[mental4astro (Alexander)]

My first view of full colour in M42 was from my home in Sydney. Don't discount your chances with your C14 - use a long eyepiece, around 50mm and have a go.

Seeing the Horsehead is more about the quality of transparency rather than just pure aperture grunt. It is possible to see it with an aperture as small as 6". For this to happen it demonstrates entirely how it is transparency dependent.

I have been able to see it without the use of filters using my 17.5" dob from my Club's old Bortle 4 site. I have also had nights when it remained totally invisible using the same scope and no matter what filter I tried.

Being able to gauge the quality of transparency is something of a lacking skill. Just because a location is "dark" it does not mean it provides routinely good transparency. Some people have not been able to see the Horsehead no matter what aperture they use all because the location they are using is not providing the goods. And many clubs have also failed to conduct the necessary feasibility studies for the site they are using beyond "this is a dark spot, it will do". These studies need to be done across at least a year to understand the routine quality of transparency and hopefully seeing too. The thing here is members of these clubs also assume that the relevant studies had been undertaken. In many instances they have not. Taking the site selection process a little further here, it also shows that dew and astro are not inseparable bedfellows.

Gauging transparency is something that does take time, but it is not difficult, no matter if you under a dark sky or urban. The principles are the same. Come to recognise any number of DSO's and other celestial features that are visible naked eye. How clearly or not these are able to be seen naked eye will tell you straight away the quality of transparency. This can also be done telescopically, such as with galaxies as these too are totally dependent on the quality of transparency in order to make out features within them, such as their arms or H2 regions say within M83. If transparency is down, at best you will struggle to see the arms in M83, at worst only see the core and maybe a diffuse disk, but no further structures.

An SQM will not give you any information regarding transparency. It can't. It is only a glorified light meter as it also doesn't know if the Milky Way is dead overhead or absent, and the Milky Way has a HUGE impact on how dark a site can get, which an SQM registers as an increase in the sky's brightness but not the quality of its transparency. If transparency is down, this also acts to tone down the brilliance of the sky, giving a false reading on how dark the sky actually is.

As some examples, from my Club's old Bortle 4 site, transparency was typically outstanding despite its proximity to Sydney. Uranus was not only a naked eye object for me, but I could also see fainter stars around it. The Tarantula Nebula is not only visible, but on nights of excellent transparency it stands out like a brilliant beacon along with mottle detail around it. Not just bright features but dark ones too. The Dark Horse of Sagittarius should appear so stark and distinct that you could reach up and feed it a sugar cube. From my home in Sydney, I use being able to see M8 & M20 together along with the Cloud of Sagittarius. I have DSO's and features dotted across the sky and across the year, naked eye and telescopic. The Horsehead is one such feature that I use as a telescopic gauge. From my Club's new Bortle 2 location, things are even more outstanding.

Transparency also impacts upon the ability to see colour just as it impacts on galaxies.

Transparency really is something that is not understood well enough by many amateurs.

The image below is of my sketch of the Flame & Horsehead nebulae done from my Club's Bortle 4 site using my 17.5" dob. Transparency was particularly good this night as I could make out the crook of the Horse's neck, not just a dark pimple. And yes, I sketch directly on black paper at the eyepiece. Sketch is A3 in size using white soft pastel, charcoal and white gel ink.

Alex.