Orion StarShoot Imager IV??

[Astrosurf]

Can anyone tell me how good this camera is? I use a Phillips SPC900NC webcam and wondered if this would be better.

Alexxx

[JamesF]

Well, I wouldn't swap one of my SPC900s for an SSIV.  I'm inclined to think that the QHY5 might actually be better than the SSIV.  I've never used one, but the specs don't look very compelling.

James

[Astrosurf]

Thanks James. I'll stick with my Phillips until I can afford much more - Lottery willing!

[ehorvath]

I just got the SSIV today....it sucks!  Extremely, extremely difficult to use.....quite frankly I couldn't see a single planet or bright star at all, even after 2.5 hours of working with it.  It is nearly impossible to get the object centered so the camera cna do it's job.  I'l probably send it back and get a refund!!!  It may work much better if you have a guided telescope but I only have a manual one (the AstroView 90mm) so for me it was a total waste! 

[JamesF]

The difficulty of getting the camera aligned with a star or planet is really nothing to do with the camera.  It's something everyone has to deal with regardless of the camera they're using and often a GOTO telescope won't be accurate enough to get the planet on the sensor first time, especially if it's not permanently set up.  It's also the case that a camera and eyepiece rarely focus at the same point and when the image is too far out of focus you can't see it on the sensor even if it is bang in the middle.

Perhaps the easiest way to go about it is to use an illuminated reticle eyepiece and use that to centre the target first using a long focal length eyepiece and then successively shorter ones.  I start with 32mm and work my way down to about 5mm.  Then I put the camera in and there's a good chance it's on the sensor.  It's also worth finding out the focuser position at which the image is in focus during the day (just use the camera to focus on a distant target) and mark that somehow.  It may be easier to use the eyepieces to centre the image with the focuser in that position as well.  You don't need the target in focus to centre it and it reduces the chance of disturbing everything when you switch to the camera.

James

[hobsey]

I completely agree with what James has said, I find it quite difficult to get the planet on the sensor even with getting it central with the eyepiece then swapping it over with the camera.

One thing James suggested to me a few months ago which I will be buying before the planetary season starts again, is a flip mirror.

[Astrosurf]

Sounds interesting. What's a flip mirror?

Thanks James. I'll try marking the focuser as you suggest.

[JamesF]

Sounds interesting. What's a flip mirror?

Imagine a diagonal, but with two eyepiece holders, one in the normal 90 degree orientation and one leaving opposite the barrel.  The mirror is hinged so that it works as a normal diagonal in one position, but can be moved so the light passes straight through to the other eyepiece holder, into which you can place your camera.  So, you can set everything up, use the eyepiece for alignment, then flip the mirror up and the image goes to the camera instead.

James

[Astrosurf]

Thanks James. Just looked it up. Looks great but a bit pricey for me at the mo!

[hobsey]

Thanks James. Just looked it up. Looks great but a bit pricey for me at the mo!

Prices do vary alot.

365astronomy do a cheap one,

http://www.365astronomy.com/skywatcher-125-flip-mirror-for-astrophotography-and-precice-focusing-p-3923.html

[Astrosurf]

Still a little pricey! But that's at the mo. Thanks for the link.

[StuW]

Another good method is to defocus the object making it a bigger target, then once you've centred the doughnut re-focus. This is the method i use very successfully. 

[JamesF]

I meant to add an illustration of the difficulty of finding a planet reliably, but forgot earlier.

The sensor of a typical planetary imaging camera at the kinds of focal lengths usually used for planetary imaging might only cover perhaps one arcminute of sky across the shorter dimension of the sensor.  If the mount is stationary, at those same focal lengths the planet image will move completely from one side of the sensor to the other in somewhere on the order of five seconds.  That means that no matter how well aligned even a permanent installation is, if the clocks you're working from are even a few seconds out the planet is never going to be where the software calculates it should be and you'll be very unlikely to find it using GOTO.

James