and wheel I could get a 2nd IS colour cam !! so could choose which one to use

[ollypenrice]

The 'new' parfocal filters from Baader are seriously good quality. They are interferometric rather and absorption (stained glass) filters and have some limited LP filtration built in. Their parfocality is, in my experience, within the tolerance that I can measure. Working fast to beat planetary rotation I think you really need this.

If you were happy to use the stained glass ones they go for next to nothing second hand as people upgrade. I just gave mine away.

Olly