Mallincam in Chicago...what should I expect.
Posted 30 July 2012 - 05:30 PM
Posted 30 July 2012 - 09:18 PM
I would use a focal reducer to get the scope down to around f3.5 to f5. You'll benefit from the wider fov and faster f speed (but not so fast like the f2 Hyperstar that you very quickly reach the sky fog levels). I would also invest in a few filters.
Because you are not EQ mounted your exposure/integration times will be limited to under a minute. This means you won't be able to take advantage of the very narrow band filters that some folks use with great results under very light polluted skies. I'd look at either a Deep Sky or an actual "light pollution filter" like the Orion Skyglow imaging, Hutech IDAS LPS v2, or Astronomik CLS-CCD. These options are not going to really cut down all your light pollution but will darken the background somewhat without diminishing the objects too much. You may also consider a step up in filter capability with the Astronomik UHC and IR cut filter combination. This combo offers more rejection of light pollution but also really diminishes the light from most objects making you rely on longer integration times (which then becomes a problem due to field rotation).
Another useful tool will be the Mallincam MCV-1E USB frame grabber. This will be your connection between the video out of the camera and your PC. This particular unit has an additional capability to reduce the black levels, this will also help diminish some of the effects of light polluted skies.
So a moderate amount of focal reduction, moderate filtering, and moderate integration times. That and with careful manipulation of the video controls and the MCV-1E you should get some very surprising images on your PC.
The choice of which higher end model Mallincam won't make much difference. A bit more money will get you longer exposure capabilities (which you won't be able to use in the city) and full PC control (nice but not absolutely necessary). There might be some advantage to getting the optional ExView HAD version of the CCD chip. This is bit a more sensitive chip which some suggest will help with filtering under heavy light polluted skies. I would suggest taking a look through the older posts on the Yahoo Mallincam group for a more definitive answer about choosing this optional chip for your conditions.
Posted 30 July 2012 - 09:38 PM
Posted 31 July 2012 - 12:20 AM
I'm about 45 miles south of Chicago so my skies are not much better than yours. Here's an idea of what I see with my MallinCam VSS+, CPC 1100, and MFR-5 reducer.
Below is a unprocessed 'snapshot' taken with a point-and-shoot camera of the monitor screen. Looks better in person.
I can't say enough about my MallinCam. I'm blown away every time I use it!
Posted 31 July 2012 - 01:28 AM
A light pollution filter designed for color imaging will be a must.
For brighter objects such as many planetary nebulae, star clusters and the brighter parts of some galaxies, and particularly when small, imaging at f/10 is viable, if mount tracking is good and field rotation is not a problem. And if the sky glow is particularly bad, you might be limited by this more than by low object surface brightness; if this is so, a focal reducer might be used more for the framing of larger objects. All of that notwithstanding, a focal reducer is useful for keeping exposure duration shorter, by virtue of the higher image surface brightness (a 0.5X reducer makes the image 4X brighter.)
Posted 31 July 2012 - 02:18 PM
I cannot endorse a mallincam more than to show you this picture:
M27 from my friend's rooftop in Brooklynn Heights, NY, right across from lower Manhattan. Using a C8 operating at F4.5 and using a Lumicon Deepsky filter - a 28sec exposure on a CG-5 mount. You may be in Chicago, but I doubt anyone can compete with the light pollution from around these parts.
P.S. I echo the prior posts - fuggetabout the Hyperstar.
Posted 02 August 2012 - 05:12 AM
M27 is a brightish object for the Mallincam and trumps the EP every time [plus colour] as my M27 30s Lodestar shot below.
Hi Peetyg - I cannot endorse a mallincam more than to show you this picture: M27 from my friend's rooftop in Brooklynn Heights, NY, right across from lower Manhattan. Using a C8 operating at F4.5 and using a Lumicon Deepsky filter - a 28sec exposure on a CG-5 mount. You may be in Chicago, but I doubt anyone can compete with the light pollution from around these parts. Cheers, Al. P.S. I echo the prior posts - fuggetabout the Hyperstar.
However from comments here under LP skies the latest cooled 'Extreme' needs dark skies for best results with the longer exposures the camera is capable of. Perhaps a step too far for suburbia
My approach from London via my Lodestar is to expose short of saturation [typically ~2m] and stack a few 60s subs AFTER removing the bright sky background from each sub A 5m stack [and often less] gets down to mag 18 stars and virtually ANY faint DSO targetted - and yes I get to see the subs in realtime - 5sec is enough to 'view' Stephens Quintet :o
Posted 02 August 2012 - 05:28 PM
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