GardenAstronomy

Images

The first scope that I had was a Skywatcher Newtonian 30P f6.9 Reflector.  This had a RA motor so that once I had found an object it would track it quite well.  However, I didn't use it much for AstroPhotography before I moved on to the Celestron NexStar 6SE.  This is a fully computerised GOTO scope and the extra 20mm aperture enabled me to see far more.  And, although it was only a ALT-AZ, it worked quite well  for imaging the Moon and planets with a basic Philips SPC900NC webcam and produced reasonable deep sky images with the Orion Starshoot Colour G3 Deep Space CCD camera once I had attached a wedge to convert it to an Equitorial mount.

 

My new scope is a Celestron SCT 9.25 AVX, a big step up both in terms of aperture and stability.

 

Both of these mounts have a focal ratio of 10, which is good for planetary viewing and imaging, but not so good for Deep Sky observing.  However, the addition of a .63 focal reducer improves that situation though this doesn't make either scope a fast one.

 

The Philips SPC900NC is a basic webcam which has been modified for AstroPhotography and is only capable of 10 fps.  It only cost me £42 and was one of the last batch that was made.  They can only now be bought second-hand and most of the 'replacement' webcams made by Celestron and others are much more expensive.  

 

Webcams are ideal for Lunar and Planetary imaging and manufacturers now offer increasingly sophisticated and high frame rate models.  I now have a ZWO ASI120MC-S  which is capable of frame rates of up to 118 fps on objects like the Moon.  It also has an auto-guider port so can be used for guiding with the CCD camera.

 

For Deep Sky imaging my CCD camera is the Orion Starshoot G3 Colour Deep Space.  Again cheap in terms of these cameras, though we are talking £350, and with only a small chip, but it has the advantage of Peltier cooling. Although it will only cool the chip down by at most 10C below ambient temperature it does mean that I can control the chip temperature and match both the light and dark frames and eliminate noise from the images.

 

AstroPhotography is the most difficult form of photography that you can practise and there is a very big learning curve involved, as I have discovered.  And one of the biggest problems is the weather such that there can be long intervals between one session and another and you forget what you learnt last time!

 

Then there is the processing. This involves learning how to use the various software package, and keeping up-to-date with them. The end results will vary depending on how much effort is put in, both in terms of capturing the images in the first place, and the subsequent processing.  No matter how much I learn I still regard myself as very much a beginner!